One-Step Aminomalononitrile-Based Coatings Containing Zwitterionic Copolymers for the Reduction of Biofouling and the Foreign Body Response

Many biomedical devices benefit from antibiofouling coatings, which can reduce biointerfacial interactions such as protein adsorption and cell attachment. In this study, we synthesized zwitterionic copolymers consisting of sulfobetaine methacrylate (SB) and 2-aminoethyl methacrylate (AE) via free radical polymerization and combined these copolymers in solution with aminomalononitrile to form zwitterionic coatings in an autopolymerization process. The successful deposition of coatings containing different SB/AE ratios was demonstrated by X-ray photoelectron spectroscopy. The onestep surface modification process was carried out on polydimethylsiloxane (PDMS), tissue culture polystyrene, and gold substrates, demonstrating that this method can be transferred to different substrate materials. The ability of optimized coatings to reduce serum protein adsorption was demonstrated by quartz crystal microbalance measurements while the ability to resist cell attachment for 24 h was demonstrated using L929 mouse fibroblasts. The stability of the coatings under physiological conditions was investigated, and resistance to cell attachment was maintained over a period of 45 days. Furthermore, the resistance of the copolymer coating to cell attachment was maintained after both ethylene oxide sterilization and autoclaving. Finally, copolymer-modified PDMS samples were investigated with regard to their ability to reduce the foreign body response in vivo. Here, a significant reduction in the capsule thickness (approximately 50%) was observed in nude mice after 2 and 4 weeks. It is expected that the one-step, facile, and versatile surface modification strategy discussed here will find applications in biomedical devices.