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Abstract

Bioprinting is a combination of 3D printing techniques and tissue engineering, using “bioinks” in order to give the tissue the desired spatial orientation. Combining pure engineering techniques with biotechnology offers some technical challenges of effectivity and biocompatibility, as the printed cells tend to be damaged by the printing process. Bioprinting has however the potential to bring organogenesis and other regenerative techniques an important step further. In the best case, it could be used to print whole organs with the original DNA of the recipient which would not only eliminate the necessity of immunosuppression with all its side effects but could also solve allocation problems and other ethical problems and controversies around organ transplantation, freeing the related ethical discussions from the pressure of urgency and emergency. Applying and combining very different techniques, an individual risk assessment for each experiment is inevitable, but in addition to speciﬁc risks a broader perspective on the social consequences and potential use and risks of established application ought not to be neglected.

Introduction

Regenerative medicine is an umbrella term for techniques that restore or replace damaged body parts and functions. The ideal would be to create an identical copy of the healthy organ and replace the damaged one. Many different techniques are used and tried in this purpose – the most obvious example is organ transplantation with organs of living or dead donors. This example is also the one that has been discussed most in ethical terms.

However, also mechanical devices have been in use for a long time in order to replace organs or certain organ functions, e.g., pacemakers and total artiﬁcial hearts, dialyzers that replace kidney function, as well as dental and orthopedic prostheses.

Proceedings in gene technology gave raise to hope that organs with the original DNA could be cloned which could solve many technical and ethical problems at the same time. Many cells and tissues can be cultured ex vivo which opens possibilities of research and different therapeutic interventions. Time and experiments showed, however, that not only genetics but also many epigenetic factors are not sufﬁciently understood so far to use only biological methods in order to create more complex organs without cloning a whole organism (which would raise severe ethical problems, at least in the case of human beings).

Since some decades, a combination of mechanical and computer techniques on the one hand, and biological materials and methods on the other hand, has opened promising research areas in regenerative medicine, one of them the broad research area of tissue engineering. Tissue engineering combines engineering and life sciences with the goal to restore, maintain, or improve tissue function or a whole organ. It includes up to three elements: (1) isolated cells or cell substitutes, (2) tissue-inducing substances, and (3) cells placed on or within matrices (scaffolds). This includes many different scientiﬁc and therapeutic purposes in regenerative medicine, most spectacularly perhaps, the construction of whole autologous organs that would not only be a solution for the lack of donor organs but would also answer the problem of adverse host response and minimize the risk of infection. In summary, there is nearly no method or technique that could not be part of tissue engineering.

Analogically, the ethical assessment of tissue engineering is complex, depending on the applied techniques, the kind (or in the case of embryos, also the origin) of subjects, and the intended goals as well as the social context. Tissue engineering involves some controversially discussed issues like embryonic or adult stem cell research, gene therapy, and enhancement, but it also includes innocuous, low-risk research like basic cell culture experiments (Gelhaus 2009a).

This research paper focuses on a special type of tissue engineering. In addition to grow the right type of cells or administer effective bioactive substances and modulators, the spatial construction of cell structures is one of the basic challenges in tissue engineering. Bioprinting is using usual 3D printing technology in order to prescribe the desired spatial structure of the produced tissue. It can be used for tissue engineering of complex organ structures, cell-based biosensors, implanted cellfactory devices, or external assist devices for organs. Respective cells are positioned either directly or “by directing spatially resolved cell behavior through pattern chemicals such as adhesion or growth promoters” (Derby 2008, p. 1717). The usual ink-jet technology can be used in order to position cells or material exactly in three dimensions, and different materials, chemicals, or cells can as “bioinks” be administered simultaneously.

Bioprinting implies however some technical problems: classical printing techniques use either high temperature or piezoelectric effects in order to position the ﬂuids exactly. Both techniques can damage living cells or administered proteins, which threatens the technique’s effectivity. Some investigators discuss the use of genetically altered materials that tolerate the printing process better (Mironov et al. 2006).

