Researchers at Aarhus University are exploring a method of regenerating brain and heart cells using light. Their technique uses water-based nanofibers coated with organic photovoltaic nanomaterials to create light-controlled neural-stimulating scaffolds inside the body. In an example of the photovoltaic effect, the nanomaterials create an electrical voltage when they are exposed to light. When the coated nanofibers are injected into tissue and the tissue is exposed to sunlight or near-infrared (NIR) artificial light, some of the light will penetrate the tissue and fall on the photovoltaic nanomaterials, thereby converting the light to electricity. In contrast to optogenetics, this light-mediated approach is nongenetic and can be used to stimulate cells electrically. The researchers said that using their method, it will be possible to locally stimulate electrically excitable cells, such as neurons in the brain, and through bioelectric signal transduction, to modulate a specific cell reaction — in this case, a regenerative response. They believe that their technique could be applied on heart as well as brain cells. “We want to develop a wireless, noninvasive, safe, and very accurate therapeutic treatment method that can regenerate heart and brain cells by means of an external light source,” professor Menglin Chen said. Associate Professor Menglin Chen (low center) and her research group at the Department of Engineering, Aarhus University. Courtesy of Ida Jensen, AU Foto. In previous work, the research group led by Chen used graphitic carbon nitride (g-C3N4), a photocatalyst with visible-light optoelectronic conversion capabilities, for its investigation of visible-light neural stimulation. The photocatalytic function of g-C3N4 was enhanced by spreading the g-C3N4 on graphene oxide-coated microfibers. “The [new] project makes it possible to create better cohesion between the natural tissue and the rigid world of microelectronics, which so far has not been able to target individual cells and their circulation, and describe their underlying mechanisms,” Chen said. “Using nanofibers as flexible, injectable scaffolds that allow cell growth, we can now integrate the nervous system or cardiovascular system with nanoelectronics and thereby stimulate regeneration. If we’re successful, this will have a major impact on implementing new treatment methods for various brain and heart conditions in the future.” The earlier research was published in Applied Materials & Interfaces (www.doi.org/10.1021/acsami.7b12733).