Optical Recording of Bioelectric Signals Using Electrochromic Materials

Non-invasive methods with high spatial and temporal resolution are highly desirable in the study of electrical signals in biological cells. Developing such methods can help uncover how a network of interconnected neurons receives, stores and processes information. Optical recording through voltage-sensitive fluorescent probes provides a flexible method for measuring neuronal activity, but these methods often suffer from photobleaching and phototoxicity, limiting their application in studying these activities for longer durations. Here, we report on electrochromic optical recording (ECORE) which uses the electrochromic properties of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) to detect electrical activity in biological cells. We demonstrate the optically-recorded spontaneous action potentials in cardiomyocytes, cultured hippocampal and dorsal root ganglion neurons, and brain slices. ECORE provides a non-invasive, highly flexible method to study electrical activities in biological cells, while also enabling the long-term recording of these activities.