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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Preparation, Functionalization and Biomedical Applications of Carbonaceous Nanomaterials

Zhang, Jianfei 06 May 2011 (has links)
Carbon nanomaterials have attracted significant attention in the past decades for their unique properties and potential applications in many areas. This dissertation addresses the preparation, functionalization and potential biomedical applications of various carbonaceous nanomaterials. Trimetallic nitride template endohedral metallofullerenes (TNT-EMFs, M₃N@C₈₀, M = Gd, Lu, etc.) are some of the most promising materials for biomedical applications. Water-soluble Gd₃N@C₈₀ was prepared by the functionalization with poly(ethylene glycol) (PEG) and hydroxyl groups (Gd₃N@C₈₀[DiPEG(OH)ₓ]). The length of the PEG chain was tuned by changing the molecular weight of the PEG from 350 to 5000. The 1H magnetic resonance relaxivities of the materials were studied at 0.35 T, 2.4 T and 9.4 T. Their relaxivities were found to increase as the molecular weight of the PEG decreased, which is attributed to the increasing aggregate size. The aggregate sizes were confirmed by dynamic light scattering. In vivo study suggested that Gd3N@C₈₀[DiPEG(OH)x] was a good candidate for magnetic resonance imaging (MRI) contrast agents. Another facile method was also developed to functinalize Gd₃N@C₈₀ with both carboxyl and hydroxyl groups by reaction with succinic acyl peroxide and sodium hydroxide thereafter. The product was determined to be Gd₃N@C₈₀(OH)~₂₆(CH₂CH₂COOM)~₁₆ (M = Na, H) by X-ray photoelectron spectrometry. The Gd₃N@C₈₀(OH)~₂₆(CH₂CH₂COOM)~₁₆ also exhibited high relaxivity, and aggregates in water. The research on both pegylated and carboxylated Gd₃N@C₈₀ suggests that aggregation and rotational correlation time plays an important role in relaxation, and the relaxivities and aggregation of the water-soluble metallofullerenes can be tuned by varying the molecular weight of the functionality. TNT-EMFs can be encapsulated inside single-walled carbon nanotubes (SWNTs) to form "peapod" structures by heating the mixture of TNT-EMFs and SWNTs in a vacuum. The peapods were characterized by Raman spectrometry and transmission electron microscopy (TEM). The peapods were then functionalized with hydroxyl groups by a high speed vibration milling (HSVM) method in the presence of KOH. The functionalized Gd-doped peapods exhibited high relaxivites and had an additional advantage of "double carbon wall" protection of the toxic Gd atoms from possible leaking. The HSVM method was modified by using succinic acyl peroxide. The modified HSVM method could functionalize multi-walled carbon nanotubes (MWNT) and single-walled carbon nanohorns (SWNHs) with carboxyl groups. In the presence of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC), carboxylate MWNTs and SWNHs could be conjugated with CdSe/ZnS quantum dots (QDs). TNT-EMFs were also encapsulated inside SWNHs to form SWNH peapods. SWNH peapods were functionalized by the modified HSVM method and then were conjugated with CdSe/ZnS QDs. The peapods were characterized by TEM. In vitro and in vivo studies indicated that SWNH peapods could serve as a multimodal diagnostic agent: MRI contrast agent (Gd₃N@C₈₀ encapsulated), radio-active therapeutic agent (Lu₃N@C₈₀ encapsulated) and optical imaging agent (QDs). / Ph. D.
2

Intracellular Transport in Cancer Treatments: Carbon Nanohorns Conjugated to Quantum Dots and Chemotherapeutic Agents

Zimmermann, Kristen Ann 05 June 2012 (has links)
Cancer therapies are often limited by bulk and cellular barriers to transport. Nanoparticle or chemotherapeutic compound intracellular transport has implications in understanding therapeutic effect and toxicity. The scope of this thesis was to study the intracellular transport of carbon nanohorns and to improve the efficacy of various chemotherapeutic agents through increased intracellular transport. In the first study, fluorescent probes (quantum dots) were conjugated to carbon nanohorns to facilitate the optical visualization of the nanohorns. These hybrid particles were characterized with transmission electron microscopy, electron dispersive spectroscopy and UV-VIS/FL spectroscopy. Their cellular uptake kinetics, uptake efficiencies, and intracellular distribution were determined in three malignant cell lines (breast – MDA-MB-231, bladder – AY-27, and brain – U87-MG) using flow cytometry and confocal microscopy. Intracellular distribution did not vary greatly between cell lines; however, the uptake kinetics and efficiencies were highly dependent on cell morphology. In the second study, the efficacy of various chemotherapeutic agents (i.e., doxorubicin, cisplatin, and carboplatin) was evaluated in AY-27 rat bladder transitional cell carcinoma cells. In the future, severe hyperthermia and chemothermotherapy (chemotherapy + hyperthermia) will also be evaluated. Doxorubicin and cisplatin compounds were more toxic compared to carboplatin. Hyperthermia has previously shown to increase the cellular uptake of chemotherapeutic agents; therefore, chemothermotherapy is expected to have synergistic effects on cell death. This work can then be translated to carbon nanohorn-based laser heating to generate thermal energy in a local region for delivery of high concentrations of chemotherapeutic agents. Although these two concepts are small pieces of the overall scope of nanoparticle-based therapies, they are fundamental to the advancement of such therapies. / Master of Science
3

