Le développement des nano et biotechnologies pousse à la recherche de techniques de caractérisation adaptées à l’étude des systèmes nanostructurés. La spectrométrie Raman exaltée de surface (SERS) est une technique d’analyse en plein essor dans ce domaine.Dans ce travail de thèse nous nous sommes attachés à étudier, par cette technique, différents types de systèmes nanostructurés : des biomolécules et des films minces inorganiques. Le but était d’accéder à des informations sur la structure et les liaisons chimiques présentes dans ces systèmes. L’étude a été complétée par des observations par microscopie électronique en transmission notamment.Dans un premier temps, a été réalisée l’étude de molécules d’intérêt biologique. L’objectif était la compréhension des modes d’interaction nanoparticules métalliques/protéines menée sur des nanoparticules d’argent bio-conjuguées avec des protéines depuis leur synthèse jusqu’à leur caractérisation. Les résultats ont montré la chimisorption des protéines à la surface de nanoparticules d'argent possiblement par leurs terminaisons azotées. La technique SERS a également été expérimentée dans le domaine des basses fréquences pour caractériser la structure de dépôts minces de caféine, molécule d’intérêt pharmaceutique.Dans un second temps, l’étude de couches minces nanostructurées par spectrométrie Raman et SERS a été réalisée. Des couches minces nanocomposites TiO2:Au, ont été étudiées pour décrire les premières étapes de croissance des nanoparticules sous l’effet de la température dans ces matériaux. Des films ultraminces de TiO2 d’épaisseur contrôlée ont été déposés sur substrats fonctionnalisés avec des nanoparticules d’or pour étudier leur exaltation par effet SERS. / This work addressed the study of several kinds of nanostructured systems, biomolecules and inorganic thin films, mainly by Surface Enhanced Raman Spectroscopy (SERS). The aim was to investigate the structure and the chemical bonds. Transmission electron microscopy (TEM) was also used to complete the structural characterization of the different samples.Firstly, the study was conducted on molecules of biological interest. The aim was to study the interaction between silver nanoparticles and proteins. With this aim, silver nanoparticles bioconjugated with different proteins (hemoglobin, cytochrome C, BSA and lysozim) were synthesized. SERS results allowed concluding that proteins are chemisorbed on the silver nanoparticules surface. SERS was also used in the low frequency range to characterize the structure of thin deposits of caffeine, a molecule of pharmaceutical interest.Raman spectroscopy and SERS were also used to study nanostructured TiO2:Au thin films. The first stages of the growth of gold nanoparticles in Au doped TiO2 thin films under annealing treatments were studied by low frequency Raman spectroscopy and TEM. Finally, it was shown that SERS effect can be used for the characterization of ultra-thin TiO2 films. With this aim, ultra-thin TiO2 films were deposited by Atomic Layer Deposition on Si substrates functionalized with gold nanoparticles and studied by SERS.

[pt] As nanopartículas, atualmente, têm sido alvo de pesquisas em diversas áreas devido as suas exclusivas propriedades magnéticas, fotônicas, optoeletrônicas e catalíticas. O presente trabalho teve como objetivo estudar a resposta SERS, bem como as possíveis interações existentes entre as nanopartículas de ouro com ácido etilenodiaminotetraacético e o seu respectivo complexo com cromo (III). Este complexo foi sintetizado e caracterizado pelas técnicas de análise elementar (espectrometria de absorção atômica e CHN), espectroscopia de infravermelho, espectroscopia Raman e espectroscopia de ultravioleta-visível. Foi possível verificar que, neste caso, o ligante EDTA se coordenou de maneira pentadentada com o íon Cr(3 mais); e que uma molécula de água ocupou a sexta posição de coordenação. Foram também sintetizadas em meio aquoso, suspensões coloidais de nanopartículas de ouro pelo método físico de ablação laser. Este método é interessante pois permite que as partículas sejam formadas sem a presença de quaisquer outros reagentes, utilizando unicamente ouro e água. Em seguida, elas foram caracterizadas pelas técnicas de espectroscopia de ultravioleta-visível, SERS, SEM e TEM. Os dados mostraram que as partículas possuíam diâmetros relativamente pequenos, entre 10 e 30 nm e que havia a presença de moléculas de monóxido de carbono adsorvidas em sua superfície, possivelmente oriundas do CO2 presente no ar que se solubiliza com facilidade em água e que em alguma etapa da ablação foi reduzido. A fim de estudar e apresentar a sensibilidade da técnica SERS, foram preparadas soluções de EDTA e do complexo sintetizado de modo que ao serem adicionadas às suspensões de