Solar Cell Nanowires As Approach For Single Cell Direct Activation

Novel fabrication techniques for nanoscale solar cells and establishment of hybrid junctions between semiconductors and biological systems offer innovative approaches for single cell direct activation and sensing. We use indium phosphide solar cell nanowires and cerebellar granule cells to investigate such a system. Here, vertically aligned nanowires serve as culturing substrate for the neurons. We demonstrate that a neural network is formed on the nanowires. Scanning microscope images show that the cells and axons stay on top of the tips caused by the high nanowire density. Cross sections via focus ion beam reveal a slight wrapping of the cell membrane around the nanowire tips. Our patch clamp experiments show that the electrophysical properties such as firing of action potentials remain similar compared to measurements on planar reference substrates. The p-n junctions are build-in vertically and thus form an electrical contact at the neural cell and the underlying substrate. This opens up for possibly using both pin and nip designed nanowires for both hyper- and depolarization of the cell.