The scaffolds should not be cytotoxic and not be altered too quickly by ions or by living cells. Alginate gels that were used ﬁrst are difﬁcult to be constructed exactly because of the gelation process. In addition, they show poor cellular adhesion. The construction of more suitable scaffolds is one of the current challenges. Furthermore, a couple of questions in terms of biocompatibility have to be answered:

Scaffold choice, immunogenicity, degradation rate, toxicity of degradation products, host inﬂammatory responses, ﬁbrous tissue formation due to scaffold degradation, mechanical mismatch with the surrounding tissue are key issues, that may affect the long term behavior of the engineered tissue construct, and directly interfere with its primary biological function. (Williams 2008, p. 2951)

Ethical Considerations

Technical Risk Benefit Analysis

Problems and risks: Classical printing techniques use either high temperature or piezoelectric effects in order to position the ﬂuids exactly. Both techniques can damage living cells or administered proteins. Though there seem to remain enough cells or enzymes in order to create active and living structures, there is little evidence as to the effect of damaged cells and proteins. Before the products are implanted in living persons, it should not only be clear that the constructions fulﬁll their intended functions but also that they do not have toxic, allergenic, or carcinogenic effects. For this purpose it is not only necessary to have tested and secure scaffold material without harmful bioactive effect but also that the damaged biological material is not noxious. Cells that are totally destroyed might be a lesser problem – though they might cause inﬂammatory reactions – than only slightly damaged cells which might continue producing defective products or in worst case have been damaged in their genome and might become cancer cells. Experiences from human gene therapy have shown that theoretical risks from gene manipulation and transfer as infections, immunological reactions, and cancer have really been provoked by therapies (Gelhaus 2006). Before trying in vivo implantation of bioprinted materials, sufﬁcient efforts have to be made to control the risks, be it by developing cleaning methods – but how to detect only slightly but dangerously damaged cells – and be it by developing methods that have less risk to damage the cells.

Another presented idea is to use genetically altered materials that tolerate the printing process better (Mironov et al. 2006). In this case, all risks of conventional gene therapy add to the risks of bioprinting, while there is no guarantee that the more resistant cells cannot be damaged at all by the process. Classical in vivo gene therapy involves – depending of the chosen transfer mechanism – risks of infection and unintended gene transfer as well as of activating cancer genes or deactivating protecting genes.

The described problems and risks apply to all types of bioprinting; more speciﬁc risks have to be analyzed with regard to the more speciﬁc interventions. At the moment one of the most sophisticated applications is the construction of minor blood vessels (Norotte et al. 2009). Risks of surgical interventions and the risk of failure in vessel reconstruction – depending on how important the recirculation for the whole organism is – add to the general risks of the technique.

As in all experimental therapy, the risks should be outweighed by the potential beneﬁt of the technique. In gene therapy, some model diseases were chosen in the beginning of clinical research, e.g., SCID, a severe genetic defect of the immune system that is difﬁcult to treat conventionally and would potentially have been healed with supply of the defective gene. Actually, the effect of gene therapy was only moderate, but from a theoretical and ethical standpoint at the respective state of knowledge, the risk-beneﬁt calculation was adequate: no good therapeutic alternatives, a big theoretical beneﬁt, and a prospective risk analysis with all scrutiny. In addition to this, a careful informed consent of the research subjects is essential – it is them who take the risks, after all – and they should be fully informed and understand as well as possible what they are consenting to.

Gathering all available knowledge about possible risks and a realistic analysis of possible beneﬁts are not only a question of prudence and a legal requirement but also a moral duty as expressed in the Declaration of Helsinki. As researchers generally are tempted to be enthusiastic about the potentials of their research, an independent instance like a research ethics committee or an institutional review group should scrutinize the research plan before starting the clinical phase of trials. With the broad range of possible applications of the technique in creating all types of tissues or organs, it is not possible to elaborate a general risk-beneﬁt calculation of the technique of bio printing as such. A strategic plan of developing the technique from the simpler and less risky to the more sophisticated and potentially more beneﬁcial is morally recommendable.

