The Experts below are selected from a list of 1632 Experts worldwide ranked by ideXlab platform

Naomi J Halas - One of the best experts on this subject based on the ideXlab platform.

  • reduction in nanoparticle size dramatically improves plasmonic photo thermal therapy efficacy in aggressive triple negative breast cancer
    IEEE Transactions on Biomedical Engineering, 2014
    Co-Authors: Cordula Urban, Naomi J Halas, Rachel Schiff, Ciceron Ayala, Martin Shea, Amit Joshi
    Abstract:

    We report 4X enhancement of tumor accumulation and 2X increase in post photo-thermal therapy survival for 100nm Gold Nanomatryushkas versus conventional 150nm silica core Gold Nanoshells in mice with xenografted human triple negative breast cancer.

  • using catalytic and surface enhanced raman spectroscopy active Gold Nanoshells to understand the role of basicity in glycerol oxidation
    ACS Catalysis, 2013
    Co-Authors: Kimberly N Heck, Naomi J Halas, Benjamin G Janesko, Gustavo E Scuseria, Michael S Wong
    Abstract:

    The origin of oxidation activity of Gold catalysts has been a subject of great interest, particularly with the discovery of selective glycerol oxidation under water-phase alkaline conditions, for which neither small Gold nanoparticles nor a catalyst support is necessary for activity. Little is known about the interactions among the catalyst surface, reactant, and hydroxyl species, which have never been examined spectroscopically because of a lack of developed in situ methods. In this work, we studied the room-temperature, water-phase reaction of glycerol oxidation using Gold Nanoshells (Au NSs), in which the Gold substrate was active for surface-enhanced Raman spectroscopy (SERS) and catalysis. Analysis of glycerol solutions at high pH values and with oxygen content indicated that glycerol and glycerolate species did not bind directly to the catalyst surface in the absence of oxygen. However, glycerate surface species formed very rapidly when oxygen was present, suggesting an Eley–Rideal-type reaction mec...

  • Self-assembled plasmonic nanoparticle clusters
    CLEO QELS: 2010 Laser Science to Photonic Applications, 2010
    Co-Authors: Chihhui Wu, Rizia Bardhan, Vinothan N. Manoharan, Peter Nordlander, Naomi J Halas, Gennady Shvets, Federico Capasso
    Abstract:

    Polymer-coated Gold Nanoshells are assembled, using capillary forces, into packed clusters with tailored surface plasmon resonances. Separation between Nanoshells is engineered to be ~2 nm. Strongly coupled resonances in nanoshell dimers and trimers are observed.

  • optically tunable nanoparticle contrast agents for early cancer detection model based analysis of Gold Nanoshells
    Journal of Biomedical Optics, 2005
    Co-Authors: Alex W H Lin, Naomi J Halas, Jennifer L West, Nastassja A Lewinski, Rebekah A Drezek
    Abstract:

    Many optical diagnostic approaches rely on changes in scattering and absorption properties to generate optical contrast between normal and diseased tissue. Recently, there has been increasing interest in using exogenous agents to enhance this intrinsic contrast with particular emphasis on the development for targeting specific molecular features of disease. Gold Nanoshells are a class of core-shell nanoparticles with an extremely tunable peak optical resonance ranging from the near-UV to the mid-IR wavelengths. Using current chemistries, Nanoshells of a wide variety of core and shell sizes can easily be fabricated to scatter and/or absorb light with optical cross sections often several times larger than the geometric cross section. Using Gold Nanoshells of different size and optical parameters, we employ Monte Carlo models to predict the effect of varying concentrations of Nanoshells on tissue reflectance. The models demonstrate the importance of absorption from the Nanoshells on remitted signals even when the optical extinction is dominated by scattering. Furthermore, because of the strong optical response of Nanoshells, a considerable change in reflectance is observed with only a very small concentration of Nanoshells. Characterizing the optical behavior of Gold Nanoshells in tissue will aid in developing Nanoshells as contrast agents for optical diagnostics.

