Dissertations / Theses on the topic 'Nanoparticle gold'
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Derrien, Thomas. "Gold nanoparticle-lipid bilayer interactions." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86727.
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The interactions of ligand-capped gold nanoparticles with lipid bilayers are investigated. The properties determining the mechanism of nanoparticle interaction using synthetic membrane models are explored. First, a specific interaction, incorporation of nanoparticles into the bilayers, is examined using novel imaging and nanoparticle synthesis techniques. Mixed ligand capped gold nanoparticles are synthesized with assorted ligand arrangements in order to relate ligand composition and structure to interaction mechanism using a dye leakage assay. Finally, in vivo experiments are conducted using peptide labeled fluorescent gold nanoparticles in live HeLa cells. It was found that gold nanoparticles are capable of crossing lipid bilayers, implying energy-independent cellular uptake mechanisms may occur. It is concluded that the structure and composition of the protecting ligands are critical in determining the magnitude of bilayer disruption.L'interaction des nanoparticules d'or avec les bicouches lipidiques est présentée dans ce mémoire. Les facteurs influençant cette interaction ont été explorés en utilisant des bicouches lipidiques synthétiques. L'interaction due à l'incorporation des nanoparticules au sein des bicouches a été étudiée par des techniques d'imagerie. Un test de fuite de fluorophore a été employé afin de déterminer l'influence de la composition et de la structure des ligands protégeant les nanoparticules sur leur incorporation dans les bicouches de lipides. Pour cela, nous avons développer une synthèse de nanoparticules protégées par deux types de ligands. Des expériences in vivo ont été réalises avec des nanoparticules d'or fonctionnalisées avec des peptides ainsi que des fluorophores, mis en contact avec des cellules vivantes de type HeLa. Nous avons constaté que les nanoparticules d'or sont capables de franchir les bicouches lipidiques en utilisant des mécanismes indépendants d'énergie. Nous concluons que la structure et la composition des ligands protégeant les nanoparticules ont une grande influence sur la perturbation qu'elles induisent dans la structure des bicouches lipidiques.
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Manohar, Nivedh Harshan. "Quantitative imaging of gold nanoparticle distribution for preclinical studies of gold nanoparticle-aided radiation therapy." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54877.
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Gold nanoparticles (GNPs) have recently attracted considerable interest for use in radiation therapy due to their unique physical and biological properties. Of interest, GNPs (and other high-atomic-number materials) have been used to enhance radiation dose in tumors by taking advantage of increased photoelectric absorption. This physical phenomenon is well-understood on a macroscopic scale. However, biological outcomes often depend on the intratumoral and even intracellular distribution of GNPs, among other factors. Therefore, there exists a need to precisely visualize and accurately quantify GNP distributions. By virtue of the photoelectric effect, x-ray fluorescence (XRF) photons (characteristic x-rays) from gold can be induced and detected, not only allowing the distribution of GNPs within biological samples to be determined but also providing a unique molecular imaging option in conjunction with bioconjugated GNPs. This work proposes the use of this imaging modality, known as XRF imaging, to develop experimental imaging techniques for detecting and quantifying sparse distributions of GNPs in preclinical settings, such as within small-animal-sized objects, tissue samples, and superficial tumors. By imaging realistic GNP distributions, computational methods can then be used to understand radiation dose enhancement on an intratumoral scale and perhaps even down to the nanoscopic, subcellular realm, elucidating observed biological outcomes (e.g., radiosensitization of tumors) from the bottom-up. Ultimately, this work will result in experimental and computational tools for developing a better understanding of GNP-mediated dose enhancement and associated radiosensitization within the scope of GNP-aided radiation therapy.
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Jones, Bernard. "Monte Carlo calculations of microscopic dose enhancement for gold nanoparticle-aided radiation therapy." Thesis, Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/34746.
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Gold Nanoparticle-Aided Radiation Therapy (GNRT) is a new paradigm in radiation therapy which seeks to make a tumor more susceptible to radiation damage by modifying its photon interaction properties with an infusion of a high-atomic-number substance. The purpose of this study was to quantify the energy deposition due to secondary electrons from gold nanoparticles on a micrometer scale and to calculate the corresponding microscopic dose enhancement factor during GNRT. The Monte Carlo code EGSnrc was modified to obtain the spectra of secondary electrons from atoms of gold and molecules of water under photon irradiation of a tumor infused with 0.7 wt. % gold. Six different photon sources were used: 125I, 103Pd, 169Yb, 192Ir, 50kVp, and 6MV x-rays. Treating the scored electron spectra as point sources within an infinite medium of water, the event-by-event Monte Carlo code NOREC was used to quantify the radial dose distribution, giving rise to gold and water electron dose point kernels. These kernels were applied to a scanning electron microscope (SEM) image of a gold nanoparticle distribution in tissue. The dose at each point was then calculated, enabling the determination of the microscopic dose enhancement at each point. For the lower energy sources 125I, 103Pd, 169Yb, and 50 kVp, the secondary electron fluence was increased by as much as two orders of magnitude, leading to a one-to-two order of magnitude increase in the electron dose point kernel over radial distances up to 50 um. The dose was enhanced by 100% within 5 um of the nanoparticles, and by 5% as far away as 30 um. This study demonstrates a remarkable microscopic dose enhancement due to gold nanoparticles and low energy photon sources. Given that the dose enhancement exceeds 100% within very short distances from the nanoparticles, the maximum radiobiological benefit may be derived from active targeting strategies that concentrate nanoparticles in close proximity to the cancer cell and/or its nucleus.
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Crew, Elizabeth. "Nanoparticle-based analytical/bioanalytical probes investigation of interactions and reactivities between gold nanoparticles and homocysteine /." Diss., Online access via UMI:, 2005. http://wwwlib.umi.com/dissertations/fullcit/1425749.
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Kanaras, Antonios G. "Enzymatic manipulation of DNA/gold nanoparticle assemblies." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402259.
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Bennett, Samantha E. "Fabrication of water-soluble gold nanoparticle aggregates." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35074.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.Includes bibliographical references (leaves 23-24).
Mixed monolayer protected gold nanoparticles were linked using octanedithiol to form aggregates containing hundreds of nanoparticles. These aggregates are an interesting material, posing potential applications in the fields of chemistry, biology and materials science. This study examined the dependence of aggregate size and morphology on temperature of formation, using AFM and TEM imaging. The aggregates formed at 70°C averaged 105nm in width, as compared to 70nm for the room temperature aggregates. The TEM images showed increased density for the 70°C aggregates. In a further study, the room temperature aggregates were functionalized through a place exchange reaction with 1 -mercapto-undecane- l-sodiumsulfonate (MUS), a thiolated ligand with a polar head group. A two-phase test of the water-solubility indicated that the aggregates were fully soluble. TEM images showed a slight increase in size, though similar morphology to the insoluble aggregates. The ability to induce water solubility in the aggregates opens up many potential applications in the field of bionanomaterials.
by Samantha E. Bennett.
S.B.
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Zarate-Triviño, D. G., Acosta E. M. Valenzuela, E. Prokhorov, G. Luna-Bárcenas, Padilla C. Rodríguez, and Molina M. A. Franco. "Chitosan-Gold Nanoparticle Composites for Biomedical Application." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35404.
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The aim of this work is to synthesize chitosan-gold nanoparticles films by direct chemical reduction of HAuCl4 in a chitosan solution and to investigate the influence of gold nanoparticles concentration on the structure of films, conductivity and healing effect on mice skin after surgery. Results obtained have shown that new chitosan-gold nanoparticle-collagen bionananocomposites demonstrated better healing effect on the mice skin after surgery than control performed on commercial TheraFormTM material.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35404
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García, Fernández Lorena. "Introducing gold nanoparticle bioconjugates within the biological machinery." Doctoral thesis, Universitat Autònoma de Barcelona, 2013. http://hdl.handle.net/10803/120221.
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El rápido desarrollo de la Nanotecnología durante las últimas décadas ofrece amplias perspectivas en el uso de materiales a micro- y nanoescala en diferentes áreas de la industria, tecnología y medicina. Sin embargo, su uso y aplicación segura y eficaz en estas áreas requieren un control mucho mayor sobre sus propiedades físico-químicas y sus interacciones moleculares relacionadas con los seres vivos. El conocimiento actual de la comunidad científica está de acuerdo en que existe una brecha considerable en la comprensión de este tipo de interfaz "Nano-Bio". Dando un paso adelante en esta dirección, este trabajo de Tesis ha tenido como objetivo proporcionar conocimientos sobre la formación racional de bioconjugados de nanopartículas de oro para modular y comprender sus interacciones y los procesos celulares.
