This thesis introduces functional nanomaterials including superatoms and carbon nanotubes (CNTs) for new layered solids and molecular devices. Chapters 1-3 present how we incorporate superatoms into two-dimensional (2D) materials. Chapter 1 describes a new and simple approach to dope transition metal dichalcogenides (TMDCs) using the superatom Co6Se8(PEt3)6 as the electron dopant. Doping is an effective method to modulate the electrical properties of materials, and we demonstrate an electron-rich cluster can be used as a tunable and controllable surface dopant for semiconducting TMDCs via charge transfer. As a demonstration of the concept, we make a p-n junction by patterning on specific areas of TMDC films. Chapter 2 and Chapter 3 introduce new 2D materials by molecular design of superatoms. Traditional atomic van der Waals materials such as graphene, hexagonal boron-nitride, and TMDCs have received widespread attention due to the wealth of unusual physical and chemical behaviors that arise when charges, spins, and vibrations are confined to a plane. Though not as widespread as their atomic counterparts, molecule-based layered solids offer significant benefits; their structural flexibility will enable the development of materials with tunable properties. Chapter 2 describes a layered van der Waals solid self-assembled from a structure-directing building block and C60 fullerene. The resulting crystalline solid contains a corrugated monolayer of neutral fullerenes and can be mechanically exfoliated. Chapter 3 describes a new method to functionalize electroactive superatoms with groups that can direct their assembly into covalent and non-covalent multi-dimensional frameworks. We synthesized Co6Se8[PEt2(4-C6H4COOH)]6 and found that it forms two types of crystalline assemblies with Zn(NO3)2, one is a three-dimensional solid and the other consists of stacked layers of two-dimensional sheets. The dimensionality is controlled by subtle changes in reaction conditions. CNT-based field-effect transistor (FETs), in which a single molecule spans an oxidatively cut gap in the CNT, provide a versatile, ground-state platform with well-defined electrical contacts. For statistical studies of a variety of small molecule bridges, Chapter 4 presents a novel fabrication method to produce hundreds of FETs on one single carbon nanotube. A large number of devices allows us to study the stability and uniformity of CNT FET properties. Moreover, the new platform also enables a quantitative analysis of molecular devices. In particular, we used CNT FETs for studying DNA-mediated charge transport. DNA conductance was measured by connecting DNA molecules of varying lengths to lithographically cut CNT FETs.

Ho Chun Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Abstracts in English and Chinese. / ABSTRACT --- p.iv / DECLARATION --- p.vi / ACKNOWLEDGEMENT --- p.vii / TABLE OF CONTENTS --- p.viii / LIST OF TABLES --- p.xi / LIST OF FIGURES --- p.xii / Chapter Chapter One: --- Introduction --- p.1 / Chapter 1.1 --- Overview --- p.1 / Chapter 1.2 --- Fundamental of CeO2 --- p.2 / Chapter 1.3.1 --- Synthesis and Modification of Ceria-based Materials --- p.5 / Chapter 1.3.1 --- Synthetic Method --- p.5 / Chapter 1.3.2 --- "Mesoporous Structure of Ce02, CexZr1-x02" --- p.6 / Chapter 1.3.3 --- Doped Ce02 Materials --- p.6 / Chapter 1.3.4 --- Fabrication of Ceria and Cerium-based Nanoparticles --- p.7 / Chapter 1.4 --- Scope of work --- p.8 / Chapter 1.5 --- References --- p.11 / Chapter Chapter Two: --- Meso- and Macro-porous Pd/CexZr1-x02 as Carbon Monoxide Oxidation Catalysts --- p.16 / Chapter 2.1 --- Introduction --- p.16 / Chapter 2.2 --- Experimental Section --- p.18 / Chapter 2.2.1 --- Sample Preparation - Synthesis of the Catalyst Support --- p.18 / Chapter 2.2.2 --- Addition of Pd to the Catalyst Support --- p.19 / Chapter 2.2.3 --- Characterization --- p.20 / Chapter 2.2.4 --- Carbon monoxide oxidation measurement --- p.21 / Chapter 2.3 --- Results and Discussion --- p.22 / Chapter 2.3.1 --- XRD analysis --- p.22 / Chapter 2.3.2 --- SEM and TEM --- p.25 / Chapter 2.3.3 --- N2-Soprtion --- p.32 / Chapter 2.3.4 --- X-ray Photoelectron Spectroscopy --- p.40 / Chapter 2.3.5 --- Thermal Catalysis Study --- p.45 / Chapter 2.4 --- Conclusion --- p.52 / Chapter 2.5 --- References --- p.54 / Chapter Chapter Three: --- Morphology-Controllable Synthesis of Ce02 Nano and Meso-structures --- p.60 / Chapter 3.1 --- Introduction --- p.60 / Chapter 3.2 --- Experimental Section --- p.62 / Chapter 3.2.1 --- Materials and Experimental Conditions --- p.62 / Chapter 3.2.2 --- Characterization --- p.64 / Chapter 3.3 --- Results and Discussion --- p.67 / Chapter 3.3.1 --- SEM and TEM Analysis --- p.67 / Chapter 3.3.2 --- XRD Analysis --- p.75 / Chapter 3.3.3 --- N2-Soprtion --- p.78 / Chapter 3.3.4 --- X-ray Photoelectron Spectroscopy --- p.84 / Chapter 3.3.5 --- FT-IR Analysis --- p.87 / Chapter 3.3.6 --- GC-MS Analysis --- p.89 / Chapter 3.3.7 --- Proposed Formation of Ce02 nanospheres and their transformation to microrods --- p.95 / Chapter 3.3.8 --- UV absorption spectra and band gap energies --- p.97 / Chapter 3.3.9 --- Thermal Catalysis Study --- p.100 / Chapter 3.4 --- Conclusion --- p.103 / Chapter 3.5 --- References --- p.105 / Chapter Chapter Four: --- Conclusion --- p.110 / LIST OF PUBLICATIONS --- p.112

