Grafting sulfobetaine monomer onto silicone surface to improve haemocompatibility

Silicone rubber has been used as a biomaterial for more than two decades and displays good mechanical and optical properties, but its chemical nature, poor antithrombogenicity, as well as its hydrophobicity, prevents its use in many demanding biomedical applications. In order to provide modified silicone with enhanced haemocompatibility, surface modification techniques were used. Ozonization was used to introduce active peroxide groups onto the silicone film surface and, subsequently, graft polymerization of N,N′‐dimethyl‐N‐methacryloyloxyethyl‐N‐(3‐sulfopropyl) ammonium (DMMSA), a zwitterionic sulfobetaine structure, onto the ozone activated silicone surface was conducted. Surface analysis was accomplished by means of attenuated total reflectance‐Fourier‐transform infrared (ATR‐FTIR), and X‐ray photoelectron spectra (XPS), and scanning electron microscopy (SEM) and contact angle measurement. ATR‐FTIR and XPS investigation confirmed the graft polymerization. The grafted film possessed a relatively hydrophilic surface as indicated by contact angle measurement. The blood compatibility of the grafted films was evaluated by platelet adhesion in platelet‐rich plasma (PRP) and protein adsorption in bovine fibrinogen using silicone film as the reference. No platelet adhesion was observed for the grafted films incubated in PRP for 120 min. The protein adsorption was reduced on the grafted films after incubated in bovine fibrinogen for 120 min. These results confirmed that the improved blood compatibility was obtained by grafting this new zwitterronic sulfobetaine structure onto silicone film. Copyright © 2003 Society of Chemical Industry