Rupture of plasma membrane under tension.

We present a study on the rupture behavior of single NIH 3T3 mouse fibroblasts under tension using micropipette aspiration. Membrane rupture was characterized by breaking and formation of an enclosed membrane linked to a tether at the cell apex. Three different rupture modes, namely: single break, initial multiple breaks, and continuous multiple breaks, were observed under similar loading condition. The measured mean tensile strengths of plasma membrane were 3.83 ± 1.94 and 3.98 ± 1.54mN/m for control cells and cells labeled with TubulinTracker, respectively. The tensile strength data was described by Weibull distribution. For the control cells, the Weibull modulus and characteristic strength were 1.86 and 4.40 mN/m, respectively; for cells labeled with TubulinTracker, the Weibull modulus and characteristic strength were 2.68 and 4.48 mN/m, respectively. Based on the experimental data, the estimated average transmembrane proteins-lipid cleavage strength was 2.64 ± 0.64 mN/m. From the random sampling of volume ratio of transmembrane proteins in cell membrane, we concluded that the Weibull characteristic of plasma membrane strength was likely to be originated from the variation in transmembrane proteins-lipid interactions.