Use of channelrhodopsin in the development of neural-network high-throughput screening devices

Abstract

Channelrhodopsin (ChR)-2 and halorhodopsin are powerful tools for the function analysis of in vivo and in vitro neural networks. However, in this chapter, another useful application of these optogenetic tools is introduced. Ion-channel biosensors have important, unique applications due to their high sensitivity and high selectivity, and the planar patch clamp, which is a planar ion-channel device, is already in commercial use as a high-throughput screening device for new drug developments. However, currently available planar patch clamp devices cannot be used for neural network analysis in which the incubation function is necessary. In this work, we have developed an incubation-type planar patch clamp by considering the application of a planar patch clamp to high-throughput screening devices using a neural network, which is considered to be extremely useful for cause analysis and new drug development for intractable brain neural network diseases. The weak point of the incubation-type planar patch clamp is extremely high baseline noise due to low seal resistance, which makes it almost impossible to use in practical devices. In this work, we have succeeded in decreasing the noise to a sufficiently low level by using a salt-bridge stable electrode. We have successfully measured the ion- channel current from a neural network incubated in a planar patch clamp biosensor for the first time. In this development of the incubation-type planar patch clamp biosensor, the excellent performance of the ChR-wide receiver with high time resolution was quite useful.