Browsing by Subject "nanoparticles"

Now showing 1 - 7 of 7
  • Thumbnail Image
    ItemOpen Access
    A Plasmonic Gold Nanostar Theranostic Probe for In Vivo Tumor Imaging and Photothermal Therapy.
    (Theranostics, 2015) Liu, Yang; Ashton, Jeffrey R; Moding, Everett J; Yuan, Hsiangkuo; Register, Janna K; Fales, Andrew M; Choi, Jaeyeon; Whitley, Melodi J; Zhao, Xiaoguang; Qi, Yi; Ma, Yan; Vaidyanathan, Ganesan; Zalutsky, Michael R; Kirsch, David G; Badea, Cristian T; Vo-Dinh, Tuan
    Nanomedicine has attracted increasing attention in recent years, because it offers great promise to provide personalized diagnostics and therapy with improved treatment efficacy and specificity. In this study, we developed a gold nanostar (GNS) probe for multi-modality theranostics including surface-enhanced Raman scattering (SERS) detection, x-ray computed tomography (CT), two-photon luminescence (TPL) imaging, and photothermal therapy (PTT). We performed radiolabeling, as well as CT and optical imaging, to investigate the GNS probe's biodistribution and intratumoral uptake at both macroscopic and microscopic scales. We also characterized the performance of the GNS nanoprobe for in vitro photothermal heating and in vivo photothermal ablation of primary sarcomas in mice. The results showed that 30-nm GNS have higher tumor uptake, as well as deeper penetration into tumor interstitial space compared to 60-nm GNS. In addition, we found that a higher injection dose of GNS can increase the percentage of tumor uptake. We also demonstrated the GNS probe's superior photothermal conversion efficiency with a highly concentrated heating effect due to a tip-enhanced plasmonic effect. In vivo photothermal therapy with a near-infrared (NIR) laser under the maximum permissible exposure (MPE) led to ablation of aggressive tumors containing GNS, but had no effect in the absence of GNS. This multifunctional GNS probe has the potential to be used for in vivo biosensing, preoperative CT imaging, intraoperative detection with optical methods (SERS and TPL), as well as image-guided photothermal therapy.
  • Thumbnail Image
    ItemOpen Access
    A standardized method to determine the concentration of extracellular vesicles using tunable resistive pulse sensing.
    (J Extracell Vesicles, 2016) Vogel, Robert; Coumans, Frank AW; Maltesen, Raluca G; Böing, Anita N; Bonnington, Katherine E; Broekman, Marike L; Broom, Murray F; Buzás, Edit I; Christiansen, Gunna; Hajji, Najat; Kristensen, Søren R; Kuehn, Meta J; Lund, Sigrid M; Maas, Sybren LN; Nieuwland, Rienk; Osteikoetxea, Xabier; Schnoor, Rosalie; Scicluna, Benjamin J; Shambrook, Mitch; de Vrij, Jeroen; Mann, Stephen I; Hill, Andrew F; Pedersen, Shona
    BACKGROUND: Understanding the pathogenic role of extracellular vesicles (EVs) in disease and their potential diagnostic and therapeutic utility is extremely reliant on in-depth quantification, measurement and identification of EV sub-populations. Quantification of EVs has presented several challenges, predominantly due to the small size of vesicles such as exosomes and the availability of various technologies to measure nanosized particles, each technology having its own limitations. MATERIALS AND METHODS: A standardized methodology to measure the concentration of extracellular vesicles (EVs) has been developed and tested. The method is based on measuring the EV concentration as a function of a defined size range. Blood plasma EVs are isolated and purified using size exclusion columns (qEV) and consecutively measured with tunable resistive pulse sensing (TRPS). Six independent research groups measured liposome and EV samples with the aim to evaluate the developed methodology. Each group measured identical samples using up to 5 nanopores with 3 repeat measurements per pore. Descriptive statistics and unsupervised multivariate data analysis with principal component analysis (PCA) were used to evaluate reproducibility across the groups and to explore and visualise possible patterns and