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Matthew T Mcdowell - One of the best experts on this subject based on the ideXlab platform.

  • studying the kinetics of crystalline Silicon Nanoparticle lithiation with in situ transmission electron microscopy
    Advanced Materials, 2012
    Co-Authors: Matthew T Mcdowell, Ill Ryu, Seok Woo Lee, Chongmin Wang, W D Nix, Yi Cui
    Abstract:

    In situ transmission electron microscopy (TEM) is used to study the electrochemical lithiation of high-capacity crystalline Si Nanoparticles for use in Li-ion battery anodes. The lithiation reaction slows down as it progresses into the particle interior, and analysis suggests that this behavior is due not to diffusion limitation but instead to the influence of mechanical stress on the driving force for reaction.

  • studying the kinetics of crystalline Silicon Nanoparticle lithiation with in situ transmission electron microscopy
    Advanced Materials, 2012
    Co-Authors: Matthew T Mcdowell, Chongmin Wang
    Abstract:

    M.T.M. acknowledges support from the Chevron Stanford Graduate Fellowship, the National Defense Science and Engineering Graduate Fellowship, and the National Science Foundation Graduate Fellowship. Portions of this work are supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Contract No. DE-AC02-76SF00515 through the SLAC National Accelerator Laboratory LDRD project and the Assistant Secretary for Energy efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, Subcontract No. 6951379 under the Batteries for Advanced Transportation Technologies (BATT) Program. S. W. L. acknowledges support from KAUST (No. KUK-F1-038-02). C. M. W. acknowledges support from the Laboratory Directed Research and Development (LDRD) program of Pacific Northwest National Laboratory. The in situ TEM work was conducted in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by DOE's Office of Biological and Environmental Research and located at PNNL. PNNL is operated by Battelle for the DOE under Contract DE-AC05-76RLO1830. W.D.N. and I. R. gratefully acknowledge support of the Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under contract no. DE-FG02-04ER46163. The authors would like to thank Dr. Mauro Pasta for helpful comments.

Chongmin Wang - One of the best experts on this subject based on the ideXlab platform.

  • studying the kinetics of crystalline Silicon Nanoparticle lithiation with in situ transmission electron microscopy
    Advanced Materials, 2012
    Co-Authors: Matthew T Mcdowell, Ill Ryu, Seok Woo Lee, Chongmin Wang, W D Nix, Yi Cui
    Abstract:

    In situ transmission electron microscopy (TEM) is used to study the electrochemical lithiation of high-capacity crystalline Si Nanoparticles for use in Li-ion battery anodes. The lithiation reaction slows down as it progresses into the particle interior, and analysis suggests that this behavior is due not to diffusion limitation but instead to the influence of mechanical stress on the driving force for reaction.

  • studying the kinetics of crystalline Silicon Nanoparticle lithiation with in situ transmission electron microscopy
    Advanced Materials, 2012
    Co-Authors: Matthew T Mcdowell, Chongmin Wang
    Abstract:

    M.T.M. acknowledges support from the Chevron Stanford Graduate Fellowship, the National Defense Science and Engineering Graduate Fellowship, and the National Science Foundation Graduate Fellowship. Portions of this work are supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Contract No. DE-AC02-76SF00515 through the SLAC National Accelerator Laboratory LDRD project and the Assistant Secretary for Energy efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, Subcontract No. 6951379 under the Batteries for Advanced Transportation Technologies (BATT) Program. S. W. L. acknowledges support from KAUST (No. KUK-F1-038-02). C. M. W. acknowledges support from the Laboratory Directed Research and Development (LDRD) program of Pacific Northwest National Laboratory. The in situ TEM work was conducted in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by DOE's Office of Biological and Environmental Research and located at PNNL. PNNL is operated by Battelle for the DOE under Contract DE-AC05-76RLO1830. W.D.N. and I. R. gratefully acknowledge support of the Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under contract no. DE-FG02-04ER46163. The authors would like to thank Dr. Mauro Pasta for helpful comments.

Yi Cui - One of the best experts on this subject based on the ideXlab platform.

Michael J Sailor - One of the best experts on this subject based on the ideXlab platform.

