Researches from Trinity College Dublin, Ireland and the University of Sao Paolo, Brazil have converted a silicone polymer, better known by Crayola’s trademarked name Silly Putty, into an incredibly sensitive strain sensor. It’s so sensitive that a piece of putty pressed against the carotid artery can detect not only the heart rate, but the blood pressure of a person. It can be made hundreds of times more sensitive than a traditional strain sensor, something the researchers demonstrated by detecting the footsteps of spiders walking over it.
The material is really just Silly Putty mixed with graphene, which is a bunch of tiny sheets of carbon one atom thick. The material is conductive and its electrical resistance varies significantly in response to physical strain put on it. A simple multimeter can be used to detect this change by placing electrodes at opposite sides of a piece of putty. Because it is so easy to use, made of cheap materials, and has high sensitivity it should find a lot of application in medicine.
Here’s a short video from Science magazine about the new material: