Why Drug Testing May Be the Most Important Application of 3D Bioprinting

3D bioprinting is, needless to say, great cause for excitement. Usually, most people’s minds go immediately to one idea: the idea that in the future, we may be able to 3D print working human organs that can actually be transplanted into patients, saving their lives without requiring a donated organ from another person. It’s understandable that people are excited about that prospect; 3D bioprinted organs potentially carry tremendous advantages. People could receive lifesaving organ transplants right away, without having to wait for a donor match, eliminating the years-long wait lists as well as the guilt that comes from benefiting from the death of another person. In addition, the idea is that 3D printed organs are formed from the patient’s own stem cells, eliminating the risk of rejection and the need for immunosuppressive drugs.

In reality, we probably won’t see 3D printed, transplantable human organs for several years yet. 3D printing an organ is more than just 3D printing layers of cells into the shape of a kidney or liver; those organs must be able to carry out all of the distinct functions of their natural counterparts, and they have to be capable of integrating with the body’s existing systems, which involves the development of nerves and blood vessels. Progress is being made in the development of 3D printed blood vessel networks, and the advancement that scientists have made over the last couple of years towards 3D printed organs really is remarkable, with working thyroid glands and ovaries being transplanted into mice, for example.

It’s easy to see progress like that and think, “Wow, we could be transplanting 3D printed organs into people by next year!” Again, it’s not that simple, but the fact that scientists have been able to 3D print live tissue at all is incredible, and the technology is already saving lives in the form of cardiac patches, for example. But lives are also being saved through a bioprinting application that gets less sensational attention. 3D printed tissue is proving to be an effective means of testing new pharmaceuticals, meaning that drugs can be thoroughly assessed and brought to market more quickly, all without harming animal test subjects.

A group of researchers from Queensland University of Technology (QUT) recently published a paper discussing the development of a new type of bioink that enables the 3D printing of cells and other biological materials as part of a single production process. You can access the paper, entitled “Mechanically Tunable Bioink for 3D Printing of Human Cells,” here. In the opinion of these researchers, the possibilities bioprinting offers for drug development may be the most important use of the technology.

“Using current methods, bringing a new drug to market has been estimated to cost US$2.5 billion, and can take more than ten years from start to finish,” the researchers state. “Even if you manage to identify a new candidate drug, the likelihood of regulatory approval is low: in 2016, less than 10% were approved.”

The reason behind the failure of so many drugs is that even when a new drug works well on animals, its effects don’t necessarily translate to humans. Human physiology is very different from that of test subjects such as mice, so what works for a mouse doesn’t always work for a person. With 3D bioprinted tissue, however, scientists can actually create the kind of complex human tissue found in organs such as the heart, liver, kidneys, etc. and see right away the effects that a particular drug will have on those tissues inside the human body.

While the use of animals for research isn’t likely to be eliminated entirely, the researchers continue, 3D bioprinted skin tissue can eliminate one use of animals in the laboratory. The testing of cosmetics on animals has always been more controversial than testing for medical purposes, and now that we have the ability to 3D print human skin, there’s really no need to test cosmetics on animals at all anymore. In 2013, the European Union passed a law against testing cosmetics on animals, and we can hope that the newer and better alternative of 3D printed skin will be reason enough for similar laws to be passed on a worldwide level.

The more distinct types of tissue that scientists are able to 3D print, the better the possibilities become for more effective pharmaceutical testing – and potentially transplantable organs in the future. Bioprinting isn’t a one size fits all solution; different types of cells require very different types of environments in order to function properly. In the recently published QUT paper, the researchers discuss how their new bioink, extracted from marine algae, can be used to 3D print human stem cells in different, distinct environments, without harm coming to the cells.

“This work paves the way toward the printing of complex tissue-like structures composed of a range of mechanically discrete microdomains that could potentially reproduce natural mechanical aspects of functional tissues,” the researchers explain.

Authors of the paper include Aurelien Forget, Andreas Blaeser, Florian Miessmer, Marius Köpf, Daniela F. Duarte Campos, Nicolas H. Voelcker, Anton Blencowe, Horst Fischer and V. Prasad Shastri. Discuss in the 3D Bioprinting forum at 3DPB.com.

[Source: The Conversation / Images: Steffen Harr]