Les métamatériaux sont des matériaux artificiels, formés par l’assemblage de nano-résonateurs, qui ont la capacité d’interagir avec les ondes qui les traversent et de conférer des propriétés inaccessibles aux matériaux homogènes. Afin de fabriquer de tels métamatériaux agissant dans le domaine du visible, un contrôle précis de l’organisation des résonateurs à l’échelle nanométrique est requis. Dans ce projet nous avons donc élaboré des voies de fabrication de type bottom-up, en organisant de façon anisotrope des nanoparticules d’or (AuNPs), qui sont des résonateurs du fait de leurs propriétés plasmoniques, dans un film de copolymères à blocs poly(styrène)-b-poly(vinylpyridine) (PS-b-PVP) nano-structuré en rangées de cylindres de PVP perpendiculaires au substrat.Au cours de ce projet, nous avons élaboré des routes de formulation permettant de produire des films de phase cylindrique hexagonale de copolymères alignés contenant des nanoparticules d’or. L’orientation des cylindres perpendiculaires au substrat a été obtenue en déposant le copolymère grâce à un solvant neutre dont la composition dépend de la fraction volumique en PVP du copolymère. La structure des films avec et sans nanoparticules a été caractérisée par microscopie et diffusion des rayons X en incidence rasante (GISAXS). Plusieurs méthodes d’incorporation des nanoparticules d’or ont été étudiées, soit en synthétisant les nanoparticules au sein du copolymère, en solution avant dépôt ou directement dans le film organisé ; soit en incorporant des nanoparticules pré-formées, en solution de copolymère ou dans le film déposé. Dans le cas de la synthèse in situ, nous avons formé les AuNPs par réduction chimique ou physique (sonication, radiolyse) d’un sel d’or dans le copolymère. L’incorporation des AuNPs pré-formées, elle, a été réalisée grâce à la fonctionnalisation des AuNPs ou par un traitement du film de copolymère afin de faciliter l’insertion des AuNPs. / Metamaterials are artificial materials, made from the assembly of nano-resonators, which can interact with incoming waves and get properties unknown for homogeneous materials. In order to fabricate metamaterials with an effect over visible light, a precise control over the organization at the nanoscale is required. The goal of this project was then the use of bottom-up approaches to achieve the anisotropic organization of gold nanoparticles (AuNPs), which are resonators due to their plasmonic properties, into a poly(styrene)-b-poly(vinylpyridine) block copolymer film, with a nanostructuration in arrays of PVP cylindrical domains perpendicular to the substrate.During this work, we investigated routes for the fabrication of copolymer films containing ordered gold nanoparticles in a hexagonal cylindrical phase. The orientation of the cylinders normal to the substrate was obtained by casting the copolymer with a neutral solvent whose composition was found dependent on the volumic fraction of PVP in the copolymer. The film structure with and without AuNPs was characterized by microscopy and Grazing-Incidence Small-Angle X-rays Scattering (GISAXS). Several incorporation methods for the insertion of AuNPs were studied, either by the in situ synthesis of the nanoparticles in solution before casting or directly into the ordered film; or by incorporating pre-formed AuNPs in the copolymer solution or in the film as-cast. In the case of the in situ synthesis, the AuNPs were formed by chemical or physical (sonication, radiolysis) reduction of a gold salt in the copolymer. The incorporation of pre-formed AuNPs was, achieved thanks to the functionalization of the AuNPs or by a treatment of the copolymer film in order to facilitate the insertion of the AuNPs.