nanopartículas, obtivessem concentração final igual a 10(-5) mol/L. Para serem analisadas via SERS, essas misturas foram gotejadas em uma placa de vidro previamente revestida com uma camada de alumínio, de modo que fosse extinta qualquer possível interferência da fluorescência oriunda do vidro. As bandas SERS obtidas foram, então, estudadas e os dados sugerem que as interações ocorridas na superfície das nanopartículas, tanto com o ligante quanto com o complexo, sejam do tipo ligação de hidrogênio. / [en] Nowadays, the nanoparticles have been target of searches in several in various areas due its magnetic, photonic, optoelectronic and catalytic exclusive proprieties. The present work aimed to study the SERS response and the possible interaction between the gold nanoparticles and ethylenediamninetatraacetic acid and its chromium (III) complex. This complex was synthesized and characterized by elemental analyses ( atomic absorption spectrometry and CHN ), infrared spectroscopy, Raman spectroscopy and Ultraviolet-visible spectroscopy techniques. It was possible to see that, in this case, the ligand EDTA coordenates as a quinquidentate with the chromium íon, and one water molecule occupied the sixty valence position. In this paper was synthesized also a aqueous colloidal solution of gold nanoparticle by the physic method pulsed laser ablation. This method is very interesting because allow the formation of the particles without the action of another reagent, utilizing just gold and quarter. After that, its was characterized by ultraviolet-visible spectroscopy, SERS, SEM and TEM. The dates showed that the particles had relatively small diameters, near 10 to 30 nm and there was the presence of carbon monoxide molecules adsorbed in its surfaces, possibility from CO2 present in the air that is so much soluble in water and in some stage of ablation was reduced. In order that study and present the sensibility of the SERS techniques, solutions of EDTA and synthesized complex was prepared in such a manner as when its added inside the colloidal solutions its final concentration was 10(-5) mol / L. In order to analyzed by SERS, these mixtures was deposited in a glass plate that before was covered by a aluminum layer so as to extinct some interference from glass fluorescence. The SERS bands got was studied and we believe that the interaction occurred in the nanoparticles surface with a both ligand and complex was by hydrogen bond.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-04T10:48:31Z No. of bitstreams: 1 douglasfazafranco.pdf: 6741495 bytes, checksum: 49d756dd3eff71da15e32191ca4e5a08 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T15:36:09Z (GMT) No. of bitstreams: 1 douglasfazafranco.pdf: 6741495 bytes, checksum: 49d756dd3eff71da15e32191ca4e5a08 (MD5) / Made available in DSpace on 2016-01-25T15:36:09Z (GMT). No. of bitstreams: 1 douglasfazafranco.pdf: 6741495 bytes, checksum: 49d756dd3eff71da15e32191ca4e5a08 (MD5) Previous issue date: 2015-08-30 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho trata da preparação de vidros baseados em polifosfatos de sódio (NaPO3)n contendo óxidos de antimônio (III) e cobre (II), onde a presença do agente redutor α-Sb2O3 foi responsável pelos processos de oxi-redução: Cu2+→ Cu+→Cu0 durante a síntese dos vidros a 1000°C. Os resultados de medidas de absorção de Raios X próxima a borda K do Cu (XANES) e de espectroscopia Eletrônica forneceram informações valiosas sobre a existência de partículas metálicas nos vidros com dimensões nanométricas. Este resultado mostra a possibilidade de se obter nanopartículas metálicas de Cu0 durante a etapa de fusão dos vidros sem a necessidade de tratamentos térmicos dos materiais em temperaturas próximas a transição vítrea. A síntese de diferentes fases cristalinas do óxido de antimônio (III): α-Sb2O3, α-Sb2O4, β-Sb2O4 e β-Sb2O3, por meio de diferentes tratamentos isotérmicos possibilitou o estudo via espectroscopia Raman e Difração de Raios X por policristais destes compostos. O diagrama de composição ternário para os vidros (0,9-x)NaPO3-xSb2O3-0,1CuO mostra as diferentes regiões de domínio vítreo de formação de vidros estáveis. O estudo espectroscópico dos vidros (0,9-x)NaPO3-xSb2O3-0,1CuO contendo nanopartículas metálicas de Cu0 dopados com 0,5 mol% de Er2O3 foi realizado via espectroscopia de Fluorescência usando diferentes radiações excitantes: 532, 633 e 785 nm. O mapeamento Raman dos vidros mostrou a intensificação da fluorescência dos íons Er3+, tanto pelo efeito da mudança do ambiente químico ao redor do íon Er3+ (cristalização) quanto pela transferência de energia dos plasmons de superfície excitados para os níveis de energia do íon terra-rara (SEF – Surface-Enhanced Fluorescence). Além disso, vidros contendo nanopartículas metálicas de Cu0 