Scientists have invented a method for optical stimulation of cells with photothermal converters of fluffy graphene grown on the silicon nanowire. It gives you the opportunity to refuse to optogenetics, because it is much more accurate, safer, and allows you to explore three-dimensional cell culture. Article published in The Proceedings of the National Academy of Sciences.
Restori Sahil (Sahil K. Rastogi) from the University Carnegie Mellon in Pittsburgh and his colleagues figured out how to make the cells respond to faint light without the use of optogenetics. To do this, they took the wire out of the silicon nanoscopic thickness, and grew along it flakes of graphene.