High-resolution Optical Recording of Bioelectric Signals Using Electrochromic Materials.

Non-invasive methods with high spatial and temporal resolution are valuable tools in the study of bioelectric signals and can help uncover how a network of interconnected neurons transmits and processes information. Optical recording using voltage-sensitive fluorescent probes is already used to measure neuronal activity. However, these methods often suffer from photobleaching and phototoxicity and are therefore limited in the long-term monitoring of these activities. We have previously reported on optical electrochromic recording (ECORE), a technique which leverages the electrochromic properties of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) in order to study electrical signals in biological cells. ECORE represents a non-invasive and highly flexible method of detecting such signals while simultaneously enabling the long-term recording of these activities. Here we report on our work to increase the spatial resolution of ECORE by incorporating a microscope objective lens into our setup. Improved spatial resolution will enable us to probe local regions of cells of interest and allow us to study these cells in more detail, adding to the benefits already presented by ECORE.