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Today’s neural implants are smaller than ever, but often remain cumbersome and prone to complications. According to researchers at Cornell University, a new iteration detailed this week in the journal Nature Electronics may offer a novel path forward for brain implants. Small enough to fit on a grain of rice, the microscale optoelectronic tetherless electrode (or MOTE) is vastly smaller than similar implants and its design could be adapted to work in other delicate areas of the body.
“As far as we know, this is the smallest neural implant that will measure electrical activity in the brain and then report it out wirelessly,” electrical engineer and study co-author Alyosha Molnar said in a statement.
MOTE measures only 300 microns long and 70 microns wide, or about the width of a single human hair. It works by encoding neural signals within small pulses of infrared light, before sending the information harmlessly through brain tissue and bone to a receiver. Although Molnar first envisioned an early iteration of MOTE in 2001, it would take over two decades before the project truly got off the ground.
He and collaborators designed the implant to rely on a semiconductor diode made from aluminum gallium arsenide. This material enables it to harvest light energy for power while also emitting light to send data. The diode is supported with a low-noise amplifier and optical encoder using the same transmission principles seen in standard microchips. Data transmission is accomplished through pulse position modulation–the same technology seen in many satellite optical communications arrays.Â
“We can use very, very little power to communicate and still successfully get