Lau, Fong Ting. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 73-77). / Abstracts in English and Chinese. / ABSTRACT --- p.III / 摘要 --- p.IV / PUBLICATIONS CORRESPOND TO THIS THESIS --- p.V / ACKNOWLEDGEMENT --- p.VI / TABLE OF CONTENTS --- p.VIII / LIST OF FIGURES --- p.X / LIST OF TABLES --- p.XII / Chapter CHAPTER I. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.1.1 --- Unique Properties of Gold Nanoparticles Possess --- p.1 / Chapter 1.1.2 --- Synthesis of Gold Nanoparticles --- p.3 / Chapter 1.1.3 --- Aggregation or Agglomeration of Gold Nanoparticles --- p.4 / Chapter 1.1.4 --- Fabrication of Well-ordered Structures Using Gold Nanoparticles --- p.6 / Chapter 1.2 --- Objective --- p.7 / Chapter 1.3 --- Organization --- p.9 / Chapter CHAPTER II. --- ARCHITRCTURE OF AUTOMATED MICRO-ROBOTIC SPOTTING SYSTEM --- p.10 / Chapter 2.1 --- Micro-sized Capillary Probes --- p.12 / Chapter 2.1.1 --- Importance of Fabrication of Micron-sized Capillary Probe Tip --- p.12 / Chapter 2.1.2 --- Experimental Procedure of Fabrication of Capillary Probe --- p.14 / Chapter 2.1.3 --- Experimental Result of Fabrication of Capillary Probe --- p.15 / Chapter 2.2 --- Programmable X-Y-Z Manipulator --- p.16 / Chapter 2.3 --- Programmable Hydraulic Syringe Pump --- p.16 / Chapter 2.4 --- CCD Video Microscope System --- p.17 / Chapter 2.5 --- Chapter Conclusion --- p.17 / Chapter CHAPTER III. --- MANIPULATION OF UNMODIFIED GOLD NANOPARTICLES BY DIELECTROPHORESIS --- p.18 / Chapter 3.1 --- Methodology of Manipulation of Gold Nanoparticles --- p.18 / Chapter 3.1.1 --- Self-assembly of Crystals by Capillary Force Induced by Solvent Evaporation --- p.19 / Chapter 3.1.2 --- Position Control by Dielectrophoretic (DEP) Force --- p.21 / Chapter 3.2 --- Experimental Preparation and Setup --- p.22 / Chapter 3.2.1 --- Microelectrodes Fabrication --- p.22 / Chapter 3.2.2 --- Circuit --- p.23 / Chapter 3.2.3 --- Injection of Solution by Microspotting Technique --- p.24 / Chapter 3.3 --- Experimental Procedure --- p.24 / Chapter 3.4 --- Experimental Result --- p.24 / Chapter 3.4.1 --- Process of Crystal Formation by Combining the Capillary Force and DEP --- p.24 / Chapter 3.4.2 --- Position of Crystal Formed between Microelectrodes --- p.25 / Chapter 3.4.3 --- Yield of Crystal Formed between Microelectrodes by Varying Voltage Applied --- p.27 / Chapter 3.5 --- Surface Analyses --- p.29 / Chapter 3.5.1 --- Scanning Electron Microscopy and Energy-Disperse X-ray Spectroscopy Analysis --- p.30 / Chapter 3.5.2 --- Atomic Force Microscope Analysis --- p.31 / Chapter 3.6 --- Possibilities served as Humidity Sensors --- p.33 / Chapter 3.7 --- Chapter Conclusion --- p.35 / Chapter CHAPTER IV. --- THEORETICAL ANALYSES OF GOLD NANOPARTICLES MANIPULATION --- p.37 / Chapter 4.1 --- Structure of Gold nanoparticles - Presence of Stabilizing Ions --- p.37 / Chapter 4.2 --- Theoretical Force Analysis Acting on Gold Nanoparticles --- p.39 / Chapter 4.2.1 --- Governing Equations --- p.39 / Chapter 4.2.2 --- Experimental Analysis --- p.45 / Chapter 4.3 --- Concentration of Gold Nanoparticles in Gold Colloidal Solution --- p.47 / Chapter 4.4 --- Chapter Conclusion --- p.48 / Chapter CHAPTER V. --- MODIFICATION OF GOLD NANOPARTICLES SURFACE --- p.50 / Chapter 5.1 --- Working Principle of Surface Modification of Gold Nanoparticles --- p.50 / Chapter 5.2 --- Criteria of Choosing the Adsorbed Molecules for Chemisorption --- p.52 / Chapter 5.3 --- Experimental Procedures of Surface Modifications --- p.54 / Chapter 5.4 --- Experimental Result of Surface Modification of Gold Nanoparticles --- p.58 / Chapter 5.4.1 --- Effect of Concentration of Dodecanethiol --- p.58 / Chapter 5.4.2 --- Stability of Surface Modified Gold Nanoparticles --- p.59 / Chapter 5.5 --- Chapter Conclusion --- p.61 / Chapter CHAPTER VI. --- MANIPULATION OF MODIFIED GOLD NANOPARTICLES BY DIELECTROPHORESIS --- p.62 / Chapter 6.1 --- Experimental Setup --- p.62 / Chapter 6.2 --- Experimental Result --- p.63 / Chapter 6.2.1 --- Comparison between Modified and Unmodified Gold Nanoparticles --- p.63 / Chapter 6.2.2 --- Manipulation Experiments using Different Frequency --- p.64 / Chapter 6.3 --- PDMS Microfluidic Channel System --- p.68 / Chapter 6.3.1 --- System Design --- p.68 / Chapter 6.3.2 --- Fabrication --- p.68 / Chapter 6.4 --- Chapter Conclusion --- p.69 / Chapter CHAPTER VII. --- CONCLUSION --- p.71 / BIBLIOGRAPHY --- p.73

