Light-Powered Wires To Modulate Brain’s Electrical Signals

The human brain largely remains a black box: How the network of fast-moving electrical signals turns into thought, movement and disease remains poorly understood. But it is electrical, so it can be hacked—the question is finding a precise, easy way to manipulate electrical signaling between neurons.

A new University of Chicago study shows how tiny, light-powered wires could be fashioned out of silicon to provide these electrical signals. Published Feb. 19 in Nature Nanotechnology, the study offers a new avenue to shed light on—and perhaps someday treat—brain disorders.

Ten years ago, the science world was alive with speculation about a recently discovered technique called optogenetics, which would manipulate neural activity with light. The problem is that it has to be done with genetics: inserting a gene into a target cell that would make it respond to light. Other ways of modulating neurons have since been suggested, but a perfect alternative remains elusive.

A team led by Asst. Prof. Bozhi Tian built minuscule wires previously designed for solar cells. These nanowires are so small that hundreds of them could sit side by side on the edge of a sheet of paper—putting them on the same scale as the parts of cells they’re trying to communicate with.

These nanowires combine two types of silicon to create a small electrical current when struck by light. Gold, diffused by a special process onto the surface of the wire, acts as a catalyst to promote electrochemical reactions.

The rod at top right is positioned to modify electrical signaling between the neurons. The entire image is smaller than the diameter of a single human hair.

When the wire is in place and illuminated, the voltage difference between the inside and outside of the cell is slightly reduced. This lowers the barrier for the neuron to fire an electrical signal to its neighboring cells,” Tian said.


Brain Cells Death Provokes Multiple Sclerosis

Multiple sclerosis* (MS) may be triggered by the death of brain cells that make myelin, the insulation around nerve fibers, according to research on a novel mouse model developed by scientists from the University of Chicago and Northwestern Medicine. The death of these cells initiates an autoimmune response against myelin, the main characteristic of the disease, which leads to MS-like symptoms in mice.This reaction can be prevented, however, through the application of specially developed nanoparticles, even after the loss of those brain cells. The nanoparticles are being developed for clinical trials that could lead to new treatments in humans.

multiple sclerosisAn image of the cerebellum from an animal early in the demyelinating phase of the late-onset disease. The green marks myelinated axons and the dark area in the center is a demyelinated lesion with T-cell inflammation (pink)

Although this was a study in mice, we’ve shown for the first time one possible mechanism that can trigger MS—the death of the cells responsible for generating myelin can lead to the activation of an autoimmune response against myelin,” said study co-senior author Brian Popko, the Jack Miller Professor of Neurological Disorders. “Protecting these cells in susceptible individuals might help delay or prevent MS.”


The study was published in Nature Neuroscience.

* Multiple sclerosis is a neurological disease involving an abnormal immune response against myelin, which leads to the progressive deterioration of a wide range of body functions. MS is thought to affect 2.5 million people worldwide, and has unclear causes and no known cure.