Dissertations / Theses on the topic 'Surface-enhanced Raman spectroscopy'
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Scherzer, Ryan D. "Degradation Resistant Surface Enhanced Raman Spectroscopy Substrates." UNF Digital Commons, 2017. http://digitalcommons.unf.edu/etd/760.
Full textXie, Yu-Tao. "Surface-enhanced hyper raman and surface-enhanced raman scattering : novel substrates, surface probing molecules and chemical applications /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202007%20XIE.
Full textGant, Virgil Alexander. "Detection of integrins using surface enhanced raman spectroscopy." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/2304.
Full textCunningham, Dale. "Fundamental studies of surface enhanced resonance Raman spectroscopy." Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438120.
Full textSockalingum, Dhruvananda. "Surface enhanced Raman spectroscopy in the near-infrared." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315640.
Full textSharma, Narayan. "Solution Processable Surface Enhanced Raman Spectroscopy (SERS) Substrate." Bowling Green State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1434375587.
Full textTsoutsi, Dionysia. "Inorganic Ions Sensing by surface-enhanced Raman scattering spectroscopy." Doctoral thesis, Universitat Rovira i Virgili, 2015. http://hdl.handle.net/10803/288213.
Full textEn este proyecto de tesis se ha conseguido desarrollar un sistema de detección, identificación y cuantificación independiente de iones inorgánicos. La detección de los iones se basa en su diferente afinidad hacia diferentes ligandos orgánicos a través de la espectroscopia de dispersión Raman aumentada por superficies (surface-enhanced Raman scattering, SERS). En resumen, como sustrato se utilizarán nanopartículas de plata o microesferas nanoestructuradas que se prepararán mediante la adsorción de nanopartículas de oro sobre la superficie de microesferas de sílice mediante el protocolo de capa por capa y su posterior crecimiento epitaxial con plata. Este último paso se realizará mediante protocolos desarrollados en nuestro laboratorio y tiene como objetivo la obtención de superficies plasmónicas discretas altamente eficientes en SERS. Los sustratos se funcionalizarán posteriormente con ligandos orgánicos tiolados con alta afinidad por iones inorgánicos (el fluoróforo orgánico, amino-MQAE y la terpiridina, pztpy-DTC). Como paso siguiente, se realizará la detección y cuantificación simultánea de los iones combinando para su detección espectroscopia SERS. Los cambios espectrales SERS en el modo de vibración de los ligandos orgánicos están correlacionados como función de la concentración de cada ion con límites de detección comparables a los de varios métodos analíticos convencionales.
In this research project we successfully developed a novel sensing system for the identification and quantification of inorganic ions independently by means of surface-enhanced Raman scattering (SERS) spectroscopy. The detection of the ions is based on their different affinity toward various organic ligands. In summary, we use as SERS-active substrates, either silver nanoparticles or composite nanostructured particles prepared by adsorption of gold nanoparticles on the surface of silica microbeads, using layer-by-layer assembly protocol and the subsequent epitaxial overgrowth of silver. This last step is performed using protocols developed in our laboratory and aims to the fabrication of highly plasmonic surfaces for SERS experiments. Next, the substrates are functionalized with thiolated organic ligands with high affinity toward inorganic ions (amino-MQAE, an organic fluorophore, and pztpy-DTC, a terpyridine). As a further step, the simultaneous identification and quantification of the ions, using SERS spectroscopy, is performed. Vibrational changes in the SERS spectra of the organic ligands are correlated as a function of the concentration of each ion with limits of detection comparable to those of several conventional analytical methods.
Yang, Mingwei. "In Situ Arsenic Speciation using Surface-enhanced Raman Spectroscopy." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3387.
Full textHuang, Qunjian. "Surface-enhanced raman scattering and surface-enhanced hyper raman scattering : a systematic study of various probing molecules on novel substrates /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202003%20HUANG.
Full textHe, Lili Lin Mengshi. "Application of surface enhanced Raman spectroscopy to food safety issues." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6859.
