Antimicrobial polyurethane catheters synthesized by grafting-radiation method doped with silver nanoparticles

Abstract

Tecoflex® polyurethane catheters were surficial modified with acrylic acid (AAc) to obtain a hydrophilic material able to host antimicrobial agents. The grafted catheters were prepared by the oxidative pre-irradiation technique using 60Co as the gamma-ray source. Graft kinetics was studied by varying the applied dose and the reaction time to obtain catheters with different grafting yields. Modified catheters were characterized by infrared spectroscopy (FTIR-ATR), thermogravimetric analysis (TGA), Cross-polarization Magic-angle spinning nuclear magnetic resonance in solid-state (CP/MAS 13C NMR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS). The modified catheters displayed notable hydrophilicity absorbing water; besides, they exhibited a critical pH of 6.5 because of grafting presence. The graft endowed the catheters with the ability to load silver nanoparticles acquiring biocidal properties with the ability to prevent bacterial proliferation on its surface. Silver-impregnated catheters showed notable antimicrobial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, presenting inhibiting halos of 8.1 and 10.2 mm on the catheter surroundings, respectively. The biocide property was confirmed when silver-impregnated catheters were challenged in a killing test against both bacteria, eradicating up to 80% of the bacterial population depending on the amount of loaded silver NPs.