Aplicações de nanomateriais em biossensores têm recebido muito interesse nos últimos anos. Entre os vários tipos de biossensores estudados, sensores de glicose têm recebido destaque devido a sua importância em diagnósticos clínicos. Apesar do grande avanço no monitoramento de glicose nas últimas décadas, ainda há muitos desafios para alcançar um monitoramento de glicemia continuo, clinicamente preciso, em conexão a um sistema fechado otimizado para a entrega de insulina no corpo. Esta dissertação descreve a fabricação de filmes layer-by-layer (LbL) obtidos a partir da enzima glicose oxidase (GOx) e dos polieletrólitos poli(amidoamina) de geração 4 (PG4) e o hibrido PG4 com as nanopartículas de ouro (PG4AuNp). As nanopartículas de ouro foram sintetizadas em meio aquoso usando o dendrímero PG4, o ácido cloroáurico (HAuCl₄4) e ácido fórmico. As medidas de espectroscopia UV-Vis dos filmes automontados em substratos de quartzo mostraram um crescimento linear em função do número de bicamadas depositados apenas para o filme PG4-GOx. No filme PG4AuNp-GOx o crescimento não é linear. Em adição às caracterizações ópticas, estrutural e eletroquímica, os filmes LbL, depositados sobre substratos de vidro recoberto com óxido de índio (ITO) foram testados para a atuação em biossensores de peróxido de hidrogênio e de glicose. A biofuncionalidade da GOx e a viabilidade do método como biossensor foi demonstrada pelo aumento da corrente em função das sucessivas adições de alíquotas de glicose à solução. Os filmes sem nanopartículas não foram sensíveis a glicose. O biossensor com melhor desempenho foi o ITO-(PG4AuNp-GOx) com 5 bicamadas, que mostrou-se linear na faixa de 0 a 4,8 mM de glicose com sensibilidade 0,013 μA/mM e limite de detecção 0,44 mmolL ¹. / Applications of nanomaterials for biosensors have been target of substantial research in the last years. Among a large number of biosensors, glucose biosensors have attracted attention due to their applications in clinical diagnostics. Despite the remarkable progress in glucose biosensors in the last decades, there are still many challenges in achieving clinically accurate continuous glycemic monitoring in connection to closed-loop systems aimed at optimal insulin delivery. This dissertation describes the fabrication of layer-by-layer (LbL) films obtained from the enzyme glucose oxidase (GOx) and the polyelectrolytes poli(amidoamine) generation 4 (PG4) and PG4 containing gold nanoparticles (PG4AuNp). Gold nanoparticles were synthesized in aqueous solution using formic acid, PG4 and HAuCl ₄. UV-vis spectroscopy showed a linear growth on quartz substrate only in the system PG4-GOx. In addition to the optical, structural and electrochemistry investigation, these LbL films deposited on ITO-coated glass were employed as electrochemical glucose biosensors. The biofunctionality of GOx and feasibility of the method as biosensor are demonstrated by the increase of reduction current upon additions of successive aliquots of glucose. The biosensor ITO-(PG4AuNp-GOx) ₅ with the optimum performance had a detection limit of 0.44 mmolL¹ with a linear response in the range from 0 to 4.8 mmolL¹ and sensibility 0.013μA/mmolL ¹.

O ranelato de estrôncio é uma droga encontrada nas farmácias com o nome de Protos®, sendo bastante consumida na forma de chás para o tratamento da osteosporose, uma patologia do tecido ósseo ligada ao metabolismo de reabsorção óssea e a produção de osteoblastos (células precursoras da matriz óssea). Sua estrutura inusitada apresenta um anel tiofeno com quatro grupos carboxílicos e um grupo nitrila, lembrando o complexante clássico EDTA. Essa semelhança inspirou o desenvolvimento desta tese, visando entender a química do íon ranelato na presença do estrôncio e outros íons metálicos, e dessa forma, obter indícios de como pode atuar ao nível molecular no organismo. Com esse objetivo, a molécula foi criteriosamente estudada baseada em espectroscopia (RMN, FTIR, Raman, EDX e Vis-UV), difração de raiosX de pó, espectrometria de massa, e modelagem molecular (MM+, ZINDO/S, DFT, TD-DFT). Ao longo do trabalho, observou-se que em meio ácido, sob exposição direta ao sol ou irradiação UV, havia a formação de uma coloração azul intensa, chamando a atenção para uma nova espécie, ainda não reportada na