Browsing by Subject "nanoparticles"

Now showing 1 - 3 of 3
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    Development and Applications of Gold Nanoparticles and Elastomeric Polymers as Biomaterials
    (2021-07) Siehr, Allison
    This thesis is focused on the development and applications of two different types of biomaterials: nanoparticles and polymers. In chapter 1, I briefly review these biomaterials. In chapter 2, we develop gold nanoparticles (GNPs) that can be driven to either self-assemble or remain colloidally stable using coiled-coil protein interactions. Control over the GNP self-assembly or stability is critical for specific biomedical applications. In chapter 3, we use the self-assembling GNPs to inhibit human immunodeficiency virus type-1 (HIV-1) by adding a targeting ligand for HIV-1. However, we found our GNPs are weak inhibitors of HIV-1. Methods to improve the inhibitor design are then discussed. In chapter 4, a biomaterials-based approach is used to elucidate the structures of HIV-1 and human T-cell leukemia virus type-1 (HTLV-1). A GNP immunolabeling strategy is used to identify HIV-1 and HTLV-1 envelope proteins, critical for viral entry and targets for vaccine development. However, the immunolabelling strategy was not robust, and alternative methods to study envelope proteins are discussed. Lastly, in chapter 5, a novel elastomeric polymer is evaluated for biomedical applications. PLA-PβMδVL-PLA polymers were synthesized in this work and shown to exhibit elastomeric properties. Next, the polymers were found to be biocompatible and biodegradable both in vitro and in vivo. Overall, this thesis demonstrates the development and applications of both gold nanoparticles and elastomeric polymers as biomaterials.
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    Effects of Freezing and Freeze-drying on Protein Conjugated Nanoparticles
    (2018-10) Su, Yafan
    Biodegradable poly(D,L-lactide-co-glycolide) PLGA nanoparticles (NPs) have been extensively investigated for drug delivery. Protein conjugated NPs provide the advantage of active targeting. To overcome the instability associated with storage of aqueous dispersions, NPs are usually lyophilized. However, the freezing and freeze-drying stress can lead to nanoparticle aggregation and protein denaturation. As such, sucrose is widely used as a cryoprotectant and minimal ‘cryoprotectant to particle ratio’ is required. In this study, we used trypsin as a model protein to conjugate on the PEGlyated NPs. The effects of the freezing and freeze-drying process on trypsin conjugated NPs was studied by comparing the size of the NPs, the morphology of the NPs under fluorescent images and the trypsin activity after of the fresh made, freeze-thawed and lyophilized NPs. A minimum sucrose to NPs ratio was founded to provide the complete protection of the trypsin conjugated NPs.
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    Growth, phase transformation, and self-assembly in iron oxide and uranium oxide nanostructures
    (2015-10) Soltis, Jennifer
    Nanomaterials have great scientific appeal due to their unique properties and prevalence in the environment, but the fundamental mechanisms that drive nanoparticle growth, phase transformation, and assembly into larger structures are still shrouded in mystery. Considerable progress has been made in elucidating these mechanisms in the past several decades, and a comprehensive picture of nanoparticle growth is closer than ever. Advances in electron microscopy and computational modeling play a particularly important role in understanding crystal growth at the atomic-level. We use a broad suite of characterization techniques, including X-ray diffraction, conventional and cryogenic transmission electron microscopy, analytical chemistry, and magnetic property measurements, in an attempt to answer fundamental questions about the processes of nanoparticle growth and phase transformation and their assembly into larger—but still nanoscale—objects. This work documents the formation of hematite and goethite via particle-mediated growth under a variety of reaction conditions and presents, for the first time, direct images of the products of hierarchical self-assembly of uranium polyoxometalate clusters.