11. Surface modification of catheters is generally required to inhibit biofilm formation and/or to eliminate bacterial infection from indwelling catheters.
12. The application of metal nanoparticles,such as silver, on the surface of medical devices has been used as an antimicrobial route to prevent bacterial adhesion and subsequent biofilm formation.
13. However, the toxicity of silver nanoparticles toward mammalian cells has been reported by several groups,and this concern limits their use in the surface modification of catheters.
14. Another approach is the development of other types of metal nanoparticles as agents for the photothermal eradication of bacteria.
15. Among the metal nanoparticles currently used in biological research, gold nanoshells (AuNSs), which consist of a thin gold shell surrounding a dielectric core, are strong candidates for this application.
16. AuNSs are biologically inert at physiological temperatures and can be engineered for photothermal ablation of cells and tissues via the heat generated by their strong surface plasmon resonance (SPR).
17. Localized SPR is a phenomenon in which light interacts with the conduction band electrons at the surface of a metal nanoparticle when the incident photons are in resonance with the collective oscillation of the electrons.
18. For AuNSs, this property can be tuned through the manipulation of the dimensions of the dielectric core and the gold shell.
19. The toxicity of AuNSs has been examined, with all available evidence indicating that, at physiological doses, AuNSs are noncytotoxic and pose no short-term health risks.
20. Numerous in vivo studies in mice have provided the best evidence that AuNSs are not only nontoxic, but also safe,including a report where mice treated with AuNSs exhibited no clinical abnormalities or side effects months after treatment.