Back in 2016 researchers at Berkeley created a micro sensor that could be activated using ultrasound. It was designed to be implanted in the body to pick up electrical signals. It could work in muscles and various organs, including the brain. Being activated by ultrasound it didn’t need a battery, nor wires to be powered and it was so tiny to look like a dust particle: neural dust since it was designed to pick up neural activity.
Now in 2018 the same team of researchers has announced StimDust, the tiniest nerve stimulator available today. It is just 6.5 cubic mm in size (for comparison a grain of rice is three to four times bigger) and it can sense neural activity, report it and affect the peripheral nerve by stimulating it. The connection with an external device, a computer, uses ultrasounds both as communications and as power source.
The researchers have tested StimDust by placing on the sciatic nerve of a rat and have been able to control the leg movements by sending pulses. The chip has been designed to be placed, using a cuff, around a nerve and stimulates the nerve with electrodes placed at its lower surface. It contains a piezocrystal that serve as antenna and a capacitor that accumulate power for its operation.
The expectation is to be able to use StimDust to interact with nerves to control epilepsy, asthma, heart arrhythmia and chronic pain.