Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Additional advisors: J. Barry Andrews, Krishan K. Chawla, Derrick Dean, Robert Pitt. Description based on contents viewed Feb. 13, 2009; title from PDF t.p. Includes bibliographical references.

Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisor: Chin-Pao Huang and Daniel K. Cha, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Includes bibliographical references (p. 149-179).

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: S. Ismat Shah, Dept. of Materials Science . Includes bibliographical references.

>Magister Scientiae - MSc / Engineered nanomaterials derived from various bulk materials are being developed in ever larger quantities and with very diverse chemical compositions. The physical and chemical properties of the smaller nanoparticles are very different compared to their larger bulk chemicals. Titanium dioxide nanoparticles (TiO2NPs) are an example of such an engineered nanomaterial. Titanium dioxide nanoparticles are mainly used as a pigment in many applications such as glazes, enamels, plastics, pharmaceuticals, cosmetics, and it is widely used in sunscreens. Human exposure to TiO2NPs can occur both during manufacturing and use.

Thesis (Ph. D.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xii, 278 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.

>Magister Scientiae - MSc / Tuberculosis still remains one of the world’s killer diseases. Pyrazinamide (PZA) is one of the most commonly prescribed anti-tuberculosis (anti-TB) drugs due to its ability to significantly shorten the TB treatment period. However, excess PZA in the body caused hepatotoxicity and liver damage. This, together with the resistance of the bacteria to treatment drugs, poor medication and inappropriate dosing, contribute significantly to the high incidents of TB deaths and diseases (such as liver damage). This, therefore, calls for new methods for ensuring reliable dosing of the drug, which will differ from person to person due to inter-individual differences in drug metabolism. A novel biosensor system for monitoring the metabolism of PZA was prepared with a nanocomposite of multi-walled carbon nanotubes (MWCNTs), polyaniline (PANI) and cytochrome P450 2E1 (CYP2E1) electrochemically deposited on a glassy carbon electrode (GCE). The nanocomposite biosensor system exhibited enhanced electro-activity that is attributed to the catalytic effect of the incorporated MWCNTs. The biosensor had a sensitivity of 7.80 μA/ μg mL-1 PZA and a dynamic linear range (DLR) of 4.92 – 160 ng/mL PZA. Bisphenol A (BPA) is a hormone-disrupting chemical used in production of epoxy resins and polycarbonates, which produce various products used on a daily basis. However, BPA can leach out of plastic during normal use and cause health effects such as cancer or disrupt the endocrine system. Moreover, BPA has also been proven to degrade from the containers in landfills and accumulate in groundwater and streams, thereby, polluting the environment while destroying aquatic organisms. Therefore, this also calls for new selective and sensitive methods for the monitoring of BPA. A novel biosensor system for monitoring the oxidation of BPA was prepared from a nanocomposite of polyaniline, polymethyl methacrylate and titanium dioxide nanoparticles, also electrochemically deposited on the GCE. Biosensor fabrication was conducted by immobilization of the enzyme manganese peroxidase (MnP) iii onto the nanocomposite film. The nanobiosensor also revealed enhanced electro activity, attributed to the incorporation of TiO2 nanoparticles. The biosensor system had a sensitivity of 0.3 μA/nM and a detection limit of 0.12 nM. This detection limit falls within the range of the allowed daily intake of BPA as recommended by the Food and Drug Administration (FDA, USA) and other regulatory bodies.

Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2017-05-02T11:56:47Z No. of bitstreams: 1 DissNESS.pdf: 3543889 bytes, checksum: 8aff5fb0c19f74c48e698260a94c29d2 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-05-04T12:15:07Z (GMT) No. of bitstreams: 1 DissNESS.pdf: 3543889 bytes, checksum: 8aff5fb0c19f74c48e698260a94c29d2 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-05-04T12:15:15Z (GMT) No. of bitstreams: 1 DissNESS.pdf: 3543889 bytes, checksum: 8aff5fb0c19f74c48e698260a94c29d2 (MD5) / Made available in DSpace on 2017-05-04T12:21:59Z (GMT). No. of bitstreams: 1 DissNESS.pdf: 3543889 bytes, checksum: 8aff5fb0c19f74c48e698260a94c29d2 (MD5) Previous issue date: 2015-10-08 / Outra / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The titanium dioxide nanoparticles (NP-TiO2) has achieved into aquatic ecosystems through different sources, such as sewer and leaching. Abiotic factors such as pH, ionic strength, water hardness may change the chemical aggregation of NPs as well as the bioavailability of metals in waters result of speciation and /or complexation with other compounds. Considering the pH variations can occur in the environment naturally or as a result of ecological accidents and the increasing use of NP-TiO2 in many different industries, this study aimed to determine the CL-50; 48 hours of NPTiO2 in different pH (acidic, neutral and basic) in juvenile Prochilodus lineatus (curimbatá) and evaluating the effects of exposure to sublethal NP-TiO2 these pH using biochemical, physiological and morphological biomarkers. After sensitivity test with KCl, the animals were tested with different concentrations of NP-TiO2 at pH 5.0, 7.0 and 8.0 for 48 hours to determine the CL-50; 48h. Subsequently, the animals were exposed to 1 mg L-1 NP-TiO2 for 48 hours at different pH. After the exposure period, blood samples were obtained via caudal puncture for ion plasma analysis and hematologic variables, and samples of gills were collected and fixed. The analytical characterization of NP-TiO2 suggest the aggregation ability are modified of the NP at different pH and at pH 5.0, the hydrodynamic diameter of the NP is much larger then the others pH, which may have create difficults for the entry of NP in organisms and caused less damage. The NP-TiO2 were considered non-toxic in pH 5,0, 7,0 and 8,0. Exposure to NP-TiO2 pH 5.0 and ionic imbalance caused in the exposed animals, possibly due to changes in the concentration of Cl- ions. Exposure to pH 5.0 and 8.0 and NP-TiO2 at pH 7.0 inhibited AC enzyme. In animals exposed to NP at pH 5.0 were not identified cloride cells with crypt surface, possibly due the blocking of these surfaces by the large NP aggregates. Changes in concentrations of ROS and SOD, CAT and GCL activity may indicate an imbalance in antioxidant system due to different pH and NPTiO2 exposure. NP exposure caused major damage at pH 7.0, where have lower hydrodynamic diameter , supporting the hypothesis that the smaller the size of the cluster,it’s easier the NP enter the body of the exposed animals. / As nanopartículas de dióxido de titânio (NP-TiO2) têm alcançado os ecossistemas aquáticos através de diferentes fontes, como esgotos e lixiviação das culturas agrícolas. Fatores abióticos como pH, força iônica, dureza da água podem alterar a agregação química das NPs e a biodisponibilidade de metais nas águas. Considerando as variações de pH que podem ocorrer no ambiente, naturalmente ou não, e a crescente utilização de NP-TiO2 nos mais diferentes segmentos industriais, o presente estudo teve por objetivo determinar a CL-50;48h das NP-TiO2 em diferentes pH (ácido, neutro e básico) em juvenis de Prochilodus lineatus (curimbatá) e avaliar os efeitos da exposição subletal a NP-TiO2 nesses pH, utilizando biomarcadores bioquímicos, fisiológicos e morfológicos. Após a realização do teste de sensibilidade com KCl, os animais foram submetidos a testes com diferentes concentrações de NP-TiO2 nos pH 5,0, 7,0 e 8,0 durante 48h para determinar a CL-50;48h. Posteriormente, os animais foram expostos à concentração de 1 mg L-1 de NP-TiO2 durante 48h nos diferentes pH. Após a exposição, amostras de sangue e de brânquias foram coletadas. Análises de caracterização das NP-TiO2 sugerem que em diferentes pH a capacidade de agregação das NP se modificam e que em pH 5,0, o diâmetro hidrodinâmico das NP é maior em relação aos outros pH, o que pode ter dificultado a entrada das NP nos organismos e causado danos menores. As NP-TiO2 foram consideradas não-tóxicas nos diferentes pH. A exposição a NP-TiO2 e a pH 5,0 causou desequilíbrio iônico nos animais expostos, possivelmente em função das alterações na concentração de Cl-. A exposição a pH 5,0 e 8,0 e a NP-TiO2 em pH 7,0 inibiu a enzima anidrase carbônica. Nos animais expostos a NP em pH 5,0 não foram identificadas CC em cripta, possivelmente devido ao bloqueio das superfícies dessas CC pelos grandes agregados de NP. As alterações nas concentrações de espécies reativas de oxigênio e da atividade das enzimas superóxido dismutase, catalase e glutamato cisteína ligase podem indicar um desequilíbrio no sistema antioxidante. A exposição as NP causou danos maiores em pH 7,0, onde os agregados apresentam diâmetro hidrodinâmico menor, corroborando com a hipótese de que quanto menor o tamanho dos aglomerado, maior a facilidade das NP entrarem no organismo dos animais expostos.

