WIRELESS 'NEURAL DUST' COULD MONITOR YOUR BRAIN

The new prototypes, made by scientists at the University of California at Berkeley, are each roughly 3 millimeters long, 1 millimeter high and 4/5 of a millimeter thick. Each neural dust mote possesses a piezoelectric crystal that can convert mechanical power from ultrasonic pulses broadcast from outside the body into electrical power. The energy from these 60 ultrasonic pulses broadcast each second drives sensors and other electronics on the motes.
The piezoelectric crystals reflect some of the incoming ultrasonic pulses. Electronics in the neural dust motes can alter the pulses that get scattered outward, and so can wirelessly transmit data they gathered. In experiments with rats, the researchers found that neural dust motes implanted in nerve and muscle fibers in the leg could record and transmit electrical data.

less than 50 percent
[link to www.popsci.com]