Imagine a world where we can peek directly into the brain, understanding its intricate workings with unprecedented detail. Well, that world is getting closer! Researchers at Cornell University, along with collaborators, have created a groundbreaking neural implant so tiny it could sit comfortably on a grain of salt. But what makes this device truly revolutionary? It wirelessly transmits brain activity data for over a year in a living animal.
This incredible feat, unveiled in Nature Electronics on November 3rd, showcases how microelectronic systems can function at an incredibly small scale. This opens up exciting new possibilities for monitoring our brains, sensing biological processes, and much more.
Developed by Alyosha Molnar, the Ilda and Charles Lee Professor in the School of Electrical and Computer Engineering, and Sunwoo Lee, an assistant professor at Nanyang Technological University, the device, called a microscale optoelectronic tetherless electrode (MOTE), utilizes a clever design. Powered by harmless red and infrared laser beams that pass through brain tissue, the MOTE sends data back using tiny pulses of infrared light, which are like the brain's electrical signals translated into a language the device can understand. A semiconductor diode, made of aluminum gallium arsenide, captures the light's energy to power the circuit and emits light to communicate the data.
The MOTE itself is remarkably small, measuring just about 300 microns long and 70 microns wide. To put that into perspective, it's far smaller than the width of a human hair! Molnar highlights that the MOTE is, to their knowledge, the smallest neural implant that can measure and wirelessly transmit electrical activity from the brain. The device uses pulse position modulation, the same coding system used in satellite communications, to send data, requiring very little power while still successfully transmitting the data optically.
The team tested the MOTE in cell cultures and then implanted it into the barrel cortex of mice—the brain region that processes sensory information from whiskers. Over a year, the implant successfully recorded electrical activity from neurons, including broader patterns of synaptic activity. And this is the part most people miss: the mice remained healthy and active throughout the process.
But here's where it gets controversial... Traditional electrodes and optical fibers can sometimes irritate the brain, triggering an immune response. The MOTE's tiny size minimizes disruption, allowing it to capture brain activity faster than current imaging systems, without needing to genetically modify the neurons.
Furthermore, the MOTE's material composition could allow for electrical recordings during MRI scans, something largely impossible with current implants. This technology has the potential to be adapted for use in other tissues, such as the spinal cord.
Molnar first envisioned the MOTE back in 2001, but the research gained momentum about a decade ago with the support of Cornell Neurotech, a joint initiative between the College of Arts and Sciences and Cornell Engineering. The team also includes Chris Xu, Paul McEuen, Jesse Goldberg, and Jan Lammerding.
What do you think? Could this technology revolutionize how we understand and treat neurological conditions? Are you excited or concerned about the ethical implications of such advancements? Share your thoughts in the comments below!
