Figure 3.

Hemifusion diaphragm growth kinetics: model predictions versus experiment of Nikolaus et al. (17). (A) Legend. Three hemifused pairs were experimentally studied: blue pair (vesicle areas $A_{\text{ves}}^{\text{large}}$ = 824 μm², $A_{\text{ves}}^{\text{small}}$ = 887 μm²), red pair (1550 and 3260 μm²), and green pair (422 and 5030 μm²). HD growth terminated in HD rupture (blue and red pairs) or vesicle lysis (green pair, smaller vesicle). (B) HD size evolution. (Data points) Experiment and (solid lines) model predictions. (Dashed lines) Predicted final equilibrium area that would have been attained had HDs not ruptured (blue and red pair). (C) Short time kinetics in panel B. (Blue and red pairs) Model fitted to data using estimated initial tension γ⁰ = 8.7 mN/m (see main text) yielding best-fit value for interleaflet friction coefficient λ = 1.1 (±0.2) × 10⁹ N s/m³. (Green pair) Model fitted to data using initial tension as fitting parameter, yielding best-fit value γ⁰ = 15 ± 2 mN/m. (Solid black line) Short time analytical model prediction (Eq. 13) for red and blue pairs. (D–F) Predicted evolutions of vesicle and HD tensions. HD tensions are consistent with observed HD rupture in panels D and E. In all cases the initial vesicle tensions exceeded the rupture threshold.