3D printing creates a tangible object by adding successive layers representing cross-sections of the object.

Types of 3D printing processes

Many types of 3D printing technologies currently exist. What they all have in common is that tangible objects are created by deposition of successive layers rather than cutting out the object out of a solid block and/or drilling, milling of boring. Every consecutive layer represents a cross-section of the object under construction. The process is controlled by a computer equipped with designated software for creation of design files, file processing and object printing (see further for details).

Several of the most common technologies for 3D printing are briefly presented below. This list is by no means exclusive.

• Liquid or semisolid ink-based technologies: SLA, FDM, EXT, PolyJet

All these three are based on deposition of layers of liquid (more or less viscous) ink that are then fused to one another by heat or directed light beam (emitted by an UV lamp or laser). The ink may be extruded from a nozzle or, when it is of higher consistency, fed from a spool.

• Stereolithography (SLA)

Stereolithographic 3D printing is perhaps the most easily comprehended of all 3D printing technologies, probably because photopolymerisation is commonly used in modern dentistry. Basically, stereolithography is light-curing of photosensitive material extruded in a layer-by-layer fashion onto a movable platform. The wavelength of the light source is most often in the UV range but other wavelengths may also be used. SLA materials polymerise via free-radical polymerisation.

Different parts of the object may need to be supported in the making of the object so as to avoid the collapse of the whole structure.  Successive layers are made to adhere to each other by cross-polymerisation of the just polymerised layer to the newly deposited layer where polymerisation is still incomplete. Since polymerisation may take some time to complete, the printed object usually needs some time in order to harden, then supports are removed (if any of these remain after the last layer has been deposited), then a final post-processing may take place.

A SLA printed 3D model is presented in Fig. 3.

Figure 3. Stereolithograph of bony labyrinth of the inner ear in man. Source: Didier Descouens, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

The ink used in SLA-based printing is usually liquid in its unpolymerised form. It is mostly epoxy or acrylic-based, although trimethylene carbonate, polycaprolactone, and polylactide-based inks may also be used. Use of such materials yields printed objects with significant rigidity that are, nevertheless, quite fragile. Thus, SLA is quite suitable for rapid prototyping and research purposes (e.g., tissue engineering scaffolds) but not for objects that need to be durable. SLA has quite high resolution (minimal layer thickness is 50 μm) and therefore is very reliable when fine detail is crucially important.

Objects created by SLA may be light-sensitive and may tend to disintegrate over time, especially when kept in light environments.

Solvents are rarely used in SLA printing, therefore, the risk of escape of fumes to the atmosphere is low. Due to the fragility of SLA-printed objects, nevertheless, discarded objects may present an environmental hazard. The use of UV calls for special precautions in order to avoid accidental exposure of surfaces, objects and operators to the curing beam. Some of the inks used for stereolithography may have significant neurotoxic and carcinogenic potential. Also, UV-mediated formation of ozone may need to be considered.

• Fused deposition modelling (FDM), also known as fused filament fabrication (FFF)

At present, this is the most commonly used technology for 3D printing. FDM technology is based on extrusion of a filament of thermoplastic ink fed from a spool through a moving heated printer nozzle. The ink within the nozzle is heated just above its melting point and is extruded in semi-solid form that solidifies almost instantly after a layer is deposited.  The object is built upon a moving platform that is gradually lowered as the structure grows (Fig. 4).

Figure 4. Working principle of FDM printers. Source: By Gringer – Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=73614647.

The minimal layer thickness for FDM is 100 μm. The most commonly used ink materials for FDM are acrylonitrile butadiene styrene (ABS), polylactide (PLA) and polyethylene terephthalate glycol (PETG). Others, such as polyphenyl ether (PPE), polyurethane (PU), polyethylene terephthalate glycol (PETG), polyphenylsulphone (PPSP), polycarbonate (PC), polyetherimide (PEI), polyether ketone (PEEK), polyamide (PA, commonly known as nylon) are also in use.  Polyvinyl alcohol (PVA) may also be used, but since it is hydrophilic, PVA is most commonly used for manufacturing easily removable supports for a structure printed using other type of thermoplastic ink.

The heatable ink for FDM may be also in the form of rods or granules. A variation of FDM uses cold extrusion of unheated ink, usually supplied as slurry or paste.

A FDM printer with spool of filament is presented in Fig. 5.

Figure 5. PRUSA i3 MK2 FDM printer (Prusa Research, Prague, Czech Republic) with spool and a completed object. Image source: Wikimedia Commons, http://reprap.org/wiki/File:Prusai3-MK2.jpg.

Being relatively low-cost, FDM is especially popular among hobbyists and desktop model makers. In addition, FDM is commonly used for rapid prototyping in engineering, in manufacture of high-performance parts and machinery, in education and in art.

The objects manufactured by FDM are significantly more durable than these produced by SLA and with very good quality of detail reproduction. Different quality FDM inks yield objects with different properties with regard to durability, rigidity and flexibility (see below).

Disadvantages of 3D printing by FDM are mainly related to potential environmental hazards (use of solvents, emission of small particles during post-processing, and the fact that the discarded objects are quite durable).

• Semi-solid Extrusion (EXT) 3D Printing

EXT 3D printing is another technology based on extrusion. The ink is usually polymer-solvent mixture with the consistency of paste. EXT materials are not thermoplastic, allowing for printing at low temperatures. Again, the object is built upon a moveable platform.

EXT is commonly used in research (e.g., tissue scaffolds) and for pharmaceutical purposes (targeted and/or timed delivery of drugs). Biosafety is ensured by using inks based on polyvinylpirrolidone, polyethylene glycol, methycelullose, hydroxypropyl methylcellulose, polycaprolactone and other materials. EXT is one of the potental approaches for priting living tissue from a hydrogel containing living cells.  Also, extrusion using viscous foodstuff paste (icing, chocolate, jelly, etc.) is a preferred method for 3D printing for the food industry (Fig. 6).

Figure 6. Extrusion printing for the food industry. Source: Grup de recerca de la Universitat de Columbia – https://www.creativemachineslab.com/digital-food.html, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=84202502

Since the material for EXT 3D printing is neither photosensitive nor thermoplastic, layers do not typically solidify instantly. Thus, newly printed 3D object may need time to set and/or dry after completion as the solvent/s evaporate. It may also be prone to warping, shrinkage and deformation. Minimal layer thickness for EXT is 800 μm. This low resolution is inherent to semi-solid extrusion techniques.

• PolyJet

PolyJet is another liquid-based 3D printing technology. Like SLA, it is based on layer-by layer UV-curing of a photosensitive polymer. The ink, however, is released from the printer head in droplets that accumulate on a building platform as directed by a designated software. PolyJet technology allows for mixing of inks, resulting in greater variety of properties for the manufactured objects.

PolyJet inks encompass great diversity of materials. Among the commonly used are ABS (different modifications), the related compound acrylic styrene acrylonitrile (ASA, more heat-resistant and UV-resistant than ABS), polycarbonate and polyetherketone ketone (PEKK). Various photosensitive materials that are used in other liquid-based 3D printing technologies may be used in Polyjet as well. There are also the specifically designed series of Vero Polyjet^TM inks patented by one of the market leaders in 3D printers and materials, Stratasys. Prominent members of biocompatible PolyJet materials are MED610 and MED620, a methacrylate-based resin used in the medicine and dentistry for rapid prototyping.

Advantages of using PolyJet are the relatively high resolution (minimal layer thickness is 160 μm, allowing for creation of stable structures with complex geometry and exquisite detail) and the great variety of properties (strength, flexibility, colours, etc.). The disadvantages are (beside the common drawbacks of 3D printing described above) the inherently high levels of emission of small particles, the use of UV light and the emission of toxic fumes when curing objects manufactured with some types of inks (e.g., ASA). Printed objects may need post-processing and may be photosensitive.

• Powder based (PB) 3D printing

PB 3D printing technology is based on deposition of successive layers of powdered material and their binding by means of a liquid binder solution or fusing using other methods (see below). The powder is deposited in a powder bed or produced by a powder jet and is then sprayed or jetted with binder, irradiated with light or heated in order to achieve integrity of the object.

Minimum layer thickness may vary greatly in PB 3D printing and layers may be as thin as 20-30 µm with some materials. This very high resolution allows for creating very complex structures with exquisite detail.  Generally, however, the layer thickness is about as 200 µm.

Powdered materials are usually produced by cryogenic grinding in a ball mill at a temperature that is below the glass transition temperature of the material. The grinding may be using low-temperature gases (liquid CO₂ or liquid nitrogen – dry powdering) or a mixture of low-temperature gas and organic solvents (wet grinding). In its simplest form, PB 3D printing is achievable using materials such as powdered starch or gypsum bound together with glue (Fig.7). Dyes and plasticiser compounds may be added to the binding solution in order to achieve the desired properties.

Figure 7. Rapid prototypes manufactured by powder-based 3D printing. Source: S Zillayali, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons.

Disadvantages of PB-based 3D printing are related, on the one hand, on the physical properties of the objects created with this type of technology, and, on the other hand, to the need for post-processing in order to achieve maximum quality. Objects built by PB 3D are inherently highly porous and, therefore, exhibit poor mechanical resistance and may be fragile.

PB-printed objects invariably need time for evaporation of solvents. Post-processing is usually necessary in order to remove excess powder (hence a certain amount of material is always wasted) and to improve the properties of the manufactured objects (strength, colour, polish, etc.). Emission of potentially harmful small particles is a serious concern in all PB-based technologies for 3D printing.

PB has been successfully used in research, dentistry and medicine for manufacture of implants and fabrication of drugs with specific pharmacokinetic properties such as rapidly disintegrating tablets, drugs with delayed, pulsatile or extended release. Biosafety of these dosage forms is ensured by using methacrylate or ethyl cellulose as carriers of the bioactive substance.

• ColorJet

ColorJet is not exactly a technology, but a brand of powder-based 3D printers and supplies manufactured in India. It offers one of the simplest solutions in PB 3D printing. The material used is most commonly white plaster powder although plastic may also be used (e.g., the company’s own patented Visijet C4 Spectrum powder). The material is layered onto a movable platform and bound by adhesive. The binder may contain different dyes, conferring different colours to the model being built.

ColorJet is most commonly used for rapid prototyping.  Minimum layer thickness is about 100 μm but may vary with different materials.

Colorjet provides a budget solution where durability, brittleness and porosity are not of great concern. Therefore, it is an acceptable solution for manufacturing of models for education, research and commercial purposes (e.g., sales models) and in art. A similar process using edible powder and binder solution is commonly used in the food industry to create customised sweets and dishes.

Objects printed by ColorJet may need extensive post-processing. Plaster structures need to harden after their completion and the solvents must evaporate. Then the object is polished and impregnated with another type of binder (usually acrylic) to achieve maximum strength and to decrease surface porosity. Fumes of solvent may be an environmental concern, as well as small particles emission.

• Selective Laser Sintering (SLS)

SLS shares the common characteristics listed above for PB 3D printing. In SLS the powdered material is layered and a directed light beam generated by the printer head partially liquefies and fuses the layers to one another as the structure is being built in a process commonly termed as necking (Fig. 8).

Figure 8. Formation of a ‘neck’ between two fusing layers (arrows). Source:  Mendoza.755 – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=76830144

Minimum layer thickness in SLS is about 100 μm.

SLS works very well with materials with high melting point and is therefore most commonly used with metal-based inks. Plastic (polyamide, polycarbonate, polystyrene and others), thermoplastic resin, glass and ceramic powders may also be used. SLS is often used for rapid prototyping in research (especially tissue scaffolding) and in dentistry. As of now, the opportunities for development of SLS-based technology in the pharmaceutical industry are quite limited as the radiant energy and the heat generated in the course of layer fusion may seriously compromise the properties of the bioactive substance.

Powdered foodstuffs (cocoa, sugar, etc.) may be used for 3D printing in the food industry.

• Selective laser melting (SLM)

SLM is often viewed as a derivation of SLS, as it is used mainly for printing with metal and metallic alloy powders. Nevertheless, while SLS printer head laser generates just enough energy to fuse the layers to one another, SLM uses a high-power laser that may melt completely a block of metal and then let is set in the desired shape similarly to casting. SLM produces objects that are significantly less porous than SLS and have better mechanical resilience due to homogenous internal structure. A disadvantage of SLM is that objects require polishing after their completion as it generates structures with increased surface graininess.

Electronic beam melting (EBM) is a subtype of SLM that uses similarly and electronic beam to melt metallic powders.

• Selective heat sintering (SHS)

SHS is based essentially on the same principle as SLS but the ink is thermoplastic and, respectively, the layer-by-layer fusion is obtained using heat generated by a thermal printer head. The most common material used in SHS is plastic (specifically, polyamide, but other polymers may also be used).

All objects produced by SLS or SHS are prone to warping and shrinkage.  Mechanical properties of the printed objects may be inconsistent from object to object as well as from batch to batch. SLS and SHS-made objects often require post-processing, such as removal of supports and coating with sealer agents in order to decrease surface porosity.

• Multi jet fusion (MJF)

MJF 3D printing is a hybrid of the ColorJet approach (use of chemical binders) and SHS (use of heat) that works mainly with polyamide (Nylon). Basically, finely grained polyamide powder is layered onto a powder bed, sprayed or jetted with binder and is then heated selectively as instructed by a pre-programmed software. Minimum layer thickness is about 80 µm. When the object is complete, post-processing takes place (removal of excess powder, polishing, etc.). MJF produces objects that are less porous and therefore more consistent in their mechanical properties than SLS or SHS and has better capacity for reproduction of fine detail. Surface finish is also better with MJF. Chemical fumes and generation of small particles is a concern, as with all PB 3D technologies.

Post-processing requirements for different 3D printing technologies

Not all objects made by 3D printing require post-processing. Nevertheless, many do need more work after the structure is complete. Whether an object needs post-processing depends on the material, the technology, the desired aesthetical or mechanical properties, and other factors.

Generally, there are several types of post-processing of 3D-printed objects:

• Setting and/or hardening

Almost all 3D printed structures need some time after their completion in order to mature and achieve optimal mechanical properties. Objects made by extrusion-based processes (especially those that use semisolid mixtures of polymer and solvent) and powder-based processes using materials that have been impregnated with binder solutions are especially sensitive to mechanical stress immediately upon completion. In this case post-processing includes the time for solvent evaporation and hardening. In some cases (but not always), this may be facilitated by increase of the ventilation in the premises where completed objects are kept.

• Supporting of unfinished structures

Complex structures containing overhangs may not be stable during manufacture without supports, albeit temporary. These supports need to be removed after the structure is complete, increasing the time to completion and the production costs (especially if this involves manual labour). In SLA-based 3D printing, supports for a structure printed with thermoplastic ink are most commonly made of polyvinyl alcohol. Since it is soluble, such supports may be easily removed during post-processing with a jet of water. The latter, however, requires plumbing, access to water and decontamination system for wastewater (which may increase the costs as well). Temporary support structures in SLS and SHS are usually made of unsintered material that may be vacuumed out or air-blasted away.

• Removal of excess material

This is crucial for object made by most powder-based methods. Excess powder needs to be removed using vacuum, air blast or a jet of water (again, this raises concerns about water supply and decontamination of wastewater).

• Polishing

Polishing is a must for improving of the mechanical characteristics of mechanical parts (especially those subjected to movement and friction) and objects with increased graininess of the surface (such as those produced by selective laser melting). Objects with aesthetical properties may also need polishing.

• Sealing of surface pores

This is an important post-processing step for technologies that yield objects with increased porosity, such as SLS or SHS. Surface pores may be sealed with impervious coatings such as cyanoacrylate coatings or by hot isostatic pressing.

• Painting

This is not commonly needed, as most 3D printing processes use differently coloured materials or differently coloured binders.

