MIT researchers have come up with a 3D printing technique that uses ink made from genetically programmed living cells. These cells light up in response to various stimuli. The team demonstrated the idea by printing a:
“living tattoo” — a thin, transparent patch patterned with live bacteria cells in the shape of a tree. Each branch of the tree is lined with cells sensitive to a different chemical or molecular compound. When the patch is adhered to skin that has been exposed to the same compounds, corresponding regions of the tree light up in response.
This approach can be used to make active materials for wearables and interactive displays.