>Magister Scientiae - MSc / Environmental pollution is always the hottest topic in public conversation and one of the most concerned aspects of human health. The thin film sputtered microelectrode devices have been developed to improve the quality of human health, by offering better monitoring capabilities. This thesis is divided into three parts and the studies were performed on chemical sensor technology currently available and under development using modified methods. In the first part of this thesis: (i) the studies are related to synthesis, characterization and polymerisation of polyaniline (PANI) and polyaniline-co-poly(2,2´-dithiodianline) (PANI-co-PDTDA). Polyaniline (PANI) and the copolymer of aniline with dithiodianiline, an aniline derivative containing S-S-links were of interest in polymer synthesis. Electrochemical synthesis was carried out in 1 M HCl and different concentrations of H2SO4 (1, 2.5, and 5 M) solutions for PANI and PANI-co-PDTDA respectively. The PANI and PANI-co-PDTDA were grown electrochemically on the surface of a glassy carbon electrode (GCE) by repetitive cyclic voltammetric scanning. Cyclic voltammetry (CV) was used to evaluate the differences between the electrochemical characteristics associated with growth of the copolymer and homopolymer, polyaniline (PANI). The surface concentration of PANI was estimated to be 2.64 × 10-1 mol.cm-2 while the film thickness was estimated to be 7.09 × 10-10cm and 1.49 × 10-9cm for scan rate and aquare root scan rate. In contrast, PANI-co-PDTDA concentrations (1, 2, 5 and 5 M H2SO4 solutions) gained a surface concentration (G) falling in the range 6.1 x 10-2 - 7.9 x 102 mol.cm-2 and a film thickness in the range 8.16 x 10 -9- 2.05x10-8cm. The second section of this thesis focused on the development of two sensors, Pt/PANI/HRP and Pt/PANI-co-PDTDA/HRP biosensors. The biosensor described in this chapter focus on the use of horseradish peroxidise (HRP) with hydrogen peroxide as substrate, was constructed with the aim of further investigation of inhibition by heavy metals (Cd2+, Pb2+ and Hg2+). To achieve this, the enzyme HRP as the catalytic bio-element, was immobilised on the surface of a platinum electrode with PANI as a mediator. Immobilisation of HRP in conducting polymer matrices of PANI and PANI-co-PDTDA were achieved by electrochemical polymerisation. The use of amperometric detection allowed for the coupling of the biosensor with a portable potentiostat system (PalmSens). Differential pulse voltammetry (DPV) as technique was used as a detection method for inhibition determination. Selection of suitable pH values for biosensor performance was evaluated and the system showed optimal performance at pH 6.8 and 7.2 for Pt/PANI/HRP and Pt/PANIco- PDTDA/HRP biosensors, respectively. The biosensors developed in this work showed detection limits (LODs) of 0.32 mM and 0.0483 mM for PANI/HRP and PANI-co- PDTDA/HRP, respectively. For the Pt/PANI/HRP biosensor, the apparent Michaelis-Menten constant (Km app) value and maximum current (Imax) were evaluated from Lineweaver-Burk plots at various H2O2 concentrations. The values were found to be 0.6 mM and 1.7 μA for the Pt/PANI/HRP biosensor, while for the Pt/PANI-co-PDTDA/HRP biosensor the results were 0.7 mM and 0.27 μA, respectively. The third section investigated the adsorptive cathodic differential pulse stripping voltammetric (AdDPSV) determination of platinum group metals (PGMs), using an ex situ bismuth coated screen printed carbon electrode (SPCE/Bi) as the working electrode and ammonium buffer solution (pH = 9.2) as the supporting electrolyte. The cathodic stripping differential pulse method was used for investigating the electrochemical behaviour and the quantitative analysis of platinum group metals (Pt, Pd and Rh) at the SPCE/Bi surface in the presence of dimethylgloxime (DMG) as a complexing agent. In order to determine the metals at improved detection limits ensuring repeatability and sensitivity, a complete optimization