An Analytical Formula for Determining the Electrical Impedance between a Single Adherent Cell and Sensor Substrate

TL;DR

This paper introduces a novel analytical formula for calculating electrical impedance between a single adherent cell and a sensor substrate, applicable even with microelectrodes smaller than the cell, aiding in single-cell analysis and sensor design.

Contribution

The paper presents the first analytical formula valid for single-cell impedance measurement with microelectrodes smaller than the cell, extending previous models for multi-cell large electrodes.

Findings

Numerical simulations confirm high accuracy of the formula.

Discrepancies between theoretical and simulated impedance are negligibly small.

The formula is useful for cell impedance analysis and sensor optimization.

Abstract

An analytical formula for electrical impedance between an adherent living cell and sensor substrate measured using a microelectrode is presented for the first time. Previously-reported formula has been applicable only for the case where many cells are on a large electrode. In contrast, our formula is valid even when a microelectrode smaller than the cell size is underneath the cell, which is often the case for the state-of-the-art single-cell analysis. Numerical simulations for verifying the accuracy of our formula reveals that the discrepancies between the theoretical impedances calculated by our formula and numerical simulation results are negligibly small. Our formula will be useful for describing cell-substrate impedance properties in equivalent circuit model analysis or sensor design optimizations.