literatura. Esse produto mostrou ser bastante estável, particularmente sob luz solar, contrastando com a maioria dos corantes orgânicos convencionais. Os espectros de RMN e de massa indicaram a formação de um novo corante bistiofeno, envolvendo o desprendimento fotoquímico de CO2 via descarboxilação do grupo ligado ao carbono 5 do anel, seguido pela dimerização. Por outro lado, na presença de íons de ouro(III), o ranelato reage rapidamente produzindo suspensões vermelhas de nanopartículas de ouro, que permanecem estáveis por longo tempo, especialmente no caso dos sais de sódio e lítio. As reações ocorrem espontaneamente à temperatura ambiente, e a cinética foi investigada espectrofotometricamente variando a proporção ouro/ranelato (em mol) de 8:1 a 1:8. As partículas formadas foram monitoradas por microscopia eletrônica de transmissão de alta resolução. Por analogia com o método de Turkevich, a reação parece envolver a oxidação do íon ranelato por AuIII, produzindo compostos com AuI e convertendo o grupo carboxilato em CO2. É possível que o AuI permaneça ligado covalentemente ao anel tiofeno, coordenando-se pelo átomo de carbono 5. Nessa forma, o composto pode iniciar a nucleação das nanopartículas por meio de reações redox sucessivas com as espécies AuIII existentes, e desproporcionamento de AuI em Au0 e AuIII. Em condições próximas da equimolar são formadas partículas esféricas, enquanto que com excesso de AuIII, partículas anisotrópicas foram observadas. No presente estágio, a química do íon ranelato ainda é muito incipiente, mas já é possível vislumbrar sua exploração em diversas áreas da química, indústria de corantes além de novas aplicações medicinais. / Strontium ranelate is a drug commercially available in Brazil as Protos®. It is widely consumed as tea infusions for the treatment of osteosporosis, a disease of the bone tissues related to the bone resorption and osteoblast replication. Its peculiar structure is composed by a central thiophene ring, exhibiting four carboxylate groups and a nitrile moiety, resembling the classical metal chelating agent EDTA. Such analogy inspired the present thesis, aiming the understanding of its chemistry in the presence of metal ions such as lithium, sodium and strontium, and expecting to provide some clues for its action in the organism. In this way, the molecule was extensively studied based on spectroscopy (NMR, FTIR, Raman, EDX and VisUV), powder X-ray diffraction, mass spectrometry, and molecular modeling methods (MM+, ZINDO/S, DFT and TD-DFT). In acidic solution, under direct solar or UV irradiation, a deep blue color was observed, calling our attention for its conversion into a new species not yet reported in the literature. This product was remarkably stable, particularly to sun light, in contrast to most conventional dyes. Our research based on NMR and mass spectra indicated the formation of a new bisthiophene dye, by the photochemical release of the carboxylate group bound at the C5 atom of the ring, followed by dimerization. On the other hand, in the presence of gold(III) ions, ranelate reacts rapidly yielding red nanoparticle suspensions which remain stable in the case of its sodium and lithium salts, but turning into blue and precipitating in the case of the strontium species. The reactions proceed spontaneously at room temperature and the kinetics were investigated spectrophotometrically by varying the ranelate/gold molar ratio from 8:1 to 1:8, and monitoring the generated nanoparticles by HRTEM. By analogy with the citrate method developed by Turkevich, the reaction seems to involve the oxidation of the ranelate ion by AuIII, yielding AuI species and converting carboxylate group into CO2. Presumably, the AuI ion remains covalently attached to the thiophene ring by coordinating to the C5 atom. In this way it can act as a nucleation center for the formation of nanoparticles by means of successive redox and disproportionation reactions with the remaining AuIII species. Under nearly equimolar conditions, spherical nanoparticles are preferentially formed. At high AuIII concentrations, formation of anisotropic gold nanoparticles is observed. The chemistry of the ranelate ions is yet at very beginning, but exciting perspectives can already be seen in chemistry, medicine and in dyes industry.