study of voltammetric parameters was performed. The proposed method was successfully applied to the determination of the real samples (sediments & water) collected in the platinum mining area in the North-West and Limpopo Provinces, South Africa. The results were compared with those obtained by the glassy carbon bismuth film (GC/BiF) voltammetric and ICP-AES spectrometry techniques. Well-shaped voltammograms with clear peak potentials were obtained in the analysis of the real samples, offering excellent perspectives on the use of the constructed modified electrodes. The calibration curves for all PGMs investigated were linear with the limit of detection (LOD) at approximately 0.008, 0.006, and 0.005 μg.L-1 for Pd, Pt and Rh, respectively.

Orientador: Elson Longo / Banca: Silvio Rainho Teixeira / Banca: Fenelon Martinho Lima Pontes / Banca: Paulo Sérgio Pizani / Banca: Ângela Antônia Sanches Delben / O programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi / Resumo: Nanopartículas cristalinas com estrutura do tipo perovskita de BaxSr1-xTIO3, Ba1-xCaxTiO3 e CaxSr1-xTiO3 (x = 0, 0,25, 0,50, 0,75 e 1) foram sintetizadas usando o método de hidrotermalização assitido por microondas. As amostras foram processadas por 40 minutos a 140ºC, sob pressão máxima de 4 bar, usando um forno de microondas doméstico adaptado. A ação das microondas, associada às condições de temperatura e pressão facilitaram a formação das faces em um tempo de síntese relativamente curto, porém não possibilitou um controle sobre o crescimento e morfologia das partículas. Um conjunto de técnicas foi utilizado para a caracerização das amostras e os resultados mostraram que o método de hidrotermalização assistido por microondas é eficiente na obtenção dos compostos cristalinos com partículas nanométricas. Foi observado que todas as amostras apresentam um comportamento fotoluminiscente que varia com a concentração x dos modificadores de rede (Ba, Ca e Sr). A emissão radiativa na região visível azul-verde apresentada por estes materiais está diretamente associada à presença de imperfeições ou defeitos de ordem local. Estes defeitos locais podem ser causados pelo deslocamento do metal de transição Ti no interior da célula unitária de cada composto que dão origem à clusters distorcidos (em quebra de simetria) ou complexos (contendo vacâncias de oxigênio ou grupos OH). A banda larga observada nos espectros de fotoluminescência é característica de materiais com grau de ordem-desordem estrutural de curto alcance indicando que, durante o decaimento radiativo, ocorre um processo multifônico, evidenciando a presença de níveis energéticos adicionais ao band gap destes materiais. As partículas de cada composto apresentam diferentes morfologias que são alteradas pela... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: BaxSr1-xTIO3, Ba1-xCaxTiO3 and CaxSr1-xTiO3 (x = 0, 0,25, 0,50, 0,75 e 1) perovskite-type nanoparticles were synthesized using the Microwave-Assisted Hydrothermal method. The samples were prepared at 140ºC for 40 minutos, under maximum pressure of 4 bar using an adapted domestic microwave oven. The action of microwaves, associated with temperature and pressure conditions facilitated the phase formation in a relatively short time, but did not permit a control on growth and morphology of the particles. A series of techniques was used to characterize the samples and the results showed that the microwave-assisted hydrothermal method is effective in obtaining crystalline compounds with nanosized particles. It was observed that all samples show a photoluminescent behavior that change with the x concentration of network modifiers (Ba, Ca and Sr.). The radiactive emission in the visible blue-green presented by these materials is directly related to the presence of imperfections or local defects. These local defects can be caused by the displacentement of Ti transition metal within the unit cell of each compound, giving rise to distorted clusters (no symmetry breaking) or complex (containing oxygen vacancies or OH groups). The broad band observed in the photoluminescence spectra is characteristic of materials with a short-range structural order-disorder degree, indicating that during radioactive decay occurs a multiphoton process, associated to the presence of additional energy levels inside the band gap of these materials. The particles of each sintesized compound present different morphologies that are altered by the x concentration of network modifiers from nano to micrometer scales. The growth mechanism follows a non-classical pathway where the particles of each compound passes through a... (Complete abstract click electronic access below) / Doutor

