At the moment, they are placed on the body and could be used to measure, store and communicate the data to nursing staff or monitor a patient’s environment. But to get beyond the research phase, the sensors must be more than tiny. And the nano monitors need power to run, too. Tomorrow Today’s report tells you how the researchers are using body heat to flick the power switch. In the studio: Michael Niedermayer, The Fraunhofer Institute for Assembly and Packaging Technologies for Microelectronics, Microsystems and Power Electronics, Berlin