Zhang Lizhi. / "July 2003." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

As another important features in VEELS, the plasmon excitations (including the volume plasmon and surface/interfacial plasmon) are also utilized to identify different phases and multi compositions within materials. The microstructure and electronic structure evolution of silicon-rich oxide (SRO) films as a function of the annealing temperature are investigated using TEM and VEELS. The as-deposited SiO film is found to be a single phase with only single volume plasmon presents in VEEL spectrum and almost no interfacial plasmon is observed. After the annealing (Tanneal>400°C), it begins to decomposite into Si and SiO2 and the single phase changed into cluster/matrix nanocomposites where the interfacial plasmon appears. The Si duster size and its concentration increase as the annealing temperature increases. / Firstly, the applications of VEELS in investigating the electronic structures of ZnO nanowires with different diameter and surface shapes are demonstrated. Using the momentum transferred technique, one of the interband transitions with dipole-forbidden nature is identified. Several size dependent features are found on the interband transitions and plasmon oscillations of ZnO nanowires with small diameter and circular cross section, which are mainly due to the large surface to volume ratio and existence of Oxygen dangling bonds on those ZnO wires. / Further explorations on the electronic structure in the vicinity of band gap are carried out for the ZnO nanowires doped with different dopants (Co, Er, Yb) and different dopant concentrations. In order to obtain trustworthy information in the very low energy range of VEELS a narrow zero loss peak and elimination of Cerenkov effect and surface losses are necessary, which can be realized by incorporation of the gun monochromator in the TEM and taking spectrum at a momentum transfer slightly greater than zero. Band tail states (∼2-3.3 eV) are found to be generated in the ZnO nanowires after the ion implantation and their density of states increase with the ion fluence increases. The partially removal of those defect states by the Oxygen annealing is also observed in VEELS. On the other hand, interesting mid-gap state(s), which is dopant-sensitive (as it is only observed in the rare earth (Er and Yb) doped ZnO nanowires, but not in the Co-doped ones), does not show obvious change after the O annealing. The impact of these electronic structure changes on the material properties are also discussed. / In the end of the thesis, some of the practical limitations and contradictories on the energy resolution (DeltaE), spatial resolution (Delta x), and the momentum resolution (Deltaq) when carrying out the various VEELS study are summarized. The compromise made among these resolution limits is also discussed. / In this work, the important experimental parameters and appropriate data processing methods to generate trustworthy data are discussed. Based on that, three material systems, i.e., pure ZnO nanowires, doped ZnO nanowires, and Si/SiO/SiO2 composite films are investigated. Various information on the material microstructure/electronic structure is interpreted using the VEELS data. / The valence-electron energy-loss spectroscopy (VEELS) contains information on the electronic structures of materials, including the band gap the single-electron interband transitions and the plasmon oscillations. When operating in transmission electron microscope (TEM), the excellent spatial resolution enables the VEELS not only exploring the local electronic structures of individual low dimensional nanostructured materials, but also building up correlations between the electronic structure and microstructure. In addition, the capability in carrying out the momentum transfer dependent study in VEELS allows the investigation on the dispersion of plasmons and single electron excitations in the momentum space. The optically forbidden transitions, which are not allowed in conventional optical method, can also be excited at high momentum transfer values using VEELS. / Wang, Juan = 價電子能量損失譜在低維納米材料中的應用 / 王娟. / "September 2007." / Adviser: Li Quan. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1267. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 122-133). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307. / Wang, Juan = Jia dian zi neng liang sun shi pu zai di wei na mi cai liao zhong de ying yong / Wang Juan.