L’objectif est d’étudier par la méthode d’échange ionique à l’argent de verres silicatés la coloration induite etla réalisation de guides d’ondes planaires. Deux méthodes de modélisation de l’échange ionique sont présentées pour évaluer les paramètres de l’échange qui sont le coefficient de diffusion, la forme du profil et la mobilité des ions. Cette technique purement thermique permet la réalisation de guides d’onde à gradient d’indice, l’ajout d’un champ électrique permet d’obtenir un profil à saut d’indice. Différentes compositions de verre sont étudiées dans le but de déterminer la variation d’indice induite par la polarisabilité de l’ion argent plus forte que les ions sodium ou lithium initialement présents dans les verres. A la suite de l’échange ionique, un recuit peut être effectué dans le but de précipiter l’argent en nanoparticules métalliques qui possèdent des propriétés d’absorption intéressantes permettant de colorer les verres : la résonance plasmon de surface (RPS). Le mécanisme de formation de ces nanoparticules dépend de la température et de l’effet redox de l’environnement. L’irradiation effectuée par un laser pulsé nanoseconde des verres échangés permet la précipitation locale des nanoagrégats d’argent à la surface des verres. L’irradiation pulsée en régime femtoseconde permet une interaction dans le volume du verre, soit avec des nanoparticules déjà présentes dans le but de modifier la couleur localement, soit avec des verres échangés dans lequel des défauts sont générés pour ensuite favoriser la formation de nanoparticules par recuit. La modélisation de la résonance plasmon de surface effectuée permet d’évaluer le mécanisme de croissance des nanoparticules dans les verres. Les méthodes de caractérisation utilisées sont la microscopie électronique à balayage, la microscopie électronique en transmission, la spectrophotométrie UV/Visible, la photoluminescence et la spectroscopie infrarouge à transformée de Fourier. / The main purpose is to study by the method of silver ionic exchange of silicate glasses the induced coloring and the realization of planar waveguides.Two methods of modelization of Ionic exchange are presented to estimate the exchange parameters which are diffusion coefficient, profile’s shape and ions mobility. This purely thermal method allows the realization of graded index waveguide, the addition of an electric field allows to obtain a step index profile. Various glass compositions are studied with the aim of determining the index variation induced by a polarizability of silver ions stronger than those of sodium/lithium ions initially contained in glasses. Following the Ionic exchange, an annealing can be made with the aim of precipitating silver in metallic nanoparticles which possess interesting properties of absorption allowing to color glasses : the Surface Plasmon Resonance (SPR). The nanoparticles formation mechanism depends on temperature and on redox effect of the medium. The irradiation made with a pulsed laser in nanosecond regime of exchanged glasses allows the local formation of silver nanoaggregates onto the glass surface. The pulsed irradiation in femtosecond regime allows an interaction into the glass volume, either with already present nanoparticles with the aim of modifying the color locally, or with exchanged glasses in which the defects are generated to favor then the formation of nanoparticles by annealing. The modelization of Surface Plasmon Resonance allows the evaluation of the nanoparticles growth mechanism in glasses. The used methods of characterization are Scanning Electron microscopy, Transmission Electron Microscopy, UV/Visible Spectroscopy, Photoluminescence and Fourier Transform Infrared Spectroscopy.