En este contexto, la primera parte de esta Tesis se centra en la síntesis de nanopartículas de oro catiónicas y sus interacciones con células. La primera estrategia desarrollada para la síntesis de nanopartículas de oro cargadas positivamente se llevó a cabo mediante el uso simultáneo de un reductor débil y uno fuerte. Se ha demostrado que los dos reductores actúan de forma secuencial en el proceso sintético para producir nanopartículas de oro catiónicas monodispersas, con tamaños comprendidos entre 10.3 nm y 19.7 nm. Se describe también un método de crecimiento de nanopartículas de oro, en el que se obtienen nanopartículas monodispersas de mayor tamaño (de hasta ~ 28 nm) a partir de nanopartículas de oro previamente sintetizadas, mediante la adición de precursor y un reductor débil. La segunda estrategia desarrollada hace frente a la creciente demanda de nanopartículas de oro catiónicas de diferentes tamaños y ligandos, mediante el empleo de una metodología de transferencia de fase de medio orgánico a acuoso. Esta combinación de métodos de síntesis orgánica y acuosa da como resultado importantes beneficios. Esta estrategia se ha optimizado para preparar nanopartículas de oro catiónicas de 4.6, 8.9 y 13.4 nm de diámetro, usando un ligando alquílico tiolado con carga positiva. Además, su aplicación práctica se demostró mediante la producción de bioconjugados de oro de 13 nm con un péptido catiónico y otro aniónico. Las propiedades físico-químicas de estos bioconjugados en medios de cultivo celular, así como su internalización y toxicidad en fibroblastos humanos han sido estudiados.
La segunda parte de esta Tesis se centra en la funcionalización racional de nanopartículas de oro con anticuerpos y la investigación de su interacción específica con receptores celulares. La formación de bioconjugados de oro con anticuerpos se ha estudiado utilizando una química selectiva, que ha permitido controlar el número de anticuerpos y su orientación en la nanopartícula. La obtención de bioconjugados bien definidos hizo posible la creación de nuevos autoensamblajes de nanopartículas mediante reconocimiento anticuerpo-antígeno. Esta estrategia también se exploró para la conjugación de un anticuerpo biológicamente relevante (Cetuximab) con nanopartículas de oro. Bioconjugados de oro con Cetuximab de configuración y multivalencia controlada se han utilizado para examinar su interacción con el receptor de superficie celular EGFR (receptor del factor de crecimiento epidérmico), un receptor de tirosina quinasa que es sobreexpresado en un gran número de cánceres.The rapid development in Nanotechnology during the past few decades offers wide prospects in using micro- and nanoscale materials in different areas of industry, technology and medicine. However, their safe and efficient use and implementation in such areas require much greater control over their physicochemical properties and their related molecular interactions in living systems. Current knowledge in the scientific community agrees that a considerable gap exists in our understanding of such “Nano-Bio” interface. As a step forward in this direction, this Thesis work aimed to provide insights into the formation of rationally designed gold nanoparticle (Au NP) bioconjugate architectures to modulate and understand cellular interactions and processes. In such a context, the first part of this Thesis is focused on the synthesis of cationic Au NPs and their interactions with cells. A first strategy was developed in which the synthesis of positively charged Au NPs was performed by using simultaneously a weak and a strong reducer. It is shown that both reducers act sequentially in a one-pot synthesis to yield monodisperse cationic Au NPs with sizes comprised between 10.3 nm and 19.7 nm. A two-step seeding growth method is also described in which preformed Au NPs are grown larger (up to ~28 nm in size) by addition of fresh precursor solution and a weak reducer. A second strategy faces the rising demand of cationic Au NPs of different sizes and ligands by employing an organic-aqueous phase transfer methodology. Important benefits resulted from the combination of organic and aqueous synthetic methods. This strategy was optimized to prepare cationic Au NPs of 4.6, 8.9 and 13.4 nm in diameter using a positively charged alkanethiolate ligand. In addition, its practical application was demonstrated by producing ~ 13-nm-in-size cationic and anionic peptide-Au NP bioconjugates. The physicochemical properties of these bioconjugates in cell culture media as well as their uptake and toxicity on human fibroblast cells are discussed. The second part of this Thesis is focused on the rational functionalization of Au NPs with antibodies and investigating their interactions with cellular receptors. A site-directed chemistry was explored to prepare Antibody-Au NP bioconjugates with controlled ratio and orientation of bioconjugation. The formation of well-defined bioconjugates made possible the creation of novel NP-based assemblies using antibody-antigen cross-links. This strategy was also explored for the conjugation of a biologically relevant antibody (Cetuximab) with Au NPs. Cetuximab-Au NP bioconjugates of controlled configuration and multivalency were used to examine their interaction with the cell surface receptor EGFR (epidermal growth factor receptor), a receptor tyrosine kinase overexpressed in a large number of cancers.
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Tombe, Sekai Lana. "Characterization and application of phthalocyanine-gold nanoparticle conjugates." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1004517.
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This work presents the syntheses, photophysical and photochemical characterization of arylthio zinc phthalocyanines and their gold nanoparticle conjugates. Spectroscopic and microscopic studies confirmed the formation of the phthalocyanine-gold nanoparticle conjugates which exhibited enhanced photophysicochemical properties in comparison to the phthalocyanines. The studies showed that the presence of gold nanoparticles significantly lowered fluorescence quantum yields and lifetimes. However, this interaction did not restrict the formation of excited singlet and triplet states and hence the formation of singlet oxygen required for photocatalysis. The conjugates showed significantly higher singlet oxygen quantum yields and therefore enhanced photocatalytic activity compared to the phthalocyanines. The zinc phthalocyanines and their gold nanoparticle conjugates were successfully incorporated into electrospun polymer fibers. Spectral characteristics of the functionalized electrospun fibers indicated that the phthalocyanines and phthalocyanine-gold nanoparticle conjugates were bound and their integrity was maintained within the polymeric fiber matrices. The photophysical and photochemical properties of the complexes were equally maintained within the electrospun fibers. The functionalized fibers were applied for the photoconversion of 4-chlorophenol and Orange G as model organic pollutants.Microsoft� Word 2010
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Mthethwa, Thandekile Phakamisiwe. "Metallophthalocyanine-gold nanoparticle conjugates for photodynamic antimicrobial chemotherapy." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1017923.
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This thesis presents the synthesis of neutral and cationic metallophthalocyanines and their gold nanoparticles conjugates. The spectroscopic characterization of these compounds is presented herein. The studies presented in this work shows that the conjugation of gold nanoparticles influenced both photophysical and photochemical properties. Gold nanoparticles were found to enhance the singlet oxygen quantum yield while lowering the fluorescence quantum yields. This work also looks at the effect of anisotropic gold nanoparticles such as nanorods and bipyramids on the photophysical behaviour of the metallophthalocyanines. The effect of the size of the gold nanorods was investigated herein. The results show that photophysical and photochemical properties can be influenced by both size and shape of the nanoparticles. Physical characterization about the loading of nanoparticles was also looked into. Parameters such as the surface area, the number of surface atoms, the number of atoms as well as the number of nanoparticles loaded on the surface of the phthalocyanines were studied. The self-assembled monolayers formed by phthalocyanines on gold surfaces were studied using the X-ray photoelectron spectroscopy (XPS). The gold nanoparticles synthesized herein include both organic and water soluble, different capping agents (citrate, tetraammonium bromide (TAOBr) and cetrimethylammonium bromide (CTAB). The concentration of the gold nanoparticles was measured on the inductively coupled plasma (ICP) and their size and shape were obtained from the transmission electron microscopy (TEM) images. A cationic aluminium phthalocyanine and its conjugates were used for photoinactivation of bacteria and fungi. The results show significant reduction and higher activity in the presence of gold nanoparticles, especially nanorods. A small chapter in this work presents an attempted work on the binding of metallothionein protein with protophorphyrin (IX). The pH and concentration dependent binding studies were investigated
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Ngomane, Nokuthula. "Gold nanoparticle–based colorimetric probes for dopamine detection." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/d1021261.
