Rational design of a zwitterionic–phosphonic copolymer for the surface antifouling modification of multiple biomedical metals

Abstract

The lack of blood compatibility and antifouling ability is still one of the challenges of bare metallic implants and devices for biomedical applications. Here, based on the strong binding affinity of the phosphonic group on metallic substrates and excellent antifouling ability of zwitterionic materials, we reported the rational design of zwitterionic–phosphonic copolymers for efficient antifouling surface modification of diverse biomedical metals. Firstly, nine copolymers with a wide range of mole ratios between the zwitterionic and phosphonic components (from 10 : 90 to 99 : 1) were precisely prepared via conventional radical copolymerization. The XPS result revealed that the copolymers, even if only 1% of the phosphonic component was present, were able to bind onto the titanium alloy substrates. Water contact angle measurement showed that the more zwitterionic component in the coating copolymer, the better the surface wettability of the titanium alloy substrates. Systematic antifouling evaluation (protein adsorption, platelet adhesion, bacterial adhesion, and cell adhesion tests) results consistently indicated that the copolymers bearing the zwitterionic components, ranging from 20 to 95%, can efficiently confer perfect antifouling ability to the titanium alloy substrates, establishing a robust relationship between the composition of the copolymer and the surface antifouling property conferred to the titanium alloy substrates. In addition, the ability of the zwitterionic–phosphonic copolymers to improve the antifouling ability of other biomedical metals (pure Ti and stainless steel) and devices (scalpels) was clearly demonstrated, indicating that the zwitterionic–phosphonic copolymers could serve as general antifouling coating materials for biomedical metals.