Which process for which? Basic considerations when selecting 3D printing technology suited for a particular application

While all 3D printing technologies may have overlapping applications (e.g., rapid prototyping), there are factors that may weigh in when a 3D printing technology is selected for a particular project or a specific industrial solution. Main considerations are:

• Type of material that may be used to print an object. Many 3D printers on the market may use a variety of different materials. Architectural, sale and exhibition models as well as models made for educational purposes may conveniently be created by ColorJet, SLA and FDM technologies that use plaster or different types of plastic. Small desktop machines that serve hobbyists and artists are usually based on FDM technology. SLS/SLM and SHS are usually employed when the objects must be made from metal and metallic alloys.
• Availability of 3D printing machine. Usually, orders for a particular machine are queued and work in a ‘first come, first served’ fashion. In regions where 3D printers are hardly available, this factor may be of prime importance, prevailing over the type of material.
• Availability of material. Plastic is versatile, available and, except for high-performance polymers, relatively cheap, while metal may be more costly.
• Costs for production per object. These are related to the technology used for creation of objects, the material used and the needs for post-processing. It was already mentioned that, unlike casting, scaling up in 3D printing does not always bring the unit price down. The price per object includes not only the costs for manufacturing but also the post-processing costs (if it is needed) as well as the costs incurred by measures for decreasing environmental pollution. Among commonly used PB technologies, SHS is a more budget-oriented solution than SLS as purchase and maintenance of a thermal printer head is generally less expensive than a laser printer head. Objects manufactured by SHS are therefore generally cheaper that those made by SLS and the process may easily be scaled down for small-sized orders.
• Rapidity of manufacture, including post-processing and the time for queueing of orders. Small objects may be printed in a matter of minutes to hours. The time for printing increases with the size of the objects to a whole day and, ultimately, with very large objects, up to a several days, although the latter is rare. Post-processing times may also be a concern. Extrusion technologies does not typically need finishing, but the object may need time to set and harden. ColorJet-made objects need time for drying and setting. Powder-based technologies almost invariably need time for post-processing and it increases the costs as well as the time for manufacturing,
• Properties of the end product (mechanical properties, aesthetical value)

Plastic 3D printing ink may come in many different varieties with different mechanical properties. Depending on the purpose of the use of the object, the preferences may be for plastic (lightweight and, at the same time, durable, easily dyed, easily polished, thermo-and photocurable) or for metal (resilient, resistant to UV and heat, colouring and polishing may need special equipment and processes).

Among the plethora of varieties of plastic, different polymers with different mechanical resilience are available. Generally, SLA printing allows for finely polished structures with exquisite detail that are, nevertheless, quite brittle. It is therefore unsuited for applications where durability is crucially important. FDM yields significantly more durable objects than SLA, yet there are different grades of mechanical resilience depending on the material used. Generally, PVA, ABS and PLA are ”commodity” inks for FDM. These are relatively cheap but the resulting objects are prone to warping. Objects printed with PLA are also quite brittle. ABS-printed objects are photosensitive. Use of polyurethane yields parts with significant degree of flexibility. Next step in FDM quality is PC, PETG and PPE. These materials are used mainly as engineering materials for manufacture of mechanical parts and tools. PETG is also food-safe. High-resistance FDM inks are PEI and PEEK which are used for parts and devices that need to exhibit very high resistance, such as moving and/or strain-bearing parts and when thermal stability is crucial. All 3D printed objects might be prone to delamination under stress, but PEEK printed objects exhibit excellent layer-to layer adhesion and are therefore very durable. It is, however, quite expensive, and as the melting point is higher than of the other FDM inks, the printer needs to have the capability for heating the nozzle to high temperatures.

3D printed drug dosage forms and tissue scaffolding have specific requirements that are generally met by extrusion methods (especially semisolid extrusion such as EXT) and some of the powder-based technologies (but not these that require large amounts of radiant or infrared energy such as SLS and SHS). As minimal layer thickness for EXT is almost 1 mm, the printed structures are coarser and less detailed.

Powder-based methods have very high degree of resolution and therefore confer better reproduction of fine detail. This is especially true for SLS (it, however, works mainly with metallic powders) but MJF (works readily with plastic) also compares favourably in terms of resolution.

The structures produced by most PB technologies are also durable (except for ColorJet-printed plaster objects) but porosity may compromise their mechanical properties. When the latter is a serious issue, SLM may be a solution, provided that proper post-processing is carried out.

• Environmental concerns (related to manufacture or post-processing or the biodegradability of discarded objects).

Extrusion-based and some of the PB technologies generate solvent fumes. Powder-based technologies generate large amounts of small particles. All these have significant potential harmful effects and need to be filtered out and/or decontaminated.

Commonly used software for 3D printing

3D printing uses previously collected data that has been stored on a digital information carrier. In the course of 3D printing of a complex object, the momentary changes in the pattern of deposition of the ongoing layer are dictated by the information of specific cross-sections in the digital file representing how exactly the structure must look like at this particular point. Thus, structures with simple patterns may be represented by fewer cross-sections while digital files for structures with intricate patterns ought to contain more cross-sections, indicating where and how the structure is altered. Every cross-section represents a closed polygon and corresponds to a different position along the z axis. Cross-sections must not overlap or intersect and, at best, must be without voids in between. Small discrepancies may be cleared out by the software without significant shape and structure alterations.

Computer-assisted design (CAD) images are most commonly used for 3D printing. Those may be the conventional 2D DWG images generated by AutoCAD although these need to be converted to 3D by designated software, e.g., Sketchup Pro. Stereolithography file format (Standard Tessellation Language, STL) was the first to be specifically designated for additive manufacturing. It was developed and adapted for use in the 1980-ties by 3D Systems, a company founded by Charles Hull, the inventor of SLA. Apart from AutoCAD, commonly used CAD software capable of exporting or converting data to STL format are Alibre, Mechanical Desktop, I-DEAS, SolidDesigner, ProE and others. Online converters are also readily available, such as AnyConv (https://anyconv.com/stl-converter/).

Images generated by a 3D scanner or by photogrammetry of a typical 2D digital image (taken by a digital camera) may also do for additive manufacturing. Depending on the source of the data for the object, the final result may be more or less true to the initial image.  CAD images usually result in objects with significantly less errors than other types of digital data. These errors may be corrected later.  There are many different brands of software for photogrammetry, mainly Microsoft Windows-based (Zephyr3D, PhotoModeler, PhotoSynth and others) but there are some may use other operating systems such as Linux and MacOS (e.g., Pix4D Mapper, Metashape, OpenDroneMap and others). A detailed list of commonly used photogrammetry software with their basic characteristics may be viewed here:

https://en.wikipedia.org/wiki/Comparison_of_photogrammetry_software

Online tools for photogrammetry are also available, such as the mentioned above AnyConv (https://anyconv.com/stl-converter/).

In order to print an object, if a STL file is not available, it must be output from a piece of software such as AutoCAD or others (see above). Most professional 3D-modeling software is proprietary, but free software is also available, mainly for education purposes for beginners in the field and for hobbyists (FreeCAD, 3D Slash, TinkerCAD, Vectary, SketchUp, Leopoly, Sculptris, Rhinoceros and others). Then the resulting STL file is used by another piece of ‘slicer’ software, such as Repetier, OctoPrint, Z-Suite, Tinkerine Suite, Cura, PrusaSlicer, Simplify3D and others to generate a file containing series of thin layers. The resulting file is used by the 3D printer host to generate a 3D object. Some pieces of slicer software function also as printer hosts, such as Cura, 3DPrinterOS, OctoPrint, MatterControl and others. While most professional 3D modelling software is usually stand-alone, free software may be available as a plugin and is much more likely to be available for operating systems other than Windows.

STL files contain raw mesh data based on triangulations of the surface of CAD models. Thus, the surface of every facet of the object is represented by a polygon mesh that must conform to a set of rules. The basic rules are four, namely:

The ‘vertex to vertex’ rule – each triangle must share 2 vertices with its neighbouring triangles;

The ‘right-hand rule’ – the vertices must be listed in counter-clockwise fashion;

The ‘pointing outwards’ rule – the direction of normal vector should point outwards;

The ‘all-positive rule’ – all the coordinates of the triangle vertices must be represented by positive numbers.

An example may be viewed in Fig. 9.

Figure 9. A polygon mesh representing a 3D image of a dolphin. Source: Chrschn, Public domain, via Wikimedia Commons.

STL files may store information in binary encoding or in ASCII encoding. Files in binary are, generally, smaller and may be easily shared, while ASCII files are used to manually read and check the STL file, e.g., when testing new CAD interfaces.

Complex objects may be a challenge to STL files as there are too many surfaces to be taken in to account in the calculations. In addition, the early STL files had very limited properties for representing colour, texture, material and internal structure (although this was resolved later). Some types of software, such as the prototypic AutoCAD may only export designs of solid objects to STL. Non-adjoining surfaces (e.g., containing gaps or overlaps) are difficult to process or adapt in STL files and would not print. Thus, in 2006 an improved version of STL formats was released that eventually was transformed in another, more versatile CAD file format, the Additive Manufacturing File format (AMF). Nevertheless, many 3D printers used today, especially those that work in the small scale, will use STL files.

AMF files can readily represent internal structure using use face-vertex polygon layout and curved triangles to define a discrete unit of volume of material. Multiple volumes may be specified for a single object. AMF files also contains information about the material, the colour and texture of the printed object or its parts and the order for printing.

Jonathan Hiller, one of the inventors of the AMF file format hosts a detailed and user-friendly site providing CAD software or 3D modelling and tutorials: https://sites.google.com/site/jonhiller/software.

Free architectural CAD drawings for AutoCAD and 3D modelling software are readily available on the Internet, e.g. https://www.arcat.com/, https://www.tinkercad.com/, https://www.sketchup.com/ and others. A free 3D CAD image is presented in Fig. 10.

Figure 10. A 3D CAD model for use in 3D printing. Source: OKFoundryCompany from Richmond, USA, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons.

Free STL files, 3D printer files and 3D printer designs are available for use from www.thingiverse.com, www.youmagine.com, www.myminifactory.com, https://library.zortrax.com/, https://www.cgtrader.com/, https://cults3d.com/en, https://www.youmagine.com/ https://www.turbosquid.com/Search/3D-Models/free/stl,  and other sites.

STL editor software is available for multiple sources such as https://www.meshlab.net/, https://www.blender.org/, https://www.freecadweb.org/, https://www.3dslash.net/index.php, https://www.sketchup.com/, and others.

3D bioprinting is an evolving technology with applications throughout the complete range of biomedical research.

Application areas of 3D bioprinting

3D bioprinting is an evolving technology with applications throughout the complete range of biomedical research. The method employing a biological substrate or ‘bioink’, made of structural components, growth media, and cells, can produce on 3D printing equipment biological structures that closely imitate the structure of cells in living organisms. Using the same manufacturing model as traditional 3D printing, a number of 2D slices are divided from a 3D model by a computer to print a correct biological composition layer-by-layer with a precise arrangement of tissues and cells. 3D bioprinting approach gives an opportunity to solve issues in drug development, regenerative medicine, organ donation, and cancer treatment. This emerging technology offers great accuracy on spatial placement of cells, proteins, DNA, drug particles, growth factors and biologically active substances to guide better tissue formation. This powerful technology seems to be more promising for improving tissue fabrication toward physiologically relevant tissue constructs, tissue models, tissues and organs and organs-on-a-chip models for medicine and pharmaceutics.

Bioprinting technology has a wide application in various areas such as tissue engineering and regenerative medicine, transplantation and clinics, drug screening and high-throughput assays and cancer research (Fig. 1). Bioprinting for tissue engineering and regenerative medicine has been studied for more than a decade, and anatomically correct cell-laden constructs and scaffolds have been produced for various tissue types: from connective and epithelial tissues to muscle and nervous tissues. With its great advantage in modelling and precisely placing multiple cell types, bioprinting has overcome one of the major shortcomings of traditional scaffold fabrication techniques and has facilitated the construction of native-like tissues with a heterocellular microenvironment. Although most of the effort has been targeted toward the fundamental science behind major bioprinting techniques such as laser-, droplet- and extrusion-based bioprinting, considerable attention has recently been given to bioprinting for functional tissue production. Particularly, considerable work has been devoted to bioprinting for transplantation. As additional progress has been made in biomaterials, cell, and transplantation technologies, bioprinting will translate from bench to bedside when authorized for human use and has a multitude of advantages in operating rooms in the near future. Before transitioning into clinical practice, bioprinting has already made a great jump in pharmaceutical use because it does not require any regulatory approvals and there is currently an emerging bioprinting market for tissue fabrication for drug testing and high-throughput assays. Bioprinted tissue models (e.g. liver), fabricated from multiple cell types and facilitating a complex heterocellular physiological environment, have been used in drug screening. Moreover, bioprinting has recently been applied in cancer research to investigate cancer pathology, growth, and metastasis in a physiologically relevant microenvironment. Here, a comprehensive review is presented of the application areas of bioprinting technology and in-depth discussion is presented on successfully bioprinted tissue types for tissue engineering and regenerative medicine, transplantation and clinics, drug screening, and high-throughput assays, and cancer research. For each application area, the advantages and limitations of existing technologies are discussed.

Figure 1. Application areas of bioprinting technology.

Regenerative medicine is probably one of the most thrilling future applications of 3D bioprinting. Scientists hope that bioprinting can be used to directly print tissues such as skin, and to create organs, tissues, and structures for transplantation. 3D bioprinting is believed to be successfully applied for the transplantation and production of multilayered tissue types like nerve, cardiac, blood vessel, bone, and skin (Fig. 2). Researchers anticipate that in the future tissues and eventually whole organs could be transplanted to patients produced from their own cells. With the help of 3D bioprinting, transplant rejection and long donor lists could become an issue of the past. In addition, numerous tissue constructs were bioprinted and implanted subcutaneously to evaluate in vivo differentiation of cells and functionality of implants. Despite these experiments, none of the bioprinted tissues has been clinically used for humans because no approval has been granted yet. There are no regulations laid down for bioprinters or bioprinted products. However, with the growing interest worldwide and emerging businesses in the bioprinting market, the success with the first technology going through regulations will be exemplary for preceding technologies and products.

Although bioprinting technology is still in its early stages in clinics, 3D-printed plastic, ceramic or metallic implants for bone tissue replacement have been already successfully transplanted into humans. In addition to permanent implants, a recent work published in New England Journal of Medicine presented a unique case of transplantation of a 3D-printed bioresorbable airway splint into an infant. No unexpected problems have been observed with the splint and full resorption of the device is anticipated to take around 3 years. This was an exemplary case for clinical use of 3D-printed scaffolds and optimistically will lead to similar success with bioprinted tissues and organs. Despite the achievements in bioprinting research, bioprinting for transplantation in a hospital requires further improvements and translational efforts. Organs and tissues that do not need significant vascularization (i.e. skin and cartilage) are expected to be clinically translated very soon. However, tissues and organs that are metabolically highly active (i.e. heart, pancreas, and liver) are extremely challenging.

Figure 2. 3D printing strategy

One of the arguments for the clinical translation potential of bioprinted tissues and organs originates from the bioprinting technology itself. Bioprinting involves living cells in bioink and the use of patient-specific cells is relatively new in bioprinting. Stem cells, such as embryonic stem cells and induced-pluripotent stem cells, have been prospective unlimited sources of patient-specific cells for production of tissues and organs. Patient-specific cells can be differentiated and then bioprinted or bioprinted and then differentiated toward multiple lineages to construct tissues and organs that will cause minimum immunogenicity risk.

Another key area where 3D bioprinting is expected to succeed is in the drug development. Most of the drug testing is currently carried out by using 2D cell cultures. Like cancer research, these cultures do not simulate natural cell behaviour. Xenografting (human cell transplantation) to animals is now employed to help solve this issue. However, this approach is challenging due to the biochemical, metabolic, and genetic differences between the species. It has been suggested that these issues are the main reason for the high rate of failure in assessment of the new drug candidates. Despite continuing efforts to improve the drug development process, only one out of 10,000 new chemical substances and one out of ten drug candidates enters clinical trials, reaches the final approval stage, and enters the market. On the other hand, the use of 3D bioprinting for pharmaceutical testing rather than in vivo studies does not need regulatory approval. Thus, the throughput of drug development will possibly be extensively multiplied. Among different methods for engineering 3D in vitro systems, bioprinting has serious advantages such as controllability on size and microarchitecture, high-throughput capacity, co-culture opportunities, and low risk of cross-contamination. That is why the bioprinted tissues and organs have been increasingly considered as potential models to be used in drug toxicology and high-throughput screening.

Liver and tumour tissue have been a focus in construction of tissue models for pharmaceutics. In this respect the fabrication of a bioprinted liver micro-organ model for drug metabolism has been investigated (Fig. 3). The bioprinted 3D liver micro-organ has been used for simulation of the physiological liver response to drug administrations and toxic chemical exposure. The drug metabolism was demonstrated by the transformation of the nonfluorescent pro-drug, 7-ethoxy-4-trifluoromethyl coumarin (EFC), to an effluent fluorescent metabolite 7-hydroxy-4-trifluoromethyl coumarin (HFC). Epithelial cells and hepatocytes encapsulated in Matrigel™ were utilized to show the path of drug diffusing from the bloodstream to the tissue. Epithelial cells are the cells covering the lumen through which the drugs pass from bloodstream to the target, where hepatocytes were used as the target cell type. Based on the presented tissue model, a computational macroscale model was developed using a convection-diffusion-cell kinetics numerical framework. Latest is proven to be very helpful for future research in 3D micro-organ pharmacokinetics and toxicity.

