Frequency domain analysis of membrane capacitance of cultured cells (HeLa and myeloma) using the micropipette technique.

The membrane capacitance and conductance of cultured cells (HeLa and mouse myeloma) are investigated using the micropipette method. Mean values of the membrane capacities were found to be 1.9 microF/cm2 for HeLa cells and 1.0 microF/cm2 for myeloma cells. These values are in agreement with those obtained using the suspension method. Whereas the suspension method is unable to provide the information on membrane conductance, the micropipette method is able to measure even an extremely small membrane conductance if leakage current is negligibly small. The membrane conductances were found, using this technique, to be approximately 90-100 microS/cm2 for both HeLa and myeloma cells. One of the purposes of this study is to establish the frequency profile of membrane capacitance. It was found, however, that membrane capacitances of these cells are independent of frequency between 1 Hz and 1 KHz within the resolution of this technique.