  • near infrared laser tissue welding using Nanoshells as an exogenous absorber
    Lasers in Surgery and Medicine, 2005
    Co-Authors: Andre M Gobin, Rebekah A Drezek, Naomi J Halas, Patrick D Oneal, Daniel M Watkins, Jennifer L West
    Abstract:

    Background and Objective Gold Nanoshells are a new class of nanoparticles that can be designed to strongly absorb light in the near infrared (NIR). These particles provide much larger absorption cross-sections and efficiency than can be achieved with currently used chemical chromophores without photobleaching. In these studies, we have investigated the use of Gold Nanoshells as exogenous NIR absorbers to facilitate NIR laser-tissue welding. Study Design/Materials and Methods Gold Nanoshells with peak extinction matching the NIR wavelength of the laser being used were manufactured and suspended in an albumin solder. Optimization work was performed on ex vivo muscle samples and then translated into testing in an in vivo rat skin wound-healing model. Mechanical testing of the muscle samples was immediately performed and compared to intact tissue mechanical properties. In the in vivo study, full thickness incisions in the dorsal skin of rats were welded, and samples of skin were excised at 0, 5, 10, 21, and 32 days for analysis of strength and wound healing response. Results Mechanical testing of nanoshell-solder welds in muscle revealed successful fusion of tissues with tensile strengths of the weld site equal to the uncut tissue. No welding was accomplished with this light source when using solder formulations without Nanoshells. Mechanical testing of the skin wounds showed sufficient strength for closure and strength increased over time. Histological examination showed good wound-healing response in the soldered skin. Conclusions The use of Nanoshells as an exogenous absorber allows the usage of light sources that are minimally absorbed by tissue components, thereby, minimizing damage to surrounding tissue and allowing welding of thicker tissues. © 2005 Wiley-Liss, Inc.

Rebekah A Drezek - One of the best experts on this subject based on the ideXlab platform.

  • immunoconjugated Gold nanoshell mediated photothermal ablation of trastuzumab resistant breast cancer cells
    Breast Cancer Research and Treatment, 2011
    Co-Authors: Laura B Carpin, Germaine Agollah, Tsekuan Yu, Lissett R Bickford, Rachel Schiff, Yi Li, Rebekah A Drezek
    Abstract:

    Trastuzumab is a FDA-approved drug that has shown clinical efficacy against HER2+ breast cancers and is commonly used in combination with other chemotherapeutics. However, many patients are innately resistant to trastuzumab, or will develop resistance during treatment. Alternative treatments are needed for trastuzumab-resistant patients. Here, we investigate Gold nanoparticle-mediated photothermal therapies as a potential alternative treatment for chemotherapy-resistant cancers. Gold nanoshell photothermal therapy destroys the tumor cells using heat, a physical mechanism, which is able to overcome the cellular adaptations that bestow trastuzumab resistance. By adding anti-HER2 to the Gold surface of the Nanoshells as a targeting modality, we increase the specificity of the Nanoshells for HER2+ breast cancer. Silica–Gold Nanoshells conjugated with anti-HER2 were incubated with both trastuzumab-sensitive and trastuzumab-resistant breast cancer cells. Nanoshell binding was confirmed using two-photon laser scanning microscopy, and the cells were then ablated using a near-infrared laser. We demonstrate the successful targeting and ablation of trastuzumab-resistant cells using anti-HER2-conjugated silica–Gold Nanoshells and a near-infrared laser. This study suggests potential for applying Gold nanoshell-mediated therapy to trastuzumab-resistant breast cancers in vivo.

  • quantitative tool for rapid disease mapping using optical coherence tomography images of azoxymethane treated mouse colon
    Journal of Biomedical Optics, 2010
    Co-Authors: Amy M Winkler, Rebekah A Drezek, Photini F S Rice, Jennifer K. Barton
    Abstract:

    Optical coherence tomography (OCT) can provide new insight into disease progression and therapy by enabling nondestructive, serial imaging of in vivo cancer models. In previous studies, we have shown the utility of endoscopic OCT for identifying adenomas in the azoxymethane-treated mouse model of colorectal cancer and tracking disease progression over time. Because of improved imaging speed made possible through Fourier domain imaging, three-dimensional imaging of the entire mouse colon is possible. Increased amounts of data can facilitate more accurate classification of tissue but require more time on the part of the researcher to sift through and identify relevant data. We present quantitative software for automatically identifying potentially diseased areas that can be used to create a two-dimensional "disease map" from a three-dimensional Fourier domain OCT data set. In addition to sensing inherent changes in tissue that occur during disease development, the algorithm is sensitive to exogeneous highly scattering Gold Nanoshells that can be targeted to disease biomarkers. The results of the algorithm were compared to histological diagnosis. The algorithm was then used to assess the ability of Gold Nanoshells targeted to epidermal growth factor receptor in vivo to enable functional OCT imaging.

