Flexible electronics make possible new wearable and implantable medical devices that conform to the body’s complex curvatures. While a great deal of progress has been made to make such technologies a reality, a lot of them are hard to manufacture, suffer from problems such as poor breathability, and don’t perform well inside the body.

Now scientists at Purdue University are reporting on the development of paper-based electronic devices (EPEDs) that they have dubbed as “smart stickers”. Made of cellulose, they are made to be able to be wirelessly powered and to eventually be used as building blocks to create health monitoring and therapeutic medical devices. They’re naturally breathable and the wires, made of conductive nanoparticles deposited within the stretchable and flexible fabric, are shaped in squiggly lines to stretch and flex along with the substrate and the body part it’s resting on.

You might be wondering how a wet paper substrate can remain strong when in a wet environment, such as when attached to sweaty skin. The magic is made possible by infusing the cellulose with both hydrophobic and hydrophilic molecules, creating an omniphobic substrate that repels both water and oils. The devices can work even underwater while working as electrocardiograms, electromyograms, and electrooculograms.

The Purdue researchers claim that their smart stickers will only be pennies to manufacture each and they will be so comfortable to wear that you won’t even know one is on or in you.