Browsing by Author "Ayala-Orozco, Ciceron"

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    Au Nanomatryoshkas as Efficient Near-Infrared Photothermal Transducers for Cancer Treatment: Benchmarking against Nanoshells
    (American Chemical Society, 2014) Ayala-Orozco, Ciceron; Urban, Cordula; Knight, Mark W.; Urban, Alexander Skyrme; Neumann, Oara; Bishnoi, Sandra W.; Mukherjee, Shaunak; Goodman, Amanda M.; Charron, Heather; Mitchell, Tamika; Shea, Martin; Roy, Ronita; Nanda, Sarmistha; Schiff, Rachel; Halas, Naomi J.; Joshi, Amit
    Au nanoparticles with plasmon resonances in the near-infrared (NIR) region of the spectrum efficiently convert light into heat, a property useful for the photothermal ablation of cancerous tumors subsequent to nanoparticle uptake at the tumor site. A critical aspect of this process is nanoparticle size, which influences both tumor uptake and photothermal efficiency. Here, we report a direct comparative study of ∼90 nm diameter Au nanomatryoshkas (Au/SiO2/Au) and ∼150 nm diameter Au nanoshells for photothermal therapeutic efficacy in highly aggressive triple negative breast cancer (TNBC) tumors in mice. Au nanomatryoshkas are strong light absorbers with 77% absorption efficiency, while the nanoshells are weaker absorbers with only 15% absorption efficiency. After an intravenous injection of Au nanomatryoshkas followed by a single NIR laser dose of 2 W/cm2 for 5 min, 83% of the TNBC tumor-bearing mice appeared healthy and tumor free >60 days later, while only 33% of mice treated with nanoshells survived the same period. The smaller size and larger absorption cross section of Au nanomatryoshkas combine to make this nanoparticle more effective than Au nanoshells for photothermal cancer therapy.
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    Enhancing the photocurrent and photoluminescence of single crystal monolayer MoS2ﾠwith resonant plasmonic nanoshells
    (AIP Publishing LLC., 2014) Sobhani, Ali; Lauchner, Adam; Najmaei, Sina; Ayala-Orozco, Ciceron; Wen, Fangfang; Lou, Jun; Halas, Naomi J.
    Monolayer molybdenum disulfide (MoS2) produced by controlled vapor-phase synthesis is a commercially promising new two-dimensional material for optoelectronics because of its direct bandgap and broad absorption in the visible and ultraviolet regimes. By tuning plasmonic core-shell nanoparticles to the direct bandgap of monolayer MoS2 and depositing them sparsely (<1% coverage) onto the material's surface, we observe a threefold increase in photocurrent and a doubling of photoluminescence signal for both excitonic transitions, amplifying but not altering the intrinsic spectral response.
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    Heavy oil viscosity reduction at mild temperatures using palladium acetylacetonate
    (Elsevier, 2021) Xu, Yan; Heck, Kimberly N.; Ayala-Orozco, Ciceron; Arredondo, Jacob H.; Zenor, William; Shammai, Michael; Wong, Michael S.
    Metal-ligand compounds (“MLCs”) have been shown to reduce heavy oil viscosity and upgrade oil quality. However, MLCs generally require high treatment temperatures (around 250 °C), which is undesirably energy-intensive. We identified palladium(II) acetylacetonate (“PdA”) as a model MLC that can operate at mild temperatures (<200 °C). We studied its effectiveness on heavy oil viscosity reduction in the range of 80–300 °C using viscometry, SARA analysis, GC–MS, XPS, and XRD to characterize Peace River oil samples thermally treated with and without PdA. This MLC effectively lowered oil viscosity at all treatment temperatures, whereas thermal-only treatments did not reduce viscosity below 160 °C. The thermal treatment with PdA in the 130–250 °C range reduced viscosity by up to ~35% more than the thermal treatment alone. GC–MS and TGA results indicated the PdA partially decomposed at 80 °C and higher temperatures, releasing acetylacetone (“HA”), which lowered oil viscosity. The temperature and HA effects did not completely account for the observed viscosity reduction from thermal treatment with PdA, indicating there were other significant effects. In the 80–130 °C range, the asphaltene fraction increased due to PdA or its decomposition products intercalating into the asphaltene clusters. At temperatures around 250 °C, the resin fraction decreased, correlating to in situ formed metallic Pd that catalytically hydrogenate the resin sulfonyl groups to aliphatic sulfur. This new understanding of the temperature-dependent impact – acetylacetonate ligand, MLC-asphaltene attraction, and palladium metal catalyst formation – on oil viscosity changes provides an improved approach to developing new MLCs for field-relevant conditions.
