Visible light is able to regulate neurite outgrowth.

The pheochromocytoma cell line PC12 displays neuronal characteristics. PC12 cells differentiate their phenotype from a proliferating cell to a neurite-bearing neuron upon treatment with nerve growth factor (NGF). The neurite outgrowth of PC12 cells on polystyrene tissue culture flasks and extracellular matrix protein-adsorbed glass plates was reversibly controlled using visible light. The percentage of cells with neurites decreased with increasing light intensity. Furthermore, neurite outgrowth was dramatically suppressed with light intensities over 300 Lux (approximately 130 microW). Neurite outgrowth occurred in the absence of irradiation by visible light, but did not occur or was limited with irradiation, depending on the membranes on which PC12 cells were cultured. These results hold promise for the creation of patterned neuronal networks corresponding to patterned irradiation of visible light on nerve cells.