title: Gold nanoshell-decorated silicone surfaces for the near-infrared (NIR) photothermal destruction of the pathogenic bacterium E. faecalis.
abstract: Catheter-related infections (CRIs) are associated with the formation of pathogenic biofilms on the surfaces of silicone catheters, which are ubiquitous in medicine. These biofilms provide protection against antimicrobial agents and facilitate the development of bacterial resistance to antibiotics. The application of photothermal agents on catheter surfaces is an innovative approach to overcoming biofilm-generated CRIs. Gold nanoshells (AuNSs) represent a promising photothermal tool, because they can be used to generate heat upon exposure to near-infrared (NIR) radiation, are biologically inert at physiological temperatures, and can be engineered for the photothermal ablation of cells and tissue. In this study, AuNSs functionalized with carboxylate-terminated organosulfur ligands were attached to model catheter surfaces and tested for their effectiveness at killing adhered Enterococcus faecalis (E. faecalis) bacteria. The morphology of the AuNSs was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), while the elemental composition was characterized by energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). Furthermore, optical and photothermal properties were acquired by ultraviolet-visible (UV-vis) spectroscopy and thermographic imaging with an infrared camera, respectively. Bacterial survival studies on AuNS-modified surfaces irradiated with and without NIR light were evaluated using a colony-formation assay. These studies demonstrated that AuNS-modified surfaces, when illuminated with NIR light, can effectively kill E. faecalis on silicone surfaces.
authors.affiliation: Department of Chemistry and the Texas Center for Superconductivity and ‡Department of Electrical and Computer Engineering University of Houston , Houston, Texas 77204-5003, United States.
authors.forename: Orawan
authors.initials: O
authors.lastname: Khantamat
authors.forename: Chien-Hung
authors.initials: CH
authors.lastname: Li
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Jamison
authors.forename: Wei-Chuan
authors.initials: WC
authors.lastname: Shih
authors.forename: Chengzhi
authors.initials: C
authors.lastname: Cai
authors.forename: T Randall
authors.initials: TR
authors.lastname: Lee
mesh_terms: D018441:Biofilms / Q000528:radiation effects; D055499:Catheter-Related Infections / Q000382:microbiology / Q000517:prevention & control; D013293:Enterococcus faecalis / Q000254:growth & development / Q000502:physiology / Q000528:radiation effects*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007259:Infrared Rays; D057145:Nanoshells / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry*; D013696:Temperature
chemical_list: D012828:Silicones; D006046:Gold
keywords: E. faecalis; catheter-related infections; gold nanoshells; photothermal; polydimethylsiloxane; surface plasmon resonance