Schiller, P.: Molecular Statistical Model for Adsorbed Membrane Particles. Mol. Phys., submitted


Indirect membrane-mediated forces influence aggregation, segregation and freezing processes of large particles inserted into a membrane or adsorbed to its surface. Colloidal particles, polymers, peptides and proteins are the source of deformations of the lipid double layer. These perturbations cause membrane- mediated attractive or repulsive forces between the particles. A molecular statistical treatment is useful to investigate the lateral organisation of peripheral and trans-membrane peptides. To describe aggregation and freezing phenomena a density functional which includes conventional short range forces and membrane-mediated effects is proposed. The method is applied to an ensemble of adsorbed peptides. It is investigated how the elastic splay-distortion modulus, the surface tension, the compression-expansion modulus of the bilayer and the cross section of adsorbed particles influence aggregation and freezing. Assuming conventional values for the material parameters, membrane mediated attractive forces are found to be sufficiently strong to enforce aggregation.