Self‐sterilization using silicone catheters coated with Ag and TiO 2 nanocomposite thin film

Ag/titanium dioxide (TiO 2 )‐coated silicon catheters were easily fabricated with Ag nanoparticles deposition on both the inside wall and the outside wall of TiO 2 ‐coated catheters by TiO 2 photocatalysis. This is an application of the silicon catheters coated with TiO 2 , 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/TiO 2 ‐coated silicon catheters exhibited a strong bactericidal effect even in the dark. When the 2–5 × 10 5 of colony‐forming units of Escherichia coli , Pseudomonas aeruginosa , or Staphylococcus aureus were respectively applied to the surface of the Ag/TiO 2 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/TiO 2 ‐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/TiO 2 catheter which was loaded with 2 nmol cm −2 of Ag, was ∼1.2 times higher (at maximum) than that on TiO 2 coating alone. Furthermore, the Ag nanoparticles can be pre‐eminently and uniformly deposited onto the TiO 2 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 TiO 2 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