TINY MEDICAL IMPLANTS POWERED BY ULTRASOUND

Stanford University: Wireless Medical Sensors Powered Remotely with Ultrasound

Engineers at Stanford University have devised a way of remotely charging medical implants using ultrasound. The research reflects the need for a reliable way of powering medical implants without having to resort to using large, cumbersome batteries or the use of external leads, which heighten the risk of infection. Ultrasound has been deemed medically safe and is used in a variety of medical applications, such as fetal imaging or to accelerate the effect of drugs in a targeted area.

The implant designed by the Stanford team contains a piezoelectric “power plant” which consists of a small amount of piezoelectric material. This material converts mechanical stress into an electric current, in this case ultrasound pulses exert pressure on a tiny spring, the resulting electricity powers the implant. An antenna attached to the implant allows signals to be sent to and from an external wireless receiver. The electrical current can also be harnessed to deliver a series of small shocks as part of a pain management treatment. The implant is the size of the head of a ballpoint pen, but researchers hope to shrink this down by a factor of ten, which would for example allow clinicians to implant a network of sensors in the brain to gain a better understanding of neural processing.