Fig. 5: Neural photostimulation in vitro.

a Electrophysiology patch-clamp measurement setup. The illumination source is a blue LED with the central wavelength of 445 nm. b Neural activity of primary hippocampal neurons cultured on the biointerface in response to a train of 20 pulses (20 ms, 50 mW cm⁻² at 1, 2, 5, 10, 20 Hz). Blue bars represent the start of the pulses. c Successful spike ratio under different illumination intensities. 20 pulses of 20 ms at 1 Hz were applied in various intensities (n = 20, mean ± s.d.). d Intracellular membrane potential change with respect to a distant Ag/AgCl electrode was measured after the photostimulation of primary hippocampal neurons on the glass:ITO control (red) and the biointerface (black) under illumination of 100 mW cm⁻² with 20 ms illumination pulses. Blue semi-transparent area shows the 445 nm light illumination period. e Successful spike ratio of neurons on the glass:ITO/ZnO/P3HT control (gray) and the biointerface (black) under different illumination frequencies of 20 ms, 50 mW cm⁻², 20 pulses (n = 20, mean ± s.d.). f The resting membrane potential of neurons on biointerface were measured before and after 1 min optical stimulation with 20 ms pulses at 2 Hz (n = 20, mean ± s.e.m.). g The mean latency with respect to the spike peak to the stimulation onset and also the jitter as the standard deviation of latencies for all neurons (n = 20, mean ± s.e.m.).