A heat sensor for living cells could offer new views of cell metabolism, rapid antibiotic testing

When living cells grow, divide or respond to drugs, they give off tiny amounts of heat that offer information about what the cells are doing. But because these heat signals are so vanishingly small, they have traditionally been impossible to measure directly. Researchers in the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a calorimeter—a device that measures the heat transfer between a living system and its environment—that can detect metabolic heat signals on the order of 100 picowatts, or trillionths of a watt, in living cells.