  • porous Silicon Nanoparticle delivery of tandem peptide anti infectives for the treatment of pseudomonas aeruginosa lung infections
    Advanced Materials, 2017
    Co-Authors: Ester J Kwon, Michael J Sailor, Erkki Ruoslahti, Matthew Skalak, Alessandro Bertucci, Gary B Braun, Francesco Ricci, Sangeeta N Bhatia
    Abstract:

    There is an urgent need for new materials to treat bacterial infections. In order to improve antibacterial delivery, an anti-infective nanomaterial is developed that utilizes two strategies for localization: i) a biodegradable Nanoparticle carrier to localize therapeutics within the tissue, and ii) a novel tandem peptide cargo to localize payload to bacterial membranes. First, a library of antibacterial peptides is screened that combines a membrane-localizing peptide with a toxic peptide cargo and discovers a tandem peptide that displays synergy between the two domains and is able to kill Pseudomonas aeruginosa at sub-micromolar concentrations. To apply this material to the lung, the tandem peptide is loaded into porous Silicon Nanoparticles (pSiNPs). Charged peptide payloads are loaded into the pores of the pSiNP at ≈30% mass loading and ≈90% loading efficiency using phosphonate surface chemistry. When delivered to the lungs of mice, this anti-infective nanomaterial exhibits improved safety profiles over free peptides. Moreover, treatment of a lung infection of P. aeruginosa results in a large reduction in bacterial numbers and markedly improves survival compared to untreated mice. Collectively, this study presents the selection of a bifunctional peptide-based anti-infective agent and its delivery via biodegradable Nanoparticles for application to an animal model of lung infection.

  • Gated Luminescence Imaging of Silicon Nanoparticles.
    ACS nano, 2015
    Co-Authors: Jinmyoung Joo, Erkki Ruoslahti, Xiangyou Liu, Venkata Ramana Kotamraju, Yoonkey Nam, Michael J Sailor
    Abstract:

    The luminescence lifetime of nanocrystalline Silicon is typically on the order of microseconds, significantly longer than the nanosecond lifetimes exhibited by fluorescent molecules naturally present in cells and tissues. Time-gated imaging, where the image is acquired at a time after termination of an excitation pulse, allows discrimination of a Silicon Nanoparticle probe from these endogenous signals. Because of the microsecond time scale for Silicon emission, time-gated imaging is relatively simple to implement for this biocompatible and nontoxic probe. Here a time-gated system with ∼10 ns resolution is described, using an intensified CCD camera and pulsed LED or laser excitation sources. The method is demonstrated by tracking the fate of mesoporous Silicon Nanoparticles containing the tumor-targeting peptide iRGD, administered by retro-orbital injection into live mice. Imaging of such systemically administered Nanoparticles in vivo is particularly challenging because of the low concentration of probe in the targeted tissues and relatively high background signals from tissue autofluorescence. Contrast improvements of >100-fold (relative to steady-state imaging) is demonstrated in the targeted tissues.

  • enhanced magnetic resonance contrast of iron oxide Nanoparticles embedded in a porous Silicon Nanoparticle host
    Proceedings of SPIE, 2013
    Co-Authors: Joseph M Kinsella, Michael J Sailor, Shalini Ananda, Jennifer S Andrew, Joel Grondek, Miaoping Chien, Nathan C Gianneschi, Erkki Ruoslahti, Miriam Scandeng
    Abstract:

    In this report, we prepared a porous Si Nanoparticle with a pore morphology that facilitates the proximal loading and alignment of magnetite Nanoparticles. We characterized the composite materials using superconducting quantum interference device magnetometry, dynamic light scattering, transmission electron microscopy, and MRI. The in vitro cytotoxicity of the composite materials was tested using cell viability assays on human liver cancer cells and rat hepatocytes. An in vivo analysis using a hepatocellular carcinoma (HCC) Sprague Dawley rat model was used to determine the biodistribution properties of the material, while naive Sprague Dawley rats were used to determine the pharmocokinetic properties of the nanomaterials. The composite material reported here demonstrates an injectable nanomaterial that exploits the dipolar coupling of superparamagnetic Nanoparticles trapped within a secondary inorganic matrix to yield significantly enhanced MRI contrast. This preparation successfully avoids agglomeration issues that plague larger ferromagnetic systems. A Fe 3 O 4 :pSi composite formulation consisting of 25% by mass Fe 3 O 4 yields an maximal T2* value of 556 mM Fe −1 s −1 . No cellular (HepG2 or rat hepatocyte cells) or in vivo (rat) toxicity was observed with the formulation, which degrades and is eliminated after 4–8 h in vivo. The ability to tailor the magnetic properties of such materials may be useful for in vivo imaging, magnetic hyperthermia, or drug-delivery applications.

  • enhanced magnetic resonance contrast of fe3o4 Nanoparticles trapped in a porous Silicon Nanoparticle host
    Advanced Materials, 2011
    Co-Authors: Joseph M Kinsella, Shalini Ananda, Jennifer S Andrew, Joel Grondek, Miaoping Chien, Miriam Scadeng, Nathan C Gianneschi, Erkki Ruoslahti, Michael J Sailor
    Abstract:

