Specific membrane capacitance, cytoplasm conductivity and instantaneous Young's modulus of single tumour cells

As label-free biomarkers, biophysical properties of cells are widely used for cell type classification. However, intrinsic biophysical markers, e.g., specific membrane capacitance (C-specific membrane), cytoplasm conductivity (sigma(conductivity)) and instantaneous Young's modulus (E-instantaneous) measured for hundreds of single cells were not yet reported. In this study, single cells in suspension (adherent cells treated with trypsin) were aspirated through a microfluidic constriction channel at 25 degrees C, and the entry processes and impedance profiles were recorded and translated to C-specific membrane, sigma(conductivity) and E-instantaneous. C-specific membrane, sigma(conductivity) and E-instantaneous of five cell types were quantified as 2.10 +/- 0.38 mu F cm(-2), 0.91 +/- 0.15 S m(-1) and 5.52 +/- 0.95 kPa for H460 cells (n(cell) = 437); 2.52 +/- 0.54 mu F cm(-2), 0.83 +/- 0.12 S m(-1) and 5.54 +/- 1.04 kPa for H446 cells (n(cell) = 410); 2.45 +/- 0.57 mu F cm(-2), 0.99 +/- 0.18 S m(-1) and 5.16 +/- 1.68 kPa for A549 cells (n(cell) = 442); 1.86 +/- 0.31 mu F cm(-2), 1.07 +/- 0.18 S m(-1) and 3.86 +/- 0.81 kPa for 95D cells (n(cell) = 415); 2.03 +/- 0.35 mu F cm(-2), 0.99 +/- 0.16 S m(-1) and 3.49 +/- 0.70 kPa for 95C cells (n(cell) = 290). The database of C-specific membrane, sigma(conductivity) and E-instantaneous may serve as a reference for future studies of cellular biophysical properties.