Nanofibras poliméricas obtidas por eletrofiação possuem alta relação superfície-volume, e podem ser recobertas com nanomateriais que interajam com os grupos funcionais dos polímeros. Neste trabalho, nanofibras de poliamida 6/polialilamina hidroclorada (PA6/PAH) com diâmetro da ordem de 100 nm e sem defeitos foram recobertas com nanotubos de carbono (CNTs) e nanopartículas de ouro (AuNps) para produzir sensores e biossensores. A versatilidade da plataforma com as nanofibras foi demonstrada com três aplicações distintas. A adsorção de CNTs sobre as nanofibras permitiu a detecção do neurotransmissor dopamina com medidas de voltametria de pulso diferencial com sensibilidade na faixa de 1 a 70 μmol.L-1 e limite de detecção de 0,15 μmol.L-1, sem interferência do ácido úrico e ácido ascórbico. Nos imunossensores para detectar o antígeno CA 19-9, biomarcador para câncer de pâncreas, as nanofibras de PA6/PAH recobertas com CNTs ou AuNPs receberam camada adicional do anticorpo anti-CA 19-9. Usando medidas de espectroscopia de impedância eletroquímica, esses imunossensores puderam detectar CA 19-9 em tampão e em soro de sangue de pacientes de câncer com diferentes probabilidades de desenvolver câncer de pâncreas. A seletividade dos imunossensores também foi testada com possíveis interferentes no sangue. Na terceira aplicação, obteve-se sinergia com a codeposição de CNTs e AuNPs sobre as nanofibras para a formação de um biossensor contendo uma camada da enzima tirosinase. Imagens de microscopia eletrônica mostraram uma estrutura 3D interconectada, formada pelas nanofibras de PA6/PAH, AuNPS e CNTs. O biossensor foi usado para detectar bisfenol A com cronoamperometria na faixa de 0,05 a 1,1 μmol.L-1 e limite de detecção de 8 nmol.L-1. Conclui-se que nanofibras poliméricas constituem excelente plataforma para sensores e biossensores pela possibilidade de incorporação de outros nanomateriais para aplicações específicas. / Electrospun polymer nanofibers have a high surface-volume ratio, and can be coated with nanomaterials that interact with the functional groups of the polymers. In this work, defect-free nanofibers of polyamide 6/polyallylamine hydrochloride (PA6/PAH) with a diameter of ca. 100 nm were coated with carbon nanotubes (CNTs) and gold nanoparticles (AuNps) to produce sensors and biosensors. The versatility of the platform with nanofibers has been demonstrated with three distinct applications. The adsorption of CNTs on the nanofibers allowed the detection of the neurotransmitter dopamine with differential pulse voltammetry measurements with sensitivity in the range of 1 to 70 μmol.L-1 and detection limit of 0.15 μmol.L-1, without interference of uric acid and ascorbic acid. In the immunosensors to detect CA 19-9 antigen, biomarker for pancreatic cancer, PA6/PAH nanofibers coated with CNTs or gold nanoparticles (AuNPs) received an additional layer of anti-CA 19-9 antibody. Using electrochemical impedance spectroscopy measurements, these immunosensors were able to detect CA 19-9 in buffer and in blood serum from cancer patients with different probabilities of developing pancreatic cancer. The selectivity of the immunosensors was also tested with possible interferents in the blood. In the third application, synergy was obtained with co-deposition of CNTs and AuNPs on the nanofibers for the formation of a biosensor containing a layer of the enzyme tyrosinase. Electron microscopy images showed an interconnected 3D structure, formed by PA6/PAH nanofibers, AuNPS and CNTs. The biosensor was used to detect bisphenol A with chronoamperometry in the range of 0.05 to 1.1 μmol.L-1 and detection limit of 8 nmol.L-1. It is concluded that polymer nanofibers are an excellent platform for sensors and biosensors because of the possible incorporation of other nanomaterials for specific applications.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-03-28T11:07:06Z No. of bitstreams: 1 raissaainsworthrustichelliteixeira.pdf: 2551742 bytes, checksum: 145f3cc79735bb0d0f7aff4e788e3ed6 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-04-09T19:23:22Z (GMT) No. of bitstreams: 1 raissaainsworthrustichelliteixeira.pdf: 2551742 bytes, checksum: 145f3cc79735bb0d0f7aff4e788e3ed6 (MD5) / Made available in DSpace on 2018-04-09T19:23:22Z (GMT). No. of bitstreams: 1 raissaainsworthrustichelliteixeira.pdf: 2551742 bytes, checksum: 145f3cc79735bb0d0f7aff4e788e3ed6 (MD5) Previous issue date: 2018-02-23 / O presente trabalho visou a construção de um sistema utilizando nanopartículas de ouro (AuNPs) juntamente com as biomoléculas direcionadoras, ácido fólico (HFol) e anticorpo anti-receptor de folato, para aplicação em testes in vitro com células de câncer de mama MDA-MB-231 e MCF-7 a fim