outliers in EV and liposome data sets. RESULTS: PCA revealed good reproducibility within and between laboratories, with few minor outlying samples. Measured mean liposome (not filtered with qEV) and EV (filtered with qEV) concentrations had coefficients of variance of 23.9% and 52.5%, respectively. The increased variance of the EV concentration measurements could be attributed to the use of qEVs and the polydisperse nature of EVs. CONCLUSION: The results of this study demonstrate the feasibility of this standardized methodology to facilitate comparable and reproducible EV concentration measurements.
  • Thumbnail Image
    ItemOpen Access
    Gallium plasmonics: deep subwavelength spectroscopic imaging of single and interacting gallium nanoparticles.
    (ACS Nano, 2015-02-24) Knight, Mark W; Coenen, Toon; Yang, Yang; Brenny, Benjamin JM; Losurdo, Maria; Brown, April S; Everitt, Henry O; Polman, Albert
    Gallium has recently been demonstrated as a phase-change plasmonic material offering UV tunability, facile synthesis, and a remarkable stability due to its thin, self-terminating native oxide. However, the dense irregular nanoparticle (NP) ensembles fabricated by molecular-beam epitaxy make optical measurements of individual particles challenging. Here we employ hyperspectral cathodoluminescence (CL) microscopy to characterize the response of single Ga NPs of various sizes within an irregular ensemble by spatially and spectrally resolving both in-plane and out-of-plane plasmonic modes. These modes, which include hybridized dipolar and higher-order terms due to phase retardation and substrate interactions, are correlated with finite difference time domain (FDTD) electrodynamics calculations that consider the Ga NP contact angle, substrate, and native Ga/Si surface oxidation. This study experimentally confirms previous theoretical predictions of plasmonic size-tunability in single Ga NPs and demonstrates that the plasmonic modes of interacting Ga nanoparticles can hybridize to produce strong hot spots in the ultraviolet. The controlled, robust UV plasmonic resonances of gallium nanoparticles are applicable to energy- and phase-specific applications such as optical memory, environmental remediation, and simultaneous fluorescence and surface-enhanced Raman spectroscopies.
  • Thumbnail Image
    ItemOpen Access
    In vivo small animal micro-CT using nanoparticle contrast agents.
    (Front Pharmacol, 2015) Ashton, Jeffrey R; West, Jennifer L; Badea, Cristian T
    Computed tomography (CT) is one of the most valuable modalities for in vivo imaging because it is fast, high-resolution, cost-effective, and non-invasive. Moreover, CT is heavily used not only in the clinic (for both diagnostics and treatment planning) but also in preclinical research as micro-CT. Although CT is inherently effective for lung and bone imaging, soft tissue imaging requires the use of contrast agents. For small animal micro-CT, nanoparticle contrast agents are used in order to avoid rapid renal clearance. A variety of nanoparticles have been used for micro-CT imaging, but the majority of research has focused on the use of iodine-containing nanoparticles and gold nanoparticles. Both nanoparticle types can act as highly effective blood pool contrast agents or can be targeted using a wide variety of targeting mechanisms. CT imaging can be further enhanced by adding spectral capabilities to separate multiple co-injected nanoparticles in vivo. Spectral CT, using both energy-integrating and energy-resolving detectors, has been used with multiple contrast agents to enable functional and molecular imaging. This review focuses on new developments for in vivo small animal micro-CT using novel nanoparticle probes applied in preclinical research.
  • Thumbnail Image
    ItemOpen Access
    Inner ear delivery: Challenges and opportunities.
    (Laryngoscope investigative otolaryngology, 2020-02) Szeto, Betsy; Chiang, Harry; Valentini, Chris; Yu, Michelle; Kysar, Jeffrey W; Lalwani, Anil K

