Here is interesting work out of Yale, where biomed engineers created artificial microcirculation:
The researchers used two important engineering enhancements to develop stable functional microcirculation. First, they created a “micro-scaffold” of a macroporous hydrogel polymer. The hydrogel is a three-dimensional, sponge-like material — highly water-saturable, with a structure of connected pores for cells to grow on and through.
Second, they seeded the hydrogel scaffolds with endothelial cells that make up blood vessel structure along with nerve progenitor cells from the brain. Because there is often an association of nerve connections with vascular networks, they tested to see if a combination of the blood vessel-forming and nerve-forming cells would enhance development of the vascular networks.
“By their nature, hydrogels are well suited for the transport of soluble factors, nutrients or drugs, and waste,” said Lavik. [Erin Lavik, assistant professor of Biomedical Engineering -ed.] “The hydrogel scaffold materials are generally highly biocompatible and safe to implant due to the presence of large volumes of water.”