Biomedical scientists and students need not have expertise in 3D printing technology in order to produce organ tissue models for drug screening or other applications. A method devised at the University of California San Diego (UCSD) simplifies the process for printing human organ and tissue models.

The technique uses a commercial 3D printer and was demonstrated in the fabrication of blood vessel networks capable of keeping a breast cancer tumor alive ex vivo, and a model of a vascularized human gut. A scaffold digitally designed with Autodesk is executed with polyvinyl alcohol (PVA), followed by application of a thick UCSD students construct a vascularized gut model using their team’s new 3D bioprinting technique. Source: David Baillot/UCSD Jacobs School of Engineeringlayer of biologically relevant matrix matter. After solidification, the scaffold structure is flushed out to form blood vessel channels. Interior walls are coated with endothelial cells that are kept viable as cell culture media flows through the bioprinted vessels.

The printed blood vessels were used to keep breast cancer tumor tissues alive for at least three weeks, far longer than tissues kept in a standard 3D cell culture. A vascularized gut model with two channels was also developed. One was a straight tube lined with intestinal epithelial cells to mimic the gut, and the other was a blood vessel channel, lined with endothelial cells, that spiraled around the gut channel. Nourished with appropriate media, the structures assumed natural morphologies within two weeks: the gut channel sprouted villi, the tiny finger-like projections lining the inside of the intestinal wall.

In addition to pharmaceutical screening, the 3D printing approach could be used in place of animal models.