European Space Agency advances tissue replacement by turning everything upside down.
Organs and tissue become diseased, aged or dysfunctional and replacements are needed for extension of both lifespan and healthspan. However, organs available for transplant are in short supply and xenotransplantation is still at the animal experiment stage, so science is looking to 3D-bioprinting to fill the gap.
Longevity.Technology: How does researching how astronauts can be helped in space have implications for people needing new tissue on back on Earth? The more researchers can develop bio-material and bio-printing techniques to push-back the boundaries of what is possible, the faster we will get to a situation where transplants are 3d-bioprinted to order.
The TRL score for this Longevity.Technology domain is currently set at:
The TRL score for the technology addressed in this article is: “Late proof of concept demonstrated in real-life conditions.”
3D-bioprinting involves combining cells and growth factors to create tissue-like structures that imitate natural tissues by building in a layer-in-by-layer manner. Bioprinted cells with an extracellular matrix are deposited into a 3D-gel layer by layer to produce the required tissue or organ. So far research in this field has yielded functioning tissues including bone, ovaries and skin that could be used in a human body . 3D-bioprinting has also begun to incorporate the printing of scaffolds that can be used to regenerate joints and ligaments .
Now scientists are taking the field into the unknown by experimenting to see how bioprinting would fare in space. The European Space Agency’s 3D Printing of Living Tissue for Space Exploration project wants to be able to print human tissue to treat astronauts in space or even on Mars. Due to the expense and difficulty of conducting experiments in space or in weightless conditions, researchers from University Hospital of Dresden Technical University in Germany, as part of a consortium together with prime contractor OHB System AG and life sciences specialist Blue Horizon, decided to tackle the problem by seeing if samples of bone and skin could be produced upside-down .
Human blood plasma was used as the bio-ink with plant and algae-based materials added in order to increase the viscosity and stop the mixture from pooling out or going in the wrong direction. The additional materials were chosen because they could be carried on the mission. Nieves Cubo, one of the researchers, explains: “Skin cells can be bioprinted using human blood plasma as a nutrient-rich ‘bio-ink’ – which would be easily accessible from the mission crewmembers. However, plasma has a highly fluid consistency, making it difficult to work with in altered gravitational conditions. We therefore developed a modified recipe by adding methylcellullose and alginate to increase the viscosity of the substrate. Astronauts could obtain these substances from plants and algae respectively, a feasible solution for a self-contained space expedition.
“Producing the bone sample involved printing human stem cells with a similar bio-ink composition, with the addition of a calcium phosphate bone cement as a structure-supporting material, which is subsequently absorbed during the growth phase .”
Being able to bioprint skin would allow astronauts to heal burns and abrasions on a space mission; bone grafts might be needed as fractures are more likely in zero-gravity of space or on Mars where the gravity is a third of that on Earth .
Producing 3D-bioprinters that can give reliable results in difficult situations can only be a good thing. It would allow transplanted tissue to be available in hospitals that have no facilities and perhaps allow to mobile facilities to travel to outlying places to perform procedures. Using readily-available plant and algae substances to maintain viscosity might reduce the cost of the procedure allowing wider experimentation and development as well as rolling out the procedure to the developing world or poorer members of society. The more researchers can develop the technique and push back the boundaries of what is possible, the faster we will get to a situation where transplants are 3d-bioprinted to order, meaning no more transplant waiting lists and diseased and decrepit organs are a thing of the past. This situation would be out of this world for both extending lifespan and improving our quality of life.