apresentaram resultados satisfatórios quando a possibilidade de utilização como substratos SERS (Surface-Enhanced Resonance Spectroscopy), sendo observada a intensificação do sinal Raman dos modos vibracionais da o-fenilenodiamina usando o vidro x = 0,6 como substrato. / This Thesis deals with the preparation of glasses based on sodium polyphosphate, containing antimony (III) and copper (II) oxides. The presence of α-Sb2O3 reducing agent was responsible for redox processes: Cu 2+→ Cu+→ Cu0 during synthesis of the glasses at 1000°C. The results of X-ray absorption measurements near the K edge of Cu (XANES) and electronic spectroscopy provided valuable information on the presence of metallic particles in glasses with nanometric dimensions. This result shows the possibility of obtaining metallic Cu nanoparticles during the melting step of glass preparation, without the need for posterior treatments. The synthesis of the different crystal phases of antimony (III) oxide, i.e., α-Sb2O3, α-Sb2O4, β-Sb2O4 and β-Sb2O3, through different isothermal treatments enabled the study through Raman spectroscopy and X-ray Diffraction. The ternary composition diagram for glass NaPO3-Sb2O3-CuO shows the different regions of vitreous domain. The spectroscopic study of glasses (0.9-x)NaPO3- xSb2O3-0,1CuO, containing Cu nanoparticles doped with 0.5 mol% of Er2O3 was realized by fluorescence spectroscopy using different exciting radiation: 532, 633 and 785 nm. The Raman mapping of these glasses showed the intensification of fluorescence of Er3+ ions, both the effect of changing the chemical environment around the Er3+ ion (crystallization) as the energy transfer from the excited surface plasmons for energy rare-earth ion levels (SEF - Surface-Enhanced Fluorescence). Additionally, glasses containing Cu nanoparticles showed satisfactory results of use as SERS substrates (Surface-Enhanced Resonance Spectroscopy), with the observed enhancement of the Raman signal of the vibrational modes of using phenylenediamine and the glass with x = 0.6 as substrate.

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No. of bitstreams: 1 linuspaulingdefariapeixoto.pdf: 3833578 bytes, checksum: 7044b2daa711546991179b32265a99dc (MD5) Previous issue date: 2015-08-21 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho visou a síntese e caracterização de nanopartículas de ouro (AuNPs) e sua aplicação na construção de biossensores plasmônicos utilizando para a detecção as técnicas de LSPR (ressonância de plasmon de superfície localizado) e SERS/SEF (espalhamento Raman intensificado por superfície / fluorescência intensificada por superfície). As AuNPs foram sintetizadas na forma de nanobastões (AuNRs) e nanobipirâmides (AuNBs) utilizando o método de crescimento por partículas precursoras (seed) e utilizando surfactantes para direcionamento do crescimento das mesmas. Devido ao melhor rendimento obtido para AuNRs, avaliou-se apenas sua sensibilidade em suspensão ou imobilizadas em lâminas de vidro. Para a imobilização em vidro, o 3-mercaptopropiltrimetoxisilano foi utilizado como molécula ligante entre o vidro e as AuNPs e posteriormente os substratos modificados foram caracterizados por espectroscopia UV-VIS, microscopia eletrônica de varredura e voltametria cíclica. A superfície dos AuNRs foi modificada para a detecção de duas biomoléculas-prova: (1) estreptavidina, realizada pelo mecanismo de interação por bioafinidade com a biotina, utilizando cisteamina como ligante entre as AuNPs e a biotina; (2) anti-BSA, através do mecanismo de interação antígeno-anticorpo, ativando a superfície das AuNPs (previamente modificada com ácido mercaptoundecanóico) com N-(3-dimetilaminopropil)-N′-etilcarbodiimida e N-hidroxisuccinimida. A sensibilidade LSPR foi monitorada pelo deslocamento do máximo da banda do plasmon longitudinal dos AuNRs frente ao aumento do índice de refração local devido às modificações na superfície dos AuNRs, alcançando 297 nm RIU-1. A detecção por SERS foi realizada através do modo extrínseco, utilizando um corante (IR-820) como molécula marcadora sobre a superfície dos AuNRs. Os biossensores construídos tiveram desempenho satisfatório na detecção de moléculas provas, além de boa sensibilidade frente a modificações no índice de refração do meio; isso foi observado tanto para AuNPs em suspensão ou imobilizadas em lâminas de vidro. Os procedimentos reportados são simples, rápidos e eficientes para a aplicação em biossensores. Adicionalmente, a integração das AuNPs em suspensão (modificadas com moléculas marcadoras) com as AuNPs imobilizadas nas lâminas de vidro, se mostrou um método interessante para a detecção de biomoléculas utilizando SERS/SEF. / This work was focused on the synthesis and characterization of gold nanoparticles (AuNPs) for applying as LSPR (localized surface plasmon resonance) and SERS/SEF (surface enhanced Raman spectroscopy / surface enhanced fluorescence) based biosensors. AuNPs were synthesized in two different forms, nanorods (AuNRs) and nanobipyramids (AuNBs), controlling the growth of seeds by using surfactants. A better yield was obtained to AuNRs and therefore, only the sensitivity of these nanoparticles was evaluated either using the AuNRs in suspension or immobilized on glass slides. A monolayer of 3-mercaptopropylmetoxisilane was used as a linker between AuNPs and glass surface, and after the modified glass slides were characterized with UV-VIS spectroscopy, scanning electronic microscopy and cyclic voltammetry. AuNRs surface was modified aiming the detection of two probe molecules: (1) streptavidin allowed by the bioafinity for biotin, using cysteamine as monolayer between AuNPs and biotin; (2) anti-BSA allowed by an antigen-antibody interaction activating the surface (previously modified with mercaptoundecanoic acid) with N-(3-dimetilaminopropil)-N′-etilcarbodiimide and N-hidroxisuccinimide. The LSPR sensitivity was evaluated by monitoring shifts in the longitudinal plasmon mode of AuNRs with changes in local refractive index due to surface binding events, reaching 297 nm RIU-1. SERS sensitivity was carried out in an extrinsic mode using a dye (IR-820) as SERS label on AuNRs surface. The biosensors developed in this work (AuNPs in suspension and adsorbed on glass slides) are efficient as biosensor as they presented good sensitivity for change in refractive index and for surface binding with probe molecules. The main advantages of these biosensors is the simple methodology summed to the short time of analysis. In addition, coupling the labeled AuNPs in suspension with the AuNPs adsorbed on glass slides is an interesting methodology for SERS/SEF detection of biomolecules.

O uso de técnicas espectroscópicas para o estudo de questões ambientais é uma área de pesquisa que vem experimentando importante desenvolvimento em tempos recentes. Essas técnicas abrangem métodos espectroscópicos intensificados, que proporcionam grande sensibilidade e seletividade para a detecção de espécies químicas em baixas concentrações. Nesta dissertação, propomos a introdução de uma nova metodologia aplicada ao estudo da fotodegradação de moléculas de interesse ambiental. Utilizamos técnicas de espectroscopia Raman intensificada pela superfície (SERS) para a análise dos processos de fotodegradação de azo-corantes mediados por dióxido de titânio. Nosso primeiro passo para o desenvolvimento dessa metodologia foi realizar um estudo comparativo acerca de diferentes métodos para preparação de um substrato SERS-ativo - sobre cuja superfície viríamos a proceder a fotodegradação de corantes e simultaneamente o estudo espectroscópico desse processo. A dificuldade na preparação do substrato reside no fato de que é necessário produzir uma superfície simultaneamente fotocatalítica (pela presença do semicondutor TiO2) e com atividade SERS (pela presença de partículas de Ag nanoestruturadas). Assim, três diferentes métodos para a preparação do substrato foram estudados, buscando obter atividade SERS aliada à reprodutibilidade. Escolhido o método mais satisfatório, utilizamos o substrato para realizar estudos SERS dos processos de fotodegradação de dois corantes: vermelho do Congo e verde de Janus. Considerando que a degradação fotocatalítica pode envolver oxidação e redução das moléculas, foi realizado também o estudo espectroeletroquímico dos dois corantes, buscando correlações que ajudassem a esclarecer as transformações envolvidas nas etapas iniciais da fotodegradação dessas substâncias. Nossos estudos revelaram que as primeiras etapas dos processos de fotodegradação dos dois corantes seguem mecanismos diferentes: enquanto no caso do vermelho do Congo há evidências de oxidação, no caso do verde de Janus as evidências apontam para um processo de redução. A combinação de dados da fotodegradação de corantes com seu estudo via eletroquímica - utilizando técnicas de espectroscopia intensificada para a identificação e caracterização de produtos - mostrou-se bastante promissora, no sentido de oferecer informações relevantes sobre os complexos mecanismos envolvidos nos processos de fotodegradação. / The use of spectroscopic techniques for the study of environmental questions is a research area has been experiencing important developments in recent years. These techniques embrace intensified spectroscopic methods, which offer great sensibility and selectivity for the detection of chemical species in low concentrations. In this work, we propose the introduction of a new methodology to be applied to the study of photodegradation of environmentally relevant molecules. We employed surface-enhanced