Project Summary/Abstract Potentiometric Probes The overall goal of this Phase II SBIR project is to commercialize tools, invented by the founders of Potentiometric Probe, LLC, for high-fidelity optical recording of electrical activity in cardiac cells, tissues, and whole hearts. Potentiometric Probes develops organic voltage-sensitive dyes (VSDs) that convert the changes in voltage across cell membranes to visible changes in fluorescence. Instead of individual electrodes, this technology enables the use of sensitive high-speed cameras, where each pixel can be considered an electrode, for massively parallel high throughput screening, or for high-resolution spatiotemporal maps of electrical signal propagation. Importantly, our VSDs are unique in enabling dual-wavelength ratiometric recording of electrical activity; this is particularly important for cardiac studies because it eliminates contraction-induced motion artifacts, permitting high-fidelity records of the action potential waveform. Human stem cell-derived cardiomyocytes (hiPSC-CMs) and tissues derived from them are increasingly being used for research and development purposes, including screening new drugs for cardiotoxicity, and in the future may be used for “personalized medicine” and the analysis of patient-derived cells. We believe high throughput recording of accurate action potential waveforms from hiPSC-CMs and tissues will be a major market for the proposed technology. Ultimately, the technology may also be applied clinically for high-resolution imaging of action potential propagation in the heart. In this proposal, Potentiometric Probes will synthesize a set of stable, non-toxic ratiometric VSDs with a broad selection of spectral windows, allowing accurate recordings even from beating hearts. The performance of these VSDs will also be fully characterized and validated for their compatibility with sensitive cell lines for both long-term and high-throughput recordings.

Project Narrative Potentiometric Probes Potentiometric Probes is developing fluorescent dyes that convert electrical signals of heart cells and tissue into optical signals that can be recorded with cameras. These probes allow researchers to screen drugs rapidly for cardiotoxicity, as well as to study how electrical signals are generated and propagate in the heart, providing insights into mechanisms of genetic diseases and links to cardiac arrhythmias and failure.