Researchers create sand grain-sized implantable wireless sensor

Researchers at the University of California at Berkeley have made so-called ‘neural particles’ the size of a large grain of sand that can be implanted in the body and receive their energy from ultrasound, which can also be used to read the sensor.

The ‘neural dust’ can be used to monitor or stimulate functions in the body in real time, such as nerves, muscles or organs. The sensors are controlled via an external transducer or transducer that drives a piezoelectric crystal. Attached to that crystal is a simple electronic circuit that responds to the voltage between two electrodes. The voltage across the electrodes can then be read via the returning ultrasound.

The researchers previously conducted experiments with radio waves, but they do not penetrate deep enough into the body, which means that radiation doses may be too high to communicate with the sensors. It is also easier with ultrasound to reach very small devices, says one of the researchers on the university’s site.

The first versions of the sensors still consisted of coated circuits with an epoxy resin, but at the moment the ‘dust’ are made from biocompatible thin films that can possibly remain in the body for more than ten years.

The first goal of the project was to create a next-generation brain-machine interface that would eliminate the need to implant electrodes in the brain with a wire that exits through a hole in the skull. Before that happens, the sensors have to be made a bit smaller, namely about 50 micrometers.

Source: Cell