Electrical Stimulation of ASAP1 with a Combination of Microelectrode Array and Fluorescent Techniques

Optical noninvasive methods are modern tools in studying subcellular ion exchanges and corresponding membrane voltage alterations. In past decades, genetically encoded voltage indicators (GEVIs) received attention due to the low toxicity and enhanced detection limits. The very promising GEVI Accelerated Sensor of Action Potentials 1 (ASAP1) was expressed in HEK293 cells and extracellular stimulation was performed using a microelectrode-arrays integrated pulse generator. The results demonstrate high fluorescence response and changes, fast kinetics 1.5±0.3 ms, and enhanced amplitude of fluorescence response, even if the voltage sensor is not completely repolarized. The results bring verification of advantageous properties of ASAP1 and confirm a big potential of modern voltage sensitive dyes and their application in neural activity sensing where these properties play an important role. At the same time, our testing method showed as a very advantageous in voltage sensitivity dyes properties validation.