neural dust

Tiny wireless, battery-free sensors that are placed inside the body and powered and read using ultrasound from outside it. Developed at UC Berkeley and first shown in rats in 2016.

Each 2016 sensor, or mote, was about 3 millimetres long and 1 millimetre across, implanted on a nerve or muscle. It holds a piezoelectric crystal and a simple circuit. An ultrasound transducer outside the body sends pulses; the mote reflects them back slightly changed by the electrical activity it is touching, and that change is read as the signal. Ultrasound was chosen over radio because it travels through tissue far better at this size. A 2018 version, StimDust, can also stimulate nerves.

The early work was on nerves and muscles. The inventors describe the brain as a future target, with further shrinking of the motes.

Related terms: neural interface, hardware, piezoelectricity, injectable mesh electronics

Sources: Sprinkling of neural dust opens door to electroceuticals — Berkeley News (2016); Berkeley engineers build smallest volume, most efficient wireless nerve stimulator — Berkeley News (2018)