Took the following from an american website after a bit of web searching. You may have already seen this sounds fascinating. No experience of it myself.
A key to the research dedicated to regrowing fingers and other body parts is a powder, nicknamed "pixie dust" by some of the people at Brooke. It's made from tissue extracted from pigs.
The pixie dust powder itself doesn't regrow the missing tissue, it tricks the patient's body into doing that itself. All bodies have stem cells. As we are developing in our mothers' wombs, those stem cells grow our fingers, toes, organs -- essentially our whole body. The stem cells stop doing that around birth, but they don't go away. The researchers believe the "pixie dust" can put those stem cells back to work growing new body parts.
The powder forms a microscopic "scaffold" that attracts stem cells and convinces them to grow into the tissue that used to be there. "If it is next to the skin, it will start making skin. If it's next to a tendon, it will start making a tendon, and so that's the hope, at least in this particular project, that we can grow a finger," Wolf said.