    Magnetic Nanoparticles have been investigated for a broad range of clinical and diagnostic applications including immunoassays, targeted drug delivery, magnetic resonance imaging (MRI), and magnetic hyperthermia.[1–4] One of the earliest clinical applications of magnetic Nanoparticles was the use of superparamagnetic iron oxide to enhance image contrast in MRI,[5–8] due to the ability of these Nanoparticles to increase proton relaxation rates. Coating of superparamagnetic iron oxide Nanoparticles (SPIONs) with dextran provides a non-toxic and non-immunogenic material that circulates effectively in the body, allowing enhanced imaging of liver, spleen and lymphatic tissues. These particles are used clinically to deliniate hepatic lesions in patients with cirrohis or hepatocellular carcinoma (HCC) and to identify lymph node metastases.[5, 9] The superparamagnetic materials are sequestered within Kupffer cells, whose function is to recycle iron from non-viable red blood cells. Malignant HCC tissues lack functional Kupffer cells, resulting in reduced uptake of the Nanoparticles compared to healthy tissue. More recently, methods have been developed that allow SPIONs to aid in the detection of solid tumors.[9–15]

  • porous Silicon Nanoparticle photosensitizers for singlet oxygen and their phototoxicity against cancer cells
    ACS Nano, 2011
    Co-Authors: Ling Xiao, Luo Gu, Stephen B Howell, Michael J Sailor
    Abstract:

    Porous Si Nanoparticles, prepared from electrochemically etched single crystal Si wafers, function as photosensitizers to generate 1O2 in ethanol and in aqueous media. The preparation conditions for the porous Si Nanoparticles were optimized to maximize (1) the yield of material; (2) its quantum yield of 1O2 production; and (3) its in vitro degradation properties. The optimal formulation was determined to consist of Nanoparticles 146 ± 7 nm in diameter, with nominal pore sizes of 12 ± 4 nm. The quantum yield for 1O2 production is 0.10 ± 0.02 in ethanol and 0.17 ± 0.01 in H2O. HeLa or NIH-3T3 cells treated with 100 μg/mL porous Si Nanoparticles and exposed to 60 J/cm2 white light (infrared filtered, 100 mW/cm2 for 10 min) exhibit ∼45% cell death, while controls containing no Nanoparticles show 10% or 25% cell death, respectively. The dark control experiment yields <10% cytotoxicity for either cell type.

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

  • energy transfer mechanism and auger effect in er3 coupled Silicon Nanoparticle samples
    Journal of Applied Physics, 2010
    Co-Authors: A. Pitanti, N. Prtljaga, N. Daldosso, Fabrice Gourbilleau, Richard Rizk, B. Garrido, D Navarrourrios, L. Pavesi
    Abstract:

    We report a spectroscopic study about the energy transfer mechanism among Silicon Nanoparticles Si-np, both amorphous and crystalline, and Er ions in a Silicon dioxide matrix. From infrared spectroscopic analysis, we have determined that the physics of the transfer mechanism does not depend on the Si-np nature, finding a fast 200 ns energy transfer in both cases, while the amorphous nanoclusters reveal a larger transfer efficiency than the nanocrystals. Moreover, the detailed spectroscopic results in the visible range here reported are essential to understand the physics behind the sensitization effect, whose knowledge assumes a crucial role to enhance the transfer rate and possibly employing the material in optical amplifier devices. Joining the experimental data, performed with pulsed and continuous-wave excitation, we develop a model in which the internal intraband recombination within Si-np is competitive with the transfer process via an Auger electron-“recycling” effect. Posing a different light on some detrimental mechanism such as Auger processes, our findings clearly recast the role of Si-np in the sensitization scheme, where they are able to excite very efficiently ions in close proximity to their surface. © 2010 American Institute of Physics. doi:10.1063/1.3476286

  • Energy transfer mechanism and Auger effect in Er3+ coupled Silicon Nanoparticle samples
    Journal of Applied Physics, 2010
    Co-Authors: A. Pitanti, D. Navarro-urrios, N. Prtljaga, N. Daldosso, Fabrice Gourbilleau, Richard Rizk, B. Garrido, L. Pavesi
    Abstract:

    We report a spectroscopic study about the energy transfer mechanism among Silicon Nanoparticles (Si-np), both amorphous and crystalline, and Er ions in a Silicon dioxide matrix. From infrared spectroscopic analysis, we have determined that the physics of the transfer mechanism does not depend on the Si-np nature, finding a fast (く200 ns) energy transfer in both cases, while the amorphous nanoclusters reveal a larger transfer efficiency than the nanocrystals. Moreover, the detailed spectroscopic results in the visible range here reported are essential to understand the physics behind the sensitization effect, whose knowledge assumes a crucial role to enhance the transfer rate and possibly employing the material in optical amplifier devices. Joining the experimental data, performed with pulsed and continuous-wave excitation, we develop a model in which the internal intraband recombination within Si-np is competitive with the transfer process via an Auger electron-“recycling” effect. Posing a different light on some detrimental mechanism such as Auger processes, our findings clearly recast the role of Si-np in the sensitization scheme, where they are able to excite very efficiently ions in close proximity to their surface.