Dielectric properties of human B and T lymphocytes at frequencies from 20 kHz to 100 MHz.

Dielectric properties of the human B and T lymphocytes were measured. The experiments were performed at frequencies from 20 kHz to 100 MHz for different cell concentrations at 24 and 37 degrees C. An end of the line capacitive sensor and a computer-controlled automatic network analyser were utilised. Cole-Cole dielectric parameters were determined by curve fitting using a computer program. Specific membrane capacitances (Cm) were calculated from the experimental data (assuming a membrane charging mechanism) to be 0.77 and 2.89 microF cm-2 for the T and B lymphocytes, respectively. The fitted relaxation time is located in the centre of the calculated relaxation time distribution spectrum for the B lymphocytes, while it is shifted towards higher values of the relaxation time equivalent to the larger cells for the T lymphocytes. The distribution of the relaxation times was estimated on the basis of the Maxwell-Wagner dispersion reflecting membrane-charging processes.