Microelectrophoresis studies of the binding of glycosaminoglycans to phosphatidylcholine liposomes.

The binding of the glycosaminoglycans (GAG) chondroitin sulfate and heparin and the homologous molecule dextran sulfate to multilamellar dimyristoyl phosphatidylcholine (DMPC), dilaureyl phosphatidylcholine (DLPC) and egg lecithin liposomes was investigated by microelectrophoresis measurements. Drastic changes of the zeta potential of the liposomes to negative values indicate the binding of the highly anionic macromolecules. Binding depends strongly on Ca2+ and NaCl concentrations in the medium and does not occur in the absence of Ca2+. The adsorption is saturated at concentrations of about 0.1 mg/ml chondroitin sulfate and heparin and 0.01 mg/ml dextran sulfate. In the gel state of the phospholipid bilayer more GAG can associate with the surface compared to the fluid state.