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    Impurity-Induced Plasmon Damping in Individual Cobalt-Doped Hollow Au Nanoshells
    (American Chemical Society, 2014) Thibodeaux, Christyn A.; Kulkarni, Vikram; Chang, Wei-Shun; Neumann, Oara; Cao, Yang; Brinson, Bruce; Ayala-Orozco, Ciceron; Chen, Chih-Wei; Morosan, Emilia; Link, Stephan; Nordlander, Peter; Halas, Naomi J.; Laboratory for Nanophotonics; Rice Quantum Institute
    The optical properties of plasmonic nanoparticles in the size range corresponding to the electrostatic, or dipole, limit have the potential to reveal effects otherwise masked by phase retardation. Here we examine the optical properties of individual, sub-50 nm hollow Au nanoshells (Co-HGNS), where Co is the initial sacrificial core nanoparticle, using single particle total internal reflection scattering (TIRS) spectroscopy. The residual Co present in the metallic shell induces a substantial broadening of the homogeneous plasmon resonance line width of the Co-HGNS, where the full width at half-maximum (fwhm) broadens proportionately with increasing Co content. This doping-induced line broadening provides a strategy for controlling plasmon line width independent of nanoparticle size, and has the potential to substantially modify the relative decay channels for localized nanoparticle surface plasmons.
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    Light-activated molecular machines are fast-acting broad-spectrum antibacterials that target the membrane
    (AAAS, 2022) Santos, Ana L.; Liu, Dongdong; Reed, Anna K.; Wyderka, Aaron M.; van Venrooy, Alexis; Li, John T.; Li, Victor D.; Misiura, Mikita; Samoylova, Olga; Beckham, Jacob L.; Ayala-Orozco, Ciceron; Kolomeisky, Anatoly B.; Alemany, Lawrence B.; Oliver, Antonio; Tegos, George P.; Tour, James M.; Smalley-Curl Institute; NanoCarbon Center; Welch Institute for Advanced Materials
    The increasing occurrence of antibiotic-resistant bacteria and the dwindling antibiotic research and development pipeline have created a pressing global health crisis. Here, we report the discovery of a distinctive antibacterial therapy that uses visible (405 nanometers) light-activated synthetic molecular machines (MMs) to kill Gram-negative and Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus, in minutes, vastly outpacing conventional antibiotics. MMs also rapidly eliminate persister cells and established bacterial biofilms. The antibacterial mode of action of MMs involves physical disruption of the membrane. In addition, by permeabilizing the membrane, MMs at sublethal doses potentiate the action of conventional antibiotics. Repeated exposure to antibacterial MMs is not accompanied by resistance development. Finally, therapeutic doses of MMs mitigate mortality associated with bacterial infection in an in vivo model of burn wound infection. Visible light–activated MMs represent an unconventional antibacterial mode of action by mechanical disruption at the molecular scale, not existent in nature and to which resistance development is unlikely.
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    Multifunctional fluorescent and MRI-active nanostructure
    (2022-11-22) Halas, Nancy J.; Ayala-Orozco, Ciceron; Bishnoi, Sandra; Henderson, Luke; Neumann, Oara; Pautler, Robia; Nordlander, Peter; Rice University; William Marsh Rice University; United States Patent and Trademark Office
    A Magnetic Resonance Imaging (MRI) enhancement agent includes a plurality of particles, each particle including: a metal core; a dielectric shell disposed on the metal core comprising at least one MRI contrast agent; and a metal shell disposed on the exterior surface of the dielectric shell that encapsulates the dielectric shell.
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    Nanoparticles Heat through Light Localization
    (American Chemical Society, 2014) Hogan, Nathaniel J.; Urban, Alexander S.; Ayala-Orozco, Ciceron; Pimpinelli, Alberto; Nordlander, Peter; Halas, Naomi J.; Laboratory for Nanophotonics; Rice Quantum Institute
    Aqueous solutions containing light-absorbing nanoparticles have recently been shown to produce steam at high efficiencies upon solar illumination, even when the temperature of the bulk fluid volume remains far below its boiling point. Here we show that this phenomenon is due to a collective effect mediated by multiple light scattering from the dispersed nanoparticles. Randomly positioned nanoparticles that both scatter and absorb light are able to concentrate light energy into mesoscale volumes near the illuminated surface of the liquid. The resulting light absorption creates intense localized heating and efficient vaporization of the surrounding liquid. Light trapping-induced localized heating provides the mechanism for low-temperature light-induced steam generation and is consistent with classical heat transfer.