Raman spectroscopy to the analysis of photodegradation of azo-dyes mediated by titanium dioxide. First, we performed a comparative study concerning the different methods for the preparation of SERS-active substrate, onto which we would carry out simultaneously the photodegradation of dyes and the spectroscopic study of the process. The difficulty in the preparation of such substrates resides in the fact that it is necessary to produce a surface which is all together photocatalytic (by the presence of the semiconducting TiO2) and SERS-active (by the presence of nanostructured silver). In this context, three different preparation methods were investigated, with the purpose of achieving good SERS activity and reproducibility. The optimized SERS-active substrate was employed to study the photodegradation of two azo-dyes: Congo red and Janus green. Considering that the photocatalitic degradation process might involve either the oxidation or the reduction of molecules, the spectroelectrochemical study of both dyes was also performed, in order to in order to search for important correlations that would help to clarify the transformations involved in the initial steps of the photochemical decomposition of these substances. The obtained results revealed that the first steps of the degradation processes of both dyes followed different routes: whereas for Congo red there are evidences of an oxidation process, for Janus green the evidences point to a reduction mechanism. The combination of the data relative to the photochemical behavior of the dyes and their electrochemical study - using enhanced spectroscopic techniques for identification and characterization of products - has proven to be very promising, in the sense of offering relevant information with respect to the complex mechanisms that are involved in photodegradation processes.

L’imagerie par Résonance des Plasmons de Surface (SPRI) est une technique d’analyse d’interactions moléculaires présentant de nombreux avantages. Elle peut être appliquée en temps réel et sans marquage, pour étudier un grand nombre d’interactions simultanément sur un même échantillon. La transduction d’un événement d‘interaction entre deux molécules complémentaires en un signal optique, repose sur la perturbation de l’onde plasmonique évanescente créée à la surface d’un film métallique mince.Toutefois, bien que la mesure SPR soit directe et sans marquage, sa spécificité repose entièrement sur celle des molécules sondes déposées à la surface de la puce et donc sur la chimie ayant servi à les immobiliser. Cette limitation devient problématique pour adresser les grands enjeux de santé actuels, liés à la détection de molécules à l’état de traces. En particulier, de nouveaux systèmes d’analyse plus sensibles sont requis pour pouvoir diagnostiquer le cancer au plus tôt, ou encore détecter la présence de contaminants agro-alimentaires en faible concentration.Dans cette perspective d’amélioration de la spécificité de détection, ce travail porte sur la mise au point d’un instrument bimodal couplant la SPRI, capable de quantifier la capture de molécules cibles, à la Spectrométrie Raman Exaltée de Surface (SERS), qui permet d’identifier la nature des molécules capturées en déterminant leur « empreinte » moléculaire. Cette thèse s’inscrit dans un projet ANR regroupant un consortium de partenaires académiques et un industriel.Ce document se concentre sur le développement de l’instrument optique combinant les deux systèmes de détection en un seul prototype. La mesure SPRI est réalisée en configuration Kretschmann, tandis que l’analyse SERS s’effectue par le dessus, en milieu liquide, à travers un hublot. Ces deux mesures simultanées sont rendues possibles grâce à la mise au point d’un substrat métallique nanostructuré. Une caractérisation détaillée du système optique est tout d’abord présentée, puis de premiers résultats de validation de la mesure bimodale sur un cas modèle d’interaction biomoléculaire ADN sont démontrés. Ces expériences prometteuses confirment le fonctionnement de l’instrument bimodal dans la perspective d’applications d’intérêt biologique. / Surface Plasmon Resonance Imaging (SPRI) is a powerful technique to study molecular interactions providing a real time, label free and high throughput analysis. The transduction of an interaction between complementary molecules into an optical signal is based on the perturbation of a plasmonic evanescent wave supported by a thin metallic film.However, despite its direct and label free assets, the specificity of SPR measurements is only guaranteed by the probe molecules grafted on the metallic surface and therefore by the quality of the surface chemistry. This limitation becomes an issue when addressing major health concerns relying on the detection of trace