  • optically tunable nanoparticle contrast agents for early cancer detection model based analysis of Gold Nanoshells
    Journal of Biomedical Optics, 2005
    Co-Authors: Alex W H Lin, Naomi J Halas, Jennifer L West, Nastassja A Lewinski, Rebekah A Drezek
    Abstract:

    Many optical diagnostic approaches rely on changes in scattering and absorption properties to generate optical contrast between normal and diseased tissue. Recently, there has been increasing interest in using exogenous agents to enhance this intrinsic contrast with particular emphasis on the development for targeting specific molecular features of disease. Gold Nanoshells are a class of core-shell nanoparticles with an extremely tunable peak optical resonance ranging from the near-UV to the mid-IR wavelengths. Using current chemistries, Nanoshells of a wide variety of core and shell sizes can easily be fabricated to scatter and/or absorb light with optical cross sections often several times larger than the geometric cross section. Using Gold Nanoshells of different size and optical parameters, we employ Monte Carlo models to predict the effect of varying concentrations of Nanoshells on tissue reflectance. The models demonstrate the importance of absorption from the Nanoshells on remitted signals even when the optical extinction is dominated by scattering. Furthermore, because of the strong optical response of Nanoshells, a considerable change in reflectance is observed with only a very small concentration of Nanoshells. Characterizing the optical behavior of Gold Nanoshells in tissue will aid in developing Nanoshells as contrast agents for optical diagnostics.

  • near infrared laser tissue welding using Nanoshells as an exogenous absorber
    Lasers in Surgery and Medicine, 2005
    Co-Authors: Andre M Gobin, Rebekah A Drezek, Naomi J Halas, Patrick D Oneal, Daniel M Watkins, Jennifer L West
    Abstract:

    Background and Objective Gold Nanoshells are a new class of nanoparticles that can be designed to strongly absorb light in the near infrared (NIR). These particles provide much larger absorption cross-sections and efficiency than can be achieved with currently used chemical chromophores without photobleaching. In these studies, we have investigated the use of Gold Nanoshells as exogenous NIR absorbers to facilitate NIR laser-tissue welding. Study Design/Materials and Methods Gold Nanoshells with peak extinction matching the NIR wavelength of the laser being used were manufactured and suspended in an albumin solder. Optimization work was performed on ex vivo muscle samples and then translated into testing in an in vivo rat skin wound-healing model. Mechanical testing of the muscle samples was immediately performed and compared to intact tissue mechanical properties. In the in vivo study, full thickness incisions in the dorsal skin of rats were welded, and samples of skin were excised at 0, 5, 10, 21, and 32 days for analysis of strength and wound healing response. Results Mechanical testing of nanoshell-solder welds in muscle revealed successful fusion of tissues with tensile strengths of the weld site equal to the uncut tissue. No welding was accomplished with this light source when using solder formulations without Nanoshells. Mechanical testing of the skin wounds showed sufficient strength for closure and strength increased over time. Histological examination showed good wound-healing response in the soldered skin. Conclusions The use of Nanoshells as an exogenous absorber allows the usage of light sources that are minimally absorbed by tissue components, thereby, minimizing damage to surrounding tissue and allowing welding of thicker tissues. © 2005 Wiley-Liss, Inc.

  • optically tunable nanoparticle contrast agents for early cancer detection model based analysis of Gold Nanoshells
    Journal of Biomedical Optics, 2005
    Co-Authors: Alex W H Lin, Naomi J Halas, Jennifer L West, Nastassja A Lewinski, Rebekah A Drezek
    Abstract:

    Many optical diagnostic approaches rely on changes in scattering and absorption properties to generate optical contrast be- tween normal and diseased tissue. Recently, there has been increasing interest in using exogenous agents to enhance this intrinsic contrast with particular emphasis on the development for targeting specific molecular features of disease. Gold Nanoshells are a class of core- shell nanoparticles with an extremely tunable peak optical resonance ranging from the near-UV to the mid-IR wavelengths. Using current chemistries, Nanoshells of a wide variety of core and shell sizes can easily be fabricated to scatter and/or absorb light with optical cross sections often several times larger than the geometric cross section. Using Gold Nanoshells of different size and optical parameters, we employ Monte Carlo models to predict the effect of varying concen- trations of Nanoshells on tissue reflectance. The models demonstrate the importance of absorption from the Nanoshells on remitted signals even when the optical extinction is dominated by scattering. Further- more, because of the strong optical response of Nanoshells, a consid- erable change in reflectance is observed with only a very small con- centration of Nanoshells. Characterizing the optical behavior of Gold Nanoshells in tissue will aid in developing Nanoshells as contrast agents for optical diagnostics. © 2005 Society of Photo-Optical Instrumentation En-

Jennifer L West - One of the best experts on this subject based on the ideXlab platform.