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    Sub-100 nm gold nanomatryoshkas improve photo-thermal therapy efficacy in large and highly aggressive triple negative breast tumors
    (Elsevier, 2014) Ayala-Orozco, Ciceron; Urban, Cordula; Bishnoi, Sandra; Urban, Alexander; Charron, Heather; Mitchell, Tamika; Shea, Martin; Nanda, Sarmistha; Schiff, Rachel; Halas, Naomi; Joshi, Amit
    There is an unmet need for efficient near-infrared photothermal transducers for the treatment of highly aggressive cancers and large tumors where the penetration of light can be substantially reduced, and the intra-tumoral nanoparticle transport is restricted due to the presence of hypoxic or necrotic regions. We report the performance advantages obtained by sub 100 nm gold nanomatryushkas, comprising concentric gold–silica–gold layers compared to conventional ~ 150 nm silica core gold nanoshells for photothermal therapy of triple negative breast cancer. We demonstrate that a 33% reduction in silica–core–gold-shell nanoparticle size, while retaining near-infrared plasmon resonance, and keeping the nanoparticle surface charge constant, results in a four to five fold tumor accumulation of nanoparticles following equal dose of injected gold for both sizes. The survival time of mice bearing large (> 1000 mm3) and highly aggressive triple negative breast tumors is doubled for the nanomatryushka treatment group under identical photo-thermal therapy conditions. The higher absorption cross-section of a nanomatryoshka results in a higher efficiency of photonic to thermal energy conversion and coupled with 4–5 × accumulation within large tumors results in superior therapy efficacy.
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    Targeting pancreatic cancer with magneto-fluorescent theranostic gold nanoshells
    (Future Medicine, 2014) Chen, Wenxue; Ayala-Orozco, Ciceron; Biswal, Nrusingh C.; Perez-Torres, Carlos; Bartels, Marc; Bardhan, Rizia; Stinnet, Gary; Liu, Xian-De; Ji, Baoan; Deorukhkar, Amit; Brown, Lisa V.; Guha, Sushovan; Pautler, Robia G.; Krishnan, Sunil; Halas, Naomi J.; Joshi, Amit
    Aim: We report a magneto-fluorescent theranostic nanocomplex targeted to neutrophil gelatinase-associated lipocalin (NGAL) for imaging and therapy of pancreatic cancer. Materials & methods: Gold nanoshells resonant at 810 nm were encapsulated in silica epilayers doped with iron oxide and the near-infrared (NIR) dye indocyanine green, resulting in theranostic gold nanoshells (TGNS), which were subsequently conjugated with antibodies targeting NGAL in AsPC-1-derived xenografts in nude mice. Results: Anti-NGAL-conjugated TGNS specifically targeted pancreatic cancer cells in vitro and in vivo providing contrast for both NIR fluorescence and T2-weighted MRI with higher tumor contrast than can be obtained using long-circulating, but nontargeted, PEGylated nanoparticles. The nanocomplexes also enabled highly specific cancer cell death via NIR photothermal therapy in vitro. Conclusion: TGNS with embedded NIR and magnetic resonance contrasts can be specifically targeted to pancreatic cancer cells with expression of early disease marker NGAL, and enable molecularly targeted imaging and photothermal therapy.
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    The Surprising in Vivo Instability of Near-IR-Absorbing Hollow Au-Ag Nanoshells
    (American Chemical Society, 2014) Goodman, Amanda M.; Cao, Yang; Urban, Cordula; Neumann, Oara; Ayala-Orozco, Ciceron; Knight, Mark W.; Joshi, Amit; Nordlander, Peter; Halas, Naomi J.
