Electrochemical impedance spectroscopy supporting live imaging for barrier assessment in a microphysiological system

Correlating real-time biophysical data with morphological changes is essential for the understanding of tissue development and function in microphysiological systems (MPS). Although electrochemical impedance spectroscopy (EIS) is a powerful tool for noninvasive live monitoring, the inherent complexity of deciphering impedance spectra remains a limitation when it comes to precisely interpreting dynamic biological tissue alterations. Here, we present a microfluidic platform with a sandwich-like chip architecture embedding partially transparent, IrOx based electrodes. By localizing the electric field to the central cell culture area, the device ensures the EIS and microscopy monitoring of the tissue at the same location. As a proof of concept, we cultivated a gut-on-chip model for 14 days under perfusion. Impedance spectra were fitted to an equivalent electrical circuit model to extract the elementary contributions of the system. Indeed, our results show that the fitted parameters and the experimental data are coherent, demonstrating the high sensitivity of EIS to capture barrier dynamics. Crucially, the platform allowed for the simultaneous verification of the cell presence and coverage through live microscopy throughout the entire experimental duration. This paves the way for directly correlating biophysical signatures and real-time imaging, providing a robust framework for robust and reliable multi-parametric tissue characterization.