Engineers create the world’s smallest wireless brain chip, smaller than a grain of salt.

A research team from Cornell University, in collaboration with scientists from other countries, has developed the smallest wireless brain chip to date. This microchip is capable of recording brain activity and transmitting data for a long time, and its size is no larger than a grain of salt.

This new innovation, published in the journal Nature Electronics, shows that it is possible to record neural signals over long periods using very small devices. Operating without wires or batteries, these devices use light to transmit energy and data within living brain tissue.

Known as MOTE (Micro-Optical-Electronic Unconducted System), the device is about 300 microns long and only 70 microns wide. This makes it the smallest wireless brain chip capable of directly transmitting neural electrical activity.

This chip relies on red and infrared lasers, which safely penetrate brain tissue to provide it with energy. At the same time, data is transmitted outward via short pulses of light carrying encoded neural activity signals.

The system uses a semiconductor diode made of aluminium, gallium and arsenic to collect light energy and power the circuit. In addition, there is a low-noise signal amplifier and an optical encoder similar to the technologies used in modern electronic chips.

The chip was first tested in cell cultures, then implanted in the barrel cortex in the brains of laboratory mice, the area responsible for processing sensation through whiskers. Over the course of more than a year, the device successfully recorded nerve impulses and synaptic activity, without negatively affecting the animals’ health or activity.

Professor Alyosha Molnar, who supervises the research, explained that the small size of the device reduces brain tissue irritation and immune response, which is a common problem with traditional chips. He also noted that the technology allows electrical activity to be recorded more quickly than neuroimaging systems, and without the need for genetic modification of neurons.

The researchers believe that the design of the device may in the future allow for simultaneous brain recordings with MRI, which is currently almost impossible with conventional slices. The technology could also be adapted for use in other tissues such as the spinal cord, or combined with future technologies such as smart cranial plates.

The idea for this innovation dates back to 2001, before actual research began to flourish about ten years ago within the Cornell Neurotech initiative.

It is noteworthy that the study was supported by the US National Institutes of Health (NIH), and that the manufacturing work was partially completed at the Cornell Nanotechnology Facility, with support from the National Science Foundation (NSF).

This achievement opens the door to a new generation of brain-machine interfaces and microbiosensors, with broad potential in the fields of neuromedicine and biotechnology.