Modified 3D printers developed at Wake Forest Institute for Regenerative Medicine in North Carolina, US, that print human cells in hydrogel-based scaffolds, backed by USD$24m (£15m) from the U.S. Department of Defence, have accomplished the feat of printing miniature human organs to test new vaccines in a lab. The “body on a chip” project replicates human cells to print heart, liver, lung and blood vessel imitating structures.
“You are actually testing human tissue,” Dr Anthony Atala, Institute Director of the 
Bioink containing cell is printed into agarose gel moulds [IMAGE CREDIT: Modern Meadow]