    Objectives

    The treatment of inner ear disorders remains challenging due to anatomic barriers intrinsic to the bony labyrinth. The purpose of this review is to highlight recent advances and strategies for overcoming these barriers and to discuss promising future avenues for investigation.

    Data sources

    The databases used were PubMed, EMBASE, and Web of Science.

    Results

    Although some studies aimed to improve systemic delivery using nanoparticle systems, the majority enhanced local delivery using hydrogels, nanoparticles, and microneedles. Developments in direct intracochlear delivery include intracochlear injection and intracochlear implants.

    Conclusions

    In the absence of a systemic drug that targets only the inner ear, the best alternative is local delivery that harnesses a combination of new strategies to overcome anatomic barriers. The combination of microneedle technology with hydrogel and nanoparticle delivery is a promising area for future investigation.

    Level of evidence

    NA.
  • Thumbnail Image
    ItemOpen Access
    Rhodium nanoparticles for ultraviolet plasmonics.
    (Nano Lett, 2015-02-11) Watson, Anne M; Zhang, Xiao; Alcaraz de la Osa, Rodrigo; Marcos Sanz, Juan; González, Francisco; Moreno, Fernando; Finkelstein, Gleb; Liu, Jie; Everitt, Henry O
    The nonoxidizing catalytic noble metal rhodium is introduced for ultraviolet plasmonics. Planar tripods of 8 nm Rh nanoparticles, synthesized by a modified polyol reduction method, have a calculated local surface plasmon resonance near 330 nm. By attaching p-aminothiophenol, local field-enhanced Raman spectra and accelerated photodamage were observed under near-resonant ultraviolet illumination, while charge transfer simultaneously increased fluorescence for up to 13 min. The combined local field enhancement and charge transfer demonstrate essential steps toward plasmonically enhanced ultraviolet photocatalysis.
  • Thumbnail Image
    ItemOpen Access
    Transient anomalous diffusion of tracer particles in soft matter
    (2009) McKinley, Scott A; Yao, Lingxing; Forest, M Gregory
    This paper is motivated by experiments in which time series of tracer particles in viscoelastic liquids are recorded using advanced microscopy. The experiments seek to infer either viscoelastic properties of the sample [Mason and Weitz, Phys. Rev. Lett. 74, 1250-1253 (1995)] or diffusive properties of the specific tracer particle in the host medium [Suh et al., Adv. Drug Delivery Rev. 57, 63-78 (2005); Matsui et al., Proc. Natl. Acad. Sci. U. S. A. 103, 18131-18136 (2006); Lai et al., Proc. Natl. Acad. Sci. U. S. A. 104, 1482-1487 (2007); Fricks et al., SIAM J. Appl. Math. 69, 1277-1308 (2009)]. Our focus is the latter. Experimentalists often fit data to transient anomalous diffusion: a sub-diffusive power law scaling (t(v), with 0 < v < 1) of mean-squared displacement (MSD) over a finite time interval, with longtime viscous scaling (t(1)). The time scales of sub-diffusion and exponents v are observed to vary with particle size, particle surface chemistry, and viscoelastic properties of the host material. Until now, explicit models for transient sub-diffusive MSD scaling behavior [Doi and Edwards, The Theory of Polymer Physics (Oxford University Press, New York, 1986); Kremer and Grest, J. Chem. Phys. 92, 5057-5086 (1990); Rubinstein and Colby, Polymer Physics (Oxford University Press, New York, 2003)] are limited to precisely three exponents: monomer diffusion in Rouse chain melts (t(1/2)), in Zimm chain solutions (t(2/3)), and in reptating chains (t(1/4)). In this paper, we present an explicit parametrized family of stochastic processes (generalized Langevin equations with prescribed memory kernels) and derive their closed-form solutions which (1) span the complete range of transient sub-diffusive behavior and (2) possess the flexibility to tune both the time window of sub-diffusive scaling and the power law exponent v. These results establish a robust family of sub-diffusive models, for which the inverse problem of parameter inference from experimental data [Fricks et al., SIAM J. Appl. Math. 69, 1277-1308 (2009)] remains to be developed. (C) 2009 The Society of Rheology. [DOI: 10.1122/1.3238546]