Tiny leds can be injected into the brain

The devices can be operated wirelessly and include leds, temperature and light sensors, miniature heaters and electrodes that can both stimulate and record electrical activity. The leds themselves can be as small as single cells and are printed onto the end of a flexible plastic ribbon. Using a micro-injection needle, they can be injected precisely and deeply into the brain, with a minimum of disturbance to the brain tissue. "These materials and device structures open up new ways to integrate semiconductor components directly into the brain," said John Rogers, the Swanlund professor of materials science and engineering at the University of Illinois. "More generally, the ideas establish a paradigm for delivering sophisticated forms of electronics into the body: ultra miniaturised devices that are injected into and provide direct interaction with the depths of the tissue." Rogers believe the devices could provide neuroscientsits with a new way of measuring and manipulating the brain and other living tissues. One obvious application is in optogenetics experiments, which involve genetically modifying neurons to make them fire in response to light. "These cellular scale, injectable devices represent frontier technologies with potentially broad implications," Rogers concluded. "This is just the first of many examples of injectable semiconductor micro devices that will follow."