Full textSACCO, ALESSIO. "Metrological Approach to Tip-enhanced Raman Spectroscopy." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2827709.
Full textKier, Ruth. "Flow systems for use in surface enhanced resonance raman spectroscopy." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249054.
Full textMarshall, Addison Robert Lee. "Surface enhanced Raman spectroscopy for single molecule detection and biosensing." Thesis, University of Hull, 2017. http://hydra.hull.ac.uk/resources/hull:16553.
Full textNicolson, Fay. "Through barrier detection using surface enhanced spatially offset Raman spectroscopy." Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30290.
Full textPanagoulia, Danai. "Surface enhanced Raman spectroscopy of the ionic liquid-metal interface." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/422133/.
Full textWei, Haoran. "Surface-Enhanced Raman Spectroscopy for Environmental Analysis: Optimization and Quantitation." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/93204.
Full textPHD
Hansson, Freja. "Detection of Contaminants in Water Using Surface Enhanced Raman Spectroscopy." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-85943.
Full textTouzalin, Thomas. "Tip-enhanced Raman spectroscopy on electrochemical systems." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS364.
Full textThe in situ investigation of electrochemical interfaces structures at the nanoscale is a key element in the understanding of charge and electron transfer mechanisms e.g. in the fields of energy storage or electrocatalysis. This thesis introduces the implementation of tip-enhanced Raman spectroscopy (TERS) in liquid and in electrochemical conditions enabling the nanoscale analysis of electrified solid/liquid interfaces through the strong and local electric field enhancement at gold or silver scanning tunneling microscopy (STM) probes. The ability of TERS to image inhomogeneities in the coverage density of a self-assembled monolayer (SAM) through a layer of organic solvent on gold was demonstrated. A TERS-inspired analytical tool was also developed, based on a TERS tip used simultaneously as a single-hot spot surface-enhanced Raman spectroscopy (SERS) platform and as a microelectrode (EC tip SERS). The reduction of an electroactive SAM could then be monitored by electrochemical and in situ SERS measurements. In situ electrochemical STM-TERS was also evidenced through the imaging of local variations of the electric field enhancement on peculiar sites of a gold electrode with a lateral resolution lower than 8 nm. Finally TERS also demonstrated to be efficient in investigating the structure of organic layers grafted either by electrochemical reduction or spontaneously. This work is therefore a major advance for the analysis of functionalized surfaces
Boddu, Naresh Kumar. "Trace analysis of biological compounds by surface enhanced Raman scattering (SERS) spectroscopy /." Connect to resource online, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1229542206.
Full textChowdhury, Mustafa Habib. "The use of Surface Enhanced Raman Spectroscopy (SERS) for biomedical applications." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4816.
Full textSyed, Azfar A. "Surface enhanced Raman spectroscopy for ultra-sensitive detection of energetic materials." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/4644.
Full textWigginton, Krista Rule. "Surface Enhanced Raman Spectroscopy as a Tool for Waterborne Pathogen Testing." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29330.
Full textPh. D.
Jain, Ishan. "Paper-Based Sensors for Contaminant Detection Using Surface Enhanced Raman Spectroscopy." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/53946.
Full textMaster of Science
Shadi, Iqbal Tahear. "Surface enhanced resonance Raman spectroscopy of dyes : semi-quantitative trace analysis." Thesis, University of Greenwich, 2005. http://gala.gre.ac.uk/6296/.
Full textSyed, A. A. "Surface enhanced raman spectroscopy for ultra-sensitive detection of energetic materials." Thesis, Department of Materials and Applied Science, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/4644.
Full textIsraelsen, Nathan. "Surface-Enhanced Raman Spectroscopy-Based Biomarker Detection for B-Cell Malignancies." DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4605.
Full textCARA, ELEONORA. "Tailored fabrication of nanostructured substrates for surface-enhanced Raman spectroscopy applications." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2735516.
Full textCoyle, Candace Mikki. "Surface-enhanced Raman spectroscopic studies of organonitriles on copper colloids." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=919.