On the other hand, it is the vision of bigger improvements in regenerative medicine that inspires research and justiﬁes taking risks at all. In principle, all existing tissues and organs might be grown artiﬁcially, and printing technologies alleviate the right orientation in space, possibly allowing producing more complicated structures without ﬁrst understanding and mastering the biological ontogenesis and its steps and factors – a shortcut to organ production. All from heart valves, blood vessels, bones, muscles, and sinews to the liver, kidney, and eyes are imaginable and partly under research. Only having more and more advanced biomechanical replacements of more complex organ function is an exciting perspective, the more in an aging population that experiences organ failures as a common reason of suffering, dysfunction, and ﬁnally death (Hammerman and Cortesini 2004). The imagination of fully biological tissues and organs that even might be grown of the patient’s own cells is even more fascinating, as it skips many practical and also some ethical problems. Immunosuppression is a necessity in conventional organ and most tissue transplantation that gives reason to many side effects, deteriorated life quality, infection, and cancer risk. Using own cells would eliminate this costly need.

Producing organs artiﬁcially at all could replace the need for donor organs, both living and dead donors. No matter which incentives and procedures of allocation are currently used, there is a persisting lack of organs for organ transplantation, and an artiﬁcial production probably could supply organs for all who need them (or can pay for them). Furthermore, all allocation decisions and the recruitment of organs from dead as well as from living donors are accompanied with difﬁcult ethical questions on justice, responsibility, ownership of the body (living and dead), and piety, not mentioning delicate questions of death deﬁnitions, commercialization, and crime, in the big business of health and surviving.

If bioprinting can help a step further in this, there is not only potential for big therapeutic advancement, but also a possible reconciliation of a couple of complicated moral dilemmas and disagreements.

Origin Of The Material

Another point to consider in the ethical assessment of a technology is the origin of the used material. Using living material is not only a question of ownership and possible exploitation but also of the moral status of the material. For some types of tissue engineering, embryonic stem cells are used. The status of the human embryo is highly controversial. Some regard it as one cell type like all others; others contribute a moral status comparable to the status of adult, autonomous persons (or even more because of the innocence and vulnerability of the embryo) to it (Steinbock 2007). No scientiﬁc evidence can solve this problem, because it is not a matter of evidence but of normative attribution. A whole range of potentiality arguments and religious convictions have been developed in this moral conﬂict that cannot be summarized here; but using cells that do not directly derive from germline cells evades a lot of moral troubles. Though in principle also stem cells can be used in bioprinting techniques, the interesting aspect in bioprinting with cells is that one evades needing certain ontogenetic knowledge that the embryonic cells before differentiation do possess. The need for early pluripotent or omnipotent cells should diminish with bioprinting methods, replacing otherwise required material from problematic sources.

Alternative biological materials are organs and tissues from living or dead human donors, from living or dead animals, from existing embryonic stem cell lines, from adult stem cells, and from existing differentiated cell lines. Moral concerns about the origin of the materials diminish gradually in this enumeration. In human living organ donation, the donor’s interests and will are highly to consider. In dead donor’s donation, the ownership rights over one’s own dead body as well as aspects of piety are more contestable. The moral status of embryonic stem cells is controversial, but for already existing embryonic cell lines no further embryos have to be sacriﬁced. Adult stem cells are isolated from blood or tissue samples of adult persons who are in low risk by the intervention and can give their informed consent. Finally, existing differentiated cell lines are quite unproblematic if they have been created according to valid moral standards and owner rights are respected.

If one uses autologous cells of the respective patient for bioprinting, the origin of the cell is unproblematic as far as the patient gives her informed consent.

Some more considerations are required if the applied cells, tissues, or organs are derived from animals or require animal experimentation before being used in human beings.