"Apr 2002." / The numerals in title is subscript. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Este estudo investigou a síntese de espinélio MgAl204 (MA) por combustão em solução (SCS), a caracterização microestrutural dos pós obtidos, a sua sinterização e a sua ação inibidora da combustão de carbono. Como precursores, foram empregados o nitrato de alumínio, nitrato de magnésio e sacarose em água. A fase cristalina somente foi obtida após um tratamento térmico a 900°C do pó como-sintetizado. Os pós obtidos foram caracterizados por análise termodiferencial (ATD) e termogravimétrica (ATG), granulometria por dispersão a laser (GDL), BET para análise de área superficial, análise cristalográfica por difração de Raios X (DRX) e por espectroscopia Raman e FTIR, e a morfologia por microscopia eletrônica de varredura (MEV) e microscopia eletrônica de transmissão (MET). Os pós de MA apresentaram-se como constituídos de cristalitos nanométricos, com tamanho médio de 21,69nm (calculado via software WinFit) e 35,32nm (estimado por MET). Por análise granulométrica, constatou-se um tamanho de aglomerado médio de 8,21μm, em uma distribuição tetramodal, com uma larga distribuição de tamanho. A área superficial dos pós MA, tratados termicamente a 900°C, alcançou 17,47m²/g. Por MEV, constatou-se que esses aglomerados apresentam uma morfologia irregular, além de vazios (poros internos). Os pós de MA assim obtidos foram prensados uniaxialmente e queimados em diferentes temperaturas (1350-1650°C). Os corpos sinterizados foram caracterizados quanto às propriedades físicas (densidade aparente, absorção de água, porosidade aparente e retração linear), mecânicas (resistência à flexão 4 pontos) e quanto à microestrutura (por MEV). A maior densidade aparente obtida foi de 2,607g/cm3, para uma temperatura de 1650°C, representando uma densificação de 51%, para uma retração linear de 10,06%. A máxima resistência à flexão foi de 51,33MPa e o maior módulo de elasticidade 26,13GPa. A avaliação da ação inibidora dos pós de MA foi realizada pela sua incorporação a diferentes teores em flocos de grafite e posterior aquecimento em termobalança. Constatou-se que os pós de MA apresentaram potencial para o uso como aditivos antioxidantes de materiais à base de carbono em altas temperaturas, pois levaram à diminuição da perda de massa do grafite durante o seu aquecimento e a um aumento da temperatura onset. / This study investigated the synthesis of MgAl204 spinel (MA) by combustion in solution, microstructural characterization of the powders, the sintering process and the inhibiting action of carbon combustion. As precursors were used aluminum nitrate, magnesium nitrate and sucrose in water. The crystalline phase was obtained only after a heat treatment at 900 ° C of the as-synthesized powder. The powders were characterized by differential thermal analysis (DTA) and thermogravimetric (TGA), laser scattering for particle size, BET for analysis of surface area, crystallographic analysis by X-ray diffraction (XRD) and by Raman and FTIR spectroscopy, and morphology by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The powders were presented as consisting of nanosized crystallites with an average crystallite size of 21,69nm (calculated via Winfit software) and 35,32nm (estimated by TEM). The sieve analysis had an average agglomerate size of 8,21μm, in a tetramodal distribution with a wide size distribution. The surface area of the powders calcined at 900°C reached 17,47m²/g. By SEM, it was verified that these clusters have an irregular morphology, and voids (internal pore). The MA powders thus obtained were uniaxially pressed and fired at different temperatures (1350-1650). The powders sintered were characterized by physical properties (bulk density, water absorption, apparent porosity and linear shrinkage), mechanical (flexural strength 4 points) and the microstructure (SEM). The higher bulk density obtained was 2,607g/cm3, to a temperature of 1650 ° C, representing a densification of 51%, for a linear shrinkage of 10.06%. These ceramic samples also had the highest flexural strength (of 51,33MPa) and higher elastic modulus (26,13GPa). The evaluation of the inhibitory action of MA was held by its incorporation into different levels of graphite flakes and subsequent heating in thermobalance. It was noted that the MA powders showed potential use as antioxidant additives of carbon based materials in high temperatures that led to decreased mass loss of graphite flakes during their heating and an increase in the onset temperature.

