I often talk about how health tech wearables ultimately will have to “disappear” into our lives. This means that you don’t have to remember to put on the device or pick it up, you don’t have to remember to recharge it, and you don’t need to remember to transfer data to or from the device. It will have to be a “set it and forget it” design. One of the leading candidates for a format is a “temporary tattoo” that can be applied directly to the skin.

There are many hurdles in the way of practical health tech tattoos, however. They must survive bending and stretching, like human skin. And they must be easy and inexpensive to fabricate. Researchers at Carnegie Mellon and the University of Coimbra in Portugal have come up with a new approach that addresses both of these problems. They have suspended silver nanoparticles in liquid metal to create a material that can be printed on standard tattoo paper using ink jet printers. The process does not require an expensive clean room or high temperature sintering.

The result is an inexpensive device that can be applied directly to the skin using just a damp sponge. The device can conform and adhere to uneven surfaces, such as the outside of a human brain. The end result is that we may see all sorts of biosensor devices delivered in an inexpensive and convenient form factor.