Microscale Electrical Impedance Tomography Method for Cell Phase Separation Detection

Microscale solution to the double-layer problem in Electrical Impedance Tomography (EIT) is proposed for cell phase separation detection by combining Organic Electrochemical Transistors (OECTs) and EIT. In this study, a microscale sensor is designed for Liquid-Liquid Phase Separation (LLPS) detection. Firstly, the equivalent circuit model of OECTs is expanded according to the EIT theory which is applied to array OECTs. The equivalent capacitance (C*), reflecting the polarization of the organic thin film and the electrolyte interface, is calculated using impedance analysis method. Based on the EIT theory, the channel capacitance voltage (VE) is proposed as the boundary voltage for the EIT problem, which is calculated by the OECTs control equation. Secondly, the OECTs-EIT sensor is designed to validate the proposed method. The sensor model is simplified by calculating the VE, on which the corresponding excitation-measurement pattern is proposed for data acquisition. The inverse problem of EIT is solved using sensitivity field theory. Finally, the performance of the proposed method is evaluated by simulating the LLPS observed in ex vivo experiments, with the image correlation coefficients of the reconstructed images larger than 0.9.