Reduced Protein Adsorption on Polymer Surface Covered with a Self-Assembled Biomimetic Membrane

We have synthesized phospholipid polymers containing 2-methacryloyloxyethyl phosphorylcholine(MPC) moieties as new blood compatible polymers and have evaluated their interactions with blood components. It was found that in the absence of anticoagulants blood clotting was delayed, and blood cell adhesion and activation were effectively prevented on the MPC copolymer surface. Protein adsorption on the MPC copolymer from human plasma was also reduced with increasing MPC fraction. The MPC copolymers are able to collect phospholipid molecules from plasma due to MPC moiety-phospholipid interactions and the accumulated phospholipids appear to create a self-assembled biomimetic membrane structure on the MPC copolymers which minimizes protein adsorption. When the MPC copolymer was treated with dipalmitoylphosphatidylcholine(DPPC) liposomal solution, DPPC molecules having the organized liposomal structure were adsorbed on the MPC copolymer surface. On the other hand, DPPC molecules were randomly adsorbed on conventional polymers. The amounts of plasma proteins adsorbed on the polymer surfaces decreased on pretreatment with DPPC liposomal solution for all polymers case, but the smallest amounts of adsorbed proteins were found on the MPC copolymer. The differences in protein adsorption on the different polymers probably reflect the differences in the state of organization of adsorbed phospholipid molecules on the polymer surfaces.