Cerium Oxide Nanoparticles (CeO2-NPs) are commonly used in polishing, engine enhancement agents and many other commercial products. Increased applications and accidental release have raised concerns on the potential impact of CeO2-NPs on the environment. Most previous studies focused on the short term effect of CeO2-NPs. Information is severely lacking on the long-term impact of CeO2-NPs at environmentally relevant concentrations. The main goal of the current dissertation was to investigate the chronic phytotoxicity of CeO2-NPs on two plant species, tomato (Solanum lycopersicum L.) and Turnip mustard (Brassica rapa L.) fast growing variety, and the physiological and biochemical responses of these two plant species to CeO2-NPs. Four specific objectives were established. The first objective was to investigate the effects of combined CeO2-NPs and TiO2-NPs exposure on tomato plant growth and oxidative stress. The second objective was to investigate the impact of a lifecycle exposure to CeO2-NPs on wild type tomato growth and fruit yield and to evaluate the transgenerational effects of CeO2-NPs exposure on plant growth and the oxidative stress of the second generation tomato seedlings. The third objective was to compare the influence of CeO2-NPs and bulk CeO2 particles on plant growth and oxidative stress of standard fast growing Brassica rapa. The final objective was to evaluate the risks of CeO2-NPs exposure over three generations on Brassica plant growth, oxidative stress and reproduction. The results suggested that firstly, CeO2-NPs pre-exposure at concentrations of 4 and 40 mg/kg dry soil followed by 1000 mg/L of TiO2-NPs post-treatment increased H2O2 content and antioxidant proteins activities compared with CeO2-NPs alone and TiO2-NPs alone, and reduced biomass of the tomato plants compared with CeO2-NPs alone. Secondly, irrigation of CeO2-NPs at concentrations up to 10 mg/L stimulated wild type tomato plant growth, but exposure to CeO2-NPs over a lifecycle harmed plant growth and induced higher H2O2 content in tomato seedlings of the second generation. Thirdly, bulk CeO2 exposure at irrigation concentrations of 10, and 100 mg/L were more beneficial for Brassica rapa plant growth than CeO2-NPs at equivalent concentrations. CeO2-NPs irrigation at 10 and 100 mg/L increased H2O2 content and antioxidant proteins activities than bulk CeO2 at equivalent concentrations. However, the mustard plants treated by CeO2-NPs or bulk CeO2 showed changes of H2O2 content in different growth stages, which illustrated that CeO2-NPs and the bulk counterpart induced the change of H2O2 content differently. Finally, irrigating mustard plants with 10 to 1000 mg/L CeO2-NPs over three generations resulted in an inhibited plant growth, stronger oxidative stress, less seed yield and poorer reproduction of offspring plants. To our knowledge, this is the first report on the chronic (multigenerational) effects of CeO2-NPs on plant growth and oxidative stress of tomato and mustard plants grown in soil.

xix, 262 p. / Tridecameric inorganic hydroxo/aquo nanoclusters comprise a very small fraction of compounds under the large and varied umbrella of inorganic clusters. The Anderson-Evans cluster is a subset of these larger polymetallic tridecameric clusters. A novel synthesis of M 13 nanoclusters containing the Anderson-Evans cluster as cores has been discovered. This synthesis proceeds with the aid of a key organic reagent, which reacts with the nitrate counter anions of the starting material removing them from the solution. This forces the formation of a higher nuclearity species. Research continues to focus on the generality of the reaction as it applies to both inorganic and organic synthesis, as well as on extensive characterization of the novel clusters by a variety of analytical methods. These nanoelusters have proven to be useful as single-source precursors for the preparation of thin film oxides due to their high purity and crystallinity. Chapter I is a literature review of Anderson-Evans clusters in the context of how they comprise the core substructure in the reported tridecameric nanoclusters. Attention is also given to the numerous clusters or complexes that are absent from this series. Chapter II chronicles the discovery and synthesis of [Ga 13 (μ 3 -OH) 6 (μ 2 -OH) 18 (H 2 O) 24 ](NO 3 ) 15 a nanocluster previously thought to be unstable. Chapter III describes the modification of the reaction to prepare other tridecameric inorganic nanoclusters with increases in yield and purity. Chapter IV reports the isolation of a series of new heterometallic