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 (Cspecific membrane), cytoplasm conductivity (σconductivity) and instantaneous Young’s modulus (Einstantaneous) 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 °C, and the entry processes and impedance profiles were recorded and translated to Cspecific membrane, σconductivity and Einstantaneous. Cspecific membrane, σconductivity and Einstantaneous of five cell types were quantified as 2.10±0.38 μF cm−2, 0.91±0.15 S m−1 and 5.52±0.95 kPa for H460 cells (ncell=437); 2.52±0.54 μF cm−2, 0.83±0.12 S m−1 and 5.54±1.04 kPa for H446 cells (ncell=410); 2.45±0.57 μF cm−2, 0.99±0.18 S m−1 and 5.16±1.68 kPa for A549 cells (ncell=442); 1.86±0.31 μF cm−2, 1.07±0.18 S m−1 and 3.86±0.81 kPa for 95D cells (ncell=415); 2.03±0.35 μF cm−2, 0.99±0.16 S m−1 and 3.49±0.70 kPa for 95C cells (ncell=290). The database of Cspecific membrane, σconductivity and Einstantaneous may serve as a reference for future studies of cellular biophysical properties.