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Colorimetric probes have become important tools in analysis and biomedical technology. This thesis reports on the development of such probes for the detection of dopamine (DA). Liquid and different solid state probes were developed utilizing un–functionalized gold nanoparticles (UF–AuNPs). The liquid state probe is based on the growth and aggregation of the UF–AuNPs in the presence of DA. Upon addition of the UF–AuNPs to various concentrations of DA, the shape, size and colour change results in spectral shifts from lower to higher wavelengths. The analyte can be easily monitored by the naked eye from 5.0 nM DA with a calculated limit of detection of 2.5 nM (3σ) under optimal pH. Ascorbic acid (AA) has a potential to interfere with DA detection in solution since it is often present in biological fluids, but in this case the interference was limited to solutions where its concentration was beyond 200 times greater than that of DA. Since most of the previously reported colorimetric probes, especially those for DA are solution based, the main focus of the thesis was in the development of a solid state based colorimetric probe in the form of nanofibre mats. To overcome the interference challenges experienced in the solution studies (the interference by high concentrations of AA), the suitability of molecularly imprinted polymers (MIPs) for the selective detection of DA was investigated. The results showed that the MIPs produced did not play a significant role in enhancing the selectivity towards DA. A probe composed of just the UF–AuNPs and Nylon–6 (UF–AuNPs + N6) was also developed. The UF–AuNPs were synthesized following an in situ reduction method. The probe was only selective to DA and insensitive to other catecholamines at physiological pH. Thus, the probe did not require any addition functionalities to achieve selectivity and sensitive to DA. The liquid state probe and the composite UF–AuNPs + N6 nanofibre probe were successfully applied to a whole blood sample and showed good selectivity towards DA. The simple, sensitive and selective probe could be an excellent alternative for on–site and immediate detection of DA without the use of instrumentation. For quantification of DA using the solid state probe, open–source software imageJ was used to assist in the analysis of the nanofibre colours. It was observed that the intensity of the colour increased with the increase in concentration of DA in a linear fashion. The use of imageJ can also be a great alternative where the colour changes are not so clear or for visually impaired people. The solid state probe developed can detect DA qualitatively and quantitatively. The work also forms a good foundation for development of such probes for other analyte.
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Zhao, Pengxiang. "Nanoparticules d’ or : fonctionnalisations et applications en nanomédecine et nanomatériaux." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14556/document.
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Des nanoparticules d’or fonctionnelles ont été synthétisées avec pour objectifs l’élaboration de nanomatériaux pour applications biomédicales et propriétés physiques originales. L’étude de la fonctionnalisation a conduit à utiliser le chimie “click” entre des nanoparticules d’or portant des ligands thiolates azoturés et des alcynes terminaux en utilisant un catalyseur au cuivre (I) renforcé par un ligand polyazoté, ce qui a permis d’introduire des fonctions très variées. En particulier le récepteur folate a été greffé de cette façon pour la synthèse de nouveaux vecteurs du docétaxel, un puissant agent anti-cancéreux dont l’étude est menée en collaboration. Des nanoparticules d’or fonctionnelles ont aussi servi de support pour le greffage de complexes du fer (II) à transition de spin, ce qui a permis de réaliser l’étude en 2D par différentes techniques physiques en collaboration. Enfin un nouveau ligand azoté a été mis au point pour la synthèse de nanoparticules d’or originalesThe thesis concerns functionalizations and applications of gold nanoparticles (AuNPs). In the aspects of functionalization of AuNPs, we concentrated on efficiently functionalized AuNPs by “Click” chemistry. In the aspects of applications, the PEG capped AuNPs was prepared to encapsulate vitamins, which has a potential use in hydrophobic part of human body; the folate functionalized AuNPs was used for docetaxel delivery for cancer therapy; the novel synthesis of triazole stabilized AuNPs used for biosensors; and the citrate capped AuNPs introduced into the silica thin films to check the SERS effect and spin crossover of iron complexes
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McLeod, Angus R. "Characterisation of gold nanoparticles on substrate." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/80106/5/Angus_McLeod_Thesis.pdf.
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This thesis investigated the interaction between light and gold nanoparticles, for gold nanoparticles sitting on a variety of surfaces. The work was both experimental and theoretical in nature. Using a custom designed experimental set-up we were able to probe the interaction of light with individual nanoparticles. We were also able to predict the interaction of light with gold nanoparticles sitting on graphene substrates. The work presented lays the groundwork for more extensive investigation of surfaces enhanced by the addition of gold nanoparticles.
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Roberts, Robert Christopher. "Jet Printed Au Nanoparticle Films For Microelectromechanical Systems." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1342809712.
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Wardlow, Nathan. "Role of local enhancement effects in gold nanoparticle therapy." Thesis, Queen's University Belfast, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.728684.
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Muir, M. F. "Gold nanoparticle dose enhancement and plasma induced cellular damage." Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.580102.
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Targeting the dose delivered to cancer cells while minimizing damage to sur- rounding healthy tissue is the primary objective of radiotherapy. To achieve this multiple beams of X-rays with MeV energies are collimated to match the shape of a target volume, improving the contrast ratio between the dose to cancerous cells against the dose to healthy cells. Another possibility which has been explored is the use of materials with a high atomic number to preferentially enhance dose, due to their increased photoelectric absorption of keV energy X-rays. By using nanoparticles of these high Z elements it is possible to distribute them at the sub-cellular level. The work presented in this thesis investigates the dose en- hancement due to the addition of spherical nanoparticles of gold in vitro, for a range of monoenergetic kilovoltage X-rays. In order to perform these studies an X-V translation system was constructed which allowed samples to be manipulated in a horizontal beam of X-rays pro- duced from a synchrotron. Samples were rastered through a beam of X-rays at a pre-calculated rate which was determined from an in-line dosimeter. Control of the target dose was possible by adjusting the rate samples were shuttled through the beam. This translation system was used to irradiate both y-H2,AX and clone- genic assays in order to investigate the effect of monoenergetic X-ray driven gold nanoparticle dose enhancement. Manual counts of the mean number of foci per cell from the y-H2AX assay showed an energy dependent dose enhancement due to gold that was inconsistent . with a macroscopic model of dose. The development of an analysis algorithm to determine the nuclear distribution of damage, along with a microscopy technique which exploits the surface plasmon resonances of gold, gave information about mechanism. These studies found that the location of gold nanoparticles and 2the range of electrons emitted when ionized, are significant factors behind the observed energy dependance. The results from clonoqenic studies found there was a significant enhancement in the formation of single lethal events for irradiated cells with gold. There was little enhancement in the production of sub-lethal events for the same group of cells. These findings also deviate from a macroscopic dose enhancement model. Application of a local effect model, which considers the nanodosimetry around a gold particle, provides an explanation for these observations. An opportunity arose during this thesis to study the effect liquid produced plasmas have on cells. Using a submerged electrode, monolayers of cells were exposed to an electrical discharge plasma and the effects were measured using both the y-H2AX and clonogenic assays. Generating a plasma produces many of the damaging agents produced by X-ray irradiation (such as electrons and radicals). Studies showed that the cells responded similarly when exposed to plasmas or X-rays, yielding Poissonian distributions of nuclear double strand breaks, and a linear quadratic dependance of cell death. The results presented here would be useful as a first step in the assessment of risk from plasma exposure compared to a known standard like X-rays.
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Taylor, Richard William. "On the sub-nm plasmonics of gold nanoparticle clusters." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648264.
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Rao, Tingling. "Nanomanufacturing of Gold Nanoparticle Superstructures from the "Bottom-Up"." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1366289133.
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Smith, Beverly. "Investigating Thermal Transformations of Ligand-Stabilized Gold Nanoparticles: Influence of the Structural Attributes of the Nanoparticle and Its Environment on Thermal Stability." Thesis, University of Oregon, 2015. http://hdl.handle.net/1794/19259.
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Ligand-stabilized metal nanoparticles (LSNPs) have garnered significant attention for use in applications including sensing, catalysis, and thin film fabrication. Many uses rely on the size-dependent properties of the metal nanoparticle core. Therefore, preservation of nanoparticle core size is of paramount importance. In other uses, the low processing temperatures afforded by metal LSNPs make them attractive as precursors for conductive thin films. In these distinctly different applications, understanding nanoparticle thermal stability is crucial.
A key finding of this research is that nanoparticle sintering is dependent upon both core size and ligand functionality. Multi-technique analysis of four types of gold nanoparticles (AuNPs) with different ligand compositions and core sizes illustrates that more volatile ligands reduce the onset temperature for sintering. Also, AuNPs of larger core size with the same ligand composition exhibit lower sintering onset temperatures. Correlation between measurements reveals that only a small amount of ligand loss is necessary to trigger rapid sintering and that ligands are excluded to the surface of the porous gold films.