Full textTitle from document title page. Document formatted into pages; contains xvii, 169 p. : ill. Vita. Includes abstract. Includes bibliographical references.
Willner, Marjorie Rose. "Environmental Analysis at the Nanoscale: From Sensor Development to Full Scale Data Processing." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/94644.
Full textPh. D.
Sheremet, E., A. G. Milekhin, R. D. Rodriguez, T. Weiss, M. Nesterov, E. E. Rodyakina, O. D. Gordan, et al. "Surface- and tip-enhanced resonant Raman scattering from CdSe nanocrystals." Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-161500.
Full textDieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
Mabbott, Samuel. "Optimisation of solid-state and solution-based SERS systems for use in the detection of analytes of chemical and biological significance." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/optimisation-of-solidstate-and-solutionbased-sers-systems-for-use-in-the-detection-of-analytes-of-chemical-and-biological-significance(de70094c-8da0-4326-bfb2-6adf00b86af9).html.
Full textDoherty, Matthew David. "Plasmonic nano-antenna arrays for surface enhanced Raman spectroscopy and other applications." Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601361.
Full textSirimuthu, Narayana M. S. "Increasing the range and reproducibility of quantitative surface-enhanced Raman spectroscopy (SERS)." Thesis, Queen's University Belfast, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431477.
Full textMallinder, Benjamin. "Detection of deoxyribonucleic acid by surface enhanced resonance Raman scattering spectroscopy (SERRS)." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248771.
Full textBoddu, Naresh K. "Trace Analysis of Biological Compounds by Surface Enhanced Raman Scattering (SERS) Spectroscopy." Youngstown State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1229542206.
Full textDe, Jesus Jenny Padua. "HEAVY METAL DETECTION IN AQUEOUS ENVIRONMENTS USING SURFACE ENHANCED RAMAN SPECTROSCOPY (SERS)." Miami University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=miami1513185193940902.
Full textPapadopoulou, Evanthia. "Detection of DNA components and DNA sequences by surface-enhanced Raman spectroscopy." Thesis, Queen's University Belfast, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546409.
Full textFrano, Kristen A. "Surface-Enhanced Raman and Single-Molecule Spectroscopy Studies of Fugitive Artists' Pigments." W&M ScholarWorks, 2015. https://scholarworks.wm.edu/etd/1539791830.
Full textCarneiro, Leandro de Bispo. "Detecção do peptídeo p17 (HIV) baseado em SERS (Surface-enhanced Raman Spectroscopy) /." Araraquara, 2015. http://hdl.handle.net/11449/138424.
Full textBanca: Marcelo Nalin
Banca: Antonio Aparecido Pupim Ferreira
Banca: Gustavo Fernandes Souza Andrade
Banca: Airton Abrahan Martin
Resumo: A espectroscopia de Raman intensificada por superfície (SERS, termo em inglês Surfaceenhanced Raman Spectroscopy) é uma técnica promissora que mostra a sensibilidade para a detecção da interação de biomoléculas que são importantes para detecção precoce de doenças. O vírus da imunodeficiência humana (HIV) têm sido um grande problema por várias décadas. Existem vários métodos de deteção baseados na interação específica de anticorpos, tais como, o ELISA e os testes rápidos (TR's). No entanto, novas estratégias têm sido desenvolvidas para rápido diagnóstico do vírus HIV, e uma prova de conceito de detecção do peptídeo p17-1 foi descrito neste trabalho. A proteina matriz p17 é uma essencial proteína no ciclo de replicação do vírus HIV. As fases iniciais da replicação do vírus envolve a pré integração do complexo do DNA no núcleo do p17 desempenhando um papel na ligação de RNA viral e transporte para a membrana. Neste trabalho foram descritos duas plataformas SERS para a detecção do vírus HIV baseado no peptide p17 -1 (sequência LSGGELDRWEKIRLPGG). O anticorpo foi imobilizado em um substrato de ouro usando duas diferentes camadas automontadas (SAM). A primeira SAM, os substratos de ouro foram imersos em uma solução aquosa de 11 mercaptoundecanóico (MUA). Na segunda SAM, os substratos foram imersos em uma mistura aquosa de politietileno glicol (SHPEG- COOH e SH-PEG-CH3). Aqui serão chamados de SAM-MUA e SAM-PEG, respectivamente. Ambas as SAM's foram imersas emu ma solução de anticorpo (anti-p17) e foram descritas como plataforma d captura MUA e PEG. Ambas plataformas foram funcionalizadas com o peptídeo p17-1. Sondas SERS foram preparadas com nanopartículas de ouro e revestidas com uma molécula Raman reporter (azul de Nilo A) e funcionalizadas com um anticorpo anti-p17. Estas estruturas (sonda SERS e plataformas de captura) formam um ensaio sanduíche...