Figure 3. Bioprinted tissue models for drug testing and high-throughput screening. (a) Bioprinted liver tissue. (b) bioprinted kidney tissue (c) bioprinted skin tissue (d) 3D bioprinted bone repair material (e) printed cell-containing hydrogel (f) multicellular 3D bioprinted cardiac tissue constructs.

Evolving microengineering technologies allow adaptable production of 3D cell-based microarrays including soft lithography, surface patterning, microfluidic-based manipulation and bioprinting. Among them, bioprinting technology has the advantage of creating co-culture and single-cell array with precise control on cell density. A recent study utilized a novel inkjet-based bioprinting method for fabricating a high-throughput miniature drug-screening platform. The authors bioprinted Escherichia coli-laden alginate to array a chip on coverslips. Using layer-by-layer approach droplets of three antibiotics were printed on the spots of cells. Results showed similar cell viability, functionality and antibacterial effects of antibiotics in inkjet bioprinted and micropipetted samples.  Thus, the inkjet-bioprinted high-throughput arrays is proven to be effective method to minimize the duration of typical drug screening tests. Furthermore, cell-based biosensors (CBBs) were presented, where acoustic-based bioprinting was used to create a microarray of smooth muscle cell droplets in collagen. The bioprinted microarray was then subjected to different environmental conditions (e.g. temperature) and the effect of the applied stimuli as well as the bioprinting process parameters on cell viability was assessed. In addition to 3D bioprinting of high-throughput cell microarrays, controlled delivery of drug candidates into cell microarrays is also an important factor for effective drug screening. Different methods have been proposed for controlled drug delivery onto cell microarrays, including drug patterning, drug stamping, aerosol sprays and microfluidic drug loading.

The immense future possibilities of 3D bioprinting technology in biomedical field has already been well documented. One of the areas where scientists are hoping 3D bioprinting to prove beneficial is the cancer research. The tumour microenvironment, as well as the biological structures and substances surrounding the tumour is an essential elements of cancer behaviour and is not yet fully understood. Up to now animal models and 2D cell cultures have been employed in these investigations. However, they do not precisely demonstrate the behaviour of human cancer cells in vivo, which includes a complicated interaction between tumour cells with both the cellular environment and other cells. Latest research suggest that 3D models more precisely reflect tumour cell behaviour and bioprinting is a promising technique that could be effective in such studies. One advantage that 3D bioprinting possesses is that cells can be explicitly designed into a 3D model with its extracellular and structural elements. Alternative approaches differ in that they require self-assembly, which is much more time-consuming, or scaffolding, where the support matrix is developed independently from the cell culture. Furthermore, 3D bioprinting provides both the opportunity to print particular tissue and cell structures and also to be specific to the patient. The cells of a patient can be biopsied, grown, and bioprinted, appropriate structures to be fabricated, and drug response or effective dose to be investigated.

However, the use of bioprinting approach in cancer research is new and only a few studies have been performed in this emerging application area. For the first time, the bioprinting of tumor tissue was demonstrated with human ovarian cancer (OVCAR-5) cells and MRC-5 fibroblasts. In this study, an inkjet-based bioprinting platform with dual-ejectors was used. The proposed approach did not only show a tool for cancer research but also offered a great platform for high-throughput screening. The same researchers performed bioprinting of HeLa cells to form cervical tumor models. Although these two studies presented bioproduction of tumor spheroids using bioprinting technology, the construction of larger tissue models to examine cancer cell migration and metastasis is also crucial. Another approach was concentrated on the use of a laser-based 3D projection printing system to bioprint HeLa cells and noncancerous 10 T1/2 fibroblasts in PEGDA along with a microvascular network with channel widths of 25, 45, and 120 μm to simulate blood vessel diameters. In addition to scaffold-based approaches, scaffold-free bioprinting of a breast cancer model using the NovoGen Bioprinting™ platform was also performed. In this attempt cancer cells were surrounded by a physiologically relevant stromal medium comprising MSC-differentiated adipose cells, mammary fibroblasts and endothelial cells.

Recent investigations have demonstrated that 3D bioprinting is an emerging approach having broad application in various areas including basic research in tissue engineering, regenerative medicine and cancer pathogenesis, tissue bioprinting for transplantation and clinics, and could be successfully applied in pharmaceutics for drug testing and high-throughput screening. Currently, there are around 15 different tissue types used in different experimental studies. However, there still exist several other human tissues that have not been touched yet. In this regard, future attempts must be made in bioprinting of other tissue and organ models that are challenging but can revolutionize medicine. This also depends on the innovations in the field of tissue engineering as bioprinting research vitally depends on our understanding of unexplored tissue types. In addition, one of the new directions in bioprinting should be focused on biofabrication of new types of organs, such as bionic organs or organs that do not exist in nature.

The majority of 3D bioprinting research has developed around homocellular tissue models using a single cell type. However, native tissues have a heterocellular nature with multiple cell types organised in highly complex anatomy. Although simple bioprinting tissue models are relatively acceptable in fundamental research, fabrication of functional tissue for clinical or pharmaceutical studies requires inclusion of multiple cell types. Thus, some of the functionality of cells can be enabled or further boosted by cell–cell interactions. Therefore, bioprinting multiple cell types need further investigations of the optimum culture conditions including the right medium and reagents to support their growth and behaviour.

Contemporary attempts in translation of bioprinting to transplantation are mainly limited to murine models. However, murine models are small with physiological conditions that significantly differ from those of humans. For example, a small pancreatic tissue with 3D bioprinted islets can be implanted into a diabetic murine model and can regulate insulin secretion. On the other hand, the average volume of islets in a mouse pancreas is approximately 100,000 times smaller than those in human pancreas. Therefore, bioprinting of scale-up tissues and organs is extremely important to construct them at clinically relevant dimensions. Larger animals such as a porcine model can be a transitional step toward trials on humans because these animals correspond to human physiology more closely than small animals. To scale-up bioprinting organs for clinical use, the fabrication of hierarchical vascular networks is crucial in addition to their mechanical strength, elasticity, and long-term structural stability. Additionally, integration of nerve tissues and forming innervation is a critical step toward functional tissue and organ production because tissues such as cardiac, muscle, and skin require innervation, which is currently a challenge in bioprinting. The majority of bioprinting research involves the use of hydrogel-based bioinks as they are a favorable environment for the 3D growth of cells. However, hydrogels have weak mechanical properties when they are used at low concentrations to support cell proliferation. In addition, biodegradable materials such as thermoplastics can be utilized as a background frame for the scale-up of tissues and organs. Available biomaterials, such as synthetic polymers, are strong, but their degradation is difficult, time-consuming, and does not match with the tissue regeneration process closely. Therefore, new biomaterial development is vital for the progression in bioprinting of tissues and organs for clinical use. Apart from the biomaterials, selection of the right cell source is also a critical factor or successful clinical and pharmaceutical use. For personalized medicine it is challenging to obtain different primary cell types. Stem cells represent a promising source of cells and further investigations are needed to establish standard protocols for differentiation of stem cells into various stable and functional cell lineages.

Another prominent way of tissue fabrication for high-throughput screening are the miniature 3D-array platforms such as tissue-on-a-chip or organ-on-a-chip models. Blend of bioprinting technology with other technologies such as microfluidics is essential for producing physiologically simulated, complex and long-term viable target micro-organ arrays. Application of technologies generating picoliter droplets with low level of cell damage and having single cell sorting capabilities should be encouraged in bioprinting of cell microarrays. Controlled drug delivery onto cell microarrays should be also considered and implemented.

Although several attempts are made in engineering cancer microenvironment using bioprinting technology, further advancements are needed for construction of a physiologically relevant complete microenvironment, comprising tumour site, healthy site, and microvascular network in between, to perform cancer metastasis research. Tumour tissue models should be precisely placed within bioprinted vascularized parenchymal tissues to study their growth, tumour cell intravasation and extravasation.

The field of synthetic biology has exploded over the past decade, having a major influence on fields such as metabolic engineering, protein engineering, digital biology, and whole-genome engineering.

Biosensors & Biochips Technologies: Contribution to the Future Sustainable Life

The field of synthetic biology has exploded over the past decade, having a major influence on fields such as metabolic engineering, protein engineering, digital biology, and whole-genome engineering. In the framework of iterative “design-build-test” development cycles, a significant portion of synthetic biology innovation has taken place. In the field of synthetic biology, progress can be associated with innovations in each of the processes of “design”, “build” and “test”. For example, there has been a major push to standardize elements within synthetic biology, with significant attention being paid to modularity and “plug and play” components. This modularization, along with the accelerated progress in systems biology, has allowed the “design” stage to become less time-consuming and less reliant on advanced knowledge. In recent years, the cost of DNA sequencing and synthesis has also decreased dramatically, allowing large constructs to be synthesized cheaply. In the ‘build’ phase, this has facilitated a rapid improvement, helping researchers to investigate a larger percentage of the space of the biological solution. Finally, within the synthetic biology “test” phase, high-throughput screening has also become a focal point. The increased “design” and “build” potential has contributed to an increased demand for success in the assessment of the plethora of new designs. In turn, this was done by incorporating robots and high-throughput analytics into the laboratory setting, in which new models can be evaluated to a level that is not achievable for human researchers.

Biosensors represent a groundbreaking emerging technology for high-throughput screening that can be implemented. Most precisely, they are classified as an analytical tool consisting of biological components used to detect and generate a signal for the presence of a target ligand. Synthetic biology is at the forefront of biosensors, both as a tool for high-throughput screening, but also as the direct result of developments within the field of synthetic biology itself. In addition, because of the unparalleled specificity and sensitivity that biological parts provide relative to conventional analytical methods, biosensors have gained expanded interest as alternatives to traditional analytics.

The design and construction of biosensors is a multidisciplinary endeavour and can include expertise in areas such as protein engineering, molecular biology, affinity chemistry, molecular dynamics of nucleic acid, materials sciences, and nanotechnology. Biosensors interface with a target ligand at their most simple stage, undergo some type of modification, and output a signal. There is a great variety of potential configurations in all the parts of this process. Target ligands range from single atoms such as calcium, to entire proteins such as thrombin, all the way through. Processes as varied as enzymatic activity, fluorescence, electrical current generation, and transcriptional activity include output signals. The mechanisms that transduce ligand recognition into functional signals are just as diverse.

In the field of analytics, biosensors represent a significant step forward. In order to move analytics away from purely physics- or chemistry-based frameworks, the integration of biological components in sensory diagnostics has begun. This has allowed analytical functions that are not well adapted to conventional methods to conduct a vast diversity and specificity of biological components. The theoretical and demonstrated biosensor applications cover a significant range of human society and activity. Biosensor applications are grouped into three broad categories, depending on their measurement scale.

• Group Diagnostics: Environmental, Agricultural, and Industrial Applications
• Point-of-Use Diagnostics: Medical, and Security Applications
• Single-Cell Diagnostics: Metabolic Engineering, and Synthetic Biology Applications

The current food production faces immense challenges from the increasing human population, the maintenance of clean resources and food quality, and the protection of the environment and climate. Food sustainability is mainly a cooperative effort that results in the development of technology funded by both governments and companies. Several attempts have been supported to overcome challenges and improve the drivers in food production. Via their applications, biosensors and biosensing technologies are widely used to solve the major challenges of food production and its sustainability. As a result, there is a rising need for biosensing technology in the area of food sustainability. A technological system combining several technologies is defined by microfluidics. Nanomaterials, with its biosensing technology, is known to be the most innovative tool strongly associated with world populations in dealing with health, energy, and environmental issues. The need for point of care (POC) technology in this area focuses on analytical tools that are fast, simple, precise, compact, and low-cost.

For our existence and lives, food with its production industry is essential; and its sustainability is essential in continuous human growth on the planet. Current food production is facing immense difficulties from increasing human population, maintaining clean resources and food quality, and protecting environment and climate. Some of these issues stem from food production itself; others stem from other food production-related industries. Food recalls, for example, trigger major damage to food brands’ credibility and prestige, with an estimate of $15 million per incident over the last few years. 48 million sick cases are responsible for 3000 fatalities annually due to foodborne illnesses.

Food safety is largely a cooperative effort arising from both governments and companies in technology development. In order to pose new challenges in food safety issues, information technologies such as blockchain technology can accelerate communication between food quality, media and consumers. Five challenges can be summarized as the main challenges in the sustainability of food production: the production challenge of food safety and security; the quality challenge of food diversity and quality; the economic challenge in the leading food system, including its packaging and supply chain; the environmental challenge, including the processing of food waste; and the engineering challenge in the creation and generation of novel food.

Basically, a biosensor is an analytical instrument used to measure a sample’s molecule of interest (target). In general, a bio-recognition factor (aptamer, antibody, enzyme, etc.) that is unique to the target is used. A physiochemical or biological signal is elicited by molecular recognition events between the recognition element and the target compound, which is transformed into a measurable quantity by the transducer. Signals are shown in either optical (colorimetric, fluorescence, chemiluminescence and plasmon surface resonance) or electrical (voltammetry, impedance and capacitance) or any other chosen format (Figure 3).

Figure 3. Classification of biosensors based on transducer and bio-recognition elements used in food analysis

As one of the primary objectives of food analysis, food safety is a major health issue in both animal and human lives. The advancement of food safety analytical technology means that it thrives in line with the rising interest in and emphasis on food supply safety issues. In food safety analysis, traditional approaches are labour-intensive, time-consuming, and need trained technicians. The application of microfluidics in food safety analysis provides fresh insight about how to detect foodborne toxins, allergens, pathogens, hazardous substances, heavy metals, and other contaminants effectively and rapidly. Microfluidics’ features, such as it miniaturize-capability, compact and reducible quantities of samples and reagents, make it a perfect technology for the development of food sustainability. Complex food matrix preparation and difficult manufacturing steps are the current challenges in the application of microfluidics to food sustainability. These challenges can be addressed by leveraging physical properties dependent on specific test targets, designing complex real food analysis microfluidic platforms, and incorporating into microfluidic systems biomolecules such as food proteins and DNA.

Nanomaterials in biosensing technology

With its biosensing technology, nanomaterials are the most promising tool in dealing with health, energy and environmental problems associated with population in the world. Particles smaller than 100 nm in at least one size dimension are known as nanomaterials. These nanomaterials are biocomposite polymers based on metal, metal oxide and carbon, and different types of nanoparticles have been established, such as magnetic iron, aluminum, gold, silver, copper, silica, zinc, zinc oxide, cerium oxide and titanium dioxide nanoparticles, and single/multiple walled carbon nanotubes (CNTs). Nanotechnology and its agricultural development have been greatly extended in different fields. These fields include food production, crop protection, detection of pathogens and toxins, purification of water, food packaging, disposal of wastewater, and environmental remediation. Improving the productivity and performance of applications is the priority of these agricultural fields.

In the field of food safety and protection, biosensing technologies have been developed for nutrient and quality detection, detection of pathogens and detection of toxins, as listed below.

Nutrient and quality detection

Food protection measures can be split down into two categories: post-harvest loss and food biosecurity. Food biosecurity means food contamination and degradation, which is addressed in the later sections, by environmental, political, unfair economic gain, warfare, or exacting revenge. Post-harvest loss, on the other hand, suggests the nutrients and edible conditions in food that need to be maintained between the harvest period and the moment of consumption by technologies. Since time differs from minutes to years, in maintaining and reducing losses, technologies focusing on reducing post-harvest losses are important.

To maintain food quality and to avoid post-harvest losses, new technology such as biosensing can be used. Biosensors have been developed, for example, to detect and analyse quantities of sweeteners in foods that can be used to detect both natural and artificial sweeteners. Sweeteners are widely used in food production and processing, but they have recently been identified in humans as causing health problems. A multi-channel biosensor has been developed to use electro-physiological sensing from taste epithelia to detect and analyse both natural and artificial sweeteners. To detect long-term signals from sucrose, glucose, cyclamate, and saccharin, respectively, the signals are studied through spatiotemporal techniques. The biosensor can distinguish between different concentrations with dose-dependent increased responses of the taste epithelium from different sweeteners. It can also distinguish between two natural sweeteners: sucrose and glucose, with two signal patterns. For glucose, the detection range is 50-150 mM, and for saccharin, 5-15 mM.