Development of a Hollow-Core Fiberoptic Microneedle Device for the Treatment of Invasive Bladder Cancer

Hood, Robert L. 12 September 2011 (has links)
The hydraulic resistance characterization manuscript chronicles the early development of the hollow-core fiberoptic microneedle device (FMD). The study determined that for straight tubing with an inner bore of 150 ?m and a length greater than 50 mm long, Poiseuille's Law was shown to be accurate within 12% of experimental data for the pressure range of 69-517 kPa. Comparison between different needle design geometries indicated that tip diameters <55 ?m cause a significant increase in hydraulic resistance. Tubing length should be kept to a minimum and tip diameter should be kept above this threshold to reduce overall hydraulic resistance. The bladder treatment study describes the fabrication and testing of the FMD for treatment of invasive urothelial cell carcinomas (UCCs). Experiments investigating the fluid dispersal of single-walled carbon nanohorns (SWNHs) in the wall of inflated, healthy ex vivo bladders demonstrated that perfusion of 2 cm° on the bladder wall's surface can be achieved with a 5 minute infusion at 50 ?L/min. Irradiation of the SWNH perfused bladder wall tissue with a free space, 1064 nm laser at an irradiance of 0.95 W/cm° for 40 seconds yielded a 480% temperature increase relative to similar irradiation of a non-infused control. Co-delivery experiments demonstrated both SWNH and light delivery though a single hollow-core fiber to heat the bladder wall 33 °C with an irradiance of 400 W/cm°, demonstrating that the FMD can be used to achieve hyperthermia-based therapeutic effects via interstitial irradiation. / Master of Science
4

Design and Validation of Medical Devices for Photothermally Augmented Treatments

Andriani, Rudy Thomas 15 September 2014 (has links)
*1-Dimensional Advective-Diffusion Model in Porous Media Infusion of therapeutic agents into tissue is makes use of two mass transport modes: advective transport, and molecular diffusion. Bulk infusion into a 0.6% wt agarose phantom was modeled as an infinite, homogenous, and isotropic porous medium saturated with the same solvent used in the infused dye tracer. The source is assumed to be spherical and isotropic with constant flow rate and concentration. The Peclet numberdecreases with power function Pe = 15762t0.337 due to the decrease in mean dye-front pore velocity as V goes to Vfinal. Diffusive mass transport does not become significant during any relevent time period. *Arborizing Fiberoptic Microneedle Catheter We have developed an arborizing catheter that allows multiple slender fused-silica CED cannulae to be deployed within a target volume of the brain via a single needle tract, and tested it in a widely accepted tissue phantom. The arborizing catheter was constructed by bonding and encapsulating seven slender PEEK tubes in a radially symmetric bundle with a progressive helical angle along the length, then grinding a conicle tip where the helical angle is greatest. The catheter was tested by casting 0.6% wt agarose around the device with all needles deployed to a tip-to-tip distance of 4 mm. Phantom temperature was maintained at 26 ± 2°C. 5% wt Indigo Carmine dye was infused at a rate of 0.3 uL/min/needle for 4 hours. N=4 infusions showed a Vd/Vi of 139.774, with a standard deviation of 45.01. This is an order of magnitude greater than single-needle infusions under similar conditions [45]. The arborizer showed the additional benefit of arresting reflux propagating up the lengths of individual needles, which has historically been a weakness of single-needle CED catheter designs. *In Vivo Co-Delivery of Single Walled Carbon Nano-horns and Laser Light to Treat Human Transitional Cell Carcinoma of the Urinary Bladder in a Rodent Model Using a rodent model we explored a treatment method for Transitional Cell Carcinoma (TCC) in the urinary bladder in which Single Walled Carbon Nanohorn (SWNH) solution and 1064 nm laser light are delivered into tumorous tissue via a co-delivery Fiberoptic Microneedle Device (FMD). Preliminary treatment parameters were determined by injecting SWNH solutions with concentrations of 0 mg/mL, 0.17 mg/mL, or 0.255 mg/mL into ex vivo porcine skin and irradiating each for three minutes at laser powers of 500 mW, or 1000 mW. The combination with the greatest temperature increase without burning the tissue, 0.17 mg/mL at 1000 mW, was selected for the in vivo treatment. TCC tumors were induced in a rodent model by injecting a solution of 106 AY27 urothelial carcinoma cells into the lateral aspect of the left hind leg of young, female F344 rats. When tumors reached 5-10 mm3, rats were anesthitized and treated. SWNH solution was injected directly into the tumor and irradiated until the target temperature of 60degC was achieved. The rats were then recovered from anestesia and monitored for 7-14 days, at which point they were humanely sacrificed, and the tumors prepared for histological examination. Histological assessment of areas of FMD treatment correlated well with gross morphological appearance. Foci of tumor necrosis showed sharp (1-2 mm) delineation from areas of viable tumor (not treated) and normal tissue. We believe we have demonstrated the feasibility of using the FMD for treatment of urothelial carcinoma using an animal model of this disease, and are encouraged to continue development of this treatment and testing in larger animal models. / Master of Science
5

