Health sensors that attach directly to your organs to are potentially very useful, since they can measure miniscule electrical signals and other details that might otherwise fly under the radar. There's just one problem: actually sticking those devices on to something that soft and squishy is tough. However, a team of Japanese researchers may have a solution. They've developed gel-based sensors that monitor electrical activity and strain while adhering to just about anything, including the gooey wet insides of your body. The key is the gel itself, which is made of the polyvinyl alcohol you might find in protective gloves or eye drops; it allows a grid of sensors to make contact without peeling or slipping off.