Animal Ethics

Animal research is a necessity in clinical research in order to reduce the risks of new therapies for human beings. On the other hand, animals are sentient living creatures, and their use in painful and deadly experiments is ethically disputed. After all, moral status is not innate but subject to reasonable grounds. According to some ethical accounts, ethical regard depends on reciprocity and well-understood self-interest. In this case, animals have no moral rights and animal research is not problematic, though still there is no need to be crueler than necessary. But in interest or need oriented approaches, the moral claim is equivalent to the possible good or evil an organism can experience, and accordingly, animal research especially in higher developed animals is intolerable. Tissue engineering offers the opportunity of designing speciﬁc human cell lines for testing the effects of new pharmaceuticals and therefore could replace (at least in part) the requirement of animal research with their sometimes questionable evidence concerning human beings. In fact, animal research ﬁnds itself in a conﬂict between epistemology and ethics. On the one hand, research animals should be as close to humans as possible in order to obtain valid ﬁndings. On the other hand, their resemblance to humans makes their moral negligence objectionable. Tissues in culture could be an answer to this problem, at least in some cases, as they are not sentient and only can have interests and needs in a very metaphorical way. Yet at the same time, they can produce ﬁndings that are often even better transferable to whole human beings than animal experiment results (Gelhaus 2009a). So ﬁrms that offer designed cell cultures attempt to capitalize on this moral advantage by drawing its attention to potential buyers, and animal protectors demand the use of these alternatives whenever possible (Nordgren 2004).

On the other hand, as for every experimental therapeutic approach, new tissue engineering projects require accessory animal experiments at every step of development, from the testing of used materials, matrices, cells, and signaling substances to the proof of the therapy principle itself and to clinically relevant animal models. Bioprinting at its current stage of development is in clear need of animal studies on mammalians, and there is no hope that it could come to clinical application without consuming laboratory animals. Having once reached a level of effectivity that would allow in vivo therapy with cell lines or at best autologous cell cultures of the respective patient, further animal experimentation with regard to bioprinting would be superﬂuous. It is however doubtable if one could excuse actual moral faults with a desired result of making these deeds unnecessary later. A likewise excuse would be that stealing enough money now would be excused by the fact that one never needed to do this again later because of the gathered wealth. However, if tissue engineering in general and bioprinting as a part of it would make the use of animals for therapeutic and research goals superﬂuous, this would be a positive effect. As long as pigs and cattle are slaughtered in order to eat them, however, there does not seem to be a bigger problem in using their organs and tissues also for therapeutic reasons. If the wish and hope for knowledge in itself can morally justify, animal experimentation is another and more controversial question. However, this is not speciﬁc for bioprinting but for all clinical research. In theory, tissue engineering could replace many needs for animal experimentation, but bioprinting is no example for this, as the biocompatibility of bigger structures, in contrast to, e.g., chemical substances, can only be shown in bigger organ relations.

Alternative Techniques

An important part of ethical deliberation is the assessment of alternative action. This has to be done for each single research approach, but some things can be sketched generally for bioprinting techniques with the idea of combining conventional engineering techniques with cell culture methods. Direct alternatives are other scaffolding methods that use either growth inductors or living cells for all kinds of regenerative medicine.

A different approach would be to use purely biological or biochemical methods in order to create the desired tissues or organs. The advantage would be that no potentially dangerous scaffold materials, biodegradable or not, are required. The disadvantage is that the biological organogenesis is far more complex and probably much more difﬁcult to reach in vitro than biomechanical combination methods (Hammerman and Cortesini 2004).

The technically easiest and nearest, though also time-consuming, method to produce autologous organs and tissues is regenerative cloning. This has already been done in different mammalian animal experiments, and there is no reason to assume it is technically more difﬁcult in human beings. The problem with this alternative is an ethical one. Disregarding the foreseeable unsuccessful tries on the way that are more easily tolerated in other animals, it is still a human being that is grown in reproductive cloning, roughly speaking an identical twin with time delay. There is no reason not to attribute full human rights to the clone and thereby no moral excuse for sacriﬁcing her to her older twin, taking her organs and tissues for the use of the “original.”