Détection d'antigènes de noix avec des nanosondes de nanocornes de carbone

St-Pierre, Laurence 06 1900 (has links)
La détection d’antigènes à large échelle s’avère être un enjeu majeur dans le secteur de la production alimentaire. Le défi persistant encore à ce jour est la détection spécifique et quantitative des protéines allergènes dans les produits commercialisés, comestibles, cosmétiques ou autres. La technique la plus répandue en industrie pour la détection de matériel biologique spécifique est le test enzyme-linked immunosorbent Assay (ELISA). ELISA permet un dosage de diverses protéines au sein d’un échantillon, mais ne détecte qu’un seul antigène à la fois, ce qui est couteux et peu efficace. La hausse des réactions allergiques notées chez la population de divers pays demande à ce qu’une technique plus efficace et moins couteuse soit développée. Dans le cadre de ce mémoire, une méthode alternative au test ELISA pour la détection d’allergènes de noix sera présentée. Cette nouvelle méthode appelée RIISA (Raman imaging immunosorbent assay), fait intervenir les propriétés de diffusion Raman de nanostructures de carbone, tel que les nanotubes et les nanocornes de carbone, pour les adapter comme sonde optique. L’objectif de ce travail est d’adapter cette méthode pour la détection triplex, permettant la reconnaissance RIISA entre trois couples d’antigène-anticorps, soit d’amande, de cachou et de noisette. Les sondes sont fonctionnalisées d’anticorps permettant la reconnaissance avec la protéine et comportent aussi un colorant encapsulé dans la cavité interne, ce qui permet la différenciation des couples. Le système de détection est couplé à l’imagerie Raman pour permettre une sensibilité plus aigüe du système. Un phénomène de réaction croisée entre les anticorps et les antigènes empêche toutefois de réaliser une détection en triplex. La preuve de concept sera donc démontrée en utilisant les trois monoplexes, et ce, avec divers colorants mettant en évidence la polyvalence du système de détection présenté. / Large scale antigen detection is a major issue in the food production sector. The challenge that still persists nowadays is the specific and quantitative detection of allergenic protein products on the market, whether edible, cosmetic or otherwise. The most widely used technique in the industry for the specific biological detection of allergens is the Enzyme-linked immunosorbent assay (ELISA). This assay detects various proteins in a simple sample. The ELISA test can detect only one allergen at a time and its quantitative detection is limited. In addition, the increase in allergic reactions observed in the population of various countries require a more efficient and less expensive technique to be developed. As part of this master’s thesis, an alternative method to the ELISA assay to detect nut allergens will be presented. This assay, called Raman imaging immunosorbent assay (RIISA), uses carbon nanostructure based nanoprobes consisting of carbon nanotubes and nanohorns. The objective is to develop a triplex detection system using RIISA, that selectively recognizes between three antigen-antibody pairs, namely almond, cashew, and hazelnut. The dye encapsulated nanoprobes are functionalized with antibodies recognizing the protein and for simultaneously differentiating the couples. The presented detection system is coupled with Raman imaging and allows a more acute sensitivity of the system. However, cross reactions between the antibodies and the antigens prevent the triplex detection. The proof of concept will be demonstrated using the three monoplex couples with various dyes that highlight the versatility of the developed system.

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