By Bella Moyer

Figure 1
A visual representation of the bioprinting process for a liver sample (Bhatt 2024).

Every day, seventeen lives are lost due to the lack of donor organs for over 100,000 people currently on the transplant waitlist (U.S. Department of Health & Human Services, 2024).  Current advances in bioprinting technology are hopeful to reduce this drastic, alarming number.  Bioprinting refers to the layer-by-layer fabrication of living tissues and organs using 3D printing techniques. Researchers have already successfully printed mini-organs, blood vessels, and tissue scaffolds. However, despite this progress, significant scientific, technical, and ethical hurdles remain before fully functional, transplantable human organs can be printed. 

Current research has found that organs can be made with a combination of bio ink and pluripotent stem cells (PSCs).  The organs are formed by a multi-step process that combines stem cell biology, tissue engineering, and 3D bioprinting technology (Figure 1).  Bio ink is a printable, gel-like material that contains living cells, and it must be biocompatible, viscous, and supportive of cell survival and growth.  PSCs are cells that can become any type of cell in the body and are either derived from embryos or created from adult cells.  Before printing, the PSCs need to become the specific type of cell required.  This is done by exposing the PSCs to specific growth factors, chemicals, and environmental cues.  Once the cells are created, they are mixed with a hydrogel to make a bio ink.  The bio ink is then printed layer by layer to a precise 3D shape of the organ based on the digital model retrieved from a CT or MRI scan (Murphy & Atala, 2014).  

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