AuNPs with ligand shells composed of two alkanethiols of different chain length and volatility indicate that the onset temperature of sintering can be tuned further through incorporation of a small amount of more volatile alkanethiol into a ligand shell of lower volatility. Mixed LSNPs further reveal that AuNP thermal stability depends upon the ligand shell composition and its intermolecular interactions, which can result in markedly different sintering behavior for different ligand compositions. Long-chain alkanethiol AuNPs sinter after only a small amount of ligand loss, whereas short-chain alkanethiol AuNPs sinter following complete ligand loss and the formation of metastable bare AuNPs. Heated AuNP films prepared with mixed-ligand AuNPs exhibit ligand-dependent differences in film morphology.
To probe AuNP thermal stability in 2D-assemblies, self-assembly using larger ‘marker’ nanoparticles enables the study of small 1.5 nm AuNP arrays with successive TEM monitoring throughout ex situ heating. Monitoring images of the same area shows short-range (1-2 nm) nanoparticle migration/coalescence. In contrast to 3D assemblies, AuNP growth occurs at temperatures as low as 60 °C.
This dissertation includes previously published and unpublished co-authored material.10000-01-01
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Tang, Lu. "Nanoparticules mimes des propriétés biologiques des GAGs : vers un inhibiteur sélectif de CXCL12." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS072.
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L'Héparane Sulfate (HS), un polysaccharide linéaire, module les activités biologiques de nombreuses protéines. Afin d'élucider les interactions entre l'HS et les protéines, la synthèse chimique d'HS est un outil précieux, mais elle peut être difficile. Notre équipe a montré que des mélanges combinatoires obtenus par auto-assemblage de différentes combinaisons de dérivés disaccharidiques (lactose et lactose persulfaté) sur surfaces planes d'or peuvent reconnaître spécifiquement certaines protéines se liant à l'HS, telles que les isoformes de la chimiokine CXCL12 ou IFNγ. Avec ces dérivés, nous avons réalisé un auto-assemblage sur des nanoparticules d'or. Mais à cause de la toxicité des nanoparticules d'or, nous avons aussi adapté cette méthode à des nanoparticules lipidiques. En utilisant les conditions qui ont déjà été améliorées pendant la synthèse des dérivés lactose et lactose persulfaté, nous avons préparé deux autres dérivés disaccharidiques plus proches de la structure réelle d'HS. Ces nouveaux dérivés sont utilisés pour réaliser des nanoparticules d'or et nanoparticules lipidiques afin de comparer les propriétés avec les lactose et lactose persulfaté. Les tests d'affinité avec différentes protéines sont en cours de réalisationHéparan Sulfate (HS) is a linear polysaccharide that modulates the biological activities of numerous proteins. In order to elucidate the interaction between HS and proteins, the synthesis of HS is an invaluable tool, but the synthesis is sometimes difficult. Our group has demonstrated that the combinatorial mixtures obtained by self-assembly of different combinations of disaccharide derivatives (lactose and persulfated lactose) on gold plan surfaces could recognize specifically some HS binding proteins, such as the isoforms of the chemokine CXCL12 or IFNγ. Because of the toxicity of gold nanoparticles, we have also adapted this method to lipid nanoparticles. Using the conditions that have already improved during the synthesis of lactose and persulfated lactose derivatives, we have synthesized two other disaccharide derivatives, which were closer to the real structure of HS. These new derivatives were used to prepare the gold and lipid nanoparticles at the aim of comparing the properties with lactose and persulfated lactose. The tests of affinities with different proteins are in progress
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Geitner, Nicholas. "A Study of Gold Nanoparticles for Application in Semiconductor CdS Nanosheet Biosensor Devices." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1311893825.
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Mukundarajan, Sriram. "Synthesis of Alkylthiol-containing Fluorene Derivatives for Gold Nanoparticle Functionalization." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3570.
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A novel synthetic methodology has been developed for attaching fluorene derivatives, containing different types of electron donating and accepting groups at the 2 and 7 positions, to gold nanoparticles of different sizes by exploiting the affinity of the thiol functional group for gold. The distance between the dye and nanoparticles was varied by introducing two alkyl chains containing different number of carbon atoms at the 9 position on the fluorene ring system. The methodology that was developed gave enough scope for performing Radiative Decay Engineering (RDE) studies, in order to investigate the impact of gold nanoparticles on the singlet oxygen quantum yields of fluorene dyes that already exhibit high singlet oxygen quantum yields as well as high two photon absorption (2PA) cross-sections. The dialkylation of the fluorene derivatives was accomplished by reacting the dye with [alpha], [omega]-dibromoalkanes containing different number of carbon atoms in a biphasic reaction mixture containing toluene and aqueous sodium hydroxide solution in the presence of tetrabutylammonium bromide (TBAB) as a phase transfer catalyst. The bromine atom on the alkyl chains was converted to thioester by reaction with potassium thioacetate. This was followed by the hydrolysis of the thioester to form the thiol moiety. The compounds synthesized were characterized using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. Functionalization of gold nanoparticles was attempted by bringing into contact a solution of the thiol compound in toluene and an aqueous gold nanoparticles solution. UV-vis absorbance spectroscopy was used to monitor the progress of the attachment. Surface Enhanced Raman Scattering (SERS) spectroscopy was used to probe the enhancement of Raman signal by the metallic nanoparticles.M.S.
Department of Chemistry
Arts and Sciences
Industrial Chemistry
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Almeida, Carina Marisa dos Santos. "Gold nanoparticle-DNA conjugates for oligonucleotide vectorization towards gene silencing." Master's thesis, Faculdade de Ciências e Tecnologia, 2011. http://hdl.handle.net/10362/6212.
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Dissertação para obtenção do Grau de Mestre em
Genética Molecular e BiomedicinaThe main objective of the work presented in this thesis was to develop a gene silencing system by taking advantage of the nanovectorization capability and optical properties of gold nanoparticles. The idea is based on the construction of a DNA structure containing a therapeutic oligonucleotide with the ability to form Hoogsteen hydrogen bonds with double-stranded DNA, producing a DNA triple helix, besides silencing the gene of interest. Hoogsteen bonds, more unstable than the conventional Watson-Crick bonds, permit the achievement of lower melting temperatures. This attribute, coupled with the ability to generate heat by laser irradiation of the gold nanoparticles used, will allow the release of the therapeutic oligonucleotide and subsequent gene silencing without significant increase in the medium’s temperature. Thus, the thesis comprises three major sections: structure design and formation, vectorization, and gene expression silencing; the tasks involved in each of these sections were conducted in parallel. The design of the obtained structure took into account the desired melting temperature, stability at physiological conditions of the sequence-forming nucleotides, the number of Hoogsteen bonds and ionic conditions. To evaluate the formation of this structure, spectroscopic techniques were mainly used: FRET analysis and ultraviolet melting curves. Both approaches allowed the identification of interactions in the presence of therapeutic oligonucleotide compared with its absence, which may indicate structure formation. In addition, melting curves allowed the determination of the temperature of release of this oligonucleotide – 40ºC. The double-stranded DNA functionalization to gold nanoparticles has been achieved, but there was no difference in electrophoretic migration when the three oligonucleotides were present. However, the therapeutic oligonucleotide was able to efficiently inhibit gene expression in in vitro transcription and translation assays with efficiency up to 95% and 60% respectively.
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Acreman, Andrew. "Gold nanoparticle liquid crystal composites : synthesis, characterisation and optical nonlinearities." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/379319/.
