Surface-initiated RAFT polymerization of sulfobetaine from cellulose membranes to improve hemocompatibility and antibiofouling property

Two major complications generally occur in blood-contacting devices, namely thrombus formation and microbial invasion and infection. Therefore, hemocompatible and antibiofouling surfaces, which function as barriers to bacterial and cell adhesion, are essential. Herein, we report the successful grafting of zwitterionic polysulfobetaine brushes onto a cellulose membrane (CM) via surface-initiated reversible addition-fragmentation chain-transfer (SI-RAFT) polymerization for improving hemocompatibility and antibiofouling property. Both pristine and polysulfobetaine brush-modified CM substrates were characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), water contact angle measurements (WCA), X-ray photoelectron spectroscopy analysis (XPS), and atomic force microscopy (AFM). Experimental observations demonstrated the successful grafting of polysulfobetaine brushes, where brush thicknesses were found to increase gradually with polymerization time and monomer concentrations. Tests conducted by investigating platelet adhesion, hemolytic rates and protein adsorption indicated that polysulfobetaine brush-grafted CMs had excellent hemocompatibility featuring lower platelet adhesion and protein adsorption properties without causing hemolysis. E. coli adhesion and HeLa cell adhesion tests showed that grafted CMs had superior antibacterial adhesion properties and long-term cell adhesion resistance for up to four days. The functionalized cellulose substrate described holds great potential for use in biomedical applications.