de promover um sistema de entrega controlada dos fármacos anastrozol e tamoxifeno. Entre os diferentes adsorbatos utilizados, as interações do cristal violeta (CV), mercaptoetanol (ME), HFol, polímero PEGSH, anastrozol e tamoxifeno, foram analisadas através das técnicas espectroscópicas eletrônica (UV-VIS-NIR), Raman e espalhamento Raman intensificado por superfície (SERS). A espectroscopia SERS foi aplicada, também, para mapeamento do sinal do CV (marcador SERS) dos sistemas completos em células de câncer MCF-7 a fim de avaliar o efeito da presença e ausência das biomoléculas direcionadoras na afinidade com as células. O mapeamento realizado mostrou a importância da presença do anticorpo aumentando de 13%, no sistema sem nenhum identificador celular, para 30% do sinal de CV, no sistema com apenas anticorpo como biomolécula direcionadora, e aumentou de 30% para 65% na presença do HFol. As AuNPs modificadas com HFol e anticorpo, quando conjugadas com tamoxifeno, diminuíram a concentração mínima efetiva do fármaco na ação contra as células MCF-7, mostrando-se um sistema com potencial aplicação para entrega controlada de fármacos. / The present work was aimed on the construction of a system using gold nanoparticles (AuNPs) with two targeting biomolecules, folic acid (HFol) and anti-folate receptor antibody, for application on in vitro tests with breast cancer cells MDA-MB-231 and MCF-7 to form a drug delivery system with anastrozole and tamoxifen. Among the different used adsorbates, the interactions of crystal violet (CV), mercaptoethanol (ME), HFol, polymer (PEGSH), anastrozole and tamoxifen, were analysed through electronic spectroscopy (UV-VIS-NIR), Raman and Surface Enhanced Raman Scattering (SERS). SERS spectroscopy was also applied on mapping of CV signal (SERS marker) of the complete systems with cancer cells MCF-7 in order to evaluate the effect of the presence or absence of these targeting biomolecules on the affinity with cancer cells. The performed mapping showed the relevance of the presence of the antibody by increasing from 13%, on the system with no biomolecules, to 30% of the CV signal, on the system with just antibody as biomolecule and increased from 30% to 65% in presence of HFol. AuNPs modified with folic acid and antibody, when conjugated with tamoxifen, reduced the minimum effective concentration of the drug in the action against MCF-7 cells, indicating that this system has a potential to be applied as a drug delivery system.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-10-11T17:19:04Z No. of bitstreams: 1 rodrigomanoeldasilvajusto.pdf: 3782513 bytes, checksum: 8fe8e477946fd755b8b6786ffe63347b (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-10-16T14:32:04Z (GMT) No. of bitstreams: 1 rodrigomanoeldasilvajusto.pdf: 3782513 bytes, checksum: 8fe8e477946fd755b8b6786ffe63347b (MD5) / Made available in DSpace on 2018-10-16T14:32:04Z (GMT). No. of bitstreams: 1 rodrigomanoeldasilvajusto.pdf: 3782513 bytes, checksum: 8fe8e477946fd755b8b6786ffe63347b (MD5) Previous issue date: 2018-07-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nanopartículas de ouro (AuNPs) estabilizadas com diferentes compostos orgânicos tem-se comportado como excelentes catalisadores de reações orgânicas como oxidação. Assim, torna-se interessante o estudo da preparação e caracterização de diferentes AuNPs e avaliar seu comportamento frente a catálise de reações de oxirredução. Neste trabalho foram sintetizadas nanoparticulas metálicas de ouro estabilizadas com o aminoácido N-acetil-L-cisteína (NAC-AuNPs) e sua atividade catalítica frente a aldeídos aromáticos e aminas foi investigado. NAC-AuNPs foram caracterizadas por técnicas espectroscópicas de absorção no UV-VIS, espalhamento Raman e espalhamento raman intensificado por superfície (SERS – Surface Enhanced Raman Scattering), medida do potencial zeta através do espalhamento dinâmico de luz (DLS –Dynamic Light Scattering) e microscopia eletrônica de varredura (MEV). No presente trabalho, NAC-AuNPs foram obtidas de forma satisfatória com dimensões da ordem de 25 nm e inicialmente promoveram a oxidação do benzaldeído em condições brandas (diclorometano como solvente, temperatura ambiente, 48 horas de reação sob agitação) a ácido benzoico com uma conversão de 97%. Posteriormente, a tentativa de obter uma amida através da adição de octilamina e cloridrato de 1-Etil-3-(3-dimetilaminopropil) carbodiimida (EDC, ativador de ácido carboxílico) ao mesmo sistema reacional sob agitação por 24 horas (amidação one-pot) conduziu espantosamente a formação de uma imina com excelente conversão e rendimento (>99% e 98%). A partir daí, experimentos controles concluíram que a presença do ativador EDC era dispensável e