  • hydrogel nanoparticle composites for optically modulated cancer therapeutic delivery
    Journal of Controlled Release, 2014
    Co-Authors: Laura E Strong, Shreyas N Dahotre, Jennifer L West
    Abstract:

    Abstract A poly(N-isopropylacrylamide-co-acrylamide) (NIPAAm-co-AAm) hydrogel with near-infrared (NIR) absorbing silica–Gold Nanoshells was designed as a platform for pulsatile delivery of cancer therapeutics. This hydrogel was designed to have a lower critical solution temperature (LCST) above physiologic temperature, such that the material will transition from a hydrated state to a collapsed state above ~ 40 °C. Additionally, the silica–Gold Nanoshells used were designed to have a peak extinction coefficient in the NIR, where penetration of light through tissue is maximal. This heat-triggered material phase transition of the composite was found to follow exposure of NIR light, indicating the ability of the NIR absorption by the Nanoshells to sufficiently drive this transition. The composite material was loaded with either doxorubicin or a DNA duplex (a model nucleic acid therapeutic), two cancer therapeutics with differing physical and chemical properties. Release of both therapeutics was dramatically enhanced by NIR light exposure, causing 2–5 x increase in drug release. Drug delivery profiles were influenced by both the molecular size of the drug as well as its chemical properties. The DNA therapeutic showed slower rates of nonspecific delivery by passive diffusion due to its larger size. Additionally, only 70% of the more hydrophobic doxorubicin was released from the material, whereas the more hydrophilic DNA showed over 90% release. Further, hydrogel composites were used to deliver the doxorubicin to CT.26-WT colon carcinoma cells, eliciting a therapeutic response. This work validates the potential application for this material in site-specific cancer therapeutic delivery.

  • gadolinium conjugated Gold Nanoshells for multimodal diagnostic imaging and photothermal cancer therapy
    Small, 2014
    Co-Authors: Andrew J Coughlin, Jeyarama S Ananta, Nanfu Deng, Irina V Larina, Paolo Decuzzi, Jennifer L West
    Abstract:

    Multimodal imaging offers the potential to improve diagnosis and enhance the specificity of photothermal cancer therapy. Toward this goal, we have engineered gadolinium-conjugated Gold Nanoshells and demonstrated that they enhance contrast for magnetic resonance imaging, X-Ray, optical coherence tomography, reflectance confocal microscopy, and two-photon luminescence. Additionally, these particles effectively convert near-infrared light to heat, which can be used to ablate cancer cells. Ultimately, these studies demonstrate the potential of gadolinium-Nanoshells for image-guided photothermal ablation.

  • application of inaa to the build up and clearance of Gold Nanoshells in clinical studies in mice
    Journal of Radioanalytical and Nuclear Chemistry, 2007
    Co-Authors: W D James, Leon R Hirsch, Jennifer L West, P D Oneal, J D Payne
    Abstract:

    Clinical studies have been carried out for detailed measurements of the build-up and clearance of engineered Gold nanoshell in the tissues of dosed mice. These optically tunable Nanoshells are under consideration for a new therapy for tumors. The proposed therapy would involve the injection of the Nanoshells and their preferential accumulation in tumor sites. This will be followed by irradiation with a monochromatic near infrared laser, which will induce cellular hyperthermia, thereby eradicating the tumor. Neutron activation analysis has been used for the detection and quantitation of Gold, and therefore, the Nanoshells, in dosing materials, blood, bones and other tissues as well as tumors at varioius sacrifice times following dosing. Feasibility studies have shown instrumental neutron activation analysis to be uniquely suited for detection of the Gold Nanoshells over a wide dynamic range. This allows for the study of high concentrations of Gold in tissues which scavenge the shells from the blood (liver, spleen, kidney) as well as for much lower concentrations in those which do not (muscle, brain). In particular, the tissues from animals sacrificed after the longest post dose delay (28 days) and the control animals required experimental optimization to ensure the lowest possible determination limits. The mass of Gold in the tissue samples ranged from our determination limit (about 70 pg) to a few micrograms.