L’une des solutions proposées pour la diminution du coût par watt d'électricité produite par le photovoltaïque est de réduire la quantité des matériaux semiconducteurs entrants dans la fabrication de la cellule solaire. La 3ème génération des cellules solaires en couches minces nanostructurées vient pour répondre à cette exigence. Les matériaux CIGS sous leurs structures chalcopyrites, sont de nouveaux matériaux semiconducteurs fortement recommandés pour la fabrication des cellules solaires à base de couches minces. La synthèse par la méthode de pulvérisation cathodique et la caractérisation de ces derniers matériaux ont été l’objectif général de cette thèse. Toutes les couches ont été déposées grâce à une seule cible constituée par des grains nanométriques de CIGS, ces derniers ont été obtenus par la voie solvothermale. Dans la première partie de ce travail, nous avons étudié l’effet des différents paramètres de synthèse (température, durée de synthèse, le traitement thermique et l’effet du taux molaire de gallium et d’indium) sur les propriétés des nanoparticules CIGS, les mécanismes réactionnels mis en jeu ont été aussi étudié. Les conditions de synthèse optimales sont une température et une durée de synthèse égale à 220 °C et 24 heures. Après un traitement thermique, les nanoparticules de CIGS sont cristallisées suivant la structure chalcopyrite, avec l’absence des pics correspond aux phases secondaires, les diamètres des grains varie entre 15 et 30 nm. Dans la deuxième partie, Nous sommes intéressés à l’élaboration et la caractérisation des couches absorbantes ternaire et quaternaire de type CIS et CIGS (x = 0 et x = 0.3) obtenues par pulvérisation cathodique en variant la puissance de dépôt de 60 à 100 W. Toutes les couches élaborées présentent la phase chalcopyrite avec (112) comme axe d’orientation préférentiel de croissance. La taille moyenne des grains a le même ordre de grandeur que les poudres initiales. Les couches de CIGS sont généralement de type de conduction p avec des faibles valeurs de résistivités. Les caractérisations optiques des couches présentent une bonne absorption de l’ordre de 95 % dans la gamme de visible et le proche infra-rouge. La variation du coefficient d’absorption en fonction de l’énergie du photon, nous a permis de déterminer l’énergie du gap optique. Les valeurs obtenues pour les différentes couches sont cohérentes avec l’optimum pour la conversion photovoltaïque. / One of the proposed solutions for reducing the cost of electricity produced by the photovoltaic is to reduce the amount of incoming semiconductor materials in the manufacture of the solar cell. The 3rd generation solar cells based on nanostructured thin film come in response to this requirement. CIGS under their structures chalcopyrite are highly recommended for the manufacture of this solar cells type. The synthesis of these materials using sputtering method and their characterization were the overall goal of this thesis. All films were deposited onto glass substrates from single target composed trough nanoparticles of CIGS, which are obtained by the solvothermal route. In the first part of this work, we studied the effect of different synthesis parameters (temperature, synthesis time, the heat treatment and the effect of the molar ratio of gallium and indium) on the properties of CIGS nanoparticles. The reaction mechanisms were also studied. The optimum synthesis conditions are a temperature and a synthesis time equal to 220 ° C and 24 hours. After heat treatment, the nanoparticles are crystallized according CIGS chalcopyrite structure, with the absence of the peaks corresponding to the secondary phases, grain size between 15 and 30 nm. In the second part, we are interested in the deposition and characterization of ternary and quaternary absorbent thin film CIS and CIGS (x = 0 and x = 0.3) obtained by sputtering deposition by varying the power of pulverization from 60 to 100 W. All layers have crystallized in the chalcopyrite structure with the preferential orientation in the (112) plane were obtained. The average grain size has the same order of magnitude as the initial powders. All films are generally p-type conduction with low resistivity values. Optical characterizations of the layers exhibit a good absorption in the visible range and the near infrared. The variation of the absorption coefficient as a function of photon energy enabled us to determine the energy of the optical gap. The values obtained for the different layers are consistent with the optimum for the photovoltaic conversion.

