Fig. 4: ECORE recording of hiPSC-cardiomyocyte action potentials using polymer thin films.

a Schematic drawing of a hiPSC-cardiomyocyte cultured on top of electrochromic polymer thin films. b Optical micrograph of hiPSC-cardiomyocytes monolayer cultured on a P(OE3)-E thin film at day 10. The experiment was repeated independently with similar results at least 5 times. ECORE recording trace of a single hiPSC-cardiomyocyte 8 days after cell seeding using c PEDOT-epoly thin film, d PEDOT-spin thin film, e P(OE3)-D thin film, and f P(OE3)-E thin film. g Comparison of the recording performance for hiPSC-cardiomyocytes action potentials 7–10 days after cell seeding in terms of reflectance change, ΔR, using four polymers. Data are presented as mean ± SD; n = 20, 15, 17, 24 cells for PEDOT-epoly, PEDOT spin, P(OE3)-D, and P(OE3)-E films. h A 10-min recording trace of a single hiPSC-cardiomyocyte 10 days after cell seeding on a P(OE3)-E film at 10 kHz recording frequency. i Zoomed-in traces at 0, 100, 200, 300, 400, and 500 s show that the optical signal remains stable over the long recording period. j, k Quinidine as a voltage-gated sodium channel blocker. l A representative recording trace of an hiPSC-cardiomyocyte using P(OE3)-E when 1 and 4.6 μM of quinidine were added at indicated times during recording. Quantifications of m the extracellular action potential amplitude in terms of ΔR, and n the peak-to-valley timescale as a function of time. The times of quinidine additions were noted on the trajectories.