Direct electrical and optical stimulation of the brain has helped to study this organ and to develop new therapies to address various conditions. The spinal cord, though also part of the nervous system and similarly susceptible to stimulation, is more difficult to work with because it flexes, stretches, and compresses, which means that the leads that deliver stimulation must be just as pliable as the surrounding tissues.
Conventional optic fibers, the kind used in optogenetics studies, bend fairly well but don’t stretch or compress. The spinal cord area sees as much as 10% change in tissue length, something a typical optical fiber can’t overcome. A similar issue exists for electric stimulation leads.
Now researchers at MIT have developed a fiber that is very elastic, while accurately transmitting both a light signal through its core or an electric one through its exterior. It’s made of a transparent elastomer that has the consistency of rubber, stretching and compressing by up to 30%, and silver nanowires that are conductive of electricity but don’t crack like brittle metal wires.
The researchers successfully used the new fibers in freely moving mice, showing that they are able to both read the electrical signals from the spinal cord, as well as stimulate it using both electricity and light.
Study in Science Advances: Flexible and stretchable nanowire-coated fibers for optoelectronic probing of spinal cord circuits…
Via: MIT…