Entropy-driven tension and bending elasticity in condensed-fluid membranes

Numerical simulation of the stochastic dynamics of inclusions in biomembranes in the presence of surface tension

“…The range of values for the surface tension was chosen to be in line with the discussions presented previously [20,21].…”

“…t = 10 −4 s, over which the values of the components of D t were computed has to be justified. We justify this choice by noticing that the diffusion time scale, t D , for a stochastic particle of mass m is given by [27] Since the relevant time scale for Brownian particles is at least, t D = 10 −9 s, then in order for the criterion of long-time dynamics, as embodied in (20), to be applicable to our model, the correlation time, t, in (13) and (15) over which the diffusion constants were calculated, must satisfy the condition [27] t ≫ t D .…”

“…For instance, it has been shown that [19] the area dependence of surface tension can lead to a stable hole of finite size in the biomembrane. Furthermore, interesting phenomena have been observed when biomembranes are perturbed by the action of microscopes [20], or in recent years by laser tweezers [21]. The typical effect of such tweezers on an initially flaccid biomembrane has been reported [21] where the application of the laser tweezers on a vesicle over few minutes caused the shape fluctuations of the biomembrane to disappear.…”

“…Such an spontaneous expulsion is quite surprising [19], since it involves the opening of a large hole, of energy much larger than the thermal energy. In comparison, using mechanical manipulation, rather than tweezers, of very large vesicles, tensions as low as, σ ≥ 10 −6 erg/cm 2 [20] have also been recorded. It is, therefore, quite reasonable to assume that surface tension in the above range plays a significant role in the dynamic behaviour of a biomembrane.…”

“…We performed numerical simulations of the space-time motion of inclusions described by (20) by adopting the following iterative scheme [33] …”