Detection of pathogens

Due to their reduced format, biosensors targeting pathogen detection such as bacteria (Table 1) and fungi (Table 2) started more than two decades ago; one device to address multiple problems, and a multi-panel signal detection. The ligand motif is a crucial element in the biosensor design for pathogen detection since it determines the sensitivity and efficiency of the device. The aim is to establish a fast, specific, and sensitive platform to detect in food samples the presence or absence of pathogens. It has been discovered that there is no ideal ligand, and various ligands have different advantages. The combination of bioreceptors to detect a large variety of microbes in different samples poses current challenges in pathogen biosensor detection; new synthetic ligand designs such as aptamers, small molecules, and peptides; and the incorporation of different ligands into a portable device to achieve rapid, effective, and low-cost detection.

Detection of toxins

The mainstream of development in food safety is electrochemical biosensors for rapid detection and assessment of food toxins. Numerous platforms have been developed to allow customized and individualized devices to meet particular environmental and organizational requirements and to reach the nM to fM detection limit levels. For example, to encourage unique binding profiles, bioreceptor arrays address individual electrodes functionalized with different bioreceptors with binding targets. In addition to electrochemical biosensing, toxin and chemical detection in food production have been applied to other biosensors such as optic and piezoelectric sensing (Figure 4). In order to sense toxins, fluorescent nanoparticles have been produced in foods and bodies, including on-surface, inter- and intra-cellular foods.

Figure 4. Predominant food contaminants and the target analytes in the food manufacturing industries

Toxin extraction from complicated food samples is one of the main obstacles in creating a fully automated toxin detector. To automatically assess their harmful levels from food and water samples, potential systems are expected to extract, process, and measure toxins. In identifying, discriminating, and quantifying chemical toxins in food matrices, sophisticated separation strategies have been coupled with SERS. In addition, even though they are typically in lower amounts, chemical contaminants from food processing can be a challenge. Lower stability, selectivity and sensitivity are another challenge in food toxin detection, where MIPs can be a solution to provide stable and low-cost alternatives.

Heavy metals like Ag⁺, As³⁺, Cd²⁺, Hg²⁺, Pb²⁺, and Zn²⁺ are known as chemical pollutants that form stable states of oxidation and interfere with metabolic pathways, resulting in health problems. Aptamer and DNA-based biosensors can detect heavy metals at both nanoscale and very large-scale levels, which are appropriate for food safety screening and monitoring. In order to detect arsenate in food, a heavy metal detecting biosensor is based on genetically modified bacterial cells and a green, fluorescent signal amplifier. With a detection range of 5-140 μg/L of arsenic, its arsenic detection lasts just one hour and can be integrated with optical power output for its future biosensing optical fibre. Other biosensing technologies like aptamers, nanoparticles and graphene electrodes have been successfully applied to the identification and evaluation of arsenic, with the potential to be produced as fast, simple, easy-to-use, and low-cost devices.

Nanotechnology has been adapted to two separate fields of agri-food pesticides: as a pesticide delivery vector for pesticide management and as a trace-amount detector for pesticides. In the first field, nanoparticles are able to slowly modify pesticides to target insect pests, which helps prevent groundwater and topsoil pollution, reduce pesticide levels and improve efficiency. In the second field, bio- or biomimetic-based nanotechnology, like antibodies, enzymes, aptamers, and MIP-like macromolecules, improves stability, selectivity, sensitivity, and speed of detection. Furthermore, bacterial, fungal, algal, and mammalian cells are all cell-based biosensors used in pesticide and herbicide detection, helping to establish fast, reliable, real-time, and cost-effective tools for decontamination procedures and preventive casualty damage.

Carcinogens, odorants, and marine contaminants are other toxins that are significant in food production. Carcinogens are a complex group of trace amount of toxins, like pesticides, heavy metals, mycotoxins, and acrylamide, in which the difficulty of identifying trace-amounts is a challenge; and imprinted aptamers, nanotechnology, and biosensing are optimistic for promising future use. Sensitive and soluble molecules effective in odour detection for olfactory animal systems are odorant binding proteins. A nanosensor combining localized SPR and small odorant binding proteins from honeybees has been established in which the detection range is 10 nM – 1 mM using a quantitative array of nanocups. To monitor and preserve a stable environment for marine food systems, marine contaminant detection is used. Finally, through their sensitive detection capabilities, miniaturized devices, wireless communication, and small-scale networks, biosensors can be applied to marine food safety to be established as advanced analytical and monitoring tools.

Another development kit for food safety biosensors focuses on the detection of genetically modified organisms (GMOs) in food products. Since the 1990s, GMOs in all fields of agricultural products have been considered a biotechnology revolution. To present, more than 45 percent of the world’s soybeans, 40 percent of corn, and 50 percent of cotton are GM products; and GM is also used in livestock. Recent research, however, indicates that GMO products can affect human and animal bodies through gastrointestinal problems, antibiotic resistance, allergenicity, diversity of farm products degradation, and undesired gene flow to other species. Biosensors are designed to measure GMOs in foods and feeds using isothermal DNA amplification and fast detection signal detection to identify GM genes. Detecting unidentified DNA genes that can be resolved by high-throughput technology like the combination of biosensing and arrays, and the development of databases of GMO genes are the key challenges in GMO detection.

Biosensors & Biochips for environmental monitoring

Due to the strong connection between environmental pollution and human health/ socioeconomic progress, environmental monitoring has become one of the priorities on a European and global scale. Biosensors have been commonly used as cost-effective, rapid, in situ, and real-time analytical techniques in this field. The recent development of biosensors with new transduction materials obtained from nanotechnology and for multiplexed pollutant detection, involving multidisciplinary experts, explains the need for compact, fast, and smart biosensing devices. Several recent developments exist in the monitoring of air, water, and soil contaminants by biosensors under real conditions, like pesticides, highly toxic components and small organic molecules, including toxins and endocrine disrupting chemicals.

Biosensors used in environmental monitoring can be categorized as optical (including optical fibre and surface plasmon resonance biosensors), electrochemical (including amperometric and impedance biosensors) and piezoelectric (including quartz crystal microbalance biosensors) based on their transduction or as immunosensors, aptasensors, genosensors and enzymatic biosensors based on their recognition elements, respectively when are used antibodies, aptamers, nucleic acids, and enzymes. The majority of biosensors in environmental monitoring are recognized as immunosensors and enzymatic biosensors, but the development of aptasensors has recently increased due to the beneficial characteristics of aptamers, like ease of modification, thermal stability, in vitro synthesis and the ability to design their structure, to differentiate targets with different functional groups and to rehybridize.

Study on the design of biosensors for the monitoring of organic pollutants, potentially toxic elements and pathogens in the environment has led to the sustainable development of civilization due to the environmental pollution issues confronting human health. Various chromatographic techniques (such as gas chromatography and high-performance liquid chromatography combined with capillary electrophoresis or mass spectrometry) are conventional analytical methods used for environmental monitoring of pollutants, but they require costly reagents, time-consuming sample pre-treatment and costly equipment. Therefore, for monitoring pollutants responsible for adverse effects on habitats and human health, more sensitive, cost-effective, fast, easy to function, and compact biosensing devices are desperately needed to overcome the magnification of environmental issues. In the case of accidental release of pesticides or acute poisoning, for example, common methods are not appropriate for in situ measurements where fast, miniaturized, and portable equipment like environmental monitoring biosensors is required. In this regard, the role of nanotechnology in the creation of rapid and intelligent biosensing devices is crucial for the success of environmental pollutant detection; most recent biosensors include nanomaterials and novel nanocomposites in their systems, which are beneficial for improving analytical performance, such as sensitivity and detection limits.

For the detection and monitoring of different environmental pollutants, biosensors, including immunosensors, aptasensors, genosensors and enzymatic biosensors have been documented using antibodies, aptamers, nucleic acids, and enzymes as recognition elements.

Pesticides

Pesticides are among the most significant environmental pollutants because of their large presence in the environment. Organophosphorus insecticides, for example, are commonly used in agriculture and represent a group of pesticides which, due to their high toxicity, are of immense environmental concern. Easy, responsive, and miniaturized in situ methodologies like biosensors have therefore been established as analytical strategies for their detection and monitoring, without the need for comprehensive sample pre-treatment.

Disposable amperometric enzymatic (acetylcholinesterase) biosensors were proposed for the detection of organophosphorus insecticides using paraoxon as a model analyte applying a cysteamine self-assembled monolayer on gold screen-printed electrodes. The disposable biosensors showed a linear spectrum of up to 40 ppb with a 2 ppb detection limit and a 113 μA mM cm^-2 sensitivity. Using the self-assembled monolayer, good analytical output could be due to the highly oriented enzyme immobilization. Recoveries of 97 ± 5 percent (n = 3) were reported after being tested in river water samples spiked with 10 ppb of paraoxon, indicating the effectiveness of such enzymatic biosensors. Furthermore, the use of disposable screen-printed electrodes dispenses with time-consuming methods like the reactivation of immobilized enzymes utilizing, for example, obidoxime solution and pralidoxime iodide (PAM) or the use of the renewable enzyme membrane needed for the second application of biosensors.

Nanoparticles based on iridium oxide have been used in the disposable enzymatic biosensor with tyrosinase based on low-cost screen-printed carbon electrodes for the detection of chlorpyrifos in river water samples. Linear biosensor response (0.01–0.1 μM) and low detection limit (3 nM) were reported, which could be due to the high conductivity of nanoparticles of iridium oxide and tyrosinase efficiency. Recovery tests were carried out in river water samples with the addition of 0.1 μM of chlorpyrifos and recoveries of 90 ± 9.6 percent were obtained with a residual standard deviation (RSD) smaller than 10 percent (n = 3) to demonstrate the applicability of the biosensor.

Acetamiprid was detected by colorimetric aptasensors and water samples by impedimetric aptasensors in real environmental samples, like fresh surface soil samples. A linear range of 75 nM to 7.5 μM and a detection limit of 5 nM were observed with the colorimetric aptasensor, while a wider linear range (50 fM to 10 μM) and a lower detection limit (17 fM) were observed with the impedimetric aptasensor. Gold nanoparticles, multi-walled carbon nanotubes (MWCNT) and reduced graphene oxide nanoribbons were used in that biosensor as a composite to sustain the electrode surface acetamiprid aptamer, which could be responsible for higher electron transfer and improved analytical performance of the biosensor. A related detection limit (33 fM) was observed by an aptasensor based on silver nanoparticles anchored on nitrogen-doped nanocomposite graphene oxide constructed for acetamiprid detection in wastewater samples.

Pathogens

The existence of pathogens in environmental matrices, and especially in water compartments, could pose a serious risk to human health, and some biosensors have recently been suggested for monitoring the environment. For example, for the detection of metabolically active Legionella pneumophila in complex environmental water samples, rapid and precise optical biosensors based on surface plasmon resonance have been proposed. In one study, the detection principle was based on the identification of bacterial RNA by the immobilized RNA detector probe on the gold surface of the biochip. For signal amplification, streptavidin-conjugated quantum dots were used, and the detection period was approximately three hours, indicating the viability of the biosensing device for successful bacteria detection in the range of 10⁴-10⁸ CFU mL^-1.

Potentially toxic elements

The contamination by heavy metals and corresponding ions of the natural waters can pose significant risks to human health, and compact, low-cost, and rapid heavy metal analyses are a global priority concern. As a model target for testing an optical DNA biosensor for the detection of heavy metal ions that are extremely toxic and common pollutants in the environment, mercury ions (Hg²⁺) were used. The biosensor was compact, low-cost, and rapid with in situ screening of Hg²⁺ in natural waters in less than 10 min. The detection principle is focused on the capacity of certain metal ions to bind selectively to certain bases to form stable metal-mediated DNA duplexes; in the case of Hg²⁺, thymine bases can be selectively coordinated to form stable thymine-Hg²⁺-thymine complexes. In the detection range between 0 and 1000 nM, a detection limit of 1.2 nM was achieved, which is lower than the maximum value requested by the United States Environmental Protection Agency (10 nM)

For the detection of Pb²⁺ in water samples (pond and lake water samples) using DNAzymes/carboxylated magnetic beads and DNA aptamers, two fluorescence based optical biosensors have recently been suggested. The detection limits of 5 nM and 61 nM, respectively, were observed by biosensors based on DNAzymes and DNA aptamers, with a respective linear detection range of 0 to 50 nM and 100 to 1000 nM. The use of label-free unique dye (SYBER Green I), which was intercalated with double stranded DNA, showing strong fluorescence intensities, as seen in Figure 5. Moreover, the absence of biosensor fluorescence intensity is observed only with the dye (curve a). With the DNAzyme + Pb²⁺ (curve b) the fluorescence intensity increases with the addition of the dye + DNAzyme + Pb²⁺, illustrating the sensitivity of the biosensor towards Pb²⁺.

Figure 5. Fluorescence emission spectra for detection of Pb²⁺

Toxins

Harmful toxins like brevetoxins and microcystins are created by the eutrophication of aquatic systems by the algal blooms of cyanobacteria, and thus accurate and cost-effective systems are needed for the early detection of such toxins. For the sensitive detection of brevetoxin-2, a marine neurotoxin, an electrochemical aptasensor has been used composed by gold electrodes functionalized with cysteamine self-assembled monolayers. A detection limit of 106 pg mL^-1 was achieved and strong selectivity was observed for brevetoxin-2 against other toxins of various groups, like okadaic acid and microcystin. The feasibility of the aptasensor for detecting brevetoxin-2 in real samples was achieved by analysing shellfish and strong recoveries (102-110 percent) were reported, indicating no interaction with the aptasensor response from the shellfish matrix.

Endocrine disrupting chemicals

In water samples, bisphenol A was detected as an endocrine disrupting chemical by aptasensors based on the fluorescence principle with functionalized aptamers (fluorescein amidite) and gold nanoparticles and based on evanescent-wave optical fibre. The evanescent-wave optical fibre aptasensor was compact and found to be rapid, cost-effective, sensitive and selective for the detection of bisphenol A in water samples, with the benefit of no requirement of any pre-concentration or treatment steps.  Furthermore, the aptasensor can be reused for 90 s by regeneration with a 0.5% sodium dodecyl sulphate (SDS) solution and further washing with a phosphate buffered saline (PBS) solution (pH 7.2) for over a hundred assay cycles without any noticeable loss of efficiency. Similar detection limits (0.1 and 0.45 ng mL^-1) were observed in both optical biosensors where the DNA molecule probe, which is the complementary sequence of a small fraction of the bisphenol A aptamer, was adsorbed by electrostatic interaction in the surface of gold nanoparticles and covalently immobilized on the surface of the fibre. Lately, for the detection of bisphenol A in river water samples using molybdenum carbide nanotubes, another fluorescence-based aptasensor was proposed. With such a label-free, inexpensive, and easy to use aptasensor, a low detection limit of 0.23 ng mL⁻¹ has been obtained. The specificity of the aptasensor was evaluated by analysing other molecules with structures similar to that of bisphenol A (e.g., 4,4J-biphenol, bisphenol AF, and 4,4J-sulfonyldiphenol) and only background signals showing high specificity for bisphenol A were identified for these molecules.

A disposable and label-free electrochemical immunosensor based on a field effect transistor with SWCNT has recently been employed in seawater samples for assessing another endocrine disrupting chemical – 4-nonylphenol. The immunosensor has a high reproducibility (0.56 ± 0.08%), an average recovery of 97.8% to 104.6% and a low detection limit (5 μg L^-1), which is lower than the recommended maximum concentration of 7 μg L^-1 specified by the corresponding regulations. In seawater samples such as 4-nonylphenol, the biosensor could be used to detect hazardous priority substances, even at low concentrations and with an easy and low-cost methodology.

Other environmental compounds

New, fast, and accurate analytical methodologies have been needed for the early detection and monitoring of various other hazardous compounds liberated during algal blooms. Due to the excellent sensitivity and specificity of nucleic acid probes to their complementary binding partners, biosensors have been developed to detect algal RNA. For the enhanced selective and sensitive detection of RNA from 13 harmful algal organisms, an electrochemical genosensor based on screen-printed gold electrode was recently reported; the genosensor could distinguish RNA targets from environmental samples (spiked seawater samples) containing 10⁵ cells, considered to be the limit of detection.