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This thesis presents a theoretical and experiment investigation into the optical properties of gold nanoparticle liquid crystal composites. The experimental work can be divided into four sections; the synthesis of the nanoparticles, the creation of the gold nanoparticle liquid crystal composites and the investigation into their electro-optical properties and the nonlinear properties of hybrid photoconductive cells. A large variety of gold nanoparticles were chemically synthesised with varying size distributions and functionalized. The samples functionalized with chemicals containing aromatic chemical groups were observed to aggregate. The optical properties of these aggregates were investigated by measuring their absorption and scattering efficiencies. The samples displayed a decrease in their molar absorption coefficient from 10 cm⁻¹μM⁻¹ to 4.61 cm⁻¹μM⁻¹ and an increase in the molar scattering coefficient by several orders of magnitude. Gold nanoparticles were also synthesised directly in the liquid crystal host by sputter doping. In this case it was found that the size of these particles could be increased by heating the host liquid crystal above the clearing temperature of the liquid crystal. The synthesised nanoparticles as well as samples from other groups were used to produce gold nanoparticles liquid crystal composites. With the exception of one sample functionalized with mesogenic compounds all of the samples displayed a solubility lower that the samples synthesised by sputtering indicating that, unless carefully selected, the thiol surfactants were detrimental to the solubility of the nanoparticles in a liquid crystal. Four samples, a pure liquid crystal and three doped with low concentrations (0.01% by weight) of gold nanoparticles were used to fill hybrid photoconductive cells. Two of the samples, made from comparatively larger, less soluble, nanoparticles displayed a dramatic increase in the nonlinearity of over an order of magnitude in comparison to the undoped liquid crystal. While previous work has illustrated that ferro-electric nanoparticles can lead to a similar increase in the nonlinearities, however these can be attributed to increases in the display parameters of the host liquid crystal. A electro-optic characteristics of the gold nanoparticle samples showed no such increase. The two samples which displayed an increase in the nonlinearity also displayed a substantial increase in the conductivity, and consistently it was concluded that this was the cause of the increase in the nonlinearity. The theoretical section of the thesis models thermal nonlinearities which could be observed in high concentration liquid crystal gold nanoparticle composites. By considering the attenuation of the pump and probe beams throughout the cell and the effect that this has on the thermal profile within the cell an excellent agreement with experimental data was achieved. The model further predicted that due to this attenuation there exists an optimum concentration of absorbents. The model was further extended to consider the effect of a magnetic field induced reorientation of the liquid crystal. This adaptation accounted for the thermal change in the diamagnetic anisotropy and elastic constants as well as the change in the thermal refractive index grating and absorption of the nanoparticles due to the reorientation of the liquid crystal. The reorientation caused a decrease in the magnitude of the refractive index grating from 9x10⁻⁵ cm²W⁻¹ to zero by the application of a magnetic field of the order of 0.01 Tesla. If the field was further increased the medium would switch from a self-defocusing to a self-focusing regime.
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Daugherty, Brian Taylor. "Improved Detection of Gold Nanoparticle Labels for Paper-based Analytics." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1437.
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Point-of-care diagnostic devices are well-suited, and typically designed, for remote and/or resource-limited environments. The obvious application is for healthcare in the developing world; however, other additional important uses exist, including for security (biothreat agent detection) and human health and research during future manned deep space exploration missions.
The objective of this thesis was to develop, and experimentally validate, techniques for improved quantified detection of labels used in lateral flow assays. Limits of detection were characterized for: (a) optical approaches, i.e., unaided eye, mobile electronic device camera images and microscope images with image analysis software developed through this thesis, and (b) a conductance based approach with direct measurement of electrical impedance in the detection region using hardware and software that were developed. Analysis of camera images from mobile electronic devices enables simultaneous detection of many targets on a multiplexed assay. Additionally, a peripheral device was designed which was intended to provide conductimetric analysis capabilities to mobile electronic devices.
The detection limit of gold nanoparticles for the unaided eye was determined at a concentration of (3.98 ± 0.40)×10-11 M; mobile electronic device image analysis, microscope image analysis, and the conductance based approach showed improvements by approximately a half to a third, an order of magnitude, and three orders of magnitude, respectively.
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Donoeva, Baira. "Study of catalytic and biological activity of gold-containing metal nanoparticles." Thesis, University of Canterbury. Chemistry, 2014. http://hdl.handle.net/10092/9761.
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Small particles of gold (< 100 nm) have attracted great interest among researchers due to the unique combination of their physicochemical properties. Among various research areas catalysis and bio-nanotechnology represent the largest areas of growth for gold nanoparticle research.
Catalysts play a crucial role in the life of the modern society. More than 85 % of all chemical processes are catalytic, and this number is increasing every year. There is a constant demand to develop more efficient and durable catalysts in order to address increasing energy demands and environmental requirements. The first part of the thesis is focused on the study of catalytic activity of supported gold and mixed-metal catalysts, derived from atomically precise phosphine-stabilised gold and mixed-metal clusters in the liquid-phase oxidation of cyclohexene and one-pot synthesis of imines. Various characterisation techniques (TEM, diffuse-reflectance UV-vis, XPS, etc.) as well as kinetic studies were used in order to establish the optimal structure of gold catalysts. The effect of catalytic support, nature of hetero-metal atom for mixed metal-systems and type of catalyst pre-treatment were also examined.
Gold nanoparticles are actively studied in various biomedical applications as they are offering new approaches to the detection and treatment of life-threatening diseases, such as cancer. The second part of this work discusses our preliminary investigations of biological activity of gold nanoparticles, stabilised with cancer-targeting molecules. In particular, the cytotoxicity of gold nanoparticles was studied using 11 different cancer and normal cell types. Gold uptake and particle localisation inside the cells were also investigated.
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Austin, Lauren Anne. "Exploring some aspects of cancer cell biology with plasmonic nanoparticles." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54236.
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Plasmonic nanoparticles, specifically gold and silver nanoparticles, exhibit unique optical, physical, and chemical properties that are exploited in many biomedical applications. Due to their nanometer size, facile surface functionalization and enhanced optical performance, gold and silver nanoparticles can be used to investigate cellular biology. The work herein highlights a new methodology that has exploited these remarkable properties in order to probe various aspect of cancer cell biology, such as cell cycle progression, drug delivery, and cell death. Cell death mechanisms due to localized gold and silver nanoparticle exposure were also elucidated in this work. Chapter 1 introduces the reader to the synthesis and functionalization of gold and silver nanoparticles as well as reviews their implementation in biodiagnostic and therapeutic applications to provide a foundation for Chapters 3 and 4, where their use in spectroscopic and cytotoxic studies are presented. Chapter 2 provides the reader with detailed explanations of experimental protocols for nanoparticle synthesis and functionalization, in vitro cellular biology experiments, and live-cell Raman spectroscopy experiments that were utilized throughout Chapters 3 and 4. Chapter 3 presents the use of nuclear-targeted gold nanoparticles in conjunction with a Raman microscope modified to contain a live-cell imaging chamber to probe cancer cell cycle progression (Chapter 3.1), examine drug efficacy (Chapter 3.2), monitor drug delivery (Chapter 3.3), and detect apoptotic molecular events in real-time (Chapter 3.4). In Chapter 4, the intracellular effects of gold and silver nanoparticles are explored through live-cell Rayleigh imaging, cell cycle analysis and DNA damage (Chapter 4.1), as well as through the elucidation of cytotoxic cell death mechanisms after nanoparticle exposure (Chapter 4.2) and live cell imaging of silver nanoparticle treated cancer cell communities (Chapter 4.3).
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Eroglu, Esra. "Synthesis And Characterization Of New Conducting Polymer- Nano Particle Composites." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615631/index.pdf.
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In this study, conjugated monomers containing fluorene units2-(9,9-dihexyl-2-(thiophen-2-yl)-9H-fluoren-7-yl)thiophene (TFT) and 5-(9,9-dihexyl-2-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-9H-fluoren-7-yl)-2,3dihydrothieno[3,4b ][1,4] dioxine (EFE) were synthesized on the basis of donor-acceptor-donor approach and their electrochemical polymerization were achieved via potential cycling. Optical and electrochemical properties of their corresponding polymers, poly(2-(9,9-dihexyl-2-(thiophen-2-yl)-9H-fluoren-7-yl)thiophene) PTFT, and poly(5-(9,9-dihexyl-2-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-9H-fluoren-7-yl)-2,3dihydrothieno[3,4b ][1,4] dioxine) PEFE, were investigated and it was found that polymer films exhibited quasi-reversible redox behavior (Epox= 1.10 V for PTFT, Epox = 0.70 V and 1.00 V for PEFE) accompanied with a reversible electrochromic behavior, yellow to dark green for PTFT, yellow to parliament blue for PEFE. Their band gap values (Eg) were found to be 2.36 eV and 2.26 eV for PTFT and PEFE, respectively. Furthermore, gold nanoparticles (AuNP) were prepared and their interaction with polymer films, PTFT and PEFE, were investigated using spectroscopic techniques. The fluorescence properties of the polymers and their composites, prepared by the interaction of AuNP with polymers, were also investigated.
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Pati, Paramjeet. "Sustainable Nanotechnology: Life Cycle Thinking in Gold Nanoparticle Production and Recycling." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/75132.
