Aims: 

High-resolution measurements of cell impedance provide valuable information on various cellular processes such as exocytosis, ion channel gating, or fertilization. The best recent techniques have limited applicability due to their inherent constrains and high complexity.

Methods: 

We report here the Q-method, a simple method of high-resolution impedance measurement based on measurements of charge by integrating the cell current in response to square wave stimulation. The charge is decomposed into specific components related to segments of the voltage stimulus and analyzed using simple relations for fast and direct estimation of the cell impedance parameters.

Results: 

The major advantages of the Q-method are its inherently low sensitivity to low-pass filtering, rejection of periodic interference signals, the capacitance resolution at theoretical limits, and simultaneous high-resolution low-crosstalk monitoring of the membrane resistance, the series resistance and the parasite capacitance, in addition to the membrane capacitance. High-resolution recordings of the cardiac myocyte capacitance and resistance under unstimulated control conditions are presented and their fluctuation is analyzed using the detrended analysis.

Conclusion: 

We show that Rm and Cm may behave independently during experiment and therefore may reflect independent cellulular processes that indicate collective changes in the state of the cell that have to be understood.