Optimization of sulfonated polyethyleneimine zwitterionic coating mediated by polydopamine for poly(vinyl chloride) antifouling

Although poly(vinyl chloride) (PVC) has been widely used as blood-contacting materials in extracorporeal circuits and indwelling medical devices, its hydrophobicity also is a limitation due to the adsorption of plasma proteins and the immediately followed thrombosis cascade and bacterial infections. Herein, we developed a mild and simple strategy for improving the hydrophilicity and antifouling properties of the surface via mussel-inspired chemistry. Different amounts of 1,3-Propanesultone (1,3-PS) were attached onto the polyethyleneimine (PEI), so as to modify it into the zwitterion, called PES_X. Two layer-by-layer approaches about PES_X grafting on PVC substrates were designed. One strategy was by coating PES_X after coating polydopamine (PDA) on PVC surface, obtaining PDA-PES_X coatings. The other was by grafting PES_X after co-deposition treatment of PDA and PES_X with appropriate feeding ratio on PVC, obtaining PDA/PES_X-PES_X coatings. The study results indicated that the PDA/PES_0.5-PES_0.5 coatings with optimized PEI molecular weight and sulfonation degree, presented about 2.5–3 times reduction in BSA adsorption (0.77 μg/cm²) compared with PDA/PES_0.5 (1.93 μg/cm²) and PDA-PES_0.5 (2.26 μg/cm²), and kept long time antifouling stability. Moreover, the more excellent antifouling performance of PDA/PES_0.5-PES_0.5 was also seen on fibrinogen (Fg), γ-globulin (γ-GL), and the mixture of these proteins. Meanwhile, PDA/PES_0.5-PES_0.5 could prevent the adhesion of blood components and bacteria on the surface as well as maintain excellent hemocompatibility and cytocompatibility. We had hopes that our simple and mild strategy will find practical application in surface engineering of clinical use in blood-contacting medical devices.