“Optical recording of bioelectrical signals using electrochromic materials”
Key organs in our body such as brain and heart rely on bioelectrical signals to function. Recording bioelectrical signals such as action potentials provides significant information regarding the physiological nature of brain and heart. Intracellular electrophysiological recording method using patch clamp affords large signals but is highly invasive to cells and has low recording throughput. Extracellular recording method using flat electrode is noninvasive but can only record from cells that locate near the electrodes. Optical electrophysiological recording methods, on the other hand, provide high spatial flexibility to record from any cells of interest. However, current optical recording methods rely on inserting voltage-sensitive fluorescent reporters into the cell membrane, which suffer from limited recording signal-to-noise ratio and duration due to photobleaching and phototoxicity. I will introduce a label-free optical electrophysiological recording method named ElectroChromic Optical Recording (ECORE) that merges the high spatial flexibility of optical recording methods with the high signal stability of electrode-based recording methods. The ECORE method does not use any fluorescent reporters. Instead, it detects cell action potentials through the voltage-sensitive optical absorption change of conjugated electrochromic polymers outside the cells. Therefore, ECORE does not perturb cell physiology and is not limited by photobleaching or phototoxicity. It also allows for long-term electrophysiological recordings over weeks for both neural and cardiac systems.