Graphene 'camera' captures real-time electrical activity of beating heart

Scientists today track electrical signals and voltage changes in neurons and muscle cells by labeling individual cells or probing with electrodes. Scientists have now developed a new type of sensor that employs a sheet of graphene to get a continuous measure of electric field in these tissues. Electric fields change graphene's reflectance. The physicists found a way to amplify and measure the changes caused by action potentials in a beating embryonic chicken heart.