Tough Hydrogel Coating on Silicone Rubber with Improved Antifouling and Antibacterial Properties

Silicone rubber catheters have a wide range of medical applications. However, silicone rubber is subject to biofouling, biofilm formation, and microbial infection, which can decrease its success and performance because of lipophilicity. In this report, a tough hydrogel was grafted onto the surface of silicone rubber to endow it with antifouling and antibacterial properties. First of all, an acrylamide (AAm)-, 2-methacryloxyethyl phosphorylcholine (MPC)-, and zinc methacrylate (ZMA)-derived poly(AAm-MPC-ZMA) hydrogel was coated on the surface of silicone rubber mediated by a poly(vinyl acetate) (PVAc) primer layer. Second, the composition and hydrophilicity of the hydrogel-coated rubber were evaluated by X-ray photoelectron spectroscopy (XPS) and a contact angle analyzer. The results indicated the success of the poly(AAm-MPC-ZMA) hydrogel coating, inducing a decrease in the contact angle from 107.01 to 23.22°. Bovine serum albumin (BSA) was further used to test the nonspecific protein absorption of the modified silicone rubber. It was found that BSA deposition on the surface of silicone rubber decreased from 0.33 to 0.07 mg/cm2 after coating, indicating an antifouling effect. In addition, the incorporation of ZMA gave silicone rubber significant antibacterial properties against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. As a preliminary application test, a silicone rubber catheter was coated with the poly(AAm-MPC-ZMA) hydrogel, which showed improved hydrophilicity and reduced adhesion against biological soft tissues. Taken together, the poly(AAm-MPC-ZMA) hydrogel coating generated a highly hydrophilic silicone rubber with excellent antifouling and antibacterial properties, which has great potential in the application of medical catheters.