Self‐sterilization using silicone catheters coated with Ag and TiO2 nanocomposite thin film

Abstract

Ag/titanium dioxide (TiO₂)-coated silicon catheters were easily fabricated with Ag nanoparticles deposition on both the inside wall and the outside wall of TiO₂-coated catheters by TiO₂ photocatalysis. This is an application of the silicon catheters coated with TiO₂, which possess a self-sterilizing and self-cleaning property combining with UV light illumination (Ohko et al., J Biomed Mater Res: Appl Biomater 2001;58:97). Ag/TiO₂-coated silicon catheters exhibited a strong bactericidal effect even in the dark. When the 2–5 × 10⁵ of colony-forming units of Escherichia coli, Pseudomonas aeruginosa, or Staphylococcus aureus were respectively applied to the surface of the Ag/TiO₂ catheters, which were loaded with ∼15 nmol cm⁻² of Ag, 99% effective sterilization occurred in a very short time: 20 min for E. coli, 60 min for P. aeruginosa, and 90 min for S. aureus. Additionally, the Ag/TiO₂-coated catheters possessed a strong self-cleaning property. Using UV illumination, the photocatalytic decomposition rate of methylene blue dye representing the self-cleaning capability, on an Ag/TiO₂ catheter which was loaded with 2 nmol cm⁻² of Ag, was ∼1.2 times higher (at maximum) than that on TiO₂ coating alone. Furthermore, the Ag nanoparticles can be pre-eminently and uniformly deposited onto the TiO₂ coating, and the amount of Ag was easily controllable from a few nanomoles per square centimeter to ∼70 nmol cm⁻² by changing the UV illumination time for TiO₂ photocatalysis. This type of catheter shows a great promise in lowering the incidence of catheter-related bacterial infections. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008