Characterization of Single-Nucleus Electrical Properties by Microfluidic Constriction Channel.

As key bioelectrical markers, equivalent capacitance (C, i.e., capacitance per unit area) and resistance (R, i.e., resistivity multiply thickness) of nuclear envelopes have emerged as promising electrical indicators, which cannot be effectively measured by conventional approaches. In this study, single nuclei were isolated from whole cells and trapped at the entrances of microfluidic constriction channels, and then corresponding impedance profiles were sampled and translated into single-nucleus C and R based on a home-developed equivalent electrical model. C and R of A549 nuclei were first quantified as 3.43 ± 1.81 μF/cm and 2.03 ± 1.40 Ω·cm (N = 35), which were shown not to be affected by variations of key parameters in nuclear isolation and measurement. The developed approach in this study was also used to measure a second type of nuclei, producing C and R of 3.75 ± 3.17 μF/cm and 1.01 ± 0.70 Ω·cm for SW620 (N = 17). This study may provide a new perspective in single-cell electrical characterization, enabling cell type classification and cell status evaluation based on bioelectrical markers of nuclei.