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Nanotechnology has enormous potential to transform a wide variety of sectors, e.g., energy, electronics, healthcare, and environmental sustainability. At the same time, there are concerns about the health and environmental impacts of nanotechnology and uncertainties about the fate and toxicity of nanomaterials. Life cycle assessment (LCA), a quantitative framework for evaluating the cumulative environmental impacts associated with all stages of a material or process, has emerged as a decision-support tool for analyzing the environmental burdens of nanotechnology. The objective of this research was to combine laboratory techniques with LCA modeling to reduce the life cycle impacts of gold nanoparticle (AuNP) production. The LCA studies were focused on three aspects of AuNP synthesis: 1) the use of bio-based ("green") reducing agents; 2) the potential for recycling gold from nanomaterial waste; and, 3) the reduction of the life cycle impacts of AuNP production by conducting the synthesis at reduced temperature. The LCA models developed for AuNPs can inform future nanotechnology-focused LCA studies. Comparative LCA showed that in some cases, the environmental impacts associated with green synthesis methods may be worse than those of conventional synthesis approaches. The main driver of the environmental burdens associated with AuNP synthesis is the large embodied energy of gold, and so-called green synthesis methods do not offset those impacts. In addition, the reaction yield, which is seldom reported in the literature for green synthesis of nanomaterials, was found to greatly influence the life cycle impacts of AuNP synthesis. Gold from nanomaterial waste was successfully recovered by using host-guest inclusion complex formation facilitated by alpha-cyclodextrin. This recycling approach involved room temperature conditions and did not require the toxic cyanide or mercury commonly used in the selective recovery of gold. A major advantage offered by this approach for selective gold recovery over conventional approaches is that the recovery does not involve the use of toxic cyanide or mercury. To reduce the energy footprint of citrate-reduced AuNP synthesis, the synthesis was conducted at room temperature. LCA models showed significant reduction in the energy footprint. The findings of this research can inform future LCAs of other nanomaterials.Ph. D.
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Sugden, Mark William. "Electrical and optical assessment of thiol encapsulated gold nanoparticle thin films." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538003.
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Davidson, A. M. "High resolution characterisation of gold nanoparticle coronae by differential centrifugal sedimentation." Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3018342/.
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Chen, Feifei. "Gold nanoparticle mediated membrane permeabilization of phytochemicals into breast cancer cells." Thesis, University of Missouri - Columbia, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10180873.
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Breast cancer is one of the most common cancers in women with a very high incident rate, especially for those women who are between 40-60 years old. Most drugs are large or non-polar macromolecules, which cannot get into cancer cells autonomously, so a method that can deliver those drugs is very important. Optoporation method has been facilitated with gold nanoparticles, which are bound to breast cancer cells, and then absorb the optical energy to improve the membrane permeabilization. Long-term dietary consumption of fruits and vegetables high in β-carotene and other phytochemicals has been shown beneficial in terms of anti-cancer, anti-aging, preventing cardiovascular disease and cataract. However they are large non-polar molecules that are difficult to enter the cancer cells. Here in this study, we applied optoporation method by using β-carotene, and tetracycline as anti-cancer drugs in various concentrations to optimize highest selective cell death/best potential for T47D breast cancer cell lines.
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Shu-HuaChiu and 邱淑華. "Gold nanoparticle-induced catalysis formation of gold/polymer Janus nanoparticles." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/12893514314054474728.
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QI, HAO. "Liquid crystal-gold nanoparticle composites." 2009. http://hdl.handle.net/1993/3166.
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Studies of liquid crystal (LC) /Au nanoparticle (NP) composites have been pursued in columnar and in nematic phases of thermotropic LCs.
Using LCs forming a columnar phase, we found that different functionalities on the corona of the Au NPs (hydrophobic vs. hydrophilic) display unique effects on the stability and ordering of the columnar LC phase.
Doping nematic LCs with non-chiral or chiral Au NPs causes the formation of textures commonly observed for chiral nematic LCs, i.e., the formation of somewhat uniform stripe textures or patterns separated by areas of homeotropic alignment of LC molecules. Two scenarios are proposed. In the first scenario, the Au NPs form topological chain-like defects and the remaining Au NPs reside at the interface inducing vertical alignment of the LC molecules. In the second scenario, chiral Au NPs transfer chirality to the nematic LC host. Further, induced circular dichroism studies proved the second scenario. Using the same chiral Au NP systems, the origin of chirality of Au NPs has also been studied, and a powerful methodology has been proposed to unravel the puzzle of chirality of chiral ligand-protected Au NPs.
Further investigations of these texture phenomena led to the discovery of using metal NPs to control the orientation and alignment of LCs. In due course, a dual alignment and electro-optical switching behaviour was found using alkylthiol-capped Au NPs doped into a nematic LC with positive dielectric anisotropy in planar namatic LC cells. This study was also expanded to Ag and CdTe NPs, which showed the same phenomenon, and all investigated NPs significantly reduced the voltage needed to re-orient the LCs in an electric field (threshold voltage).
Starting from basic and moving on to more application-oriented research, we finally also initiated structure-property relationship studies of LC/NP composites.
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Lee, Po-Han, and 李柏漢. "Multifunctional Nanocomposite of Upconversion Nanoparticle with Different Morphology of Gold Nanoparticles." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/81835215999949797699.
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碩士國立臺灣大學
化學研究所
102
Upconversion nanoparticles (UCNPs) refer to a highly potent nanomaterial for bioassay and bioimage because it can convert two or more low energy photons to a high energy photon. We demonstrate a nanocomposite consisting of UCNPs and gold nanoparticles as a multifunctional nanomaterial to apply in biomedical application. Noble metallic nanoparticles such as gold nanoparticle have a unique optical property because of the surface plasmon resonance (SPR). Furthermore NaYF4:Yb/Er upconversion nanoparticles emit the photoluminescence from green-to-red which can provide gold nanoparticles inducing photothermal effect. We further used silica coated UCNPs to functionalize amino groups on silica shell to combine 3.5 nm gold nanoparticles (UCNP@SiO2-AuNPs) or gold nanorods (UCNP@SiO2-AuNRs). The size of UCNPs and UCNP@SiO2 are define as 19 ± 1.1 nm and 26 ± 0.5 nm by HRTEM, respectively, and the silica shell is 3 ± 0.5 nm. According to the result of photoluminescence spectra, the intensity of UCNP@SiO2-AuNRs is lower than UCNP@SiO2-AuNPs and this confirm highly energy transfer from UCNP to gold nanorods. In vitro cytotoxicity study, this nanocomposites is nontoxicty to oral cancer cell through the MTT assay even the concentration of nanocomposites approaching 250 μg/mL. The photothermal effect of UCNP@SiO2-AuNRs is demonstrated by irradiating a 980 nm laser and staining with trypan blue, there is huge cell death compare to UCNP@SiO2-AuNPs. In summary, we successfully develop nanocomposites based on UCNPs which reveal obviously photothermal effect and cell imaging to overcome non-fluorescent material like gold nanorods as nanocarriers in biological application.
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Jing-XiangHong and 洪靖翔. "Gold nanoparticle-based antibody probes forimmuoprecipitation." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/36615475851946129760.
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Cheng, De-Ming, and 鄭德銘. "Plasmonic Coupling of Gold Nanoparticle on Gold Film: Experiment and Simulation." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/x5f7w8.
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碩士國立東華大學
物理學系
107
Previous studies had shown that plasmonic coupling between gold nanoparticle and gold film was highly sensitive with their extremely close gap distance. Different ways were provided to define nanogap between gold nanoparticles and gold film for plasmonic coupling effect. In order to systematically study coupling effect in an extremely close distance, self-assembly monolayer technique were used in this work. We modified four kind of molecular (3-Mercaptopropionic acid (3-MPA), 6-Mercaptohexanoic acid (6-MHA), 11-Mercaptoundecanoic acid (11-MUA), 16-Mercaptohexadecanoic acid (16-MHA)) with different length on the surface of 50 nm gold nanoparticle and Cysteamine on the gold film. By centrifugal process, we can easily deposit gold nanoparticles on gold film and control their gap distance through modified molecular. Experimental results by measuring reflecting spectrum show that there are two characteristic absorption peak when vertical polarization incident. Surface plasma resonance peak shift from 610 nm to 710 nm as gap distance decrease from to . Absorption peak from gold nanoparticle remain at 530 nm. Simulation shows that electric field enhancement between gold nanoparticles and gold film were similarly to experimental resonance wavelength. Two characteristic enhanced wavelength were also found. As gap distance decrease from 5 nm to 0.5 nm, resonance wavelength red shift from 564 nm to 697 nm. For 40 nm particle size, red shift from 575 nm to 665 nm as gap distance decrease from 2 nm to 0.5 nm. Coupling peak related to the size of gold nanoparticles and red-shifted in resonance wavelength following a power law with decreasing film-NPs gap distance. For correspondence, we change our parameter in simulation. 54 nm gold nanoparticles are replaced and apply refractive index n=1.21. As gap distance between gold nanoparticles and gold film set at 3, 2, 1 nm resonance peak shifted to 608, 629, 701 nm, respectively. Simulation results are consistent with experimental measurement though adjust gold nanoparticle diameter and apply refractive index. Furthermore, with the properties of atmospheric hydrogen plasma easily reacting with carbon-bonded molecules we applied short and long time plasma treatment to gold nanoparticles modified with long carbon chain molecular such as 11-MUA and 16-MHA, respectively. With short time process resonance wavelength red shifted slightly, absorption of gold nanoparticles remain in the same. However, in long time plasma treatment (30 min), resonance wavelength evidently shifted from 639 nm to 714 nm for 11-MUA modification, 591 nm to 619 nm for 16-MHA modification. Then, we substitute these results in the experimental fitting curve. It shows that long time plasma treatment for 11-MUA with 0.8 nm shorten gap distance red-shifted occurred in resonance wavelength for 75 nm. And 16-MHA with 1.3 nm shorten distance resonance wavelength red shifted for 28 nm. We also expect that the red shifted of the coupling resonance wavelength caused by the shortening gap distance will slow down as the plasma processing time increases. For modified long carbon chain molecular with long time plasma treatment tend to be stable. Without interaction to plasma gas, distance between gold nanoparticles and gold film no longer decreased leading no change to resonance coupling wavelength in long tome plasma treatment.