Biotechnology is a modern advanced technology grounded on science disciplines like molecular biology, biochemistry, cell biology. It accepts a lot of new techniques such as cell and tissue cultivation, cell fusion, gene recombination, microbial fermentation, and also duplication and recombination of organisms at a cellular, chromosomal, and gene level.

Biotechnology is a modern advanced technology grounded on science disciplines like molecular biology, biochemistry, cell biology. It accepts a lot of new techniques such as cell and tissue cultivation, cell fusion, gene recombination, microbial fermentation, and also duplication and recombination of organisms at a cellular, chromosomal, and gene level. In this way, it can make organisms answering to human needs, produce new products and breed new plants having novel features of high output and stress resistance. Modern biotechnology is composed of four technological systems. They are genetic, cell, enzyme, and fermentation engineering, of which genetic engineering and cell engineering are the most advanced ones.

Besides the great social and economic benefits of modern biotechnology, there is a possibility it to harm human health and the environment. This can result in many socio-economic problems, such as destroying original social and economic patterns, posing threats to biodiversity and traditional crop varieties, injuring countries or communities’ socioeconomic welfare, violating traditional ethical, moral, and religious values.

The modern biotechnological practice in the production of fiber, pharmaceuticals, and food has a powerful development of the late 20th and beginning of the 21st century. This emerging technology is often accepted as the next technological revolution possessing the potential to change fundamentally the way of societal arrangement regarding production and distribution of goods. Considerable investments have been already made in biotechnological research for new products’ development. Currently, science and technology are expected to bring consumers a big variety of genetically modified (GM) products. Besides, many GM products have already entered the food distribution chains. Despite its promise to bring significant benefits to society, public acceptance of modern biotechnology is quite diverse at the world dimension. To enable biotechnology to contribute major benefits for human beings, the international society has paid serious attention to the biosafety of the overall biotechnological production to promote its better acceptance.

Nowadays, biotechnology has been classified into few categories based on its applications. They are depicted in Fig. 1

In general, biotechnology intends to emphasize the potential benefits to society through reduction of hunger and malnutrition, suspension and healing of diseases, and increase of health and general well-being. On the other hand, there is an opinion that GM products are used as a needless interference with nature and can cause unknown and potentially disastrous consequences. At the same time in the U.S., GM crops entered the grain supply chains without raising major public concern. Besides, agricultural biotechnology is facing significant opposition in Europe and many other developed countries. Regarding the obvious public troubles about the perceived risks for humans and the environment, European Union (EU) accepted rather limited regulations on all transgenic crops in any part of the EU food system. At a global level, the situation is even more diverse: in the U.K., objection movements throw down GM crops on different occasions. Until recently, Brazil and India refused to approve any GM crop. Due to similar consumer concerns, some fast-food supply chains decided not to use GM potato in their products.

The reason against the use of gene technologies in agricultural production is grounded on the fact that some people and institutions see risks to humans and the environment, while others oppose it minding moral, ethical, and social concerns. Biotechnology frequently is running down because of its tools’ application in plants and animals, especially gene transfer across species, based on understanding “realms of God” and against “Law of Nature”. Also, there is an opinion that since genes are naturally occurring parts, which are an object of discovery (not of invention), patent ownership of genetic findings and processes is morally and ethically insolvent.

Public discussions on agricultural biotechnology also pose some social and political debates. There is a talk concerning the application of modern genetic technologies in production of commodities in developed countries that are currently imported to developing countries. It is claimed that such developments will have significant negative effects on the poverty situation in the Third world and will lead to global instability. At the same time, other researchers have the opposite opinion. Another source of care is the possibility that farmers will become steadily dependent on multinational corporations for their “means of production” bringing harmful economic, social and political effects.

The importance of this subject defines the need for a full understanding of public interests and concerns regarding an agreement between private and public decisions concerning food biotechnology. Consumer acceptance of biotechnology is strongly related not only to expected risks and benefits associated with GM products but also to their moral and ethical dimension. Further, public views about multinational corporations, trust in government, science, and technology development also reveal their attitudes towards biotechnology. It is found that consumers’ cognitive factors (e.g., levels of risk aversion, opinions about GM foods) impacted the acceptance of GM food products, while the socio-economic factors did not have significant effects. Thus, the public perceptions of biotechnology possess a lot of dimensions and are possibly affected by multiple forces, preferences, and events. For instance, positive benefits (e.g., nutritional benefits from improved/new products, environmental benefits via reduced use of pesticides, etc.) can encourage consumer acceptance of food biotechnology. On the other hand, sensibility about risks to humans and the environment is expected to have adverse effects on public acceptance of GM products. Thus, the activities to analyze and determine the factors influencing consumer attitudes towards biotechnology have to follow the procedure, denoted in Fig. 2.

Societal Impact

To evaluate the impact of modern biotechnology on society, it is not enough only to measure it by specific indicators. When the focus is on such dimensions like increase the number of patents on genetically modified organisms (GMOs), this will not indicate the dynamic forces shaping the impact of biotechnology on industrial and societal structures. The impact analysis is combining complex problems and has a variety of diverse inputs, which possess both short- and long-term effects and influence the results of the problem or use of technology, in an unrespecting way. To realize the sense about the nature of links between societies, individuals, and the balance of forces between social groups facing new technologies is of basic importance.

Establishment and spreading of knowledgeSocietal Impact

A starting point is the result of the technological impact, which depends upon the establishment and spreading of knowledge. It is regarded as preferred values, social practices, and norms of behavior of involved actors in the development and use of biotechnology. The knowledge extends beyond the collection of information on biotechnology, such as techniques, risks, etc. It also embraces the way they are shown and commented on by individuals. Risk and safety for the public cannot be assayed in the same manner as scientific risk is done. To account for these differences, it is necessary to explain how trust is created between consumers and manufacturers. In brief, such a definition of knowledge gives a piece of analysis on the impact of biotechnology and more broadly, environmental policies and practices.

From a conceptual point of view, this approach could be treated as a knowledge-based discourse. It is useful considering the expression of the biotechnological impact in the sense of the educational, social, and political background. The environmental discourses of biotechnology knowledge, and more specifically, how it is constructed, accepted, and perhaps most importantly, spread and sustained within society are taken into account as well.

Science and Technology (S&T) impact on society

In the EU there is a discussion on biotechnology and especially concerning genetic engineering and impacts arising from this technology. This issue has to be addressed strongly linked to the result of social interactions. Therefore, the way of realization of these dynamic forces should account for the interrelations and the form of resulting complexity between actors.

Another point to estimate, are two major topics when examining potential technology impacts. These are i) the immediate impact of the use and development of the technology and ii) the technology transcending risks. That means dependence on the long-term application of the technology and how to achieve and sustain a dominant position in its impact upon society from education, political and social perspectives. This could be sustained generally through more concern about the long-term consequences of S&T activities noted below:

– Publication of educational efforts in society: Performance of intensive efforts to include scientists, key public opinion leaders, and media in an existing debate on biotechnology and especially about genetic engineering. The core objective is to avoid an informational vacuum, which can facilitate anti-biotechnology activity and generate negativism in knowledge structures.

– Role of regulatory policy in society: Focusing on effective risk communication and understanding the fact that the public perception of risk can be very different from that of the scientific community.

Perception of modern biotechnology applications

Three major topics are identified and based around: i) the science, ethics, and gender of biotechnology ii) the International political economy, trade, and the environment; iii) the state and system security and warfare through biotechnology. These general themes are coming from consideration for the international relations of biotechnology. They imply the concept of power in the International Political Economy (IPE) to frame the differing discourses and complex issues of technology impacts. Based on these topics the several indicators are regarded (Fig. 3):

Modern biotechnology is regarded as a complex emerging field that exhibits high science combined with limited knowledge of part of the society. It is related to attitudes towards the natural environment, technological progress, religious and moral beliefs, and several other sets. A matrix of variables including interest of the public domains, such as science and politics, optimism about technologies, social and cultural values, engagement with the issue of biotechnology and confidence in the industry, regulation, and other civil society groups, all these factors contribute to the public’s representation of and opinions about biotechnologies (Fig. 4). Background characteristics such as gender, education, age, and religion have been found to affect people’s attitudes as well.

The serious debate on the acceptance of genetic engineering is accompanied by many pieces of evidence that object to the focus on specific applications of the technology than genetic engineering per se. Studies are showing that consumer attitudes regarding gene transfers are influenced by the type of transfers. The range of acceptance encompasses the following: i) plant to plant gene transfers; ii) animal to animal transfer; iii) animal-plant or human-animal, the last being least acceptable.

A survey on perception on modern biotechnology applications, performed among people from different countries/continents indicated that medical applications (leading to the development of medicines and vaccines, and genetic testing) are very much acceptable in comparison to food or crop biotechnology applications. However, medical applications linked to xenotransplantation or animal cloning for milk production meet serious problems. The Asian people, for instance, are less troubled for medical genetically engineered products than for genetically modified food. The investigation concerning cloning of human cells and bioremediation among the Europeans is put at the intermediate level, less assumed than genetic testing but better confessed acceptable than genetically modified crop and food.

Another survey reported that genetic testing still scored the highest support within the European population, followed by human cell cloning, the production of GM enzymes for environmentally friendly soaps, and xenotransplantation, At the bottom of this range are placed GM crops and food. Also, higher support is given to technics for the manipulation of bacteria to clean oil spills followed by disease-resistant crops; afterward are applications for fat meat and better taste tomatoes and the less support receive technologies for enhancing milk production in cows.

The Malaysian consumers are more open for use of modern biotechnology applications, which do not involve inter-species gene transfers, like food production and GM crop that only involve the transfer of plant genes. For them, the gene modifications are more acceptable in the following order: i) transfer oil palm genes to reduce its fat (saturated) content, ii) transfer human genes into bacteria to produce insulin, iii) transfer bacterial genes into soybean to make it resistant to herbicides.

An individual’s attitude towards a new technology depends on several related factors such as his/her perception of its risks and benefits, and socially communicated values and trusts in institutions representing these technologies. Concerning public perception of biotechnology, it is speculated that the attitude to genetic engineering is determined by the worth of potential benefits offered, knowledge on genetic engineering, and scientific world-view, from which the perceived risk (rational worries) and anxieties or fears (irrational worries) must be excluded. Additionally, various minor factors such as background factors must be added. It is considered that the main effect on acceptance seemingly is based on the knowledge level, awareness of benefits, confidence, and trust.
The studies of public attitude towards biotechnology indicate a lot of similarities with risk perception studies. Some authors have used the psychometric approach based on cognitive psychology and it is accepted as the most mature and dominant paradigm in risk perception studies. These psychometric methods are settled on the ground of the following views:

• To perform “risk” as a subjective idea, and not an objective one;
• To involve technical/physical and social/psychological outlooks in risk criteria;
• To take opinions of the “public” (i.e., laypeople, not experts) as the subject of interest.

Thus, the public acceptance of modern biotechnology is based on analyzing the cognitive structure of risk judgments, commonly using multivariate statistical procedures like factor analysis, multi-dimensional scaling, and multiple regression. This psychometric approach assumes that the public does not perceive technological risk due to a single dimension linked to expected injuries or fatalities close to a risk assessor’s viewpoint but interprets risk as a multidimensional concept, concerned with broader qualitative dimensions.

The key varieties of a risk perception study are the perceived magnitude of risk or dread, risk acceptance, familiarity with the hazard, and at least – the factor benefit. The importance of another dimension, ‘interference with nature’ in risk perception studies on genetic engineering is also very important.
Biotechnology is at the confluence of science and ethics. The development of technology is linked with an ethical vision, which in turn is shaped by specific issues. Loads of biotechnology can be evaluated for their benefit to human society. But it has to be considered that biotechnology has also a dangerous part. It can provoke unanticipated consequences, which can cause harmful effects or dehumanize people. So, the ethical issues of proposed effects must be carefully investigated.

The ethical evaluation of new technologies, including biotechnology, requires a different approach to ethics. There is a necessity for changes because a new technology can have a more profound impact on the world due to i) restrictions to a rights-based ethics approach; ii) the importance and difficulty of predicting consequences; iii) opportunity now to manipulate humans themselves.

The ethical questions concerning biotechnology are very different. Due to the potential for deep change in the human future, such questions must be carefully considered. In the first place, it is necessary to articulate and predict the responsibilities towards nature and others, including future generations, and then to focus on rights and freedom. The real power and potential of biotechnology require strong caution to ensure ethical progress, as biotechnology is accepted as a significant force to improve the quality of people’s lives in the 21st century.

Biotechnology is intrinsically linked to science and scientific knowledge. But sometimes there is doubt that biotechnology is closely tied to ethics. Lastly, different biotechnological trends are promoting a certain vision of life, some of which are good for life and deserved to be encouraged or pursued but others are bad and should be eliminated. This vision impacts people’s choices and influences their sense of ethically appropriate biotechnology.

At times, the link between biotechnology and ethics is described as a conflicting point. Once, there is an impression that ethics is needed only in case one wants to tell others that they are doing wrong things. To a certain degree, this is lucid, since dispute, debate, and argument are common parts of ethics consultation. But ethics is just as important in the case of consensus that the chosen pathway is good and right. Of course, there isn’t any necessity for an ethical debate when the search is a cure for cancer. Thus, the solution to perform such a search is predicted by a common understanding that to cure cancer there is an ethical reason. The efforts, resources, and creativity devoted to working out better treatments are ethically eligible and the majority of these achievements due to biotechnology.

The societal acceptability of benefits and risks imposed by modern biotech applications concern:

• Benefits vs. risks societal dispute
• Risk acceptance as a key element in risk perception
• Tools for measuring public attitudes towards risks and benefits: risk management

Benefits vs. risks societal dispute

To determine the acceptability of biotechnological applications it is very important to evaluate the perceived benefits and risks. The diagram on Fig. 5 summarizes them.

Risk acceptance

Another key variable is risk acceptance which is important to measure risk perception. But it is rarely used in attitude towards biotechnology studies. Highlighted the harsh situation with modern technologies, they are always linked with some kind of risks that pose serious problems for societies. Policy-makers have considered cost-benefit analysis as the basis of decision-making methodology for societal risk acceptance. The core question to be solved in the risk-benefit analysis is: whether this product (activity, technology) is eligible safe or how safe is safe enough? There are two main approaches for performance of risk-benefit analysis (Fig. 6).

Risk Management

The management of risk is the process that aims to diminish the effect and to balance the way people respond to it. If one wants to push away all risks, this is not a viable goal. People readily take risks performing a wide range of activities. Thus, the question about the acceptable risk is not entirely technical; its answer depends on values. In a simplified way, it is possible to set a simple threshold for acceptable risk, for instance – one in a million-lifetime risk. All the activities riskier than this threshold are “unacceptable “as well as all those less risky are “acceptable”.

However, there are two reasons why this approach is not working. The first is linked to the above-mentioned risk perception. The people are not reacting to risk simply; the acceptability of risk in the public’s mind is not simply a matter of the presumable fatal things but involves other elements of the activity. For instance, if the activities are taken voluntarily if the process leading to the risk is new/old or familiar, if the process provokes an intuitive, emotional dread reaction or not. That is why, to define an acceptable risk, the processes of risk communication and engagement described above must be included. In the second issue, some activities are essential and must be encountered even if they cause relatively high risks.

Besides, there could be other cases where inexpensive alternatives exist to perform less risky or modified activities. In these cases, the risk might be well predicted as unacceptable, due to ready alternatives. This is an economic issue that deals with several resources dedicated to risk reduction. Besides the economic problems, it is possible to consider risks, not in terms of absolute values but to their internal differences between alternatives.

However, very often it is not possible fully to escape risk; rather one must choose among different risks. Therefore, no definite acceptable threshold of allowable risk exists, as well as there is no single convenient monetized value for risk diminution. Societal desire to invest in risk reduction depends on the wide range of factors that manage risk perception, like the fear associated with the risk, its catastrophic potential, etc.

Social benefits of modern biotechnology

Biotechnologies are being used widely in such fields as medicine and hygiene, agriculture, forestry, breeding, fisheries, energy and chemical industries, metallurgical and mining industries, food, and light industries, environmental protection. Modern biotechnology has gradually demonstrated its huge potential contribution to productivity, though it has a short history of only tens of years so far. Modern biotechnology will become powerful means to reduce the world’s constraints in the fields of food, health, energy, resources, and the environment. The development and application of modern biotechnology will, over a long time, affect human beings and society deeply.

