We’ve all heard of 3D printers. It is commonly used in different fields of industry as well as for personal uses. However, did you know that 3D printers are also used to print human tissues and organs?
What are some bioprinting techniques?
Just like typical 3D printers, 3D bioprinters print out a physical model, layer by layer, but using a special ink called bioink. Bioink is composed of living cells and various biomaterials that encourage cell adhesion, proliferation, and differentiation after printing. Yet, 3D printing living cells raises multiple challenges such as keeping the cells alive while printing. There are few printing techniques to overcome such challenges. There are primarily 3 techniques: extrusion-based bioprinting, inkjet-based bioprinting, and laser-assisted bioprinting. The most widely used technique is extrusion-based bioprinting. Regarding the advantages of other bioprinting techniques, extrusion-based bioprinting is famous for its rapid printing, easy operation, and suitability for a broad range of biocompatible substances. In this method, the bioink is loaded into the cartridges and is pushed through micro-nozzles, which are about 400 microns in diameter. Then, a continuous filament is produced to form complex 3D structures.
Process of extrusion-based bioprinting
Bioprinting requires numerous intricate processes: A significant amount of the cells in the ink are destroyed if the nozzle is undersized or the printing pressure is too high. Other than this, the researchers also have to hold the structure in place until it stabilizes. Then, how are the researchers able to deal with all the complex challenges? The process of extrusion-based bioprinting answers this question.
Steps of extrusion-based bioprinting
Bioink gets loaded into the printing chamber.
The filament is pushed through the nozzle by either pneumatic pressure (air pressure) or mechanically-derived pressure.
Bioink is printed onto a layer of hydrogel.
Multiple layers of cells are built upon to form a 3D structure.
Bioink (cells) develop and fuse together while the hydrogel dissolves.
Living tissue is created.
Conclusion
There is still a long way to go to perfect this technology. However, researchers in this area have already created successful lung tissue, skin, and cartilage using bioprinters. Moreover, they also created a miniature and semi-functional version of hearts, kidneys, and livers.
As technology advances and bioprinting is perfected, we could expect remarkable results and possibilities. Not only replacing organ donors and animals in testing labs, but also printing tissues with embedded electronics, organs that surpass current human capability, and extending human life by printing and replacing organs.
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