Submitted by Liliane Ferreira (ljuvencia30@gmail.com) on 2018-02-28T14:49:21Z No. of bitstreams: 2 Dissertação - Kamilla Amaral David Rocha - 2015.pdf: 3193387 bytes, checksum: 6cc146ed197535b6a21627e8ffa4891c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-02-28T16:16:32Z (GMT) No. of bitstreams: 2 Dissertação - Kamilla Amaral David Rocha - 2015.pdf: 3193387 bytes, checksum: 6cc146ed197535b6a21627e8ffa4891c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-28T16:16:32Z (GMT). No. of bitstreams: 2 Dissertação - Kamilla Amaral David Rocha - 2015.pdf: 3193387 bytes, checksum: 6cc146ed197535b6a21627e8ffa4891c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-08-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The voriconazole (VOR) is an antifungal from the thiazole class, which has a proven action against dermatophytes, main cause of onychomycosis. Topical treatment of pathologies located in the nail is highly desirable, since oral administration of antifungal agents have been shown ineffective. Thus, the goal is the work was the development of nanostructured lipid carriers (NLC) for nail topical administration of the VOR. To quantify VOR in the nail plate, an analytical method was developed and validated by high-performance liquid chromatography (HPLC) with detection in the UV-vis. CLNs were obtained with glyceryl behenate, Miglyol®, polysorbate 80, sorbitan trioleate surfactant, and a cationic cetilpiridíneo chloride (CPC) and different drug loading. Nanoparticles were characterized for medium size, PdI, zeta potential, encapsulation efficiency and recovery, morphology by scanning electron microscopy (SEM), and the stability. Hydration factor of the formulations and permeation enhancers was performed. Analysis of dry and hydrated hooves treated with NLC were achieved by SEM. Release and in vitro permeation studies were performed with unloaded drug (VOR-free) and VOR loaded NLC. The drug quantification method was linear in the concentration range from 0.4 to 40 mg / mL. The limit of quantitation was 400 ng/mL. Furthermore, the method was able to analyze the VOR without suffering interference from components of the nail and NLC. The NLC (n = 3) loaded with drug showed positive surface charge (around +25 mV) and average size of 230 nm. The NLC obtained had 1.75% of drug load, with encapsulation efficiency of 74.52 (+ 2.13)%. Hydration factor studies showed that the formulation with the highest amount of Miglyol was able to hydrate the nail more as well as the urea, which was the best promotor enhancer for nail hydration. NLC developed with and without addition of promoters were stable for a period of 150 days. In vitro release studies showed that the release VOR from the NLC occurs in a controlled manner from the lipid matrix. There was no significant difference in drug penetration when applied CLNs with and without promoter, for the VOR-Free. Although amounts of drug were found more deeply with the use of the CLN in the sample depletion assays, which can facilitate treatment of nail affected by onychomycosis. / O voriconazol (VOR) é um antifúngico da classe tiazol, que possui ação comprovada contra os dermatófitos, principais causadores da onicomicose. O tratamento tópico localizado de patologias na unha é altamente desejado, visto que a administração oral de antifúngicos têm se demonstrado ineficiente. Desta forma, o objetivo deste trabalho consiste no desenvolvimento de carreadores lipídicos nanoestruturados (CLN) para administração tópica do VOR na unha. Para a quantificação do VOR na placa ungueal foi desenvolvido e validado um método analítico por cromatografia líquida de alta eficiência (CLAE) com detecção no UV-vis. Os CLN foram obtidos