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Supercharged silly putty can detect spider footsteps

The future of blood pressure readings could come in the form of supercharged silly putty—or as the scientists who created it call it, G-putty. So what turns silly putty into G-putty? Graphene. The thinnest, strongest material known to exist, graphene is also extremely flexible. It’s made of a single layer of bonded carbon atoms, and conducts electricity remarkably efficiently. Researchers assembled tiny sheets of graphene only a nanometer thick and inserted them into a stretchy silicone polymer (same thing as silly putty). These graphene nanosheets created a microscopic network of electrical conductors within the putty. Scientists could then measure electrical resistance, or how difficult it is for an electrical current to pass through the conductors. They connected G-putty to electrodes connected to a computer. When G-putty was held against skin near the carotid artery on a person’s neck, a soft pulse was enough to disrupt the electrical current flowing through the graphene and subsequently give them a resistance measurement, the team reports today in Science. The G-putty is basically acting as a pressure sensor. Researchers can calibrate this tech to convert resistance into vital measurements. For example, G-putty is sensitive enough to measure how much pressure blood exerts on the artery walls when the heart beats or rests, a less invasive alternative to measuring blood pressure with an arm cuff; it can even sense a spider scurry across it. The best part? The material is 250 times more sensitive than the cheapest metal-based sensor on the market. The researchers are already taking steps toward commercialization because G-putty can be easily reproduced for low costs.