que a presença de NAC-AuNPs era de extrema importância para a formação de uma imina a partir do benzaldeído tendo um ácido carboxílico como intermediário. Uma nova otimização contendo a octilamina na segunda etapa da reação foi feita para obtenção de iminas no novo sistema trabalhado e os resultados mostraram que DCM e NAC-AuNPs a 3,6 x 10-3 % m/V se mostraram como melhores condições reacionais (conversão de > 99%). Avaliou-se o escopo do substrato nas condições ótimas estabelecidas acima, com diferentes aldeídos aromáticos e aminas aromáticas e alifáticas, onde iminas puderam ser obtidas com rendimentos bons a excelentes (67% a 99%). Todos os produtos foram caracterizados por RMN de 1H e 13C; sendo que produtos que foram obtidos no estado sólido também puderam ser caracterizados por difração de raio X de pó (DRX). / Gold nanoparticles (AuNPs) stabilized with different organic compounds have behaved as excellent catalysts for organic reactions such as oxidation. Thus, it is interesting to study the preparation and characterization of different AuNPs and evaluate their reactivity towards the catalysis of oxidation reactions. In this work, gold nanoparticles stabilized with the aminoacid N-acetyl-L-cysteine (NAC-AuNPs) were synthesized and their catalytic activity towards aromatic aldehydes and amines was investigated. NAC-AuNPs were characterized through ultraviolet and visible absorption spectroscopy UV-VIS, Raman scattering spectroscopy and Surface Enhanced Raman Scattering (SERS), zeta potential measurement through Dynamic Light Scattering (DLS) and scanning electron microscopy (SEM). In the present work, NAC-AuNPs were satisfactorily obtained with dimensions around 25 nm and firstly promoted the oxidation of benzaldehyde under mild conditions (dichloromethane as solvent, ambient temperature, 48 hours of reaction under stirring) to benzoic acid with a conversion of 97%. Subsequently, the attempt to obtain an amide by adding octylamine and 1-Ethyl-3- (3-dimethylaminopropyl) carbodiimide hydro (EDC, carboxylic acid activator) to the same reaction system under stirring for 24 hours (one-pot amidation) led amazingly to the formation of an imine with excellent conversion and yield (> 99% and 98% respectively). Thereafter, control experiments concluded that the presence of EDC was dispensable and that the presence of NAC-AuNPs was of extreme importance for the formation of an imine from the benzaldehyde having a carboxylic acid as intermediate. A new optimization containing the octylamine in the second stage of the reaction was executed in order to obtain imines in the new working system, and the results showed that DCM and NAC-AuNPs at 3.6 x 10-3% m / V were presented as the optimum reaction condition (conversion of > 99%). The substrate scope was evaluated under the optimum conditions set forth above with different aromatic aldehydes and aromatic and aliphatic amines, in which imines could be obtained in good to excellent yields (67% to 99%). All products were characterized by 1H and 13C NMR; products that were obtained as powders could also be characterized by powder X-ray diffraction (XRD).

Orientadores: Daniela Zanchet, Regina Buffon / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-25T08:37:31Z (GMT). No. of bitstreams: 1 Aragao_IsaiasBarbosa_M.pdf: 4247291 bytes, checksum: 09937fc60abf375cebc0a59dc22ae39a (MD5) Previous issue date: 2014 / Resumo: Nanopartículas (NPs) e os ligantes em sua superfície vêm ganhando espaço como meio suporte devido a suas propriedades que aliam o comportamento da catálise homogênea com a heterogênea. Em longo prazo, imagina-se que o controle do ambiente local de espécies ancoradas na superfície destas NPs possa mimetizar o sítio catalítico de enzimas. Visando explorar a influência do ambiente local, foi avaliado o desempenho do catalisador de Grubbs de primeira geração em duas condições: encapsulado em matriz de sílica e na presença de NPs de ouro (NPs-Au). Apesar das reações de encapsulamento pelo método sol-gel serem rotas bastante exploradas, os resultados não foram encorajadores devido à desativação do complexo de rutênio nas condições de formação do gel, tanto pela via hidrolítica quanto não-hidrolítica. Com relação às NPs-Au, elas foram sintetizadas com misturas de ligantes (1-octanotiol e ácido 3-mercaptopropiônico), mostrando separação de fases dos ligantes, com a formação de domínios (raias). Nos estudos com catalisador de Grubbs em reações de metátese (autometátese do 1-hexeno e polimerização por abertura de anel do 1,5-ciclooctadieno), tanto a presença das NPs-Au como a de tiol livre tiveram influência negativa, levando a sua desativação prematura. Na presença de NPs-Au, houve queda da atividade, chegando