A fulminant success in bio printing presupposed, i.e., the possibility to print a whole biologically functioning human organism, the ethical problem would be the same (Harbaugh 2015). There would be no morally defendable reason over mere feasibility to use the biomechanical surrogate technique instead of the purely biological one, implying all ethical problems of cloning human beings. Rather, as no human mothers would be required that could theoretically resist to evil intentions, a printing technique for complete organisms would be even more easily to be misused than more conventional breeding techniques, for example, in order to produce slaves or soldiers. Therefore, ethically speaking, a full technical mastery of bioprinting would destroy its moral desirability. The meaning of bioprinting as technique lies is reproducing desired parts of an organism that can be used without further moral dilemmas, NOT whole organisms. Producing steaks from cattle cell lines is from an ethical and practical view preferable to producing cattle with a bioprinting method.

Social Consequences

Bioprinting techniques can be a part in the construction of better prostheses, being one method to place tissue and/or scaffolds spatially correctly. Thus they can get their place in reproductive medicine in restoring and ameliorating function in different parts of the body. If they can help to produce whole organs like, e.g., kidneys, this would be a big success for transplantation medicine with many possible advantages, the potential to offer organs to all who need them and the end of all problems around organ donation:

– The discussions about the brain death criteria insofar as they are related to applicability of dead donor’s organ donation

– Risks and consequences of living organ donation

– If organ bioprinting will be possible with the patient’s own cells, no further problems with organ rejection and immunosuppression

– Allocation decisions

– Legal, moral, and economic incitements for living and dead organ donation

All these advantages have in addition to the individual beneﬁts also quite remarkable social consequences, as they could diminish the practical and ethical dilemma in broad societal conﬂicts about autonomy, piety, the rightful place of ﬁnancial incitements in existential questions, the obligations of solidarity, justice, the concepts of life, death, personhood, and more. Obviously, these questions will in no way be solved or replaced by an eventual universal availability of bioprinted organs, but a quite expanded medical practice that deeply is rooted in certain answers to all these questions could be freed from these discussions. This would not only be a relief for the patients who get organs, but it would also free the respective discussions from the cost of many dying and suffering patients if one not subscribes to the positions in question that make usual organ donation acceptable. A permanent emergency situation would be left behind, leaving room for broader and more reasonably reﬂected deliberations that have inﬂuences on nearly all other aspects of life in societies.

On the other hand, bioprinting is another example of bioengineering that mixes the tradition of engineering with nonliving material with the special ethical and conceptual impacts of dealing with living organisms – cultivating, breeding, and manipulation. Technically exciting and inspiring, this mixture of research traditions blurs moral conventions and legal requirements. For example, nearly all review articles on bioprinting speculate about deﬁcits in effectivity which is typical for considerations in engineering – side effects are supposed to be a matter for those who apply the respective technique (Chia and Wu 2015; Derby 2008; Murphy and Atala 2014; Mironov et al. 2006; Norotte et al. 2009; Collins 2014). In research with human subjects, on the other hand, the risks of research and possible side effects are among the ﬁrst things to consider, as an incomparably higher status is attributed to the research subject as compared to living materials. But even in research on living systems in general, containment and possible side effects are more in the focus from the beginning, because in living systems that by definition have the potential to reproduce, all research is already its own application (Gelhaus 2006). From the background of engineering, the required deliberations, risk assessments, and formal requirements with the aim to reduce risks might appear strange and difﬁcult to understand. Therefore there is a risk that the achieved ethical research standards might be lower – applying rather usual standards from printing technologies than from research with human tissue. As a single case, this might appear a lesser problem, as also tissue engineering is in many cases a low-risk technology; but as part in a research program, there is a risk that more and more aspects also of human life fall under the paradigm of replace ability, taking over the machine metaphor of the body not only practically but also conceptually and diminishing the realm of humanism (Gelhaus 2009b).

Apart from these more general consideration about possible social consequences, it is of course important how and with which intentions bioprinting is used. The therapeutic intention is ethically the most uncontested application. There is, however, no technical borderline to enhancement, constructing, and printing more sustainable or more effective mechanical/biological tissue hybrids. This could be used, for instance, in sports, in military contexts, or in a general transhumanistic program, all of these ethically quite dubious. The most realistic risk might result from military research that generally applies exceptions from otherwise universal ethical standards.