molecules. In particular, new systems are required to help early diagnosis and the control of food contaminants.In view of improving measurement’s specificity, this work reports the development of a bimodal instrument coupling SPRI, allowing the quantification of captured molecules, with Surface Enhanced Raman Spectroscopy (SERS), adding the precise identification of the molecules by measuring their spectroscopic fingerprint. This PhD is part of an ANR project bringing together academic and industrial partners.This manuscript focuses on the development of the optical instrument combining the two detection systems in a unique prototype. SPRI measurements are performed in the Kretschmann configuration while SERS analysis is implemented from the top, in solution, through a glass window. Nanostructured substrates have been designed and realized to allow the simultaneous experiment.The optical system is described, characterized and validated on the model case of a DNA hybridization. These first results prove the capabilities of the bimodal instrument in the perspective of more complex biological applications.

Schnelltests sind eine weit verbreitete Analysemethode, um vor Ort schnelle analytische Aussagen treffen zu können. Ein möglicher Zugang zu Schnelltests für Analyten in geringer Konzentration könnten Messung von Oberflächenverstärkten Raman-Spektren sein. In der vorliegenden Arbeit wird insbesondere auf drei Aspekte der SERS-Messungen (= Oberflächenverstärkte Raman-Streuung) eingegangen: die Reproduzierbarkeit der SERS-Signalintensität, die Interpretation der Konzentrationskurven und die Analyse von Probengemischen. Für die Untersuchung der Reproduzierbarkeit wurden verschiedene Auftragungsmethoden und Messsysteme getestet und es wurde untersucht, wie reproduzierbar die Signalintensitäten über einen längeren Zeitraum sind. Dabei wurde festgestellt, dass die Kombination von einer homogenen Auftragung der Nanopartikelsuspensionen auf dem Papier und ein großer Durchmesser des Laser- und Detektionspunktes auf der Probe zu einer stabileren Signalintensität führen. Die bei einem Labormessaufbau eine Stabilität des Messsignals von ca. 20 % relativer Standardabweichung über einen Zeitraum von ca. 2,5 Monaten lieferte. Für die Analyse und Auswertung der Abhängigkeiten der SERS-Signalintensität von der Konzentration des Analyten wurden Konzentrationsreihen von verschiedenen Verbindungen aufgenommen. Die Messdaten konnten mit einer Langmuir-Isotherme beschrieben und mit dem Langmuir-SERS-Modell erklärt werden. Für die gemessenen Thiolverbindungen wurde zudem noch eine weitere Möglichkeit der quantitativen Analyse gefunden, die auf der Auswertung der Verschiebung von bestimmten SERS-Banden im Spektrum in Abhängigkeit von der Analytkonzentration beruht. Für die Analysen der Mehrkomponenten-Lösungen wurden die Papierbasierten Mikrofluidik-Analysesysteme (µPADs) eingesetzt. Hier konnte beobachtet werden, dass Analyten aus einer Lösung auf Grund ihrer hohen Affinität zu den Nanopartikeln abgetrennt werden können und es so möglich ist, diese zu analysieren. / Rapid tests are widely used analytical methods for obtaining analytical information immediately on site. Surface enhanced Raman scattering (SERS) is a possible detection method for compounds in diluted samples. This thesis focuses mainly on three aspects: reproducibility of SERS signal intensity, interpretation of concentration curves and analysis of sample mixtures. The signal reproducibility was investigated using different deposition methods and measurement systems and the reproducibility of measurements was tested over longer periods of time. It was found that the most stable signal intensity was obtained using a combination of homogeneous deposition of a nanoparticle suspension on paper and a detection configuration that involves large diameters of both, the laser and the detection spot on the sample. It was shown with a laboratory setup, that comparatively stable measurements are possible with a relative standard deviation of approx. 20 % over a period of approx. 2.5 months. For the analysis and interpretation of the dependence of the SERS signal intensity on the concentration of the analyte, concentration series of different compounds were measured. The measurement data could be fitted with a Langmuir isotherm and explained with the Langmuir SERS model. For the measured thiol compounds an alternative option for quantification was found: the shift of certain SERS bands in the Raman spectrum as a function of analyte concentration. For the analysis of compound mixture in solution microfluidic paper-based analytical devices (µPADs) were used. It was observed that certain analytes which have a high affinity for the nanoparticles can be separated from the solution and thereby analyzed.