Biotechnological industries are likely to become the leading industries in the 21st century. For example, crop varieties, produced by biotechnology, with novel traits of high productivity and stress resistance (aridity, coldness, high salt, etc.) are expected not only to increase grain production but also decrease the use of agricultural chemicals (such as pesticides, herbicides, and fertilizers), which will be beneficial to the environment. In the respect of medicine and hygiene, many drugs such as DNA vaccines, protein engineering medicine, monoclonal antibodies, anti-sense RNA drugs have been developed by biotechnology. Transgenic animals and plants producing some kinds of medicines (such as vaccines and hormones) may help to reduce illness in the process of everyday diet. Human Genome Project (HGP) and the research into some disease genes will discover the genetic reasons for some illnesses. Environmental pollution is getting worse at present, but biological transformation reactors created by biotechnology promise to absorb pollutants or wastes and decompose them into materials of low or no toxicity.

Therefore, in the present society characterized by knowledge-intensive industries, countries all over the world, especially the industrialized ones, take biotechnology seriously. Large quantities of manpower and financial resources are allocated to R & D in biotechnology. Relevant development strategies and policies are drawn up and support mechanisms created to stimulate the development of biotechnology.

Although there have been many studies on public attitude or perception towards biotechnology and some researchers tried to identify factors predicting attitude using either regression or correlation, there are limited studies that try to construct a structural model predicting attitude towards biotechnology.

The first documented model was developed by Kelley (1995) who proposed a structured way for the approval of genetic engineering by the Australians (Fig. 7). Later, Pardo et al. (2002) proposed another model for explanation of European attitude towards biotechnology applications. Kelley found out that approval of genetic engineering was mainly predicted by agricultural and health goals (beneficial aspects). On the other hand, scientific and genetic engineering knowledge did not predict approval. Demographic variables also did not directly affect the approval of genetic engineering (their effects were not statistically significant). Gender was found to affect knowledge and scientific world-view while age was found to affect knowledge, goal, and scientific world-view, thereby exerting a very weak (indirect) effect on approval. Education had a large effect on knowledge but not concerning attitudes. Occupation and religion did not have any effect on any of the intermediate variables. Green supporters were less favorable to genetic engineering (negative direct effect on the approval of genetic engineering) as compared to Labor Coalition supporters (politic).

It is often speculated that biotechnology is the technology to deeply transform the economy and society. Following such opinions, the development and application of biotechnology have considerable potential for far-reaching economic, social, and environmental impacts. That is why biotechnology is of strategic importance to knowledge-based economies and their governments. Nations that failed to develop biotechnology capabilities fail in realizing economic impacts.

Biotechnology-related applications are diffused over several very different industrial sectors, e.g., food production, textile finishing, pulp and paper, agriculture, power generation, chemicals and petrochemicals, and pharmaceuticals. The products manufactured by these sectors do not usually distinguish between alternative production processes. Thus, for many products, a distinction between biotech and conventional (e.g., chemical) production processes and also the introduction of some new ones would be necessary. Moreover, biotechnology is a dynamic field and certain biotechnological production methods will probably soon be re-developed, and completely new, products will appear. Current official statistics and existing companies’ surveys can provide specialized information about the diffusion of biotechnological applications, and their economic impact. The data have been constantly renovated and different techno-economic studies are performed to provide future production foresight and scenarios. Applying a blend of methods and sources, they frequently focus on expert judgment, case-studies, and various statistics.

An alternative to measuring the diffusion of biotechnology in use for major manufacturing sectors is the biotechnology-related-sales (BRS) concept. Existing studies have used various approaches for measurement (definition of the biotechnology aggregation level, examined sectors, scenario assumptions, etc.). Moreover, to assess the impact of biotechnology diffusion, an input-output model and relevant indicators have been introduced to study its effect on employment. The model studies in a comparative manner how biotechnology is affecting major application sectors. It compares the market penetration in 2004 and 2020 through the diffusion rates, measured with upper and lower limits. This approach helps not to overestimate the impact of biotechnology while capturing certain innovative biotechnological applications. The data of this survey indicate a nearly similar diffusion pattern in pharmaceuticals, food-processing, and agriculture. Diffusion is expected to increase in all sectors greatly by 2025, as indicated by the penetration of certain product groups. However, it was shown that there is a serious level of suspicion about the diffusion of biotechnology; the expectations for 2025 are highly uncertain. The analysis of this tendency, indicate that there are diffusion barriers specified in Fig. 7.

Figure 7. Main barriers interfering Biotechnology diffusion

Socioeconomical Impacts

Motivated to perceive great economic profit, a lot of famous international business corporations made considerable investments of capital in the R & D of biotechnology, and in this way are changing the previous world’s social and economic trends. Such an example is the company Monsanto (formerly US-based, and now a part of the global consortium BASF). Traditionally working in the chemical industry, after 1985 the company made serious business rearrangements, invested in 3 biotechnological sectors, and became a major consortium dealing with R & D in bio-science. After 1998, about 20 million hectares of fields all over the world were planted with Monsanto’s GM seeds. Soon after that, Monsanto took an advance on the crop seeds international market through a completely integrated system for trading GM seeds and agricultural chemicals. In this way, Monsanto received control on a big part of the human population food chain gaining tremendous profit feeding them with GM crop. This is an example of how in the current globalized world, a possibility for a few multinational corporations to decide on human food consumption emerges.

In the case of use in dairy, bovine growth hormone (BGH) produced by genetic engineering, the milk yield of a dairy cow can increase by 30 percent., which means 10 percent less fodder usage. So, the result is very impressive for the dairy industry.

A lot of medicines, like vaccines for treating malaria and cholera are provided to patients via new antigens synthesized through modern biotech methods. They make the rates of illness and death in many countries (especially in the developing ones) falling rapidly, concurring the population growth rates. In this context, a question arises about the impacts on the already insufficient economics and infrastructures of the said countries.

Impacts on biodiversity and sustainable agriculture

Many GM crops contain foreign genes from other plants, animals, and microbes. All these foreign genes can be transferred to other plants in nature through the pollens of genetically transformed plants and will cause pollution to the natural pool of genetic resources. Hence, as the majority of transgenic plants possessed economically useful features, like high productivity, disease-pest resistance, stress resistance, and farmers are attracted to economic interests to grow these plants rather than traditional crop varieties, the predicted danger for the natural resources is serious. Also, the technologies for breading of a monoculture of crop varieties in some fields may add to the loss of biodiversity. So, in a long term, this degradation of the genetic base may reduce the natural resistance of plants to diseases and insect pests and this may cause diminish in the crop yields. In this way, the global sustainable development could be compromised.

Bacillus thuringiensis (Bt) is a soil bacterium, which is used to synthesize a toxin against insects within plants. It has been used as a microbial pesticide for many years and the genes coding these insecticidal toxins could be introduced in the cell of many crops such as cotton, soybean, and rape, to create pest-resistance crops. In this case, the experts in environmental protection and the Green Peace Corporation are troubled by the fact that the toxin production is realized in the late life cycle of the transgenic plants and there is an opportunity to increase commonly the resistance of pests to the Bt toxins. So, this situation would lead to bigger usage of Bt-based pesticides, due to loss of their efficacy and causing heavy economic losses.

Impacts on public welfare

The exploitation of genetic engineering technology to humans could facilitate the diagnose and cure of genetically related diseases such as some cancers, hemophilia, etc. But such gene diagnosis may also have an opposing effect on the employment and marriage prospects of human beings. Through genetic engineering animals, plants and microbes can be transformed into bio-factories for the production of different kinds of chemicals. Thus, they can be treated as constant biological producers and at the same time, the rising potential for products outcome can cause socioeconomic problems. Assume that specific microbial strains are engineered to produce a valuable substance on large scale. In such a case, it is important to forecast the impact of this production on the world’s major producers of the same substance. If this substance counts for a significant percentage of the income of a given country, what would be the influence and consequences of this biotech production on the country’s agriculture and financial infrastructure.

Inconvenient application of biotechnology can cause many risks, like other advanced technologies. For instance, the newly introduced genes in crops made by genetic engineering can lead to allergic reactions. The economically important features of pest-resistance, herbicide-resistance, or stress-resistance, introduced in plants may get these transgenic hosts away from agricultural cultivation systems. The genes for resistance in transgenic plants can be transferred to their wild weedy relatives, and the latter can be transformed into “super” weeds, which control will be very difficult. Thus, the large-scale releases of transgenic pest-resistance crops into the environment will cause severe selection pressures to enforce the resistance of target pests.

The transgenic virus-resistance plants that are already transformed with foreign virus genes possess virus-coded proteins that may recombine with the genetic material of other viruses to yield new types of viruses with higher toxicity. If the selective killing of the target pests and pathogens is not possible, the transgenic pest-and-disease resistance crops can at once poison other organisms and also may cause harmful action via food chains on beneficial microorganisms, insects, birds, and mammals.

Moreover, many biotechnological products are alive organisms and can move and reproduce by themselves. Once they are released into the environment and are proven to be toxic, then it is nearly impossible to discard them, and the harm they create can rise with time becoming more and more serious. In this way, environmental releases of transgenic plants on a large-scale may damage the natural ecological balance in a longtime perspective.

Biosafety concerns have hindered the R & D applications of biotechnology. The public in lots of countries has signified its negative opinion, repulsion, indeed dread regarding biotechnological products. This is voiced even through demonstrations, crushing fields crops, banding the import, or baying the biotechnological products. This makes the biosafety issues at the very top of the agenda of many countries and international societies. Laws and regulations on biosafety are formulated in many countries, and biosafety issues are regarded in many international documents and treaties, like Agenda 21 and The Convention on Biological Diversity.

Biotechnology is on the way to become seriously relevant to the economy and can gain considerable importance in several application sectors in the next 10 to 15 years. However, the overall effects of modern biotechnology on the economy are quite diverse. For instance, employment estimations show that increasing the part of biotechnology in application sectors and its link to suppliers indicate the trend for reduction of employment due to productivity effects. The economic importance of biotechnology rises because of its diffusion in mature manufacturing sectors. However, diffusion in these main application sectors can influence only limited parts of overall employment. Only if biotechnology increases in other sectors might a major economy-wide impact emerge.

The deepness of biotechnological transformation of the economy depends strongly on its potential to propose the creation of new products and to improve the efficiency in the production of existing ones. Hence, it is expected that biotechnology would enable the creation of many products but the potential to raise labor productivity is estimated to be restricted. One important view is that biotechnology may transform the economy and society differently, cooperating with other technologies like ICT. Major boosts for such economic growth may emerge in combination with other technologies or efficiency gains, which raise productivity and purchasing power to realize the fruits of biotechnology.

Synthetic biology is a recent extension of biotechnology in which genes and proteins are viewed as parts or devices, with the goal of rearranging and/or assembling these parts in novel ways to create new and useful functionality.

Introduction

In 1997, the cloned sheep Dolly was presented to the world public. Since then, the topic of cloning has repeatedly made the headlines. She has three mothers and no biological father. She is genetically identical to one of her mothers. She is the first cloned mammal that is not the result of a new combination of father and mother, but was conceived from a body cell of one of her mothers. But while in Dolly’s day some researchers vehemently opposed the cloning of human cells, today they themselves work with embryonic stem cells in the hope of someday combating diseases such as cancer or Parkinson’s disease. Cloning, then, in the context of medicine, biotechnology and molecular biology, is the production of entities, individuals and populations that are genetically identical or nearly identical to the original organism or part of an organism from which they are derived. In its spontaneously occurring form, cloning is the way bacteria and some plants and animals reproduce asexually.

The most dramatically controversial area is human cloning for reproductive purposes, i.e. to produce babies that will grow into full-grown adults and full members of their society. Research on human embryos, including cloning with nuclear transfer, is widely permitted fourteen days after conception; and the subsequent cultivation and scientific and therapeutic use of human embryonic stem cells is accepted in most countries (not all). Human reproduction is at the heart of the cloning issue, ethically, with the ideas of design and the historically ever-popular theme of improving individuals and improving the human race.

Artificial cloning exploits the potential of particular, undifferentiated cells to differentiate into cells of a particular type under appropriate conditions. These cells are called stem cells. They are found both in small numbers in the body of an adult, to replace missing or dead cells there, and in early embryonic stages, from about the fourth to the seventh day after fertilisation. Only the e Only embryonic stem cells up to about the eight-cell stage can still develop into all tissue types and thus into a whole organism; they are totipotent (= omnipotent). In contrast, no whole organism can be formed from all other stem cells. They can only give rise to many different cell types or only one specific cell type, they are pluripotent or multipotent.

Biomedical research and application

Clones of higher organisms are of great interest for biomedical basic research as well as application-oriented medical research. Currently, four main possible fields of application of nuclear transfer-based cloning for medical purposes are being discussed. A first area is so-called gene pharming, i.e. the use of transgenic animals to produce therapeutically useful (human) proteins, e.g. in milk. In the foreseeable future, this will be one of the main potential applications of nuclear transfer-based cloning, as it makes the production of the corresponding transgenic animals more effective and targeted compared to conventional methods. Advantages of these active substances obtained by biogenetic manufacturing processes, such as insulin or blood factors or other human endogenous substances, are that these active substances can be obtained in a much purer way than in the conventional method via animal and human intermediates. If such animals are available, active substances can be produced in large quantities and relatively cheaply. However, there are also risks for the animals due to the genetic (transgenic) manipulation, the biological activity of the protein produced and the cloning process itself. Risks for humans can arise from changes in the products as well as from possible disease (pathogen) transmission, so they must be ruled out as far as possible by careful drug testing.

Another area where cloning could potentially be used is in the production of transgenic animals as animal models for human diseases. A major obstacle in the further development of animal models has been shown to be the fact that so far it has only been possible in mice to integrate genetically manipulated cells into the germ line of a recipient animal in such a stable way that the genetic changes can be inherited. However, the physiological and anatomical differences between mice and humans are so great that the symptoms of the genetic modification introduced in mice often do not correspond to the clinical picture observed in humans. Cloning by means of nuclear transfer using somatic cells opens up the possibility of inducing targeted genetic changes in different species (gene targeting and gene knockout). This would also make it possible for the first time to create disease models in transgenic large animals which, depending on the disease to be investigated, could be superior to previous mouse models in terms of anatomical, physiological or genetic characteristics. It is generally expected that in the medium term this will contribute to a better understanding of the clinical pictures of genetically caused human diseases and, based on this, to the development of effective treatment options. Cloning could also make a technical contribution to the transplantation of autologous tissue and to so-called cell therapy. The optimal transplant tissue is easy to characterise: its cells should be as genetically identical as possible to those of the recipient. The patient’s immune system would then no longer recognise it as foreign, and any problem of rejection would be eliminated. Therefore, an optimal solution would be to create genetically identical replacement tissue. Research results suggest that this could now be achieved by means of nuclear transfer-based cloning. In principle, another way of cultivating human replacement tissue is conceivable: With the help of the nuclear transfer method, an early embryo would be created, from which pluripotent embryonic stem cells could be obtained in culture. However, it has not yet been possible to obtain such cells in humans, even from embryos created in vitro. Moreover, such a procedure would require the ethically and legally highly problematic creation and utilisation of a human embryo, unless oocytes from animals could be used as recipients of the cell nuclei. But this development is still in its infancy and involves problems of its own, especially ethical problems that are also serious.

A fourth area in which the use of (transgenic) cloned animals is conceivable is xenotransplantation (transplantation of animal organs into humans). However, in order to construct “donor animals”, up to about a dozen genes would have to be altered in pigs, for example. This is practically impossible with conventional methods of genetic modification. Cloning could now make it possible to first provide cells in culture with the desired genetic changes before a multiply genetically modified animal could be created from them with the help of nuclear transfer-based cloning. But even if the “ideal” donor animal could be created in this way, the fundamental problems of rejection would probably remain. It is also uncertain whether the foreign animal organ will actually fulfil its function in the human recipient. The problem of animal viruses adapting to humans also remains, with the possible consequence of epidemics.

Legal aspects

From a legal point of view, it is particularly important to answer the question of which regulations govern animal cloning in Germany (and abroad), and under which conditions cloning is or is not legally permissible. There is no explicit consideration of cloning techniques in the Federal Republic in the Animal Protection Act, for example. However, the cloning of animals could be covered by the provisions of Section 7 (1) of the Animal Protection Act, as this paragraph contains provisions on animal experiments and the cloning procedures are predominantly still at the experimental stage. However, the application and impact of this paragraph are discussed in very different ways: If one does not regard the de-nucleation of the egg cell as a genetic modification in the legal sense, the transfer of the egg cell into the gestating animal does not constitute an animal experiment either. However, if one comes to the conclusion that cloning by means of nuclear transfer falls under the provisions of Section 7, Paragraph 1, Sentence 2 of the Animal Protection Act, because this involves interventions on the genetic material and, in addition, the cloning experiments can be associated with pain or harm for the genetically modified animals (or carrier animals), cloning experiments by means of nuclear transfer would clearly be subject to authorisation.

