Immobilized liposomes as a model of cells in a laminar flow field

Abstract

A feasible approach for the production of large yields of liposomes (model cell membranes) is demonstrated. The technique involves rapid evaporation of chloroform from a mixture of lipid, chloroform and methanol, which consistently produces giant unilamellar vesicles (liposomes) having a size distribution of 15-75 micrometers. The procedure is feasible at laboratory scale and produces quick results. Different methods for attaching fluorescein labeled liposomes to glass capillaries are presented. The immobilization of liposomes to glass surfaces can be applied as a useful tool for the observation of structural changes taking place on their surface when they are subjected to a uniform flow. This would permit some insight into the configurational variations taking place on a cell membrane surface in the blood stream. As a preliminary model for the computation of forces acting on the liposomes under flow, a mathematical model was developed using the direct radial basis function method. The technique is applied to three dimensional flow in a square channel which replicates the velocity profile inside the rectangular glass capillary tube.