A Microfluidic Device With Optically-Controlled Electrodes for On-Demand Electrical Impedance Measurement of Targeted Single Cells

Abstract

Electrical impedance measurement of a live cell is important for monitoring the cell’s status. Label-free and non-invasive techniques for measuring the impedance of live cells have attracted much attention. Existing techniques are capable of measuring the impedance of entire cell populations and/or the instantaneous impedance of single cells, but an approach to track and monitor the electrical properties of single cells during their growth process has not yet been reported. This paper presents a microfluidic device integrated with optically-controlled electrodes (MOCE) for electrical impedance measurement of multiple individual cells over a time period. An equivalent circuit model to quantify the seal resistance, membrane capacitance, cytoplasmic resistance of single cells is proposed. In experiments, the adherence process of C2C12 myoblast cells was characterized by measuring individual cells’ impedance data. During cell growth, the seal resistance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{seal}$ </tex-math></inline-formula> increased gradually, while the membrane capacitance stayed at approximately <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-9}$ </tex-math></inline-formula> F and the cytoplasmic resistance stayed at approximately <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{9} ~\Omega $ </tex-math></inline-formula> . The results demonstrate the feasibility and effectiveness of the MOCE-based method for on-demand single-cell electrical impedance measurement. [2020-0265]