Light-Addressed Stimulation Under Ca2+ Imaging of Cultured Neurons

Light addressing is an emerging and sophisticated technique that can induce pinpoint and/or patterned neuronal activation in cultured neurons. We previously developed a light-addressable electrode using hydrogenated amorphous silicon (a-Si: H), which was sandwiched between a tin oxide (SnO2) substrate and a passivation layer of zinc antimonate (ZnOSb2O5) dispersed epoxy. This research developed an experimental system that simultaneously implemented light-addressed stimulation and Ca2+ imaging of neuronal activities. The translucent and thin laminated structure of our electrode permitted optical accesses from two directions: Ca2+ imaging from above and light addressing from beneath. The submillisecond bright/dark switching property of our electrode offered light-addressed stimulation without causing interference with Ca2+ imaging. To provide patterned illumination for light addressing, a digital micromirror device was installed in the system as an active photomask. The system could induce pinpoint neuronal activation at a cellular level.