Photoconductivity of Surface Found to Control Adhesion of Cells

Researchers at North Carolina State University have developed a new method for manipulating the behavior of cells on semiconductor materials. The process uses light to alter the material’s conductivity.

Albena Ivanisevic, a professor of materials science and engineering at NC State and one of the authors of the related paper said, “Our work here effectively adds another tool to the toolbox for the development of new bioelectronic devices.”

A phenomenon called persistent photoconductivity enables the new approach. Materials that exhibit persistent photoconductivity become much more conductive when exposed to light. However, when the light is removed, the increased conductivity takes a long time to return to its original level.

Increased Surface Charge Makes More Cells Adhere to Surface

When conductivity increases, the charge at the material’s surface increases. And according to the researchers, that increased surface charge apparently direct cells to adhere to the surface. Ivanisevic said that this method of controlling adhesion could be used along with other methods including chemically modifying the material, and engineering the material’s roughness.

The researchers examined two groups of identical gallium nitride substrates. One group was exposed to UV light. The second group was not exposed. The UV light gave the substrates persistent photoconductive properties. Ivanisevic noted that they found more cells adhered to the material that the researchers exposed to light.

“This is a proof-of-concept paper,” Ivanisevic said. “We now need to explore how to engineer the topography and thickness of the semiconductor material in order to influence the persistent photoconductivity and roughness of the material. Ultimately, we want to provide better control of cell adhesion and behavior.”

Details of the development were published in the journal Small. Patrick Snyder, a Ph.D. student in Ivanisevic’s lab, was the paper’s lead author. Ronny Kirste of Adroit Materials and Ramon Collazo, an assistant professor of materials science and engineering at NC State were co-authors.


P. J. Snyder, R. Kirste, R. Collazo, A. Ivanisevic, “Persistent Photoconductivity, Nanoscale Topography, and Chemical Functionalization Can Collectively Influence the Behavior of PC12 Cells on Wide Bandgap Semiconductor Surfaces.” Small 2017. DOI: 10.1002/smll.201700481