a conversões nulas para razões mássicas maiores de que 1 mg de ouro/10 mg de catalisador, estando possivelmente associado à complexação das mercaptanas das NPs-Au com o complexo de rutênio. Buscando viabilizar o ancoramento do catalisador nas NPs-Au, sintetizou-se um ligante carbeno NHC com a funcionalização do esqueleto carbônico posterior do anel com um grupamento alil, que representa a primeira etapa para introdução de grupos funcionais e ancoramento em NPs / Abstract: The use of nanoparticles (NPs) and their protecting layer as support in catalysis start to be exploited, due to their unique characteristics at the interface of homogeneous and heterogeneous catalysts. At long term, the tuning of the local environment of catalytic species anchored on the surface of NPs may be a way to mimic the active site of enzymes. Aiming to explore the influence of the local environment, we evaluated the activity of the first generation Grubbs catalyst under two conditions: encapsulating it in a silica matrix and in the presence of gold NPs (NPs-Au). Although the heterogenization via the sol-gel method is a well-known and well-explored route, we could not obtain good results due to catalyst deactivation under gel formation in both hydrolytic and non-hydrolytic (nonaqueous) conditions. Considering the NPs-Au, they were synthesized with success using a mixture of ligands (1-octanethiol and 3-mercaptopropionic acid) that showed phase segregation and formation of stripes. The evaluation of the Grubbs catalyst on metathesis reactions (self-metathesis of 1-hexene and ring opening polymerization of 1,5-ciclooctadiene) showed premature deactivation in the presence of both NPs-Au and free thiol. In the presence of NPs-Au, the catalytic activity descreased, achieving null results when weight ratios bigger than 1mg of NPs-Au to 10 mg of catalyst were used, possibly associated to the interaction between the mercaptans and the ruthenium catalyst. To make possible the catalyst anchoring on the NPs-Au surface, a NHC carbene with an allyl group on its carbon backbone was synthesized, corresponding to the first step to introduce functional groups to the catalyst / Mestrado / Quimica Inorganica / Mestre em Química

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Despite the advances in therapies such as chemotherapy and radiotherapy, tumours have been shown to be resistant to the treatments. Gold nanoparticles (AuNPs) have been recognized as effective radiosensitizers of low energy (e.g. 200–500 kV) X-rays, leading to the emission of Auger electrons that cause highly localised ionizing damage to cells. Spherical AuNPs were synthesised via the reduction of the chloroaurate ions by sodium citrate. Characterisation of AuNPs involved UV-visible spectrophotometry, zeta (Z) potential, dynamic light scattering (DLS) and polydispersity index (PDI) measurements for determination of surface plasmon resonance (SPR), surface charge and stability, as well as transmission electron microscopy (TEM) for hydrodynamic core sizes, size distribution width and shape of AuNPs. Both the 5 and 10 nm AuNPs were found to be anionic with λmax absorbance of 525 nm and uniform size distribution. DLS measurement at 38.12 nm and 48.50 nm, respectively for 5 nm and 10 nm AuNPs, points to aggregation of the AuNPs. However, TEM measurements confirmed the core size of the 10 nm AuNPs. Non-malignant Chinese hamster ovary (CHO-K1), brain endothelial (BEnd5), breast (MCF-10A), isolated human lymphocytes and malignant breast (MCF-7) cell lines were treated with 50 μg/ml of AuNPs, and irradiated with either 1, 2 or 4 Gy X-rays or 1 or 2 Gy p(66)/Be neutron radiation. The γ-H2AX foci assay, cytokinesis-block micronucleus assay, MTT assay and fluorescence-activated cell sorting (FACS) was used to determine that amount of double stranded breaks (DSBs) in isolated lymphocytes, the presence and number of micronuclei (MNi) within binucleated cells (BNCs), cell viability and cell cycle progression, respectively. Preliminary experiments that established the reliability of the study regarding the induction of DNA damage after the bombardment of AuNPs by scattered low kV X-rays, were carried out on lymphocytes. Combined treatment (AuNPs and radiation) resulted in more endogenous foci in comparison to lymphocytes that were treated with AuNPs only. The CHO-K1 and MCF-7 cells showed higher MNi frequencies after the combination treatment of AuNPs and radiation compared to the number of MNi in samples exposed to AuNPs and radiation separately. The AuNPs alone influenced the cellular kinetics of all cell types. Interaction indices, which is the enhancement factor of AuNPs in combination with radiation, for AuNPs and 6 MV 2 Gy X-rays