Simultaneous Characterization of Instantaneous Young's Modulus and Specific Membrane Capacitance of Single Cells Using a Microfluidic System

This paper presents a microfluidics-based approach capable of continuously characterizing instantaneous Young's modulus (E-instantaneous) and specific membrane capacitance (C-specific membrane) of suspended single cells. In this method, cells were aspirated through a constriction channel while the cellular entry process into the constriction channel was recorded using a high speed camera and the impedance profiles at two frequencies (1 kHz and 100 kHz) were simultaneously measured by a lock-in amplifier. Numerical simulations were conducted to model cellular entry process into the constriction channel, focusing on two key parameters: instantaneous aspiration length (L-instantaneous) and transitional aspiration length (L-transitional), which was further translated to E-instantaneous. An equivalent distribution circuit model for a cell travelling in the constriction channel was used to determine C-specific membrane. A non-small-cell lung cancer cell line 95C (n = 354) was used to evaluate this technique, producing E-instantaneous of 2.96 +/- 0.40 kPa and C-specific membrane of 1.59 +/- 0.28 mu F/cm(2). As a platform for continuous and simultaneous characterization of cellular E-instantaneous and C-specific membrane, this approach can facilitate a more comprehensive understanding of cellular biophysical properties.