(634c) The Structure and Elasticity of Lipid Vesicles Interacting with End-Phosphorylated Polyethylene Glycol

The structure and dynamics of lipid membranes in the presence of extracellular macromolecules is critical for cell membrane functions and many pharmaceutical applications. End phosphorylation of a triblock polyethylene glycol, ABAPEG 11K, greatly changes the interactions between the polymer and vesicle membranes, preventing PEG induced vesicle phase separation. SANS shows Pi-ABAPEG 11K weakly interacts with DMPC vesicle membranes but does not significantly change the structure of DMPC unilamellar vesicles at 37^oC. Neutron spin-echo results show that the adsorption of Pi-ABAPEG 11K on DMPC vesicle membranes increases the membrane bending modulus . X ray reflectivity measurements confirm the weak adsorption of Pi-ABAPEG 11K on DMPC monolayer resulting in a more compacted DMPC monolayer structure.