Abstract: Surface-enhanced Raman Scattering (SERS) technique offers great promises for simplified and sensitive detection of biomolecular interactions that are relevant for early disease diagnostics. Human immunodeficiency virus (HIV) has been a problem for decades. There are several methods of diagnostics based on antibodies specific reactions, such as enzyme-linked immunosorbent assays (ELISAs) and rapid test (RT). However, new strategies have been developed for rapid HIV diagnostics and, as a proof-of-concept, peptide p17-1 was considered here. The matrix protein p17 is a structural protein that is essential in the life cycle of the retrovirus The early stages of the virus replication involve the pre integration of the DNA complex into the nucleus P17 plays a role in RNA viral binding and transport to the membrane. Here were describe two new SERS platform for HIV detection based on peptide p17-1 (sequence LSGGELDRWEKIRLPGG). The antibody anti-p17 was immobilized in a planar gold surface using two differents self-assembled (SAM) techniques. First SAM, were obtained by immersion of the surface into ethanolic solution of 11-Mercaptoundecanoic acid (MUA). Second SAM were obtained by immersion in aqueous solution aquous mixtures of (SH-PEG-COOH/SH-PEG-CH3) and polyethylene glycol (PEG,). Here were describe the two platforms as SAM-MUA and SAMPEG, respectively. Both SAM's were immersed in a solution containing the anti-p17. Samples at this step were called capture platform-MUA and capture platform-PEG. Both capture platforms were funcionalizated with the peptide p17-1. SERS probes were prepared with gold nanoparticles coated with a Raman reporter molecule (Nile Blue A) and, functionalized with an anti-p17. These structures (SERS probe and capture platforms) allow for a sandwich assay, a strategy regularly used for high-sensitivity detection. The light blue color in the SERS mapping represents peptide strong...
Doutor
Ohlhaver, Christopher M. "Use of Surface Enhanced Raman Spectroscopy for the Detection of Bioactive Lipids." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5551.
Full textGrytsyk, Natalia. "Development of the surface-enhanced infrared spectroscopic approach and surface-enhanced Raman spectroscopy coupled with electrochemistry to study reaction mechanism of membrane proteins." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF057/document.
Full textThis thesis concerns the development of surface-enhanced infrared and Raman spectroscopic approaches: surface-enhanced infrared absorption spectroscopy (SEIRAS) combined with perfusion cell and surface-enhanced Raman spectroscopy (SERS) combined with electrochemistry. Within the first project different proteins were studied: Lactose Permease (LacY), complex I and IM30.The pKa of Glu325 in LacY WT and in different mutants carrying mutations in the proton translocation active center was determined. WT complex I was oxidized with different oxidizing agents and reduced with NADH. Corresponding redox-induced conformational changes were studied. The evidence was given that Mg2+ ions induce conformational changes in the protein IM30.Within the second project the spectroelectrochemical cell containing gold grid electrode was adopted for the studies of redox active proteins. This gold grid serves both as working electrode and as SERS active substrate. First Cyt c, Hb and Mb were used to validate the setup and then the approach was extended to study a membrane protein
White, Daniel Joshua. "Nanostructured optical fibre for use as miniature surface-enhanced raman scattering sensors." Swinburne Research Bank, 2008. http://hdl.handle.net/1959.3/42062.
