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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Poster: Membranes, Biomaterials, Biopolymers

CPP 15.7: Poster

Monday, March 20, 2017, 18:30–21:00, P1C

Adhesion of deformable fluctuating interfaces by multiple types of functional complexes — •Josip Vlajčević¹ and Ana-Sunčana Smith^1,2 — ¹Rudjer Bošković Institute, Division of Physical Chemistry, Zagreb — ²PULS Group, Institut für Theoretische Physik, Univesität Erlangen-Nürnberg

We present a model for the adhesion of flexible fluid membranes to a flat substrate by functional molecules (ligand-receptor pairs) which are freely diffusing on the adherent interfaces. In the absence of molecular complexation, the membrane resides close to a flat surface in a nonspecific potential that originates from van der Waals interactions and the steric repulsion associated with thermal fluctuations. Upon molecular complexation, the interface is deformed introducing cooperative effects for further specific molecular binding. While the system containing only one type functional pairs has been intensively studied in the past, the phase behavior and the dynamics of adhesion mediated by multiple functional pairs is poorly understood.

To rectify this issue we construct a Monte Carlo scheme that appropriately accounts for the described adhesion process. We study the organization of functional pairs into domains as a function of the molecular flexibility, length, binding energies and other properties of the system, and find a very rich phase diagram as a function of these parameters. Furthermore, we apply this model to the adhesion of T-lymphocyte cells, by binding of TCR to pMHC and LFA-1 to ICAM-1 proteins, to explain the fundamental processes in the formation of the immune synapse.