Scientists recently published results that describe how they use TNT (not the explosive) to reprogram skin cells to make other types of cells they used in the body to fix problems.
The main things they did: make vascular cells to make blood flow again to test subjects (animals) with skin flaps and removed femoral arteries. They also made nerve cells to to help subjects recover from stroke.
The process has 2 parts: a chip (developed 6 years ago) that injects the "cargo," and the cargo itself -- plasmid, DNA, or even RNA. The cargo induces plasticity (it fires novel cell reprogramming factor genes into the skin cells) through tiny channels in the cell membranes (much smaller than the older process for doing this).
The researchers were "surprised how it worked so well" and don't completely understand it yet, but they've also achieved or see themselves achieving similar results in making insulin-producing cells that can sense glucose levels, changing white fat cells to brown, and working with eyes and ears.
They also explained that they see the technology going much further, relaying transfection to deeper than skin levels, since they can do this with almost any cell type. It requires no lab equipment, so they see it being done at point-of-care.