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Yang, Pei-Qi, and 楊佩琪. "Research on Plasmonic Properties of Gold Nanoparticle." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/00386464387604573081.
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Chen, Po Yi, and 陳柏宇. "Fluorescent properties of gold nanoparticle supercrystal films." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/27888973076245624715.
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碩士國立清華大學
物理系
103
In this work, we performed the photoluminescence and plasmon resonance of nanoparticle films. Using the extinction spectra as the basis of signals of plasmon resonance, and we compare the extinction and PL spectra. In the experiment we measure on three kind of nanoparticle films, close-pack gold nanoparticle films change the size and numbers of layer and deposited by using E-beam evaporator. We systematically observed simultaneous red shift in PL and extinction spectra with increasing particle size and confirm that L-mode resonance also contributed to the PL of the multilayer close-pack gold nanoparticle films. For Au nanoparticle film deposited by using E-beam evaporator, we observed blue shift of the photoluminescence peak (relative to the scattering peak).
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Rosa, João Miguel Ramalho Fidalgo. "Study of gold nanoparticle assisted neuron stimulation." Master's thesis, 2015. http://hdl.handle.net/10362/16599.
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The unique proprieties exhibited by nanoscale particles compared to their macro size counterparts allow for the creation of novel neural activity manipula-tion procedures. In this sense, gold nanoparticles (AuNPs) can be used to stimu-late the electrical activity of neuron by converting light into heat.
During this dissertation, AuNPs are synthesized by the citrate reduction method, resulting in a hydrodynamic diameter of approximately 16 nm and an absorbance peak of 530 nm. A system to control a 532 nm laser and measure the temperature variation was custom built from scratch specifically for this project. Temperature is then measured with recourse to a thermocouple and through changes in impedance. The built system had in consideration the necessities pre-sented by in vivo tests.
Trials were performed by measuring the temperature rise of colloidal AuNP solutions, having the temperature variation reached a maximum of ap-proximately 18 ºC relative to control trials; successfully showing that light is ef-fectively transduced into heat when AuNPs are present.
This novel approach enables an alternative to optogenetics, which require the animal to be genetically modified in order to allow neuron stimulation.
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Li, Ping-Yu, and 李秉宇. "Plasmonic Coupling of Gold Nanoparticle on Gold Film with Different Gap Distances." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/8a94p3.
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碩士國立臺灣海洋大學
光電科學研究所
103
Previous studies reported plasmonic coupling between gold nanoparticle and gold film with gap distance from 0.7nm to 2.1nm. The surfaces of gold nanoparticles with two kinds of particle sizes (12nm and 30nm) were modified with different molecules to create different gap distance. They found that absorption spectrum peak of 30 nm gold nanoparticle coupling with gold film will be red-shifted as the gap distance decreased. Single gold nanoparticle absorption peak was located at 536nm. However, the absorption of 12 nm gold nanoparticle coupling with gold film had two different absorption peaks. Not only coupling peak but also gold nanoparticle absorption peak red-shifted as the gap distance decreased. In this essay, we think the red shift of absorption peak of 12 nm gold nanoparticle on gold film is due to the coupling of gold nanoparticle with the tiny bump on the surface of gold film as the gap becomes small. We used COMSOL3.5a software to simulate the experiment and found absorption peak of 12nm gold nanoparticle on smooth gold film did not red-shift, but fixed at 530nm. By contrast, with the bump on the gold film, the absorption peak of gold nanoparticle red-shifted from 530nm to 561nm. We then observed the absorption spectra of 12nm gold nanoparticle modified with 3-Mercaptopropionic acid (3-MPA) on gold film with four different certified refractive index liquids (1.34, 1.35, 1.36, 1.37). Then, we used Comsol3.5a software to simulate their absorption spectra. All absorption peaks red-shifted as the refractive index increased.
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Tou, Pei-Ting, and 竇培庭. "NIH 3T3 cell metabolism with gold nanoparticle infection." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/03404616905609987923.
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碩士國立中興大學
奈米科學研究所
102
This study started with different concentrations and particle sizes of gold. The gold nanoparticle concentrations were added into NIH 3T3 cells to observe cell growth curve. The cells of a smaller diameter of gold nanoparticles had a more significant impact, so the smaller particles sizes were selected. The gold nanoparticles that were added into NIH 3T3 cells were found to have more swelling and dendritic became shorting observed by Optical microscope. The NIH 3T3 cells in the liquid were used to measure with the AFM (Atomic force microscope), observed the topography of NIH 3T3 cells with the nanoparticles at different times. The second part of this study is by fluorescence microscope, the fluorescence observation have actin skeleton of cells and the endoplasmic reticulum of cells. After adding gold nanoparticle to the actin filaments of NIH 3T3 are broken and appeared as an aspiration of dots and endoplasmic reticulum of cells becomes incomplete. The third part of the mechanical measurements is by AFM. After adding gold nanoparticles, the nucleus and dendritic adhesion force of cell became bigger than the control with increased time. The adhesion force of nucleus is greater than dendritic. The last part, observed the substrate after the conductor layer produced by optical microscope. The SEM (Scanning electrical microscopy) measured the thickness of the parameters of the deposition of silicon nitride insulating layer made and observed the surface. PDMS made for using cultured cells, after on the substrate to test cells can be successfully cultured on the substrate.
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Ni, I.-Chih, and 倪懿池. "Gold Nanoparticle Films: Assembly, Patterning,and Physical Properties." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/cz367k.
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碩士國立東華大學
物理學系
100
Nanostructures consisting of assembled nanoparticles have many interesting electrical and optical properties. For instance, assembled gold nanoparticle (AuNP) films have strong interparticle coupling effect on their surface plasmon resonance, and charge transport in AuNP films exhibits a metal to insulator transition behavior depending on the interparticle spacing s. For their wide applications to novel electric devices, optoelectronic devices, chemical sensing, and surface enhanced Raman scattering, it is important to pursue a simple, efficient method to fabricate two- and three-dimensional conductive, plasmonic AuNP films with well-defined patterns. In this report, we show a novel centrifuge assembly method to fabricate metal (Au, Ag) nanoparticle films with good coverage, morphology, thickness, and surface modification control. Besides, we combined the centrifugal assembly method with top-down lithography method to form two- and three-dimentional (3D) AuNP nanostructures. We also studied the optical and electrical properties of AuNP films. We found that the surface plasma resonance peak wavelength of AuNP films increases as the interparticle spacing s decreases. We also found s and the optical properties of AuNP films are influences by the drying effect, which can be tuned by the interactions of surface modification molecules. The electrical properties also depend on s. The resistances of AuNP films greatly changes with the interparticle spacing s. Further, we found the resistance of AuNP films were enormously reduced after an exposure of electron beam in scanning electron microscopy. The irradiation of electron beam could turn insulator-like AuNP films into metal-like films, and thus can be apply to directly “write” functional nanodevices. The conductance change of AuNP films with different electron dosages and the current-voltage behaviors at different temperatures before and after electron beam irradiation were also studies.
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"Characterization of nanocrystals and gold nanoparticle-protein assemblies." Thesis, 2009. http://hdl.handle.net/1911/61892.
