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/cm2, 0.91±0.15 S/m and 5.52±0.95 kPa for H460 cells (ncell=437); 2.52±0.54 μF/cm2, 0.83±0.12 S/m and 5.54±1.04 kPa for H446 cells (ncell=410); 2.45±0.57 μF/cm2, 0.99±0.18 S/m and 5.16±1.68 kPa for A549 cells (ncell=442); 1.86±0.31 μF/cm2, 1.07±0.18 S/m and 3.86±0.81 kPa for 95D cells (ncell=415); 2.03±0.35 μF/cm2, 0.99±0.16 S/m 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.

细胞生物物理特性作为无标记生物标志物，已被广泛应用于细胞类型分类。然而，目前尚未有针对数百个单细胞测得的固有生物物理标记物的相关报道，此类标记物包括比膜电容（specific membrane capacitance）、胞浆电导率（cytoplasm conductivity）以及瞬时杨氏模量（instantaneous Young’s modulus）。本研究将经胰蛋白酶（trypsin）处理的贴壁细胞制备为悬浮单细胞悬液，在25℃条件下将其抽吸通过微流体收缩通道（microfluidic constriction channel），记录细胞的进入过程与阻抗曲线，并将其转换为比膜电容、胞浆电导率与瞬时杨氏模量。本研究量化了5种细胞类型的上述三类生物物理参数：H460细胞（n_cell=437）的比膜电容为2.10±0.38 μF/cm²、胞浆电导率为0.91±0.15 S/m、瞬时杨氏模量为5.52±0.95 kPa；H446细胞（n_cell=410）为2.52±0.54 μF/cm²、0.83±0.12 S/m、5.54±1.04 kPa；A549细胞（n_cell=442）为2.45±0.57 μF/cm²、0.99±0.18 S/m、5.16±1.68 kPa；95D细胞（n_cell=415）为1.86±0.31 μF/cm²、1.07±0.18 S/m、3.86±0.81 kPa；95C细胞（n_cell=290）为2.03±0.35 μF/cm²、0.99±0.16 S/m、3.49±0.70 kPa。本研究构建的比膜电容、胞浆电导率与瞬时杨氏模量数据库，可为后续细胞生物物理特性相关研究提供参考依据。