Wetting of phospholipid membranes on hydrophilic surfaces - Concepts towards self-healing membranes

We report on the wetting behavior of phospholipid membranes on solid surfac es immersed in aqueous solution. Using fluorescence microscopy, the spreadi ng velocity of fluid bilayers: advancing from a lipid source is investigate d. The kinetic spreading coefficient was measured as a function of temperat ure for pure DMPC membranes and as a function of charge density and cholest erol content for binary membranes. A theoretical model for the membrane flo w is presented. which takes into account title liquid crystalline bilayer a rchitecture of the lipid membrane. The spreading power results front the me mbrane-solid VdW interaction and is dissipated in hydrodynamic shear flow a s well as by inter-monolayer friction within the bilayer. The frictional dr ag causes a dynamic tension gradient in the spreading membrane: which is ma nifested by a single exponential decay of the fluorescence intensity profil e along the spreading direction. Obstacles are shown to act as pinning cent ers deforming the advancing line interface. However, no depinning was obser ved, since the centers are circumflown without abrupt relaxation.