Determination of isotropic membrane tension in highly deflated multicomponent vesicles

Ascertain the isotropic membrane tension σ0 (and thereby the dimensionless parameter Γ = σ0 R^2/k0) for highly deflated, multicomponent cylindrical vesicles by performing equilibrium shape simulations that compute σ0 as the Lagrange multiplier enforcing membrane area incompressibility, since σ0 could not be inferred from existing experimental data and such simulations have yet to be carried out.

Background

For quantitative comparison with experiments on multicomponent tubular vesicles, the dimensionless isotropic membrane tension Γ = σ0 R^2/k0 is needed. While other parameters (viscosity ratio, bending moduli contrast, line tension, Cahn number, Peclet number) can be estimated, the isotropic tension σ0 is not reported in experiments and thus Γ remains undetermined.

The authors note that σ0 could, in principle, be obtained from equilibrium shape simulations where it appears as a Lagrange multiplier enforcing constant membrane area. They explicitly state that such simulations are difficult for highly deflated multicomponent vesicles and, to their knowledge, have not yet been performed, leaving the determination of σ0 an open task.