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The effective determination of the hydrodynamic sizes of nanomaterials functionalized with various coatings is a topic of intense research. Analytical ultracentrifugation, a lesser known characterization method that provides hydrodynamic size via a parameter termed the sedimentation coefficient, provides this information in a manner unsurpassed by alternative methods. In the first part of this thesis, I present the application of analytical ultracentrifugation to ligand-stabilized nanocrystals of cadmium selenide, iron oxide, and gold in organic solvents. This method was able to provide distinct sedimentation coefficients for these model nanocrystals, some of which were different in diameter by only an angstrom. Further, we show that the sedimentation coefficient has a significant dependence on the density of the composite material, which is based on the size of the nanomaterial and surface coating. Therefore, we introduced a descriptive size-dependent term into conventional models that accounts for both the inorganic core and organic coating to more accurately represent the overall density. We also explored the effects of different approaches for analytical ultracentrifugation data analysis on the sedimentation coefficients obtained and found that all methods yielded the same value. Finally, we elucidated experimental parameters for the ultracentrifuge that specifically affect nanomaterial samples and established best practices for studying sedimentation for these types of materials. The results from this work allow for better agreement between experimental and theoretical sedimentation coefficients, which is useful for accurately evaluating hydrodynamic sizes of nanomaterials.
In the second part of this thesis, the relationship between protein surface charge and gold nanoparticle aggregation is explored by using pH variation and chemical modification. Lysozyme and alpha-lactalbumin share a common three-dimensional fold but have significantly different isoelectric points (pI) and surface charge distributions. Myoglobin is also a small globular protein with a pK intermediate between alpha-lactalbumin and lysozyme, and a variant with a specific sulfhydryl group has been generated. These proteins have been conjugated to gold nanoparticles under varying pH conditions and following chemical modifications that impact the protein's pI. Changes in UV-visible spectra, TEM distribution, and dynamic light scattering indicate that significant aggregation depends on a positively charged protein surface.
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Chen, Po-Hao, and 陳柏豪. "Rapid detection of Salmonella using gold nanoparticle andimmunochromatography." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/8c459u.
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碩士國立臺北科技大學
化學工程研究所
99
In recent years, application of DNA molecular detection technology is developing rapidly, such as polymerase chain reaction is the important clinical diagnostic method. PCR method is accurate, but time-consuming, materials-consuming and other issues need to be improved. Therefore, our laboratory developed a immunochromatographic assay which uses DNA molecules, gold nanoparticles(GNPS) and antibodies. We designed biotin-DNA and SH-DNA probes as capture and detection probes, each probe is complementary with Salmonella 16S rDNA. The biotin-DNA probe is associated with avidin and anti-avidin antibody on the nitrocellulose membrane, while the SH-DNA probe is connected to GNPS using covalent bond. With hybridization, immunochromatography methods are used to detect Salmonella. The biggest advantage of this system is that does not require PCR amplification to determine whether a colony of Salmonella. This method can clearly distinguish E.coli between Salmonella. The detection limit of single-stranded DNA is 5 fmol. Furthermore, after silver enhancement, the detection limit is 5 amol. It is rapid, accurate, convenient, low cost and high sensitivity and specificity, which will help clinical use and promotion.
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Tsai, Shang-ting, and 蔡尚廷. "Study of dichroic behavior of spherical gold nanoparticle." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/pktzs9.
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碩士國立臺北科技大學
生化與生醫工程研究所
102
Typically, the color of spherical gold nanoparticles and aggregated nanogold is red and bluish purple, respectively. In this study, dichroic and spherical nanogold was synthesized using a seeding growth method under sodium citrate insufficiency in an aqueous solution. This particular nanogold solution is orange in reflected light and red in transmitted light. With particle assembling, the solution is fainter orange in reflected light, but purple or blue in transmitted light. The current theory for optical properties of gold nanoparticles does not fit the dichroic behaviors of gold nanoparticles. To the best of our knowing, this is the first study to report how the nanogold is synthesized affects the behavior of the nanogold.
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Hsieh, Shu-Yi, and 謝書宜. "Gold-Nanoparticle Enhanced Protein Detection in Metallic Nanostructue." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/36160615162873270306.
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Chan-Yi, Yang, and 楊正義. "The Application of Functionalized Gold Nanoparticle on Biotechnology." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/65701209710329669500.
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博士國立臺灣師範大學
化學系
95
Metal and semiconductor nanoparticles coupling with biomolecules have attracted great interests recently because the resulting materials may bring new applications in biological systems. The strong and selective binding of carbohydrate-AuNP to bacterial presents a novel method of labeling specific protein on the cell surface using carbohydrate conjugated nanoparticles. Moreover, in comparison with the conventional sandwich immunoassay, the biomolecule conjugated nanoparticles can provide a relatively easy and direct method to visualize the target receptors on the cell surface under an electron microscope. On the other hands, the multivalent interactions between carbohydrate-AuNPs and target lectins were studied by the SPR technique to quantitatively analyze the binding affinity. The results showed that the binding of mannose encapsulated AuNPs with Con A and galactose encapsulated AuNPs with VAA-I exhibited a strong multivalent effect, and the binding specificity between carbohydrate-AuNP and the lectin was similar to that of the monovalent counterparts. The relative inhibit potency (RIP) values of carbohydrate-AuNPs indicate that the larger size of AuNP and longer ligand length present excellent binding affinity both in interaction with Con A and VAA-I, respectively. Our results demonstrate that gold nanoparticle can serve as an excellent multivalent carbohydrate ligand carrier, providing a new route for designing inhibitors and biological effectors for target proteins.
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Yeh, Yi-Cheun, and 葉伊純. "Biomolecule and Gold Interaction: Electrochemistry and Nanoparticle Formation." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/63596894985279133739.
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碩士國立臺灣師範大學
化學系
95
Cytochrome c is an electron transport protein in biological system. The redox potential of this protein was measured by suing tetraoctylammonium bromide modified gold electrode. In the system, cyt c must diffuse through the TOAB layer to reach the Au surface, and the strong hydrophobic tails of TOAB may trigger cyt c denature. The measured redox potential of -0.1 V is similar to oxygen-bound iron proteins. Spectroelectrochemistry of cyt c was performed in an optically transparent thin-layer electrochemical cell at potential of -0.2 V. The final reduced cyt c exhibits split Q bands at 542, and 575 nm. When cyt c diffused inside TOAB layer, the hydrophobic interaction causes protein structure changes, and affects the iron binding sphere. From the spectrum of the reduced form, we conclude it is a low-spin, five-coordinate ferrous heme. Gold salt, HAuCl4 can be reduced in cyt c solution and gold nanocrystals were formed from this reduction. Transmission electron microscopy (TEM) images showed distorted spherical shapes of gold nanoparticles were formed with excess Cl ions. In the presence of Br- ions, multiple shapes such as triangular, hexagonal nanoplates, decahedral particle and nanorod were formed. Iodide appears to prevent the formation of gold nanocrystals. At pH 3, the Cl- containing cyt c- HAuCl4 solution showed multiple shapes of gold nanocrystals, and TEM images showed gold nanocrystals were formed within the polypeptide. Using cyt c as a reducing agent the sizes and shapes of gold nanocrystals are dominated by the nucleation and growth rate which can be fine-tuned by varying reduction potential, temperature, and pHs.
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Hsieh, You-Rong, and 謝侑融. "Thermoelectric Properties of Hematin-Gold Nanoparticle Assembled Films." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/77765191522361556457.
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碩士國立東華大學
物理學系
103
In recent years, people face the difficulty in lack of energy, so people eager to find other kinds of energies to alternate fossil fuels. Thermoelectric materials could transform thermal energy to electricity directly. However, the efficiency of transformation was not good, so thermoelectric materials didn’t yet be widely used. In researches in small materials, people find that when the size of thermoelectric materials down to nanoscale, their figure of merit will rise obviously in experiment and theory. In this work, we studied the thermoelectric properties of molecule modified gold nanoparticle assembled films influenced by surrounding gases. We use Hematin molecule and deoxygenate the Iron of Hematin （Fe3+→Fe2+）by N2H4 and survey the seebeck coefficient of two materials. We found that the Seebeck coefficient of Hematin(Fe3+)in vacuum(~10-5 Torr),nitrogen(100 Torr) and oxygen(100 Torr) were -19.9 μV/K, -0.02 μV/K and -0.84 μV/K respectively, and the Seebeck coefficient of Hematin(Fe2+) were +40.5 μV/K, -11.8 μV/K and -13.7 μV/K respectively. Because the AuNPs films could adsorb gases, the seebeck coefficient will change by the pressure of gases. In addition, we also estimate the material’s resistivity and power factor. We found that no matter where the Hematin(R)-AuNP molecular lives in vaccum or other surrounding gases, its power factor all lager than Hematin-AuNP. So, from this experiment, we can find that surrounding gases truly have the infiuence on the molecular of thermoelectric.