This work describes a master’s thesis in engineering physics at Umeå University carried out during the spring semester of 2014. In the thesis the student has constructed and tested a temperature controlled cell for cooling/heating of surface-enhanced-Raman-spectroscopy (SERS) substrates for rapid detection of volatile substances. The thesis was carried out at the Swedish Defence Research Agency (FOI) in Umeå, Sweden. A Linkam Scientific Instruments TS1500 cell was equipped with a Peltier element for cooling/heating and a thermistor temperature sensor. A control system was constructed, based on an Arduino Uno microcontroller board and a pulse-width-modulated (PWM) H-bridge motor driver to control the Peltier element using a proportional-integral (PI) control algorithm. The temperature controlled cell was able to regulate the temperature of a SERS substrate within -15 to +110 °C and maintain the temperature over prolonged periods at ±0.22 °C of the set point temperature. Gas phase of 2-chloro-2-(difluoromethoxy)-1,1,1-trifluoro-ethane (isoflurane) was flowed through the cell and SERS spectra were collected at different temperatures and concentrations. This test showed that the signal is increased when the substrate is cooled and reversibly decreased when the substrate was heated. Keywords: temperature control, Raman scattering, surface enhanced Raman spectroscopy SERS, SERS substrate, volatile substances, Peltier module, thermistor, PWM, H-bridge, PI(D) control. / Detta dokument beskriver ett examensarbete för civilingenjörsexamen i teknisk fysik vid Umeå Universitet som utförts under vårterminen 2014. I examensarbetet har en kyl-/värmecell för temperaturkontroll av substratytor för ytförstärkt ramanspektroskopi (SERS) för snabb detektion av farliga flyktiga ämnen konstruerats och testats. Arbetet utfördes vid Totalförsvarets forskningsinstitut (FOI) i Umeå, Sverige. Utgångspunkten var ett Linkam Scientific Instruments TS1500 mikroskopsteg, vilket utrustades med ett Peltierelement för kylning/värmning och en termistor för temperaturövervakning. Ett styrsystem baserat på ett Arduino Uno mikrostyrenhetskort konstruerades med ett motordrivkort (H-brygga) vilket använder pulsbreddsmodulering (PWM) för att reglera spänningen till Peltierelementet utifrån en PI-regulator. Den färdiga cellen klarade att reglera temperaturen på ett SERS-substrat i ett temperaturspann på ungefär -15 till +110 °C med en temperaturstabilitet på ±0.22 °C av måltemperaturen. Cellen testades sedan på flyktiga ämnen för att visa dess funktion. Difluorometyl-2,2,2-trifluoro-1-kloroetyleter (isofluran) i gasfas, med instrumentluft som bärargas, flödades genom cellen och SERS-spektra erhölls vid olika koncentrationer och temperaturer. Vid samtliga koncentrationer visades att lägre temperatur ger ökad signalstyrka. När ytan sedan värmdes upp sjönk signalen reversibelt tillbaka till ursprungsvärdet. Nyckelord: temperaturkontroll, ytförstärkt ramanspektroskopi, SERS, flyktiga ämnen, Peltierelement, thermistor, PWM, H-brygga, PI(D)-regulator.

