Anti-biofouling Sulfobetaine Polymer Thin Films on Silicon and Silicon Nanopore Membranes

Silicon nanopore membranes (SNM) with monodisperse pore size distributions have potential applications in bioartificial kidneys. A protein resistant thin film coating on the SNM is required to minimize biofouling and, hence, enhance the performance efficiency of SNM. In this work, a zwitterionic polymer, poly(sulfobetaine methacrylate) (polySBMA), was used to coat silicon and SNM substrates via a surface initiated atom transfer radical polymerization method. The polySBMA-coated surfaces were characterized using contact angle goniometry, X-ray photoelectron spectroscopy (XPS), ellipsometry and scanning electron microscopy (SEM). Resistance of the coatings to protein fouling was examined by measurement of fibrinogen adsorption from fibrinogen solution and human plasma on coated silicon surfaces. Results showed that the polySBMA coating suppresses non-specific adsorption of fibrinogen. The protein-repellent property of polySBMA thin film coating is comparable to that of PEG-based coatings. Analysis of the surfaces by XPS indicated that the films remained stable when stored under physiologic conditions over a 4-week period.