Broadband single-cell detection with a coplanar series gap

Using a coplanar waveguide with a series gap in conjunction with dielectrophoresis trapping, consecutive S-parameter measurements between 0.5 and 20 GHz were quickly performed with and without a Jurkat cell trapped to compensate for a relatively noisy and drifting background. This allowed the small cytoplasm capacitance, on the order of 10 fF, to be reliably extracted. The extracted cytoplasm capacitance is within a factor of 2 of the previously reported value by using a shunt trap but is believed to be more accurate. The present technique can complement previously developed microwave and RF techniques in characterizing the capacitances and resistances of plasma and membrane for complete characterization of the electrical properties of a simple cell.