  • optically tunable nanoparticle contrast agents for early cancer detection model based analysis of Gold Nanoshells
    Journal of Biomedical Optics, 2005
    Co-Authors: Alex W H Lin, Naomi J Halas, Jennifer L West, Nastassja A Lewinski, Rebekah A Drezek
    Abstract:

    Many optical diagnostic approaches rely on changes in scattering and absorption properties to generate optical contrast between normal and diseased tissue. Recently, there has been increasing interest in using exogenous agents to enhance this intrinsic contrast with particular emphasis on the development for targeting specific molecular features of disease. Gold Nanoshells are a class of core-shell nanoparticles with an extremely tunable peak optical resonance ranging from the near-UV to the mid-IR wavelengths. Using current chemistries, Nanoshells of a wide variety of core and shell sizes can easily be fabricated to scatter and/or absorb light with optical cross sections often several times larger than the geometric cross section. Using Gold Nanoshells of different size and optical parameters, we employ Monte Carlo models to predict the effect of varying concentrations of Nanoshells on tissue reflectance. The models demonstrate the importance of absorption from the Nanoshells on remitted signals even when the optical extinction is dominated by scattering. Furthermore, because of the strong optical response of Nanoshells, a considerable change in reflectance is observed with only a very small concentration of Nanoshells. Characterizing the optical behavior of Gold Nanoshells in tissue will aid in developing Nanoshells as contrast agents for optical diagnostics.

  • near infrared laser tissue welding using Nanoshells as an exogenous absorber
    Lasers in Surgery and Medicine, 2005
    Co-Authors: Andre M Gobin, Rebekah A Drezek, Naomi J Halas, Patrick D Oneal, Daniel M Watkins, Jennifer L West
    Abstract:

    Background and Objective Gold Nanoshells are a new class of nanoparticles that can be designed to strongly absorb light in the near infrared (NIR). These particles provide much larger absorption cross-sections and efficiency than can be achieved with currently used chemical chromophores without photobleaching. In these studies, we have investigated the use of Gold Nanoshells as exogenous NIR absorbers to facilitate NIR laser-tissue welding. Study Design/Materials and Methods Gold Nanoshells with peak extinction matching the NIR wavelength of the laser being used were manufactured and suspended in an albumin solder. Optimization work was performed on ex vivo muscle samples and then translated into testing in an in vivo rat skin wound-healing model. Mechanical testing of the muscle samples was immediately performed and compared to intact tissue mechanical properties. In the in vivo study, full thickness incisions in the dorsal skin of rats were welded, and samples of skin were excised at 0, 5, 10, 21, and 32 days for analysis of strength and wound healing response. Results Mechanical testing of nanoshell-solder welds in muscle revealed successful fusion of tissues with tensile strengths of the weld site equal to the uncut tissue. No welding was accomplished with this light source when using solder formulations without Nanoshells. Mechanical testing of the skin wounds showed sufficient strength for closure and strength increased over time. Histological examination showed good wound-healing response in the soldered skin. Conclusions The use of Nanoshells as an exogenous absorber allows the usage of light sources that are minimally absorbed by tissue components, thereby, minimizing damage to surrounding tissue and allowing welding of thicker tissues. © 2005 Wiley-Liss, Inc.

Christophe Leboeuf - One of the best experts on this subject based on the ideXlab platform.

  • pulsed laser irradiation of multifunctional Gold Nanoshells to overcome trastuzumab resistance in her2 overexpressing breast cancer
    Journal of Experimental & Clinical Cancer Research, 2019
    Co-Authors: Toni Nunes, Thomas Pons, Benoit Caron, Marthe Rigal, Melanie Di Benedetto, Bruno Palpant, Christophe Leboeuf
    Abstract:

    HER2-overexpressing metastatic breast cancers are challenging practice in oncology when they become resistant to anti-HER2 therapies such as trastuzumab. In these clinical situations, HER2-overexpression persists in metastatic localizations, and can thus be used for active targeting using innovative therapeutic approaches. Functionalized Gold nanoparticles with anti-HER2 antibody can be stimulated by near-infrared light to induce hyperthermia. Here, hybrid anti-HER2 Gold Nanoshells were engineered for photothermal therapy to overcome trastuzumab resistance in HER2-overexpressing breast cancer xenografts. When Gold Nanoshells were administered in HER2-tumor xenografts, no toxicity was observed. A detailed pharmacokinetic study showed a time-dependent accumulation of Gold Nanoshells within the tumors, significantly greater with functionalized Gold Nanoshells at 72 h. This enabled us to optimize the treatment protocol and irradiate the mice when the anti-HER2 Gold Nanoshells had accumulated most in the tumors. After weekly injections of anti-HER2 Gold Nanoshells, and repeated irradiations with a femtosecond-pulsed laser over four weeks, tumor growth was significantly inhibited. Detailed tissue microscopic analyses showed that the tumor growth inhibition was due to an anti-angiogenic effect, coherent with a preferential distribution of the Nanoshells in tumor microvessels. We also showed a direct tumor cell effect with apoptosis and inhibition of proliferation, coherent with an immune-mediated targeting of tumor cells by anti-HER2 Nanoshells. This preclinical study thus supports the use of anti-HER2 Gold Nanoshells and photothermal therapy to overcome trastuzumab resistance in HER2-overexpressing breast cancer.

Alex W H Lin - One of the best experts on this subject based on the ideXlab platform.

  • optically tunable nanoparticle contrast agents for early cancer detection model based analysis of Gold Nanoshells
    Journal of Biomedical Optics, 2005
    Co-Authors: Alex W H Lin, Naomi J Halas, Jennifer L West, Nastassja A Lewinski, Rebekah A Drezek
    Abstract:

    Many optical diagnostic approaches rely on changes in scattering and absorption properties to generate optical contrast between normal and diseased tissue. Recently, there has been increasing interest in using exogenous agents to enhance this intrinsic contrast with particular emphasis on the development for targeting specific molecular features of disease. Gold Nanoshells are a class of core-shell nanoparticles with an extremely tunable peak optical resonance ranging from the near-UV to the mid-IR wavelengths. Using current chemistries, Nanoshells of a wide variety of core and shell sizes can easily be fabricated to scatter and/or absorb light with optical cross sections often several times larger than the geometric cross section. Using Gold Nanoshells of different size and optical parameters, we employ Monte Carlo models to predict the effect of varying concentrations of Nanoshells on tissue reflectance. The models demonstrate the importance of absorption from the Nanoshells on remitted signals even when the optical extinction is dominated by scattering. Furthermore, because of the strong optical response of Nanoshells, a considerable change in reflectance is observed with only a very small concentration of Nanoshells. Characterizing the optical behavior of Gold Nanoshells in tissue will aid in developing Nanoshells as contrast agents for optical diagnostics.

  • optically tunable nanoparticle contrast agents for early cancer detection model based analysis of Gold Nanoshells
    Journal of Biomedical Optics, 2005
    Co-Authors: Alex W H Lin, Naomi J Halas, Jennifer L West, Nastassja A Lewinski, Rebekah A Drezek
    Abstract:

    Many optical diagnostic approaches rely on changes in scattering and absorption properties to generate optical contrast be- tween normal and diseased tissue. Recently, there has been increasing interest in using exogenous agents to enhance this intrinsic contrast with particular emphasis on the development for targeting specific molecular features of disease. Gold Nanoshells are a class of core- shell nanoparticles with an extremely tunable peak optical resonance ranging from the near-UV to the mid-IR wavelengths. Using current chemistries, Nanoshells of a wide variety of core and shell sizes can easily be fabricated to scatter and/or absorb light with optical cross sections often several times larger than the geometric cross section. Using Gold Nanoshells of different size and optical parameters, we employ Monte Carlo models to predict the effect of varying concen- trations of Nanoshells on tissue reflectance. The models demonstrate the importance of absorption from the Nanoshells on remitted signals even when the optical extinction is dominated by scattering. Further- more, because of the strong optical response of Nanoshells, a consid- erable change in reflectance is observed with only a very small con- centration of Nanoshells. Characterizing the optical behavior of Gold Nanoshells in tissue will aid in developing Nanoshells as contrast agents for optical diagnostics. © 2005 Society of Photo-Optical Instrumentation En-