New dust-sized implants can track every organ in your body

Fitness trackers have become some of the more popular types of wearable technology in recent years, but engineers at the University of California, Berkeley want to take the concept one step further by developing miniscule, wireless sensors to monitor a person’s internal health.
These devices would be approximately the same size as a grain of dust and would be implanted into a person’s body, where they would provide real-time monitoring of organs, muscles, and/or nerves, the researchers explained
Furthermore, the sensors don't use batteries and could be used to stimulate nerves and muscles, thus providing a potentialnew way to treat disorders such as epilepsy or to activate a person’s immune system. The devices, which have already been implanted in the muscles and peripheral nerves of rats, use ultrasound both as a source of power and as a way to read the collected data.
Dubbed “neural dust,” the sensors have already been reduced down to a one millimeter cube and contain a piezoelectric crystal. The crystal converts ultrasound vibrations emanating from outside a person’s body into electricity, which is used to power a tiny transistor on the device which is in direct contact with a nerve or muscle fiber, the study authors explained.

http://www.redorbit.com/news/health/1113415309/fitness-tracking-implants-080316/