tridecameric nanoclusters and a potential predictive strategy for tuning the metal ratios in the crystalline products. Chapter IV also highlights the application of the nanoclusters as precursors to thin film oxides. Initial characterization of tridecameric inorganic nanoclusters using powder and single crystal XRD, NMR, ToF-SIMS, EPMA and SEM instrumentation is explained in Chapter V. Finally, Chapter VI is a summary and a report of the current standing of a different project aimed at developing a template-assisted self-assembly of organic nanocages using two different ligand classes that were explored. This dissertation includes previously published and co-authored material. / Adviser: Darren W. Johnson

Made available in DSpace on 2014-06-11T19:35:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-10Bitstream added on 2014-06-13T19:24:19Z : No. of bitstreams: 1 000737014.pdf: 3664303 bytes, checksum: c9c3a35109af8254052a9ec5d04efbf0 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo deste estudo foi investigar o efeito de diferentes soluções coloidais de nanopartículas de prata sobre a viabilidade celular de fibroblastos (linhagem L929) e sobre a resposta inflamatória de tecido subcutâneo de ratos. Nanopartículas de prata (SNP) com tamanho médio de 5 nm foram sintetizadas através da redução do nitrato de prata pelo citrato de sódio e estabilizadas com amônia (SNP-A) ou polivinilpirrolidona (SNP-P). Para avaliar a viabilidade celular, células L929 foram expostas SNP e agentes estabilizantes (amônia (NH3) e polivinilpirrolidona (PVP)) (0,1 – 100 μg/mL), e após 6, 24 e 48 h foi realizado o ensaio de citotoxicidade celular pelo método do MTT. A resposta tecidual foi realizada com tubos de polietileno contendo SNP (1.0 μg/mL; 540 μg/mL) e agentes estabilizantes (NH3 0.13 x 10-3 mol/L e PVP 0.19 g/L) implantados no tecido conjuntivo dorsal de ratos Wistar por 7, 15, 30, 60 e 90 dias. Os espécimes foram corados com hematoxilina e eosina e foram realizadas avaliações qualitativa e quantitativa. SNP inibiram a viabilidade celular no teste in vitro de maneira concentração-dependente. SNP-A foram mais tóxicas para L929 que as partículas estabilizadas com PVP. O exame histológico mostrou que SNP 540 μg/mL induziram reação tecidual significantemente mais intensa em 30 e 60 dias comparado aos grupos controles (solução fisiológica 0,9% e fibrina) nos mesmos períodos. As respostas inflamatórias causadas por SNP 1,0 μg/mL, NH3 0,13 x 10- 3 mol/L e PVP 0,19 g/L foram similares aos controles em todos os períodos experimentais. Foi possível concluir que a exposição à SNP reduziu a viabilidade de células L929 de maneira concentração-dependente. O tipo de agente estabilizante interferiu na citotoxicidade sendo SNP-A mais tóxica para L929. Ambos... / The aim of this study was to investigate the effect of different colloidal silver nanoparticles on cell viability of mouse fibroblasts (cell line L929) and on the subcutaneous connective tissue reaction of rats. Silver nanoparticles (SNP) of average size 5 nm were synthesized by the reduction of silver nitrate through sodium citrate and were stabilized with ammonia (SNP-A) or polyvinylpyrrolidone (SNP-P). To evaluate the cell viability, L929 cell were exposure to silver nanoparticles (0.1-100 μg/mL), and after 6, 24 and 48h MTT assay was performed. The tissue reaction was carried out with polyethylene tubes containing silver nanoparticles (1.0 μg/mL; 540 μg/mL) implanted in the dorsal connective tissue of Wistar rats for 7, 15, 30, 60, and 90 days. The specimens were stained with hematoxylin and eosin and qualitative and quantitative evaluations of the reaction were carried out. Silver nanoparticles inhibited the cell viability in the in vitro test in a concentration-dependent manner. SNP-A were more toxic to L929 than particles stabilized with polyvinylpyrrolidone (PVP). Histological examination showed that SNP at 540 μg/mL induced significant tissue reaction on 30 and 60 days after implantation compared to the controls groups (fibrin and saline 0.9%) at the same periods. The inflammatory responses caused by SNP at 1.0 μg/ml, NH3 at 0.13 x 10-3 mol/L and PVP at 0.19 g/L solutions were similar to the controls groups in all experimental periods. It was possible to conclude that SNP exposure decreased the viability of L929 cells in a concentration-dependent manner. The type of stabilizing agent interfered on the cytotoxicity of SNP being SNP-A more toxic to L929. Also, both colloidal silver nanoparticles (SNP-A and SNP-P) at 540 μg/mL induced significant inflammatory response in rat’s subcutaneous tissue.

