Cell stimulation holds promise for bioelectronic interfaces

In what is claimed to be a first, researchers in North Carolina have used a material’s persistent photoconductivity to stimulate neurotype cells, an advance that could lead to bioelectronic interfaces.


A material that demonstrates persistent photoconductivity gains a negative charge on its surface when exposed to the right wavelength of light, and retains the charge when the light is removed. The correct wavelength of light, and how long the material retains its charge, varies in different materials.

Researchers know that an electric charge can stimulate a cell, but existing technologies for conducting related experiments can be invasive, time-consuming, or require specialised equipment.

“We wanted to take advantage of the electronic properties of the semiconductor gallium nitride, which is biocompatible, making it a true bioelectronic interface,” said Patrick Snyder, a PhD student at North Carolina State University (NC State) and lead author of a paper on the work. “The result is a faster, non-invasive way to stimulate cells that doesn’t require specialised equipment.”

According to NC State, the researchers exposed a gallium nitride substrate to ultraviolet (UV) light, creating a negative charge on its surface. Once the UV light was removed, researchers poured a solution containing PC12 neurotypic cells into the container with the substrate. The researchers then introduced a dye that allowed them to measure calcium levels in the PC12 cells.

The researchers found that PC12 cells were stimulated when they came into contact with the charged gallium nitride substrate – as seen with increased calcium ion levels within the cells – when compared to a control group that did not come into contact with a charged substrate.

The research team said this is evidence of altered behaviour because ions are important in neurotypic cell activity. For example, calcium ions play key roles in neuronal signalling.

“In addition to advancing our fundamental understanding of what this material is capable of, we’re optimistic that it can facilitate work by many labs interested in advancing research on cellular behaviour,” says Albena Ivanisevic, a professor of materials science and engineering at NC State and corresponding author of the paper.

The paper, “Non-Invasive Stimulation of Neurotypic Cells Using Persistent Photoconductivity of Gallium Nitride,” is published in ACS Omega.