Electrochromic optical recording (ECORE) is a label-free method that utilizes electrochromism to optically detect electrical signals in biological cells with a high signal-to-noise ratio and is suitable for long-term recording. However, ECORE usually requires a large and intricate optical setup, making it relatively difficult to transport and to study specimens on a large scale. Here, we present a compact ECORE apparatus that drastically reduces the spatial footprint and complexity of the ECORE setup whilst maintaining high sensitivity. An autobalancing differential photodetector automates common-mode noise rejection, removing the need for manually adjustable optics, and a compact laser module conserves space compared to a typical laser mount. The result is a simple, easy-to-use, and relatively low cost system that achieves a sensitivity of 16.7 {\mu}V (within a factor of 5 of the shot noise limit), and reliably detects action potentials from Human-induced pluripotent stem cell (HiPSC) derived cardiomyocytes. This setup can be further improved to within 1.5 dB of the shot noise limit by filtering out power-line interference.
@article{arxiv.2311.15506,
title = {Compact Electrochromic Optical Recording of Bioelectric Potentials},
author = {Kenneth Nakasone and Chris Zavik and Erica Liu and Burhan Ahmed and Dana Griffith and Lothar Maisenbacher and Ashwin Singh and Yuecheng Zhou and Bianxiao Cui and Holger Müller},
journal= {arXiv preprint arXiv:2311.15506},
year = {2023}
}