Assessing the Dynamics and Mechanics of the Cell Membrane

Abstract

Thermally and actively driven cell membrane fluctuations are known to be readouts for the nanomechanical interaction between the cortical cytoskeleton and the plasma membrane and the membrane. In this study, we developed a non-contact method to measure cell surface fluctuations through measurements of resistance between a microelectrode tip and the cell membrane. The system resolution was < 2 nm tested by using 2-10 Hz sinusoidal piezo stage motion with amplitudes ranging from 2 nm to 100 nm. We found that endothelial cells exhibited local membrane fluctuations of ∼20 nm at a number of characteristic frequencies. To determine the role of actin in membrane fluctuation, we treated cells with 2 μM of actin depolymerizing drug, cytochalasin D, and we found that actin depolymerization increased in fluctuation amplitude up to 2 times at all frequencies. Finally, to determine role of ATP in membrane fluctuations, we treated cells with ATP depletion drug cocktail which consisted of 25nM Antimycin A + 2mg/ml 2-Deoxy-D-Glucose, and we found that ATP depletion abolished all membrane fluctuations. Therefore, actin cytoskeleton and dynamic processes facilitated by ATP may modulate membrane functions through mechanical effects on membrane fluctuations