The syntheses, spectroscopic characterisation, photophysical and photochemical studies have been conducted for a variety of phenylthio substituted phthalocyanines (Pcs). Comparisons have been made taking into consideration the influence of the central metal ion, solvent properties and substituent type. The optical limiting properties were also determined for all the Pcs synthesised. A low-symmetry metallophthalocyanine complex was similarly characterised and the photoelectrochemical parameters determined when used as a sensitiser of nanoporous ZnO. The symmetric analogue was conjugated to gold nanoparticles to determine the influence of interactions on its photophysical properties and distinct differences occurred in the absorption and fluorescence spectra suggesting successful formation of conjugates.

The syntheses, extensive spectroscopic characterization, photophysical and photochemical studies have been conducted for a variation of d10 metallophthaloycanines (MPcs). Comparisons have been made taking into consideration the nfluence of the central metal ion, solvent properties, substituent type and position. Coordination to heavy central metals i.e. Hg gives enhanced triplet state properties. Low symmetry metallophthalocyanine complexes were similarly haracterized and the influence of nteractions with nanoparticles on their photophysical and photochemical properties determined. The MPcs have been linked and adsorbed or mixed with nanoparticles i.e. hemically functionalized single-walled carbon nanotubes SWCNT) and mercaptocarboxylic acid capped CdTe quantum dots (QDs) and changes in the spectra accounted for with respect to the proposed conjugate structures. Distinct differences ccur for linked and adsorbed or mixed conjugates in the bsorption, infrared (IR) and Raman spectra and for thermal ravimetric decay profiles, suggesting successful formation f covalent bonds (linked) and point to structurally ifferent materials. SWCNT quench MPc fluorescence by a photoinduced electron transfer mediated process to give low fluorescence quantum yields. The QDs were used as energy transfer donors and facilitate energy transfer, through Förster resonance energy transfer (FRET) from the QDs to the MPcs. Improved FRET efficiencies were found for linked MPc-QD conjugates relative to the mixed species. Photophysicochemical properties of MPcs were, in general, improved as a result of interactions with nanoparticles.

Syntheses, spectral, photophysical and photochemical studies of some neutral, anionic and cationic metallophthalocyanine derivatives are presented. The effects of central metal ions, solvents, aggregation, surfactant, nanoparticles and bovine serum albumin on the photophysical and photochemical behaviour are investigated. Mercaptocarboxylic acid stabilized CdTe quantum dots (QDs) were used as energy donors to anionic water-soluble MPcs through Förster resonance energy transfer (FRET). Energy transfer (ET) from the QDs to the MPcs occurred upon photoexcitation of the QDs. An enhancement in efficiency of ET with the nature of the cappings on the QDs was observed with few occurrences of a non-Förster type ET. QDs were found to improve the photophysicochemical behaviour of the MPcs, with the possibility of indirect production of singlet oxygen (Φ[subscript Δ]) via FRET mechanism. Interaction of the QDs with cationic water-souble MPcs produced ion-pair complexes resulting in aggregates due to strong electronic coupling. The stoichiometry of the reaction and association constants are evaluated by the continuous variation method. Improved photophysicochemical behaviour with no spectral alterations was observed in MPcs in the presence of magnetic fluid. Complexes showed high triplet quantum yields with corresponding long lifetimes and high photostability. Elucidation of the results of the interaction of bovine serum albumin (BSA) with MPcs or QDs is presented. Increased efficiency of Φ[subscript Δ] generation of MPcs in the presence of BSA coupled with large binding constants, suggesting strong interaction of the MPcs with BSA was observed. Enhanced emission intensity of QDs when linked to or in a mixture with BSA due to radiationless recombination at the surface vacancies was also observed. The study revealed positive deviation from Stern-Volmer relationship suggesting the occurrence of static and dynamic mechanisms of quenching together. Fluorescence quenching of the MPcs by benzoquinone, analysed by Stern-Volmer relationship is also presented; the results were employed in determining fluorescence lifetimes of the complexes. Photoelectrochemical characteristics of MPc-sensitized electrodeposited ZnO thin films were studied; ZnOCPc / ZnO films have been improved to an incident photon-to-currentconversion (IPCE) value of 31.1 % with an absorbed photon-to-current conversion (APCE) of 59.6 %. The best obtained so far with phthalocyanine-type sensitizers on nanocrystalline ZnO films. Fluorescent-magnetic nanocomposite with excellent photophysical properties which can be exploited for combined photodynamic and hyperthermia therapies is also presented.