Les matériaux nanocomposites poreux organisés présentent de nombreuses propriétés dans le domaine de l’adsorption. Cette étude est portée sur la synthèse de matériaux poreux de grande aire spécifique fonctionnalisés par des nanoparticules métalliques en visant des applications dans le domaine de l’adsorption: en phase liquide et en phase gazeuse.La première application concerne la détection en phase liquide de molécules à de faibles concentrations. Des nanocomposites composés d’une matrice poreuse de silice dans laquelle sont insérées des nanoparticules de métaux nobles (i.e. Ag@SiO2 et Au@SiO2) sont étudiés comme substrats SERS en couplant thermodynamique et spectroscopie Raman. Ce couplage de l’étude de la réponse Raman et de l’étude thermodynamique de l’adsorption a conduit à une meilleure compréhension de l’influence des particules sur le seuil de détection de la molécule. L’influence de plusieurs paramètres sur la réponse Raman de la molécule sonde et sur ses propriétés d’adsorption a aussi été étudiée (la taille des particules, la nature chimique du métal, etc.).La seconde application concerne le stockage d’hydrogène. Des nanocomposites composés de matrices poreuses de silice ou de carbone dans lesquelles sont incorporées des nanoparticules d’un métal de transition (i.e. Ni@SiO2 et Ni@Carbone) sont étudiés comme matériaux de stockage en couplant manométrie et microcalorimétrie d’adsorption. La mise en place d’une méthode de réduction adaptée a constitué une étape importante de ce travail. Ce couplage d’études thermodynamiques de l’adsorption a permis de déterminer les propriétés d’adsorption de l’hydrogène à basse température et basses pressions de ces matériaux. / Nanocomposite organized porous materials present many properties in particular in the field of adsorption. This study was based on the synthesis of porous materials of high specific surface area functionalized with metal nanoparticles focusing in particular on two applications in the field of adsorption: one in the liquid phase and the other one in the gas phase.The first application is the detection of molecules in the liquid phase at low concentrations. Nanocomposites composed of a porous silica matrix in which are inserted noble metal nanoparticles (i.e. Ag@SiO2 and Au@SiO2) are studied as SERS (Surface Enhanced Raman Scattering) substrates by coupling thermodynamics and Raman spectroscopy. The coupling of the Raman response study and the thermodynamics of adsorption study leads to a better understanding of the influence of the particles on the molecule detection threshold. The influence of various parameters on the Raman response of the probe molecule and its adsorption properties were also studied (the particle size, the chemical nature of the metal, etc.)The second application relates to the storage of hydrogen since Nanocomposites composed of porous silica or carbon matrices in which are incorporated transition metal nanoparticles (i.e. Ni@SiO2 and Ni@Carbon) were studied as storage materials by coupling the adsorption manometry and microcalorimetry. The establishment of a suitable reduction method was an important step in this work. This coupling of thermodynamic studies of the adsorption was used to determine the adsorption properties of hydrogen at low temperature and low pressures of these materials.

A síntese e caracterização de sistemas hetero-híbridos gerados a partir da 3,6-bi-2-piridil-1,2,4,5-tetrazina (bptz) e interações com ouro nanoparticulado são abordados nesta tese. O bptz foi estudado por meio de métodos espectroscópicos e teóricos, focalizando principalmente o efeito SERS associado à adsorção em nanopartículas de ouro. O mecanismo de transferência de carga para metais macroscópicos foi transposto para a condição nanoparticulada, envolvendo ligações químicas entre bptz e as nanopartículas. Os complexos estudados possuem fórmula geral [LmRu(µ-bptz)RuLm]Xn, com “L” indicando os ligantes periféricos 5-cloro-1,10-fenantrolina (Clphen) ou 4’-(fenil)-2,2&#8217:6&#8217,2&#8221-terpirdina (ptpy) e “X” os contra-íons. Foram investigadas suas espectroeletroquímicas eletrônica e SERS, e as mudanças de perfil vibracional foram modeladas, incorporando o mecanismo de transferências de carga entre complexo e o ouro, além dos mecanismos ressonantes e eletromagnéticos / The synthesis and investigation of heterohybrid systems encompassing 3,6-bi-2-pyridyl-1,2,4,5-tetrazine (bptz) and its ruthenium complexes associated with gold nanoparticles are dealt with in this thesis. Bptz was characterized by spectroscopic and theoretical techniques, focusing on its SERS spectra after the adsorption onto nanoparticles. The charge transfer mechanism in the SERS spectra of macroscopic metals was transposed to the nanoparticle condition, assuming the formation of chemical bonds between bptz and the nanoparticles. Complexes of general formula [LmRu(µ--bptz)RuLm]Xn, “L” the peripheric ligants 5-chlorine-1,10-phenantroline or 4’-(phenyl)-2,2&#8217:6&#8217,2&#8221-terpyrdine (ptpy), and “X” counter-ions were also investigated, with special emphasis on their electronic and SERS spectroelectrochemistry. The changes in the vibrational profiles were successfully explained by the occurrence of charge transfer between the adsorbed complex and gold, in addition to the electromagnetic and resonance mechanisms.