The future is here, apparently.  From Engadget.com:

Researchers print biometric sensors directly on skin, make wearable health monitors more durable

By Michael Gorman posted Mar 11th, 2013 at 11:54 PM

electronics aimed at athletes, but the company also makes a medical diagnostic sticker called abiostamp. Its creator (and MC10 co-founder), John Rogers has refined that design so that it’s no longer an elastomer sticker — now he can apply the biostamp’s thin, stretchy electronics directly on human skin, and bond it with commercially available spray-on bandage material. By losing the elastomer backing of the original biostamp and applying the circuits directly to the skin, Rogers and his team at the University of Illinois were able to shave the device’s thickness to 1/30th of the (already quite thin) biostamp. That super thin profile means it conforms even better to the contours of human hide and makes it shower- and swim-proof during the two weeks it lasts before being naturally exfoliated with your skin.

For those unfamiliar with what the biostamp does, it’s a mesh of circuits and sensors that can record electrophysiological data like skin temperature and hydration state of the wearer. The new biostamp won’t be in your doctor’s tool box any time soon, however, as Rogers and his team are still refining the wireless power and communication technologies it leverages. Of course, once those problems are solved, there’s a good chance we’ll see MC10 turning it into a commercial product.