Cryogenics and 3D-printing techniques could allow the replication of human tissues

In a recent article¹ published in Scientific Reports, Zhengchu Tan and a team of researchers present a cryogenic 3D printing method capable of producing stable 3D structures by using the liquid to solid phase change of a composite hydrogel ink that has been rapidly cooled below its freezing point with solid carbon dioxide (or dry ice) in an isopropanol bath. The researchers were able to successfully create complex geometric 3D structures which mimic the mechanical properties of the softest tissues found in the human body, such as the lungs or the brain. These structures could be used as “scaffolds”, which would serve as templates for human organs that require tissue regeneration. Indeed, despite being very soft, the structures do not collapse under their own weight - an issue which made other similar experimental attempts fail. The 3D-printed templates can encourage damaged tissues to regrow. Scientists say that by “seeding” porous scaffolds with cells, damaged parts of the body can easily heal without the usual problems of traditional approaches in tissue regeneration. For instance, tissue rejection will no longer be an issue because the procedure does not involve transplantation.

For now, the technique has been tried on human skin. Zhengchu Tan said in a statement that at the moment, the structures created were a few centimetres in size, but that he and his team would ideally like to create a replica of a whole organ using this technique.

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¹TAN Zhenchu, PARISI Cristian, DI SILVIO Lucy. Cryogenic 3D Printing of Super Soft Hydrogels. Scientific Reports [online]. 2017, vol. 7, 11 p. Available on: https://www.nature.com/articles/s41598-017-16668-9.pdf.