The study, published in Nature Biomedical Engineering, reports that hollow spheres made from graphitic carbon nitride were injected into the eyes of mice lacking functional photoreceptors. The particles accumulated near retinal ganglion cells, the neurons that relay visual information to the brain, and enabled light‑induced signaling that was detectable in the visual cortex and in light‑driven behavioral tests.
The work was led by Menglin Chen, PhD, an associate professor in the Department of Biological and Chemical Engineering at Aarhus University, and involved collaborators from the University of Chicago, the University of Eastern Finland, Aarhus University Hospital and the University of Copenhagen.
The nanoparticles act as a wireless interface between light and living cells: they convert incident light into local photoelectrochemical and photothermal effects that can modulate cell signaling without the need for mutation‑specific gene therapy, optogenetic modification or surgically implanted electronics.
In cell‑culture experiments, focused laser stimulation of the particles induced calcium‑transient release and synchronized beating in cardiomyocytes, while light‑emitting diode illumination paced cardiac cell networks. Similar photostimulation of isolated porcine retinal tissue activated retinal ganglion cells, demonstrating the platform’s versatility across tissue types.
When the same particles were injected into mouse eyes with advanced retinitis pigmentosa, illumination produced measurable activity in the visual cortex and elicited behavioral responses to light, indicating that the blind retina could respond to light again, although normal vision was not restored.
Chen said the approach aims to create a new type of retinal prosthesis that leverages surviving retinal neurons rather than relying on genetic modification, offering a potential treatment avenue for a broad range of degenerative eye diseases.
The authors caution that substantial work remains: delivery methods must be refined, the long‑term stability and safety of the nanoparticles in the eye need to be evaluated, and the strength and controllability of the light‑evoked responses must be improved before the concept can move toward clinical application.