Channelrhodopsin as a Noble Biomaterial Useful for the Operation and Performance Test of the Ionchannel Devices

The light-gated ion-channel protein is expected to be able to improve the performance of ionchannel devices for the multi-point screening and neural network devices based on the planar patch clamp. However, no studies with light-gated ion channels on a planar patch clamp have been reported. We constructed an incubation type of planar patch clamp biosensor using silicon-on-insulator substrates with a 1­2μm micropore in them. Channelrhodopsin 2-expressing C2C12 cells and channelrhodopsin/wide receiver-expressing HEK293 cells were seeded on the surface of the sensor chip and incubated to almost complete confluence. A laser beam (473 nm wavelength) was radiated on the cells adsorbing to the sensor chip’s micropore and the light-gated channel currents of the voltage clamp and action potentials of the current clamp modes were observed. Good signal to noise ratios were obtained, although the seal resistance was not so large, 10­30M3. The observed pulse shape of the ion-channel currents also qualitatively resembled reported results measured with a pipette patch clamp. These results strongly suggest that the light-gated ion channel proteins are useful biomaterials for ionchannel devices. [doi:10.2320/matertrans.N-M2012814]