Antibacterial and antifouling catheter coatings using surface grafted PEG-b-cationic polycarbonate diblock copolymers

Intravascular catheter-associated infections (CAIs), which are normally induced by microbial adhesion and subsequent biofilm formation, are a major cause of morbidity and mortality. Therefore, strategies to prevent CAIs are in great demand. In this study, a series of diblock copolymers of PEG and cationic polycarbonate with various compositions were synthesized by metal-free organocatalytic ring-opening polymerization, and coated onto silicone rubber (a commonly used catheter material) at different concentrations via a reactive polydopamine coating. Static contact angle and X-ray photoelectron spectroscopy measurements proved the successful coating, and quartz crystal microbalance results showed that the coating thickness increased as polymer concentration increased. Methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates – leading causes of intravascular CAIs – were employed to evaluate the antibacterial and antifouling activities of the polymer coatings. Polymer coatings with a hydrophobic component effectively killed planktonic MSSA and MRSA in solution and prevented their fouling on silicone rubber surface. Live/dead cell staining experiments revealed that polymer coatings with the optimal polymer composition possessed significantly higher antifouling activity than PEG coating. In addition, scanning electron microscopic studies showed that the polymer coating inhibited S. aureus biofilm formation over a period of 7 days. Furthermore, the polymer coating caused no significant hemolysis, and there was no blood protein adsorption or platelet adhesion observed. Therefore, PEG-b-cationic polycarbonates with optimal compositions are effective antifouling and antibacterial coatings for the prevention of intravascular CAIs.