FIGURE 3.

(A) Lysis tensions σ_L measured under continuous loading at 2 mN/m/s are plotted for temperatures of 15°C and 32–33°C for SOPC, 1:1 DOPC/CHOL, 1:1 SOPC/CHOL, 1:1 SM/CHOL, 1:1:1 DOPC/SM/CHOL, and 1:1:1 and 1:1:2 SOPC/SM/CHOL. Results for single-component SOPC and DOPC vesicles are plotted at 15°C. Fifty to eighty vesicles were tested for each system and temperature (means ± SD given in Table 1). Because membrane rupture is governed by kinetics, measurements of rupture tension have an inherent standard deviation (typically ∼10−15%). However, the standard errors (standard error = standard deviation/n^1/2) in the measurements are smaller than the size of symbols in A for n ∼50–80, which characterize the statistical uncertainties in the most frequent rupture events described by the nucleation theory given in the Appendix. (B) The lysis tensions obtained at 15°C are shown to correlate precisely with the values for thermal tension scale σ_β from fitting the kinetic model for rupture (as shown in the Appendix) to the stress-rate dependence of rupture tension.