Fig. 7: Line tension λ of contact line between droplet and vesicle membrane as a function of lipid number Nol for three different droplet sizes Ddr, calculated via the force balance relationship in Eq. (12).
From: Different pathways for engulfment and endocytosis of liquid droplets by nanovesicles
As we increase Nol, which encodes the transbilayer asymmetry, the line tension undergoes a transition from positive to negative values. The line tension is positive for Nol = 5400 and 5500, for which the whole engulfment process remains axisymmetric and leads to neck cleavage and membrane fission. On the other hand, for Nol = 5700 and 5963, the line tension has a negative value and leads to the formation of a tight-lipped membrane neck as in Fig. 4 which prevents the fission process. The dashed vertical lines provide estimates for the lipid numbers \({N}_{{{\rm{ol}}}}={N}_{{{\rm{ol}}}}^{[0]}\) which lead to λ = 0 for the different droplet sizes Ddr. The numerical values of \({N}_{{{\rm{ol}}}}^{[0]}\), which depend on the droplet size, are given in the last column of Table 1. Each red, green, and blue data point represents the mean value over n = 15 statistically independent samples obtained from three replicated simulations. Each error bar is the SEM.
