A microfluidic system enabling continuous characterization of single-cell specific membrane capacitance and cytoplasm conductivity

This paper presents a microfluidic system enabling continuous characterization of specific membrane capacitance (C_{specific membrane}) and cytoplasm conductivity (σ_cytoplasm) of single biological cells. In this study, cells were aspirated through a constriction channel while cell elongations and impedance profiles at 1 kHz and 100 kHz were measured simultaneously using microscopy imaging and a lock-in amplifier. Based on the proposed equivalent circuit model, raw data were translated to C_specific membrane and σ_cytoplasm, which were 3.67±1.00 vs. 4.53±1.51 μF/cm² and 0.47±0.09 vs. 0.55±0.14 S/m for the kidney tumor cell line of 786-O (n=302) and the vascular smooth muscle cell line of T2 (n=216), respectively.