From a constitutional point of view, a cloning ban in the Federal Republic of Germany would violate the fundamental rights of researchers and professionals under Article 5(3) (freedom of research) and Article 12(1) GG (freedom of occupation). A cloning ban or other restrictions on cloning would also constitute an encroachment on the constitutionally guaranteed freedom of science. A constitutional barrier that could justify the encroachment obviously does not exist. According to Article 12 (1) of the Basic Law, a ban on cloning, for example, would therefore be unconstitutional, as it would not be compatible with the public good and would not be covered by the legal reservation of Article 12 (1) sentence 2 of the Basic Law. The cloning of animals is thus permissible in principle under the current conditions and is subject to only limited restrictions under valid law. A “state goal of animal protection” does not exclude the use of animals by humans per se, but it increases the requirements for the necessary justification.

Ethical aspects

Different positions in the social discussion and evaluation of animal cloning can partly be traced back to different fundamental value assumptions. These also determine whether the cloning of animals is considered to have a new quality compared to conventional or other new methods of animal breeding. Some theologically based positions regard cloning, for example, as an intervention in creation to which humans have no right. Those who ascribe an “intrinsic value” or a “dignity of creation” to animals will generally consider animal cloning to be at least morally problematic. From an anthropocentric perspective, the question of the safety of products produced with the help of the cloning procedure and the ecological (impoverishment of genetic diversity) and social (industrial mass production, concentration of capital, new dependency relationships) risks and dangers possibly associated with its use are in the foreground. In view of the difficulty of reaching a moral consensus, it is necessary to consider which ethical principles should guide the possible use of animal cloning.

As a rule, ethicists consider goals in biomedical research and application to be of high priority if they are particularly urgent or even vital with regard to human health and can only be achieved with the help of cloning from higher animals. Objectives in the field of basic research can also be considered of high priority and justify cloning of higher animals if no alternative methods are available. However, should cloning be associated with considerable suffering for the animal concerned, it must be examined whether the mere interest of humans in knowledge already constitutes a sufficient reason for justification or whether justifications are only possible for certain objectives, i.e. when they are necessary to avoid considerable human suffering. Goals in the field of livestock breeding are usually mentioned as subordinate to the goals mentioned, unless they explicitly serve to secure the food basis for humans.

Conclusions and options for action

In applied research, nuclear transfer-based cloning opens up new ways to produce transgenic animals. Some therapeutically effective proteins can be produced cheaply in this way. The production of autologous replacement tissue appears to be promising from a medical and ethical point of view, and corresponding research activities are therefore particularly worthy of support. It is unclear whether it will be possible to create better examination models for human diseases in farm animals, but because of the not insignificant medical importance, efforts should also be intensified and supported in this area. Overall, the potential benefit of nuclear transfer-based cloning for the fields of research and medicine appears to be relatively high.

From an ethical point of view, an evaluation of animal cloning must in principle be based on the same criteria that are (or should be) applied to traditional animal breeding. In this regard, the establishment of a national ethics commission, which would have to deal with the moral-ethical questions of the progress of biological and biomedical technology as a whole or with the consequences of progress in biology and medicine in the non-human sphere, is also problematised in various places. Its task would be to advise political decision-makers and inform the public.

Introduction

The principle of sustainability or sustainable development is the subject of a wide range of international, national and local activities, theoretical efforts, legal and planning measures. They are accompanied by an almost unmanageable abundance of publications and documentation. However, essential questions regarding the interpretation of this principle remain unanswered.

The principle of sustainability is widely understood on the basis of the 1987 report of the World Commission on Environment and Development (the so-called Brundtland Report), whose definition is often regarded as the standard: “Humanity has the ability to make development sustainable – to ensure that it meets the needs of the present without compromising the ability of future generations to meet their own needs. The core element of this conceptualisation is environmental protection from the perspective of intergenerational and international justice. However, the report contains a second, less well-known definition, which emphasises the radical social changes required and the process character of sustainable development: “Sustainable development is (…) a process of change in which the exploitation of resources, the direction of investments, the orientation of technological development, and institutional change are made consistent with future as well as present needs.

Europe’s commitment to sustainable development

Sustainable development has been at the heart of European policy for many years and the Treaties of Europe recognize the economic, social and environmental dimensions. Economic prosperity, efficiency, peaceful societies, social inclusion and responsibility, with dignity for all in their environment, is the basis of sustainable development. Sustainable development is therefore a cross-cutting issue that affects all states. Europe is therefore obliged to meet the needs of the present and it must not risk that future generations will not be able to meet their own needs.

Ensuring sustainability is a challenge for Europe, because it ranges from youth unemployment, climate change, pollution, energy and migration policies to population aging. We must prepare for current and future challenges and respond to rapid and complex global changes and the needs of the world’s growing population. To preserve the European social model and social cohesion, it is essential to invest in our youth, promote inclusive and sustainable growth, address inequalities and manage migration prudently. The sustainability of our health and pension systems will be improved by pursuing responsible fiscal policies and reforms, because if we are to protect our natural capital, we must accelerate the transition to a competitive low-carbon, climate-resilient and resource-efficient circular economy. Thus, a strong commitment to research and innovation is needed to turn these challenges into opportunities for new businesses and jobs.

Regulation of environmental behaviour

The understanding of the sustainability principle is spread as a standard by the report of the World Commission on Environment and Development published in 1987: “Humanity has the ability to make development sustainable – to ensure that it meets the needs of the present without compromising the ability of future generations to meet their own needs.”

Intergenerational and international equity makes environmental protection a core element of the conceptualization. But the report contains a second, less known definition, which emphasizes the necessary radical social changes and the process character of sustainable development: “Sustainable development is ((…)) a process of change in which the exploitation of resources, the direction of investments, the orientation of technological development, and institutional change are made consistent with future as well as present needs.”

The so-called three-pillar model is, however, the definition most frequently used in the sustainability discourse: “Sustainability is the conception of a permanently sustainable development of the economic, ecological and social dimensions of human existence. These three pillars of sustainability interact with each other and require balanced coordination in the long term.”

Sustainability is future-oriented and at the same time utopian, i.e. it is a utopia, but not in the sense of “illusory carelessness” but rather “as an expression of a departure into a future offensively oriented towards gaining new perspectives” – especially in view of the narrowing of future options by economic, ecological and social problems.

The EU is therefore committed to a development that meets the needs of the present without risking that future generations will not be able to meet their own needs. A life in dignity for all with the resources available on this planet, characterized by economic prosperity, efficiency, peaceful societies, social inclusion and environmental responsibility, is the basis of sustainable development.

Instruments

Instruments to enforce the environmental policy (environmental planning)

Environment policy has developed in the industrialised countries primarily as a reaction to a high environment intensive growth of the industry at the beginning of the seventies in the last century as a special government department. At first it confined itself mainly to the activity of the state. In the meantime however more and more environment relevant protagonists (so called “stakeholders”) are called to account for environmental matters. Especially the direct responsibility of the producer of (potential) environmental problems plays an increasing significant role. There is also the need to exert eco-political goals and strategies in other departments: e.g. in the energy -, transport -, and industry -, agricultural – or building and construction policy. “Hard” eco-political instruments (as laws and regulations) are side by side with the “soft” methods of behavioural control.

Beside the environmental law the environmental planning forms the central set of tools, insofar ecological policy wants to take effect not only as regulatory but also as formative policy. The environmental planning can be regarded as the development of sustainable environmental strategies, which are to facilitate the achievement of regional and/or sectoral environment protection goals within a certain timeframe: e.g. the reduction of CO2-emissions by 25% within the next ten years. In the eighties of the last century the passage of national environmental plans in Denmark, Netherlands and Finland played a pioneering role in this. Therefore we will first expand on the possibilities of the environmental planning.

For enforcing the environmental policy principles and objectives two instruments are implemented in the legal framework of many states within the EU, means the different types of environmental planning and the different measures for regulation environmental behaviour. Environmental planning is an important means of precautionary protection. Such planning takes place as a multi-stage process, involving registering the current situation, forecasting future developments, and conflicts of objectives and interests. Plans can take the form of laws, statutory regulations, statutes, administrative regulations, or administrative acts, each of which has different legal consequences

Two forms of environmental planning are dominant: The so called “comprehensive planning”. It is the task of comprehensive planning concerning the environment is to determine, while exercising foresight, land use for residential, economic, and leisure purposes for a certain area, irrespective of any specific project and not limited to any specific sector. And the second one is sectoral planning: By contrast, sectoral planning is concerning the environment serves to establish environmental protection plans. They are mainly the landscape plans, clean air plans, noise abatement plans, water conservation plans, and waste management plans, all of which require additional enforcement measures.

Another important instrument to enforce the environmental policy demands is the „Environmental impact assessment” (EIA). The primary objective of this instrument is to inform the administration in good time and comprehensively about the environmental impacts of environmentally significant projects. Environmental impact Assessment is to identify, describe, and assess all of the direct and indirect impacts of a planned project on the environment, including ecological interactions, in good time, thus allowing the taking of precautionary measures, across all media and sectors, and involving the public.

Instruments to regulate the environmental behaviour

Environmental behaviour is perhaps the most important objective for environmental policy and education. There are some instruments for regulation the environmental behaviour. One has to distinguish between direct and indirect forms of regulation:

Direct regulation of behaviour pertains to legal measures designed to immediately affect environmental behaviour. The “classical” instrument of this type is environmental regulatory law, which originates from police and regulatory law and generally punishing non-compliance by imposing sanctions. Accordingly, actions with adverse environmental impact are subject to administrative control, which is characterized by legal requirements of notification, registration, licensing, authorization, approval, and other procedures of granting permission to engage in such activity. In addition, direct regulation is also exercised by means of expressly (absolutely) prohibiting or requiring certain behaviour by law.

Principles for political and legal measures

Important is to distinguish and explain the principles guiding environmental law both in a national and an international frame and understand the meaning of ‘environmental sustainability’ and ‘sustainable development’ in the context of nature protection  Serious and substantial environmental law has to be guided by some high-ranking principles. For many international and and national regulations in the field of environmental law within the European Union (e.g. in Germany), four basic principles are the basis for all processes of environmental law-making regarding the precautionary principle, the polluter-pays principle, the principle of sustainable development (concerning the integration of environmental protection and economic development) and the cooperation principle.

Other principles are often mentioned, which complete the four main principles or define them in a particular way. Some examples are Environmental procedural rights, common but differentiated responsibilities, international and intergenerational equity, common concern of humankind and the common heritage.

Precautionary principle

In its origin, the precautionary principle is rather a political than a philosophical principle and was first introduced as ‘Vorsorgeprinzip’ (principle of precaution) in the German-speaking area. It was incorporated into several national legal texts and international treaties or declarations. A good definition was given by Per Sandin: “The basic message of the precautionary principle is that on some occasions, measures against a possible hazard should be taken even if the available evidence does not suffice to treat the existence of that hazard as a scientific fact.” It can therefore be stated that the precautionary principle is based on hazard detection and scientific uncertainty. As a consequence, the burden of proof (that an action might cause severe harm to the public or the environment) falls on those who plead for measures to prevent such an harm. Whenever one can anticipate plausible harm for society or the environment, the precautionary principle should be applied. But often it is not clear whether a planned action will cause harm to the public or the environment or not, because the possible impact of human actions on the environment or human health often depends on the dynamics of complex systems, so the real consequences of actions may be unpredictable. Therefore further scientific research is required – but also caution if a current action intervenes in complex (human or natural) systems.

Nowadays the precautionary principle is incorporated into many European and international contracts and treaties. In its 1976 Report on the Environment, for example, the German Federal Government describes the precautionary principle as follows: Environmental policy is not limited to averting imminent danger and remedying damage that has already occurred. Precautionary environmental policy furthermore demands that the natural environment be protected and treated with care. The precautionary principle is embodied in a number of environmental provisions, and also involves resource conservation in addition to risk precaution.

The precautionary principle is especially important in legal regulations and decisions concerning potential risks to public health, such as the marketing of genetically modified foods, the use of growth hormones in cattle raising, or measures to prevent ‘mad cow’ disease.

Nevertheless, in real cases the policy-makers often have to struggle with a lack of valid scientific information or with irreducible conflicts between the interests of different stakeholders. Sometimes it is very difficult to estimate or assess the potential harm and to find an acceptable political compromise. But anyway, rigorous application of the precautionary principle should be avoided when there is insufficient knowledge of whether there is a real potential risk from an innovative product or an activity or not. In this case the principle could be taken immoderately as an absolute ban on all actions – which could stall all technological innovation and progress.

Polluter-pays principle (versus community-pays principle)

The polluter-pays principle states that the one causing environmental impact is principally held responsible—materially and financially—for protecting the environment and is required to prevent, correct, or financially compensate such impact. But a problem arises in cases of inherited pollution where the responsible parties often cannot be held liable and—if no other party can be held responsible—the general public must bear the cost. In such cases the polluter-pays principle would be replaced by the community-pays principle.

In environmental law, the polluter-pays principle is enacted to make the party responsible for producing pollution responsible for paying for the damage done to the natural environment. It is regarded as a general custom because of the strong support it has received in most Organisation for Economic Co-operation and Development (OECD) and European Community (EC) countries. In international environmental law it is mentioned in Principle 16 of the Rio Declaration on Environment and Development (1992).

The polluter-pays principle is an important element of environmental policy and influences, for example, political measures for reducing greenhouse gas emissions. Often this principle will be applied as the so-called ‘extended polluter responsibility’ (EPR). This concept was probably first formulated by the Swedish government in 1975. For instance, EPR can help to shift the responsibility for dealing with waste from governments and taxpayers to the real producers of the waste. OECD defines EPR as: a concept where manufacturers and importers of products should bear a significant degree of responsibility for the environmental impacts of their products throughout the product life-cycle, including upstream impacts inherent in the selection of materials for the products, impacts from manufacturers’ production process itself, and downstream impacts from the use and disposal of the products. Producers accept their responsibility when designing their products to minimise life-cycle environmental impacts, and when accepting legal, physical or socio-economic responsibility for environmental impacts that cannot be eliminated by design.

The principle of sustainability (sustainable development)

Another important principle is the principle of sustainable development, which may be viewed as an instance of applying the precautionary principle to resources. This principle is a pattern of resource use that aims to meet human needs while preserving the environment so that these needs can be met not only in the present, but also for future generations. For the first time, the term “sustainable development” was used by the Brundtland Commission (1987), which has given the most famous definition of sustainable development as development that “meets the needs of the present without compromising the ability of future generations to meet their own needs” (United Nations 1987).

The term ‘sustainable development’ seeks to combine the resources and processes of natural systems with the human needs and economic activities of social systems. Already in the 1970s the term ‘sustainability’ had been used for an economy “in equilibrium with basic ecological support systems”. On the base of the idea of sustainability and according to the alarming theses of “The Limits to Growth” many ecologists tried to create the new concept of a “steady state economy”, especially with respect to environmental concerns. In this context, ‘sustainable development’ does not refer solely to environmental issues, but also takes into account social and economic considerations: the resolving of conflicts between different competing goals and stakeholders, and the harmonising of economic growth and social welfare with environmental quality. The concept of sustainable development—both of nature and society – points out that the survival of mankind depends essentially on the survival of nature (or the natural environment), because economic and socio-cultural welfare is directly coupled with the the welfare of nature – resources, plants, animals, etc. Ultimately, the exploitation and degradation of nature can result in the inability to maintain human life and even in the extinction of mankind. The theory of sustainable development is therefore based on the assumption that societies have to manage three forms of non-substitutable capital: economic, social and natural capital.

It may be that we can find ways to replace some natural resources, but it is unlikely that we will ever be able to replace the services provided by the eco-system: for example, to protect us against dangerous cosmic radiation with an intact ozone layer, or to supply us with sufficient oxygen as the tropical forests or the algae of the oceans do. The multi-functionality of many natural resources and also biodiversity are irreplaceable. Moreover, the deterioration of natural resources and the loss of natural services (e.g. the absorption of nutrients by a lake) are often irreversible processes – like the loss of ethnic and cultural diversity (e.g. indigenous languages). Therefore only a sustainable development can secure both: the protection of a functional intact environment and the survival and welfare of human beings.