Full textThesis submitted in fulfilment for the degree of Doctor of Philosophy, Centre for Atom Optics and Ultrafast Spectroscopy, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, 2008. Typescript. Bibliography: p. 151-160.
bhardwaj, vinay. "Label-free surface-enhanced Raman spectroscopy-linked immunosensor assay (SLISA) for environmental surveillance." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2321.
Full textSutton, C. P. "Application of surface enhanced raman spectroscopy to measurements of diffusion through silastic membranes." Thesis, University of Kent, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342271.
Full textLin, Yung-Chun. "Electrochemical surface enhanced Raman spectroscopy of a beacon probe immobilized on Au electrodes." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/422134/.
Full textRodriguez, Raul D., Evgeniya Sheremet, Tanja Deckert-Gaudig, Corinne Chaneac, Michael Hietschold, Volker Deckert, and Dietrich R. T. Zahn. "Surface- and tip-enhanced Raman spectroscopy reveals spin-waves in iron oxide nanoparticles." Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-168045.
Full textDieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
GURIAN, ELISA. "Biomedical applications of Surface Enhanced Raman Spectroscopy - a step forward to clinical practice." Doctoral thesis, Università degli Studi di Trieste, 2019. http://hdl.handle.net/11368/2936825.
Full textThis PhD project aims to apply nanostructured metal surfaces as substrates for Surface Enhanced Raman Spectroscopy for the study of biofluids. This analytical technique provides the vibrational fingerprint of a sample assisted by nanostructured metal surfaces, which can enhance the scattering signal of analytes adsorbed on them: this allows detection of analytes in very low concentrations. These features tell a lot about the potential of SERS in the bioanalytics, and indeed, in this field, the use of SERS has increased over the past decade taking advantage of both sensitive detection and fingerprinting features. Above all, SERS requires the manufacturing of metal nanostructured substrates as sensors. In particular, this project is based on the development of a label-free approach: no functionalization is present on the nanoparticles surface, and, hence, no preferential affinity for a given analyte in the biological matrix is sought. Briefly, once nanoparticles are in contact with the specimen, the analytes may adsorb on them without any specific interaction other than their affinity for the metal. The outcoming SERS signal will be a snapshot of what actually reached the metal surface, namely a fingerprint of the sample. For instance, the label-free analysis of biofluids reflect the metabolic content of the fluid itself. In the “omic” era, SERS can integrate with untargeted metabolomics and provide the metabolic profile of a specimen and distinguish different samples accordingly, based on differences in such profiles. Silver colloids have been chosen, given that their performances with biofluids are known. They have been used both as colloidal suspension in water, and fixed on a paper support, according to an in-house developed protocol for the fabrication of solid substrates. The coupling of metal nanostructures substrates with SERS acts as actual sensors, able to interact with aqueous environment and detect dissolved analytes. The real advantage of the paper supports lay in the stability of the spectroscopic response: they are long lasting, easy to fabricate and to handle, cost and time effective, prone to scale up. These reasons make them potential Point of Care tool in the frame of SERS applications. The aim of this PhD thesis is twofold: to push forward our fundamental knowledge of the nanostructure-biofluid interaction and to test the feasibility of the application of SERS for specific clinical problems. These goals were pursued in three steps: 1. to develop protocols for the label-free analysis of blood fractions (serum, plasma, erythrocytes, periphereal blood mononuclear cells, and whole blood) with SERS, exploiting their features according to several treatments and SERS substrates; 2. to characterize the behaviour of biomolecules at the interface with metal nanoparticles on model systems, namely to understand the role of the protein and non-protein corona in the metabolites-nanoparticle interaction. The model system used is based on mixture of human serum albumin (i.e. the most abundant serum protein) and molecules which are commonly detected in SERS of biofluids: adenine, hypoxanthine and uric acid; 3. to apply the aforementioned knowledge to the early diagnosis of several diseases (breast cancer, non-alcoholic fatty liver diseases, cirrhosis and hepatocellular carcinoma) through serum and plasma samples by means of multivariate data analysis of SERS spectra. Considering the latter application of SERS in the field of disease diagnosis, the aim is to provide new diagnostic methods complementary to the accepted gold standards such as immunochemistry and histopathology methods. The advantages of SERS lay on the rapid response and on the non-invasiveness of the liquid biopsy approach. As a future goal, the development of SERS platforms as label-free point of care tools integrated to portable Raman instruments could bring the diagnosis
Weber, Verena. "Plasmonic nanostructures for the realization of sensor based on surface enhanced Raman spectroscopy." Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3423838.