com behenato de glicerila, Miglyol®, polissorbato 80, trioleato de sorbitano e tensoativo catiônico cloreto de cetilpiridnío (CPC), com diferentes cargas do fármaco. As nanopartículas foram caracterizadas quanto ao tamanho, PdI, potencial zeta, eficiência de encapsulação e recuperação, morfologia por microscopia eletrônica de varredura (MEV), e a estabilidade das mesmas. Avaliação do fator de hidratação das formulações e de promotores de permeação foi realizada. Análises dos cascos secos e hidratados com os CLN foram feitas por MEV. Estudos de liberação e permeação passiva in vitro do VOR livre e encapsulado em CLN foram realizados. O método de quantificação do fármaco mostrou-se linear na faixa de concentração de 0,4 a 40 μg/mL. O limite de quantificação foi de 400 ng/mL. Ainda, o método foi capaz de analisar o VOR sem sofrer interferência dos componentes da unha e dos CLN. Os CLN (n=3) carregados com fármaco apresentaram carga superficial positiva (em torno de +25 mV) e tamanho médio de 230 nm. Obtiveram-se carreadores com 1,75% de carga de fármaco e com eficiência de encapsulação de 74,52 (+ 2,13) %. A avaliação do fator de hidratação mostrou que a formulação com maior quantidade de Miglyol® foi capaz de hidratar mais a unha, assim como o promotor que apresentou melhor resultado foi a uréia (10%). Os CLN desenvolvidos com e sem adição de promotores se mostraram estáveis por um período de 150 dias. Os estudos de liberação in vitro demonstraram que a liberação do VOR a partir dos CLN ocorre de forma controlada a partir da matriz lipídica. Não houve diferença significativa na penetração do fármaco quando aplicado os CLN com e sem promotor, em relação ao VOR-Livre. Embora, quantidades de fármacos foram encontradas mais profundamente com uso dos CLN em ensaios de esgotamento da amostra, o que pode favorecer o tratamento de unhas acometidas pela onicomicose.

Superfícies híbridas nanoestruturadas Pt/Au com os depósitos de Au de 20, 50 e 100 nm de espessura foram obtidas pelo processo fotolitográfico. O molde utilizado foi um arranjo de microeletrodos interdigitados. As superfícies híbridas nanoestruturadas Pt/Au contendo 20, 50 e 100 nm de Au desenvolvidas foram caracterizadas por microscopia ótica, microscopia eletrônica de varredura, microscopia de força atômica, voltametria cíclica e espectroscopia de impedância eletroquímica. Então, aplicadas como sensores para detecção eletroquímica dos biomarcadores ácido ascórbico, ácido úrico, dopamina, hidroquinona e nitrito. Numa segunda etapa, as nanoestruturas de ouro foram recobertas com monocamada auto-organizada (self-assembled monolayers - SAM) de alcanotiol (cistamina, ácido mercaptoacético e 11-mercaptoundecanóico) visando a preparação da superfície para imobilização de biomoléculas, incluindo enzimas e anticorpos. A superfície híbrida bimetálica bifuncional nanoestruturada Pt/Au-SAM foi obtida realizando-se varreduras cíclicas em solução contendo 0,1 mol L-1 de H2SO4 em intervalos de varreduras de potenciais específicos para cada SAM, através deste procedimento foi possível remover a SAM somente da superfície da platina e mantendo sobre as nanoestruturas de ouro. A enzima glicose oxidase (Aspergillus niger) foi imobilizada por ligação covalente com auxílio de EDC/NHS e o ferroceno foi utilizado como mediador de elétrons. A caracterização eletroquímica foi feita em solução aquosa contendo 0,1 mol L-1 de ácido sulfúrico supra puro e em solução contendo 5,0 mmol da sonda redox ferrocianeto e ferricianeto de potássio utilizando-se a técnica de voltametria cíclica e espectroscopia de impedância eletroquímica. O peróxido de hidrogênio formado como produto da reação da catálise enzimática foi determinado sobre