Controlled in situ capacitance sensing of single cell via simultaneous optical tweezing

Abstract Whole cell capacitance measurement of a single or few cells at controlled distances gives valuable information on cell activities and intercellular interactions. However, conventional techniques require either averaging the values of uncontrolled number of cells cultured on or between electrodes or altering the cell membrane structure to fit cells into the patch or a narrow capillary. In this study, we report a biosensor which allows in situ capacitance measurement via simultaneous optical tweezing. Single, double, triple and multiple cells with predetermined spacing and alignments (horizontal, vertical or mixed) were carefully placed between two electrodes by using optical tweezing technique and in situ cell capacitances were measured. Measured capacitance values were further processed to represent the capacitance of an individual cell in each case. We found that calculated capacitance values non-linearly increased as the cell numbers increased depending on the cell alignments. Furthermore, comparison of capacitance values of adjacent and spaced cells indicated the presence of electrostatic interaction between neighboring cells.