of 1.6 to 1.7 and 1.3 to 1.4 have respectively been determined for CHO-K1 and MCF-7 cells, whilst that for the other cell types used in the study were not different from Unity. As expected, the interaction indices between AuNPs and p(66)/Be neutrons was lower than the interaction indices after 2 Gy X-rays, as p(66)/Be neutrons interact only with the nuclei of the AuNP's atoms and the X-ray photons interact with the orbital electrons of the atoms of the AuNPs leading to Auger electron emission. The cell viability assay showed that 50 μg/ml of AuNPs had an inhibitory effect on cellular proliferation, in all four cell linnes whereas the lower concentrations (2.5, 5 and 10 μg/ml) had no effect. Results in this study, revealed an increase in the accumulation of CHO-K1 an MCF-7 cells in the G₂/M phase of the cell cycle after being treated with AuNPs followed by X-ray radiation, suggesting that the cells have possibly been sensitised to the damaging effects of radiation. Further studies are required to quantify internalised AuNPs and to then link the possible concentration differences of the AuNPs to differences in radiation damage effects observed for the different cell types.

Doctor of Philosophy / Department of Chemistry / Christine M. Aikens / Gold and silver particles with dimensions less than a nanometer possess unique characteristics and properties that are different from the properties of the bulk. They demonstrate a non–zero HOMO–LUMO gap that can reach up to 3.0 eV. These differences arise from size quantization effects in the metal core due to the small number of atoms. These nanoparticles have attracted great interest for decades both in fundamental and applied research. Small gold clusters protected by various types of ligands are of interest because ligands allow obtaining gold nanoclusters with given sizes, shapes and properties. Three main families of organic ligands are usually used for stabilization of gold nanoclusters: phosphine ligands, thiolate ligands and DNA. Usually, optical properties of these NPs are studied using optical absorption spectroscopy. Unfortunately, sometimes this type of spectrum is poorly resolved and tends to appear very similar for different complexes. In these cases, circular dichroism (CD) and magnetic circular dichroism (MCD) spectroscopy can be applied. However, the interpretation of experimental CD and MCD spectra is a complicated process. In this thesis, theoretically simulated CD and MCD spectra were combined with optical absorption spectra to study optical activity for octa– and nona– and undecanuclear gold clusters protected by mono– and bidentate phosphine ligands. Additionally, optical properties of bare and DNA protected silver NPs were studied. Theoretical CD spectra were examined to learn more about the origin of chirality in chiral organometallic complexes, and to contribute to the understanding of the difference in chiroptical activity of gold clusters stabilized by different phosphine ligands and DNA–stabilized silver clusters. Furthermore, optical properties of the small centered gold clusters Au₈(PPh₃)₈²⁺ and Au₉(PPh₃)₈³⁺ were examined by optical absorption and MCD spectra using TDDFT. Theoretical MCD spectra were also used to identify the plasmonic behavior of silver nanoparticles. These results showed that CD and MCD spectroscopy yield more detailed information about optical properties and electronic structure of the different chemical systems than optical absorption spectroscopy alone. Theoretical simulation of the CD and MCD spectra together with optical absorption spectra can be used to assist in the understanding of empirically measured CD and MCD and provide useful information about optical properties and electronic structure.

Plasmon resonance associated with nanoparticles of gold can enable photothermal ablation of tissues or controlled drug release with exquisite temporal and spatial control. These technologies may support many applications of precision medicine. However, clinical implementations of these technologies will require new methods of intraoperative imaging and guidance. Near-infrared laser surgery is a prime example that relies on improved image guidance. Here we set forth applications of augmented microscopy in guiding surgical procedures employing plasmon resonant gold-coated liposomes. Absorption of near-infrared laser light is the first step in activation of various diagnostic and therapeutic functions of these novel functional nanoparticles. Therefore, we demonstrate examples of near-infrared visualization of the laser beam and gold-coated liposomes. The augmented microscope proves to be a promisingimage guidance platform for a range of image-guided medical procedures.