    Photothermal ablation based on resonant illumination of near-infrared-absorbing noble metal nanoparticles that have accumulated in tumors is a highly promising cancer therapy, currently in multiple clinical trials. A crucial aspect of this therapy is the nanoparticle size for optimal tumor uptake. A class of nanoparticles known as hollow Au (or Au–Ag) nanoshells (HGNS) is appealing because near-IR resonances are achievable in this system with diameters less than 100 nm. However, in this study, we report a surprising finding that in vivo HGNS are unstable, fragmenting with the Au and the remnants of the sacrificial Ag core accumulating differently in various organs. We synthesized 43, 62, and 82 nm diameter HGNS through a galvanic replacement reaction, with nanoparticles of all sizes showing virtually identical NIR resonances at ∼800 nm. A theoretical model indicated that alloying, residual Ag in the nanoparticle core, nanoparticle porosity, and surface defects all contribute to the presence of the plasmon resonance at the observed wavelength, with the major contributing factor being the residual Ag. While PEG functionalization resulted in stable nanoparticles under laser irradiation in solution, an anomalous, strongly element-specific biodistribution observed in tumor-bearing mice suggests that an avid fragmentation of all three sizes of nanoparticles occurred in vivo. Stability studies across a wide range of pH environments and in serum confirmed HGNS fragmentation. These results show that NIR resonant HGNS contain residual Ag, which does not stay contained within the HGNS in vivo. This demonstrates the importance of tracking both materials of a galvanic replacement nanoparticle in biodistribution studies and of performing thorough nanoparticle stability studies prior to any intended in vivo trial application.
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    Theranostic gold nanoshells and nanomatryoshkas for cancer therapy
    (2015-01-20) Ayala-Orozco, Ciceron; Halas, Naomi; Marti, Angel; Nordlander, Peter; Joshi, Amit
    This dissertation describes the synthesis of multifunctional gold nanoparticles designed for therapy and diagnosis of cancer (theranostics), and the evaluation of their therapeutic efficacy and bioimaging of tumors in mice. The design of these metallic nanoparticles is aimed to incorporate imaging agents (MRI contrasts and fluorophores) in compact structures with dimensions below 100 nm while keeping their NIR-light-absorbing properties and optimum surface chemistry to enhance accumulation in tumor. The therapeutic response of these metallic nanoparticles is derived from the photoexcitation of their plasmon resonance, the collective oscillation of the conduction band electrons, which was advantageously utilized to enhance the quantum yield of fluorophores resonant in the NIR where the penetration of light is maximal in biological tissue and minimally destructive. Gold nanoshells as absorbers of NIR light can convert the absorbed light into heat consequently causing hyperthermia in the surrounding medium which leads to tumor cell death. To extent the application of previously developed theranostic nanoshells to the highly lethal pancreatic cancer, chapter 2 describes a magneto-fluorescent theranostic nanocomplex targeted to neutrophil gelatinase associated lipocalin (NGAL) receptor in pancreatic cancer. Gold nanoshells (SiO2-Au core-shell nanoshell) resonant at 810 nm were encapsulated in silica epilayers doped with iron oxide and the NIR dye ICG, resulting in a theranostic gold nanoshells, which provided contrast for both T2 weighted MRI and NIR fluorescence optical imaging. The large size of this complex (200 nm) potentially can hinder the accumulation in tumor. Seeking to reduce the size of the theranostic nanoparticles, chapter 3 presents the sub-100 nm Au nanomatryoshkas (Au/SiO2/Au). Au nanomatryoshkas are strong light absorbers with 77% absorption efficiency while the nanoshells are weaker absorbers with only 15% absorption efficiency. After an intravenous injection of Au nanomatryoshkas followed by a single NIR laser dose of 2 W/cm2 for 5 min, 83% of the tumor-bearing mice appeared healthy and tumor free >60 days later, while only 40% of mice treated with nanoshells survived the same period. The smaller size and larger absorption cross section of Au nanomatryoshkas combine to make this nanoparticle more effective than Au nanoshells for photothermal cancer therapy. Chapter 4 presents the therapeutic efficacy in mice bearing large (>1000 mm3) and highly aggressive triple negative breast tumors. To equip the Au nanomatryoshkas with imaging contrast agents, fluorophores were encapsulated in the internal SiO2 layer of the Au/SiO2/Au matryoshkas as described in chapter 5. We observed strong fluorescence enhancements of the NIR dyes Cy7 and IR800. This behavior can be understood by taking into account the near field enhancement induced by the Fano resonance of the nanomatryoshka, which is responsible for enhanced absorption of the fluorophores incorporated into the nanocomplex. The combination of compact size and enhanced light emission with internal encapsulation of the fluorophores for increased biocompatibility suggests outstanding potential for this type of nanoparticle complex in biomedical applications as it is investigated and presented in chapter 6.