The breakthrough, detailed Nov. 3 in Nature Electronics, demonstrates that microelectronic systems can function at an unprecedentedly small scale, opening new possibilities for neural monitoring, bio-integrated sensing and other applications.

Development of the device, called a microscale optoelectronic tetherless electrode, or MOTE, was co-led by Alyosha Molnar, professor in the school of electrical and computer engineering, and Sunwoo Lee, an assistant professor at Nanyang Technological University who first began working on the technology as a postdoctoral associate in Molnar’s lab.

Powered by red and infrared laser beams that pass harmlessly through brain tissue, the MOTE transmits data back using tiny pulses of infrared light, which encode the brain’s electrical signals. A semiconductor diode made of aluminum gallium arsenide captures light energy to power the circuit and emits light to communicate the data. Supporting this is a low-noise amplifier and optical encoder built using the same semiconductor technology in everyday microchips.