Cooperation principle

‘The cooperation principle underscores that environmental protection is the responsibility of all of society and not just of the state: accordingly, all parts of society and the state are called on to cooperate’ (Knopp 2008: 49) The cooperation principle is the weakest of the four environmental principles, and it can hardly be considered as satisfying the requirements demanded of a guiding principle of law.

Other principles in national and international environmental law

Apart from the four basic principles, there are a number of others guiding national and international environmental law, such as the ‘grandfathering principle’ or the ‘principle that action may not result in a significant deterioration of environmental conditions’. Last but not least, we should also mention the principle of trans-boundary environmental protection: this principle mirrors the insight that environmental problems do not stop at national borders. For instance, this principle underpins much of the Water Framework Directive of the European Union where it covers the trans-boundary management of water resources in natural river basins.

National as well as international environmental laws are often based on the above called principles, especially the trans-boundary principle. This is important, because many environmental problems are border-crossing problems, for example, climate change, sea water and air pollution.

Regulation of Environmental Behaviour

Instruments to enforce environmental policy (planning)

Environmental policy has developed in the industrialised countries primarily as a reaction to the highly intensive growth of the environment industry at the beginning of the 1970s into special government departments. At first policy confined itself mainly to the activity of the state. Over the years, however, more and more protagonists with any interests in the environment field (so-called ‘stakeholders’) are being called to account on environmental matters. In particular, the responsibility of the producer of (potential) environmental problems is becoming increasingly significant. There is also a need to exert eco-political goals and strategies in other departments, for example, in policy for energy, transport and industry, agriculture, and building and construction. ‘Hard’ eco-political instruments (such as laws and regulations) exist side by side with the ‘soft’ methods of behavioural control (such as education of engineers concerning environmental awareness), for example, in the case of projects that involve many private stakeholders or the public.

Besides environmental law, environmental planning forms are a central set of tools to the extent that environmental policy tries to operate not only as a regulatory but also as a formative instrument. Environmental planning can be regarded as the development of sustainable environmental strategies to facilitate the achievement of regional or sectoral environment protection goals within a certain time-frame, for example, the reduction of CO2 emissions by 25% within the next ten years. In the 1980s the implementation of national environmental plans in Denmark, Netherlands and Finland played a pioneering role in this. We will, therefore, first expand on the possibilities of environmental planning.

To enforce environmental policy principles and objectives two instruments are implemented in the legal framework of many states within the EU that means different types of environmental planning and the different measures for regulating environmental behaviour.

Environmental planning provides an important means of precautionary protection. Planning takes place as a multi-stage process, involving registering the current situation and forecasting future developments; moreover, it has to take into account possible conflicts of interests.

Plans can take the form of laws, statutory regulations, statutes, administrative regulations or administrative acts, each of which has different legal consequences. In addition, environmental planning may involve comprehensive planning or sectoral planning. Two forms of environmental planning are dominant, the comprehensive planning. The task of comprehensive planning is ‘to determine, while exercising foresight, land use for residential, economic and leisure purposes for a certain area, irrespective of any specific project and not limited to any specific sector’ and the sectoral planning. By contrast, sectoral planning serves to establish environmental protection plans for specific sectors, chiefly landscape, clean air, noise abatement, water conservation and waste management, all of which require additional enforcement measures

Another important instrument for enforcing environmental policy demands is environmental impact assessment (EIA). The primary objective of this instrument is ‘to inform the administration comprehensively and in good time about the environmental impacts of environmentally significant projects’ EIA is used to identify, describe and assess all of the direct and indirect impacts of a planned project on the environment, including ecological interactions, in good time, thus allowing precautionary measures to be taken across all media and sectors, and involving the public.

Instruments to regulate environmental behavior

Environmental behaviour is perhaps the most important target for environmental policy and education. There are various instruments for regulating environmental behaviour, which can be distinguished as direct or indirect forms of regulation: as (1) direct regulation and (2) indirect regulation of behavior.

Direct regulation of behaviour

Direct regulation of behavior pertains to legal measures designed to immediately affect environmental behaviour. The traditional instrument of this type is environmental regulatory law, ‘which originates from police and regulatory law and generally punishes non-compliance by imposing sanctions’. Accordingly, actions with adverse environmental impact are subject to administrative control, which is characterised by legal requirements of notification, registration, licensing, authorisation, approval and other procedures of granting permission to engage in such activity. In addition, direct regulation is also exercised by means of expressly prohibiting or requiring certain behaviour by law.

Absolute legal bans (e.g. in Germany under the Federal Nature Protection Act, 2002, §§ 23 [2], 42 [1] and [2]), directly forbid certain behaviour with adverse impact on the environment. However, legislators only rarely employ measures of this type. By contrast permission procedures are the key instrument in current environmental regulatory law in many European states. Projects subject to permission are strictly prohibited without permission. ‘Erecting or operating an installation of environmental significance, using environmental media, or producing and distributing certain products may all be subject to permission’. Thus a permit is a constitutive administrative act in that it grants the applicant the right of lawfully engaging in an otherwise prohibited activity. Environmental law includes a number of so-called environmental obligations, of which basic obligations are of special significance. They impose certain obligations either on everyone or on a certain group of people. Normally, these basic obligations involve preventive and precautionary measures, most notably the conservation of resources (e.g. water or soil). Apart from those basic obligations, there are ‘numerous collateral obligations that may benefit the environment, such as promotion and performance obligations, monitoring and protection obligations, obligations to cooperate and continuously disclose information, organisational obligations and obligations to tolerate certain actions.

Indirect regulation of behaviour

Indirect regulation of behaviour does not rely on norms mandating behaviour, but aims to influence motivation: incentives are provided for environmentally friendly behaviour while leaving discretion to the addressee. The means of indirect regulation behaviour notably include informational instruments, economic instruments, such as levies certificates, and subsidies.

Information, appeals and warnings, means that according to the German Environmental Information Act (1994), providing free access to environmental information is viewed as a means of sharpening the awareness of citizens and public authorities of the need for effectively protecting the environment. These means of raising environmental awareness range from political and moral appeals to warnings, recommendations and other forms of information, such as labels and product and usage information. The most important means to indirectly regulate behaviour are environmental levies. ‘They place a price tag on the use of the environment and leave it to market participants to decide if and how they will react based on their individual cost–benefit analyses’. In practice, the inability to precisely affect behaviour via environmental levies can pose a problem. If they are set too low, polluters will opt for paying the levy instead of altering behaviour harmful to the environment. If levies are set too high, they may impede economic competitiveness. For instance, the following environmentally relevant charges are being levied in Germany in 2012 for example waste water charges, countervailing charges under nature conservation law and forest protection charges in various German States, water abstraction fees in some German States (‘water penny’) and the waste transportation charges (consumer law).

Environmental levies may be imposed as taxes, fees and contributions for benefits incurred, and special levies. Granting benefits to users of environmentally friendly products, means ‘Benefits for use’ refers to provisions that relax or lift general limitations imposed on the use of environmentally harmful products in the case of products that comply with standards that, although not required by law, are considered desirable, thus rendering such a product more environmentally friendly than others of the same kind. ‘Although this instrument does not involve financial incentives in the medium and long term, changes in consumer behaviour may be expected that may lead to crowding environmentally more harmful products out of the market’.

Or the subsidies, that means providing financial assistance is a form of indirect behaviour regulation. Subsidies are monetary or non-monetary benefits granted by the state, without any product or service being provided in return. Subsidies are generally viewed with scepticism, since they are considered to be prone to abuse and to place the cost burden of environmental protection on the general public. In the European Union there has been a tendency to cut back on environmental protection subsidies.

And finally the idea of environmental certificates is based on a market-compatible form of quantity control by the state. Certificate-based schemes do not take prices as their starting point but define an admissible level for a certain future use of the environment in quantitative terms, leaving the formation of process up to the market. This instrument has been employed for climate protection under the Kyoto Protocol. The allocated emission allowances grant the holder the right to pollute the environment only to a certain extent. Should the holder pollute the environment to a lesser degree than permitted, the holder may sell the unused pollution allowances to another polluter. ‘Enterprises may thus elect to either reduce emissions from their installations or to acquire additional emission allowances from other enterprises that have been able to reduce emissions at lower cost’. Future experience will show whether this instrument will indeed prove successful in reducing greenhouse gas emissions. Economic instruments are gaining increasing significance as a complement to environmental regulatory law. There is no single answer to the question as to what is actually the ‘proper’ choice of instruments in order to achieve an adequate balance between various environmental user interests, the interests of affected neighbours, the interests of the general public and the protection of the environment. Legislators and administrations are thus ultimately compelled to rely on trial and error to reach an appropriate decision.

The Multidimensional Sustainability Strategy

Social justice, prosperity and peace, with nature to overcome global crises, are to be seen as three interrelated and equally weighted goals of sustainability. But it remains unclear how to make a multidimensional sustainability strategy politically viable in individual countries as well as in the global community. There is indeed a great danger that this promising societal strategy will end up in the vicinity of utopia and wishful thinking based only on moral normative grounds.

An integrative sustainability strategy in the comprehensive sense is first of all about coordinating the different normatively based life perspectives of individuals, social groups, nations, present and future generations. In the process of searching for and shaping a globally sustainable development, innumerable agreements will have to be reached, both within society and internationally, which would have to be morally motivating for all actors involved.  So motivating, in fact, that these agreements could attain a degree of binding force that would allow possible violations of the agreements to be punished with sanctions. The consensus to be reached therefore goes beyond the mere coordination of different, normatively based perspectives: rather, it presupposes a generally accepted ethical framework as well as principles and standards that are ethically valid for all participants. In other words: Sustainability needs a morally suitable, politically viable and pluralistic guiding ethic that is socially and spatially and temporally transcendent, that has a high level of acceptance comparable to fundamental freedoms, and that allows operationalizable and targeted, detailed standards to be developed for ecological, economic, social, political and cultural sustainability dimensions. However, this ethic has been lacking up to now.

Precisely because of the lack of an acceptable ethics of sustainability, the uncertainty of formulating social and economic sustainability rules and justifying morally consensual action steps remains very high. Moreover, the lack of an acceptable and comprehensive ethics of sustainability favors the current dominance of one-dimensional, ecological-economic considerations in the sustainability debate and at the same time hinders the coordination, cooperation and mutual adaptation of promising actually integrative sustainability approaches and their respective goals.

The debate on ethics, which was originally conducted independently of the sustainability debate, has not yet provided any decisive impetus either, although the irreversible consequences of scientific and technological development have triggered a lively ethical debate on the responsibility of the present towards future generations. This debate was followed by the discussion on ecological justice and, more recently, on sustainability. Understandably, the first step in this discussion is to examine the extent to which previously accepted ethics of justice can be applied to ecological justice. The meager result of this discussion was, however, pre-programmed. The common justice ethics suffer from the one-dimensionality of their frame of reference. In them, social justice is a parameter of some other overarching goal.

• In utilitarianism, social justice is dependent on the maximization of total utility;
• in Marxism, social justice is only possible in a communist society, i.e., when the conditions for the equality of all people have been historically established;
• and in liberalism, social justice is a parameter of the goal of the greatest possible basic freedoms.

Seen in this light, these ethics are already inadequate for treating social justice as an independent and immediate socio-political goal. Their inadequacies become even greater, and their binding force for policy becomes weaker, if they were also to provide moral standards of value for additional and qualitatively new dimensions of justice, such as ecological, international, and intergenerational justice.

The question thus arises whether a different ethics that takes into account the requirements of integrative sustainability is conceivable. In the opinion of the author and on the basis of his insights gained so far, which of course have a provisional character, equal opportunities as an independently conceived universalistic ethics could fill the demonstrably existing orientation gap. The core of his considerations is the definition of equal opportunities as “equal starting conditions for individuals, social groups, peoples of different color, religion, culture, language, for people of different genders, and for different generations to determine their own needs, lifestyles, and options, and to have equal access to natural resources, goods, and positions. Equality of opportunity is a condition that must be constantly re-established against both historically evolved and newly emerging inequality trends”.

However, it needs to be argued in more detail whether and in what way equality of opportunity, understood in this way as a universal action-oriented ethic, can make a central contribution to overcoming the deficits outlined above for a policy of inclusive sustainability. The following considerations are taken as a starting point: The conclusion of the prevailing liberal view that the realization of equality of opportunity “precisely because of the principled universality of the individual reference cannot be specified in terms of content” and that “the magic and allure, the seductiveness and vagueness” make this concept “universally and all-roundly usable as a political fighting term”   is logically not at all compelling. Every organized individualistic society must follow general norms and rules in the interest of all individuals.  The universality of the idea of equality of opportunity consists precisely in the fact that individuals both animate each other to mutual claims and enter into obligations among themselves. It corresponds to the moral standards and conceptual logic of the principle that no individual may impair the opportunities of other individuals entirely in the sense of Kant’s categorical imperative “act in such a way that the maxim of your will could at the same time at any time be regarded as the principle of a general legislation.” Furthermore, the substantial as well as indispensable condition of equality of opportunity is equality of starting conditions. This condition is morally as well as logically integral to the principle.

The exclusion of historically grown inequalities, fortunes and positions, which have not arisen on one’s own merit but by allocation, precludes the realization of equality of opportunity. In this respect, the assumption of vagueness and complete openness of the principle for political practice is an arbitrary one and results rather from the conception of justice of classical liberalism itself. Equality of opportunity can be interpreted not only intrageneratively, but also in an intergenerational sense universal interpretation. Kant’s categorical imperative, strictly speaking, becomes normatively consequential only through an ethics of equal opportunity, thus overcoming its reputation of a merely formal principle with which no justifications of particular ends or maxims can be provided. With regard to its inter-generationally universal scope, the idea of equal opportunity also takes into account the legitimacy dilemma often problematized by ethicists but not solved: Every society would have its own ideas of needs and well-being. The present generations would not have the right to define the needs of future generations and, moreover, to prescribe the technological and social conditions for them.  This objection cannot be denied a comprehensible moral justification.

The positive turn of this objection, however, leads to the moral maxims of action for present generations that allow future generations equal opportunities to use nature according to their ideas of need, well-being, and happiness. “Our ignorance should not serve as a justification for limiting the life chances of those to come”.

Weighty arguments thus condense and underpin the view that equality of opportunity can be made fruitful as a foundation for a social theory of integral sustainability that transcends space and time across disciplines. Equal opportunity as a universal ethic and integrative sustainability as a multidimensional framework for action require an inter- or transdisciplinary (socioeconomic, ecological, political science, sociological, and philosophical) approach.

The following principles, which are still preliminary are considered to be fundamental for specifying and achieving equal opportunities

• Principle of freedom: Every human being has the same right to the most extensive total system of equal basic freedoms possible for all. A less extensive freedom must strengthen the overall system of freedoms for all (Rawls’ first principle).
• Diversity principle: Every human being has the right to cultivate and maintain specific characteristics of his or her own, such as aptitude, lifestyle and life planning, and to use them in the sense of his or her own self-realization.
• Autonomy principle: Every person has the right to the fruits of his or her own labor (the idea of self-ownership according to classical liberalism and Marxism).
• Freedom of access principle: Every person has the same right of access to natural resources and to social positions. A restriction of this right must lead to the strengthening of the same for all people living in the present as well as for future generations.
• Principle of care: Everyone is obliged to care for disadvantaged and dependent people. The restriction of autonomy accepted in this process must strengthen the overall system of autonomy for all. The definition of equal opportunities and the formulation of its principles are preliminary. It remains to be verified to what extent both the definition of equal opportunity and its individual principles are complete, each individual principle is consistent in itself and these together can be integrated into an overall concept, and finally whether these individual principles can also be anthropogenically underpinned.

The question of the hierarchy of these principles must remain open for the time being; whether an evaluative hierarchy or equal ranking is morally compelling requires detailed investigation, although there is already much to suggest that these principles would have to stand in an indissoluble relationship to each other. However, there is sufficient evidence for the hypothesis that equality of opportunity meets the requirements of a multidimensional ethics and the politics of integral sustainability much more strongly than the ethics of justice known so far. It is conceived as an integrative further development of those common ethics of justice in which either the principle of equality or the principle of freedom is absolutely dominant. Freedom, autonomy, self-realization and care, justice of achievement and justice of need give equality of opportunity a moral fitness and political capability of the highest order.