Researchers at the University of California, San Diego, have developed a small neural probe that is approximately one-fifth the width of a human hair. The probe is flexible and can be implanted for long periods without compromising the immune system, in part due to its small and unobtrusive profile.
Its miniature size means that it may also be suitable for implantation in areas where other probes cannot fit, such as between the vertebrae and in the spinal cord. Containing an electrical channel and an optical channel, the coaxial probe can both record electrical activity from neurons and stimulate neurons with light. So far, the probe has shown stable operation for up to a month after researchers implanted it in the brains of mice.
We may be on the brink of a new era of technology that can monitor and control our nerve tissue, and the medical possibilities are enormous, from reducing pain to controlling seizures. However, the essence of these technologies is where they interact with our neurons, and so neural probes are a key technological development in advanced neuromodulatory devices.
This last example is characterized by its small size, 8-14 micrometers in diameter. To put this in perspective, human hair is approximately five times thicker. This means that it can reach areas that other probes cannot, such as small peripheral nerves or even a small gap between the vertebrae and in the spinal cord itself.
“Here you need a really small, flexible probe that can fit between the vertebrae to connect with neurons and bend when the spinal cord moves,” said Axel Nimeryan, a researcher involved in the study. “For chronic neural interfaces, you want a hidden probe, something the body doesn’t even know is there, but can still communicate with neurons,” added Donald Serbuli, another researcher on the project.
In an engineering challenge, researchers introduced two channels within a probe, one for transmitting electrical data from neurons to an external device and a second optical channel for transmitting light as a means of stimulating and controlling nearby neurons. So far, researchers have tested the probe in mice and found that it provides stable operation for up to a month when implanted in the brain.
“Currently, we know relatively little about how the spinal cord works, how it processes information, and how its neural activity can be disrupted or disrupted in certain disease states,” Nimeryan said. “It was a technical challenge to record from this dynamic and small structure, and we believe that our probes and future probe arrays have the unique potential to help us study the spinal cord – not only to understand it at a fundamental level, but also to have the ability to its activity is modulated. “
Watch a video on the placement of the probe:
Learn in Natural communications: Electro-optical mechanically flexible coaxial microprobes for minimally invasive interaction with inherent neural circuits
through: University of California, San Diego