a superfície da platina em solução contendo 0,1 mol L-1 de PBS. A constante cinética aparente de Michaelis-Menten (KMapp) e a constante catalítica kcat foram calculadas e comparadas com outros transdutores relatados na literatura. A terceira aplicação foi a utilização desta superfície híbrida como um imunossensor eletroquímico para detecção de cortisol salivar. O anticorpo Anti-cortisol foi imobilizado com auxílio de EDC/NHS a SAM. Esse dispositivo foi imerso em soluções contendo 3.1 x 10-15 - 1.5 x 10-3 mol L-1 de cortisol. A relação sinal-concentração foi obtida através da técnica de espectroscopia de impedância eletroquímica observando-se a variação de transferência de carga com relação à variação de concentração de cortisol adsorvido ao dispositivo Pt/Au/SAM/Anticorpo-cortisol. Os limites de detcção obtidos foram 0,08, 207, 0,3, 11,1, 11,3, 0,2 × 10-6 e 9,3 × 10-13mol L-1 para glicose, ácido ascórbico, dopamina, hidroquinona, nitrito e ácido úrico, respectivamente. / Nanostructured hybrid surfaces Pt/Au containing 20, 50 and 100 nm of Au was obtained by the photolithographic process. The template used was an interdigitated microelectrodes array. The nanostructured hybrid surfaces Pt/Au containing 20, 50 and 100 nm of Au was characterized by optical microscopy, scanning electron microscopy, atomic force microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Then, applied as sensors for electrochemical detection of biomarkers ascorbic acid, uric acid, dopamine, hydroquinone and nitrite. In a second step, the gold nanostructures were coated with self-assembled monolayer (self-assembled monolayers - SAM) of alkanethiol (cystamine, mercaptoacetic acid and 11-mercaptoundecanoic acid) aiming at preparing the surface for biomolecule immobilization, including enzymes and antibodies. The bifunctional nanostructured hybrid surface Pt/Au-SAM was obtained by performing cyclic scans solution containing 0.1 mol L-1 H2SO4 at specific potential scans intervals for each SAM through this procedure was only possible to remove the SAM the platinum surface and holding on the gold nanostructures. The enzyme glucose oxidase (Aspergillus niger) was immobilized with EDC/NHS and ferrocene was used as an electron mediator. The electrochemical characterization was performed in an aqueous solution containing 0.1 mol L-1 of sulfuric acid and in a solution containing 5.0 mmol of potassium ferrocyanide and ferricyanide redox probe using cyclic voltammetry technique and electrochemical impedance spectroscopy. The hydrogen peroxide formed as a product of the enzyme-catalyzed reaction was measured on the surface of platinum solution containing 0.1 mol L-1 PBS. The apparent Michaelis-Menten kinetic constant (KMapp) and the catalytic constant kcat were calculated and compared with other transducers reported in the literature. The third application was the use of this hybrid surface and an electrochemical immunosensor for detecting salivary cortisol. Anti-cortisol antibody was immobilized at the SAM (mercaptocaetic acid) with EDC/NHS. This device was dipped in solutions containing 3.1 x 10-15 - 1.5 x 10-3 mol L-1 of cortisol. The signal-concentration relationship was obtained by electrochemical impedance spectroscopy technique of observing the variation in load transfer with respect to variation of cortisol concentration device adsorbed to Pt/Au/SAM/antibody-cortisol. The detection limit obtained were 0.08, 207, 0.3, 11.1, 11.3, 0.2 × 10-6 mol L-1 for glucose, ascorbic acid, dopamine, hydroquinone, nitrite, uric acid, respectively. Keywords: Nanostructured hybrid surface, sensors, biosensors, imunosensors, biomarkers, uric acid, ascorbic acid, dopamine, hydroquinone, glucose, cortisol.

