Electrochemical impedance spectroscopy in vivo for neurotechnology and bioelectronics

Review article, 2025

Electrochemical impedance spectroscopy (EIS) is a well-established electrochemical technique that provides invaluable information regarding the properties and functionality of electrodes within bioelectronic devices. EIS is the primary technique that reports on electrode properties in vivo using the implanted device itself. Nevertheless, there are many inconsistencies in the way this technique is implemented and reported on. Without a clear understanding of the experiment and experimental set-up, it is challenging to draw meaningful conclusions and for results to be extrapolated across studies to benefit and advance the field. This Review discusses in vivo EIS experiments, specifically focusing on challenges in the experimental set-up, the equipment used, data presentation and circuit modelling for neural interfaces. We propose guidelines for methodical reporting and a consistent, standardized use of terminology, paramount in understanding the performance of electrodes functioning at neural interfaces and promoting the transferability of findings across studies.