Conclusion

Bioprinting is a combination of 3D printing techniques with tissue engineering and has as such the challenge to solve problems of effectivity and biocompatibility. It is important to consider ethical precautions that go with every single of the applied techniques in question and not using an average standard or even applying the lowest common denominator.

An ethical assessment has to be done for each single project, but the combination of techniques does not only include the single risks but, in combination, generally results as well in elevated possible beneﬁts as in speciﬁc and in more general risks.

In addition to a technical risk-beneﬁt assessment, also potentials for broader social consequences should be considered, as they might result from not only the early research but a broader application. Following Hans Jonas, the imperative of responsibility requires special attention on worst case scenarios (Jonas 1979). The project of scientiﬁc research, on the other hand, is inspired by the growth of knowledge, feasibility, and visions of immortality and the end of suffering. A wise consideration should be aware of both extremes and ﬁnd ways to reduce risks both in research and application, considering not only feasibility but also possible alternatives and desired and undesired effects in a broader perspective.

Bibliography :

Chia, H. N., & Wu, B. M. (2015). Recent advances in 3D printing of biomaterials. Journal of Biological Engineering, 9, 4.
Collins, S. F. (2014). Bioprinting is changing regenerative medicine forever. Stem Cells and Development, 23 (Suppl 1), 79–82.
Derby, B. (2008). Bioprinting: Inkjet printing proteins and hybrid cell-containing materials and structures. Journal of Materials Chemistry, 18, 5717–5721.
Gelhaus, P. (2006). Gentherapie und Weltanschauung. Darmstadt: Wissenschaftliche Buchgesellschaft.
Gelhaus, P. (2009a). Ethical aspects of tissue engineering. In U. Meyer, T. Meyer, J. Handschel, & H. P. Wiesmann (Eds.), Fundamentals of tissue engineering and regenerative medicine (pp. 23–35). Berlin: Springer.
Gelhaus, P. (2009b). Der Mensch als Gen-Maschine. Zur Reichweite und Geschichte einer Metapher. Zeitschrift fur Semiotik, 31(3–4), 397–410.
Hammerman, M. R., & Cortesini, R. (2004). Organogenesis and tissue engineering. Transplant Immunology, 12, 191–192.
Harbaugh, J. T. (2015). Do you own your 3D bioprinted body? Analyzing property issues at the intersection of digital information and biology. American Journal of Law & Medicine, 41(1), 167–189.
Jonas, H. (1979, Engl. 1984). Das Prinzip Verantwortung: Versuch einer Ethik fur die technologische Zivilisation. Frankfurt/M.: Suhrkamp (Engl. The imperative of responsibility: In search of an ethics for the technological age. Chicago: The University of Chicago Press).
Mironov, V., Reis, N., & Derby, B. (2006). Bioprinting: A beginning. Tissue Engineering, 12(4), 631–634.
Murphy, S. V., & Atala, A. (2014). 3D bioprinting of tissues and organs. Nature Biotechnology, 32(8), 773–785. Nordgren, A. (2004). Moral imagination in tissue engineering research on animal models. Biomaterials, 25, 1723–1734.
Norotte, C., Marga, F., Niklason, L., & Forgacs, G. (2009). Scaffold-free vascular tissue engineering using bioprinting. Biomaterials, 30, 5910–5917.
Steinbock, B. (2007). Moral status, moral value and human embryos: Implications for stem cell research. In B. Steinbock (Ed.), The Oxford handbook of bioethics (pp. 416–440). Oxford: Oxford University Press.
Williams, D. F. (2008). On the mechanisms of biocompatibility. Biomaterials, 29, 2941–2953.
Chua, C. K., & Yeong, W. Y. (2015). Bioprinting. Principles and applications. Singapore: World Scientiﬁc.
Zhang, L. G., Fisher, J. P., & Leung, K. (2015). 3D bioprinting and nanotechnology in tissue engineering and regenerative medicine. London: Academic.