In the present thesis we propose the development of hybrid polymer titanium dioxide (TiO2) nanoparticles for use in biomedical applications. TiO2 exhibits high biocompatibility in the dark however, upon illumination in aqueous media with near UV light it produces an array of reactive oxygen species (ROS) which have the capability to induce death in neighbouring cells. The process of inducing cell death using a photosensitive material which produces ROS is known as photodynamic therapy (PDT) and is used to treat a wide range of maladies from psoriasis to cancer.We have demonstrated the ability to produce anatase nanoparticles with high control over their resulting size through a novel water mediated sol-gel synthetic method in benzyl alcohol, using either Ti(OnPr)4, Ti(OnBu)4 or Ti(OiPr)4 as the metal precursor. Through dynamic light scattering (DLS) analysis we have shown that the mechanism of nanoparticle growth appears to proceed through the agglomeration of primary nanoparticles formed instantly upon adding the reagents together. After synthesis the nanoparticles could be easily redispersed in aqueous media at pH2 with any further agglomeration being controlled by the parent alkoxide.After synthesis the nanoparticles were coated with PEG, conjugated to either a catechol or phosphate as ligand, in order to stabilise the nanoparticles at neutral pH. Uncoated nanoparticles exhibited good photoactive capability in the photooxidation of methylene blue. However, on coating with catechols the photoactivity of the nanoparticles was abolished. Coating with phosph(on)ates on the other hand preserved or even enhanced the photoactivity which makes this system promising for in vivo applications.At the same time this thesis also reports preliminary investigations on the use of TiO2 embedded into the walls of model drug loaded poly electrolyte multilayer microspheres for UV triggered delivery applications.

<p>This work reports the chemical synthesis, characterisation and electrochemical application of titanium dioxide (TiO2) and iron oxide (Fe2O3) nanoparticles in the determination of phthalates. The other part of this work involved electrochemical polymerization of aniline doped with titanium and iron oxide nanoparticles for the sensor platform in the electrolytic determination of phthalates. The TiO2 and Fe2O3 nanoparticles were prepared by sol gel and hydrothermal methods respectively. Particle sizes of 20 nm (TiO2) and 50 nm (Fe2O3) were estimated from transmission electron microscopy (TEM) The other technical methods used in this study for the characterization of the TiO2 and iron oxide Fe2O3 NPs were SEM, XRD and UV- visible spectroscopy. Cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy (EIS) were used to study the electrochemical properties of the nanoparticles. These electrochemical studies of the nanoparticles were performed with a Fe2O3 or TiO2/nafion/glassy carbon membrane electrode in 0.1 M phosphate buffer (pH 7.0) and 0.1 M lithium perchlorate (pH 6.8) under an aerobic condition.</p>