First Dust-Sized Wireless Sensors Built by TerraSwarm PIs Jose Carmena, Michel Maharbiz, and Jan Rabaey

An August 3, 2016 news article, "Sprinkling of neural dust opens door to electroceuticals," reports that a team of University of California, Berkeley engineers including TerraSwarm PIs Jose Carmena, Michel Maharbiz, and Jan Rabaey have developed the first dust-sized, wireless, implantable sensors. Measuring 1 millimeter cube, the sensors are approximately the size of a grain of sand. The batteryless sensors use ultrasound as both a power source and to communicate results, overcoming one of the major challenges to this type of technology. Unlike radio waves, ultrasound vibrations can penetrate most of the human body, and is already widely used in healthcare settings. This opens the possibility for applications deep within the body.  Piezoelectric crystal is used to convert ultrasound vibrations from outside the body into the electricity needed to power the device's on-board transistor, which is in contact with nerve or muscle fiber. Changes in the voltage of the fiber alters the circuit of the device causing variation in the echo picked up by the ultrasound receiver.

Applications include real time monitoring and stimulation of internal organs, muscles, or nerves. This technology opens the door to new diagnostic and treatment of a wide range of conditions including epilepsy, inflammation, and paralysis. Compared to currently available implantable electrodes that require wires to be passed externally, these sensors are sealed in the body decreasing the likelihood of infection and accidental displacement. The researchers are currently working on building sensors using biocompatible thin films, which would allow the sensors to function in the body for a decade or more without degradation. Future work includes developing even smaller sensors.