Anti-fouling properties of polylactic acid film modified by pegylated phosphorylcholine derivatives

Anti-fouling properties are important for both pharmaceutical and biomedical applications of polylactic acid (PLA). In this study, highly hydrated hydrophilic bilayers containing phosphatidylcholine (PC) and polyethylene glycol (PEG) were applied to PLA films to prevent the protein adsorption and blood platelet adhesion. The PLA films were coated with three PLA copolymers of PC and PEG, namely, a PLA-b-PEG block copolymer with a PC group on the end of a PEG chain (PC-PEG-PLA), a poly[2-methacryloyloxyethyl phosphatidylcholine (MPC)]-PLA graft copolymer (PMPC-g-PLA), and a PMPC-PLA graft copolymer with PEG serving as a spacer (PMPC-g-(PEG-b-PLA)). The influence of the copolymer structure on the anti-fouling properties of PLA film was then investigated. The results showed that the introduction of PC and PEG polar copolymers decreased the water-contact angle (WCA) and increased the equilibrated degree of hydration (Heq) of the PLA surface significantly. The PMPC-g-(PEG-b-PLA) copolymer achieved the lowest WCA value and the highest Heq value as it provided a higher density of PC on the outer surface. In addition, the strong hydration of the PEG and PC groups efficiently suppressed the bovine serum albumin (BSA) and fibrinogen (Fg) adsorption and subsequently inhibited platelet adhesion. The above results demonstrated that a good “anti-fouling” surface layer on the PLA substrate could be achieved by a combination of PEG and PC in copolymers.