title: Near-infrared narrow-band imaging of gold/silica nanoshells in tumors.
abstract: Gold nanoshells (GNS) are a new class of nanoparticles that can be optically tuned to scatter or absorb light from the near-ultraviolet to near-infrared (NIR) region by varying the core (dielectric silica)/shell (gold) ratio. In addition to spectral tunability, GNS are inert and bioconjugatable, making them potential labels for in vivo imaging and therapy of tumors. We report the use of GNS as exogenous contrast agents for enhanced visualization of tumors using narrow-band imaging (NBI). NBI takes advantage of the strong NIR absorption of GNS to distinguish between blood and nanoshells in the tumor by imaging in narrow wavelength bands in the visible and NIR, respectively. Using tissue-simulating phantoms, we determined the optimum wavelengths to enhance contrast between blood and GNS. We then used the optimum wavelengths for ex vivo imaging of tumors extracted from human colon cancer xenograft bearing mice injected with GNS. Systemically delivered GNS accumulated passively in tumor xenografts by the enhanced permeability and retention (EPR) effect. Ex vivo NBI of tumor xenografts demonstrated heterogeneous distribution of GNS with a clear distinction from the tumor vasculature. The results of this study demonstrate the feasibility of using GNS as contrast agents to visualize tumors using NBI.
authors.affiliation: The University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712, USA.
authors.forename: Priyaveena
authors.initials: P
authors.lastname: Puvanakrishnan
authors.forename: Jaesook
authors.initials: J
authors.lastname: Park
authors.forename: Parmeswaran
authors.initials: P
authors.lastname: Diagaradjane
authors.forename: Jon A
authors.initials: JA
authors.lastname: Schwartz
authors.forename: Chris L
authors.initials: CL
authors.lastname: Coleman
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Gill-Sharp
authors.forename: Kristina L
authors.initials: KL
authors.lastname: Sang
authors.forename: J Donald
authors.initials: JD
authors.lastname: Payne
authors.forename: Sunil
authors.initials: S
authors.lastname: Krishnan
authors.forename: James W
authors.initials: JW
authors.lastname: Tunnell
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000473:pathology*; D003287:Contrast Media; D006046:Gold; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D051379:Mice; D008819:Mice, Nude; D049329:Nanostructures; D012822:Silicon Dioxide; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D003287:Contrast Media; D006046:Gold; D012822:Silicon Dioxide