Leishmaniases is a group of diseases caused by parasites of the genus Leishmania. The estimated number of deaths from visceral leishmaniases ranges from 20,000 to 50,000 annually. The most common treatment over the past 60 years has been pentavalent antimonials. Besides the doubtful effectiveness, they present several disadvantages such as the need for parenteral administration, large doses, long treatment, severe toxicity and parasite resistance. Buparvaquone (BPQ), a drug used for veterinary treatment of theileriosis, showed promising activity against Leishmania spp. However, due to its low aqueous solubility and bioavailability, it has failed in in vivo tests. The use of nanotechnologies has the potential to overcome these drawbacks due to the following advantages: increase in drug water-solubility, increase in therapeutic efficacy and treatment toxicity reduction. Therefore, the present work aimed the development, optimization, physical-chemical evaluation and in vitro performances of nanostructured lipid carriers (NLC) for BPQ encapsulation. The NLC preparation was performed by high pressure homogenization, and surface response and factorial design were applied to formulation optimization. In vitro dissolution profiles were evaluated in phosphate buffer pH 7.4 with tween 80 0.07% w/v or sodium dodecyl sulfate 1% w/v and simulated body fluid pH 7.4. Cytotoxicity was evaluated in mouse peritoneal macrophages and leishmanicidal activity in L. infantum amastigotes. Six optimized NCL were prepared and they showed solubility improvement from 1.5- fold to 611-fold when compared with free BPQ, depending on the formulation and medium. Dissolution profiles showed the NLC formulation suitability for BPQ regarding oral administration, the release could reach 83.29% of a 4mg dose in 30 minutes for formulation of 175.1 nm, while the free drug could be dissolved only 2.89% of the same dose after 4 hours. Moreover, formulation of 230.7 nm showed 81.42% of drug release in in phosphate buffer pH 7.4 with dodecyl sulfate 1.0% w/v after 30 minutes, while BPQ did not dissolved. Cytotoxicity assay showed the safety of all formulations. The iv CC50 values were close to 500 µM, while the IC50 against amastigotes was only 456.5 nM for free BPQ. Developed NLCs showed an increase in IC50 from 2.0 to 3.1-fold when compared to free drug in the in vitro leishmanicidal evaluation. Therefore, the NLC containing BPQ are a promising alternative for the treatment of leishmaniases as oral and parenteral drug dosage forms. Additionally, they have a potential use for lymphatic targeted drug delivery, which can be an innovative approach for this neglected disease. / Leishmanioses são um grupo de doenças causadas por parasitas do gênero Leishmania. O número estimado de óbitos por leishmaniose visceral varia entre 20.000 e 50.000 por ano. O tratamento mais comum nos últimos 60 anos tem sido os antimônios pentavalentes. Além da eficácia duvidosa, eles apresentam várias desvantagens, como a necessidade de administração parenteral, altas doses, tratamento prolongado, toxicidade severa e resistência parasitária. Buparvaquona (BPQ), um fármaco usado para tratamento veterinário da teileriose, mostrou atividade promissora contra Leishmania donovani. No entanto, devido à sua baixa solubilidade e biodisponibilidade aquosa, falhou em testes in vivo. O uso das nanotecnologias tem o potencial de superar esses obstáculos devido às seguintes vantagens: aumento da solubilidade em água, aumento da eficácia terapêutica e redução da toxicidade do tratamento. Portanto, o presente trabalho objetivou o desenvolvimento, otimização, avaliação físico-química e avaliação do desempenho in vitro de carreadores lipídicos nanoestruturados (NLC) para o encapsulação da BPQ. A preparação do NLC foi realizada por homogeneização de alta pressão e superfície de resposta e planejamento fatorial foram aplicados à otimização das formulações. Os perfis de dissolução in vitro foram avaliados em tampão fosfato pH 7.4 com tween 80 a 0.07% p/v ou dodecilsulfato de sódio 1.0% p/v e fluido corporal simulado pH 7.4. A citotoxicidade foi avaliada em macrófagos peritoneais de camundongos e atividade leishmanicida em amastigotas de L. infantum. Foram preparados quatro NCL otimizados e mostraram melhora da solubilidade de 1,5 a 611 vezes quando comparado com a BPQ livre, dependendo da formulação e do meio. Os perfis de dissolução mostraram a adequação da formulação NLC para BPQ em relação à administração oral. A dissolução pode atingir 83,29% de uma dose de 4.0 mg em 30 minutos para a formulação de 175,1 nm, enquanto o fármaco livre dissolveu apenas vi 2,89% da mesma dose após 4 horas. Além disso, a formulação de 230,7 nm mostrou 81,42% de liberação do fármaco em tampão fosfato pH 7.4 com dodecil sulfato de sódio 1.0% p/v após 30 minutos, enquanto o BPQ não se dissolveu. O teste de citotoxicidade mostrou a segurança de todas as formulações. Os valores CC50 foram próximos de 500 µM, enquanto o IC50 em amastigotas foi de apenas 456,5 nM para BPQ livre. Os NLC desenvolvidos mostraram um aumento no IC50 de 2,0 a 3,1 vezes quando comparado ao;fármaco livre na avaliação leishmanicida in vitro. Logo, as NLC contendo BPQ são uma alternativa promissora para o tratamento de leishmanioses como formas farmacêuticas oral e parenteral. Além disso, eles têm um uso potencial para a sítio-específico ao sistema linfático, o que pode ser uma abordagem inovadora para esta doença negligenciada.