Wearable medical devices such as continuous heart rate monitors, insulin pumps and neural stimulators usually need access to an electric power source in order to function. While there’s a great deal of wasted energy that our body emits that can be harvested to power such devices, making it actually happen using biocompatible materials has proven to be challenging. Now, a team of engineers at Purdue University has shown that polyvinyl alcohol (PVA), one of the most common polymers used in…