Modeling and engineering aspects of channelrhodopsin2 system for neural photostimulation.

It is desirable to be able to stimulate neural cells for many different therapeutic applications. Light stimulation has many advantages over electrical stimulation if it can be achieved. Neural cells are not naturally light sensitive but they can be transformed using different strategies. Here we examine the case of genetically engineered neurons expressing green algae light-gated ion channels, Channelrhodopsin-2. We have developed a mathematical model for the photocycle of this protein, which gives results which are in good agreement with experimental measurements. We have also examined engineering aspects of using this ChR2 system as a phototransduction mechanism. The response characteristics were calculated and potentials of this system-device are discussed.