Extended Data Fig. 4: Electrical performance of the TFRFP-implanted FEH.
a, Equivalent circuit models for simulating the impedance curves of the FEH–tissue interface. b, Schematic of in vitro electrical signal recording and stimulation characterization. (i) A metal electrode served as the stimulation source, and the Pt/Ir FEH, implanted via the TFRFP or HNA method, was used for electrical signal recording. (ii) The TFRFP- or HNA-implanted Pt/Ir FEH served as the stimulation source, and a metal electrode was employed to record electrical signals. c, Simulation and experimental results showing the impedances of the FEH–tissue interfaces. d, Simulated EMG signals recorded by TFRFP- and HNA-implanted FEHs, using an actual recorded EMG signal as the signal source. e, Nyquist chart showing the tested impedances of Pt/Ir FEHs in K3[Fe(CN)6] solution, before and after withdrawal from tissue. f,g, In vitro characterization of electrical signal recording (f) and stimulation (g) at 5 and 1 Hz for TFRFP- (top) and HNA-implanted Pt/Ir FEHs (bottom) in fish tissue.
