title: Confined semiflexible polymers suppress fluctuations of soft membrane tubes.
abstract: We use Monte Carlo computer simulations to investigate tubular membrane structures with and without semiflexible polymers confined inside. At small values of membrane bending rigidity, empty fluid and non-fluid membrane tubes exhibit markedly different behavior, with fluid membranes adopting irregular, highly fluctuating shapes and non-fluid membranes maintaining extended tube-like structures. Fluid membranes, unlike non-fluid membranes, exhibit a local maximum in specific heat as their bending rigidity increases. The peak is coincident with a transition to extended tube-like structures. We further find that confining a semiflexible polymer within a fluid membrane tube reduces the specific heat of the membrane, which is a consequence of suppressed membrane shape fluctuations. Polymers with a sufficiently large persistence length can significantly deform the membrane tube, with long polymers leading to localized bulges in the membrane that accommodate regions in which the polymer forms loops. Analytical calculations of the energies of idealized polymer-membrane configurations provide additional insight into the formation of polymer-induced membrane deformations.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA. abel@utk.edu.
authors.forename: Sina
authors.initials: S
authors.lastname: Mirzaeifard
authors.forename: Steven M
authors.initials: SM
authors.lastname: Abel
mesh_terms: D004548:Elasticity; D008567:Membranes, Artificial; D044085:Microfluidics; D008962:Models, Theoretical; D043942:Nanotubes / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013718:Tensile Strength
chemical_list: D008567:Membranes, Artificial; D011108:Polymers