Fabrication and hemocompatibility of cell outer membrane mimetic surfaces on chitosan by layer by layer assembly with polyanion bearing phosphorylcholine groups.

Three random copolymers poly(2-methacryloyloxyethyl phosphorylcholine-co-methacrylic acid) (PMAs) were synthesized by free radical polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and methacrylic acid (MA) with different monomer ratios under monomer-starved conditions. The synthesized PMA polyanions were assembled on chitosan (CS) film surfaces via electrostatic interactions. Using layer by layer (LbL) assembly with PMA polyanion and chitosan polycation, PMA/CS multilayer thin films with phosphorylcholine groups on the outer surfaces were fabricated. The modified surfaces were characterized by dynamic contact angle (DCA), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Hemocompatibility of the surfaces was estimated by protein adsorption and platelet adhesion measurements. The results indicated that cell outer membrane mimetic structures were formed on the modified surfaces with PMA as the outermost layer, and the hemocompatibility of the modified surfaces was significantly improved. This facile method of fabricating cell outer membrane mimetic surfaces may have potential applications in the fields of hemocompatible coatings, drug delivery, and tissue engineering.