Full textLa Plasmonica si occupa dell’interazione di una radiazione elettromagnetica di opportuna lunghezza d’onda con gli elettroni di conduzione di un metallo. L’oscillazione collettiva degli elettroni, indotta da questa interazione, è chiamata appunto Risonanza Plasmonica. La risonanza plasmonica di superficie localizzata avviene quando gli elettroni coinvolti sono quelli di superficie di un metallo nanostrutturato con dimensioni minori o comparabili alla lunghezza d’onda di eccitazione. Da questa eccitazione deriva una forte amplificazione del campo elettromagnetico locale, localizzato nelle immediate vicinanze della nanostruttura metallica. Tale amplificazione, unita a una tecnica di rivelazione spettroscopica specifica, quale la spettroscopia Raman, può essere sfruttata per la realizzazione di sensori molecolari. La tecnica Raman è conosciuta come altamente specifica, perché in grado di fornire uno spettro caratteristico della singola molecola, identificandone univocamente la presenza e la costituzione. La sua maggiore limitazione, però, è la bassa sensibilità. Ponendo l’analita in prossimità di un substrato plasmonico, proprio nella regione di forte amplificazione del campo locale, la sensibilità di rivelazione viene fortemente aumentata, dando origine alla spettroscopia Raman amplificata da superfici (SERS). La prima parte del presente lavoro è focalizzata sulla sintesi e sulla caratterizzazione di nanoparticelle d’argento, d’oro e di nano gusci d’oro (chiamati nanoshell) e sul loro impiego per la realizzazione di substrati SERS, sia in soluzione colloidale che su substrato solido. L’utilizzo di differenti nanostrutture metalliche, dà la possibilità di sfruttare la risonanza plasmonica localizzata di superficie in un’ampia regione spettrale, che si estende dal visibile al vicino infrarosso. La caratterizzazione ottica e morfologica delle nanostrutture è stata effettuata con tecniche convenzionali, come la spettroscopia di assorbimento UV-visibile, il SERS, la microscopia elettronica a trasmissione e la microscopia a forza atomica. Ad esse è stata affiancata anche una tecnica raramente usata nell’ambito della plasmonica: la spettroscopia fotoacustica. Questa può fornire informazioni riguardanti il contributo di assorbimento, all’estinzione totale, di una nanostruttura plasmonica. Da una rigorosa misura dei fattori di amplificazione e delle proprietà di fotoacustica al variare della lunghezza d’onda, possono essere fatte alcune considerazioni riguardanti la possibile relazione tra l’estinzione (proprietà di campo lontano) e l’ amplificazione SERS (proprietà di campo vicino). Le misure dei profili di eccitazione SERS su substrati plasmonici in liquido e su supporto solido, hanno evidenziato la presenza di hot spots, ovvero di zone fortemente amplificate dall’interazione di due o più nanostrutture. I substrati SERS solidi sono risultati chimicamente stabili, omogenei e riproducibili; essi presentano valori di fattori di amplificazione attorno a 104-105. In soluzione colloidale, i fattori di amplificazione delle nanostrutture hanno raggiunto valori nell’intervallo 103-106, dipendentemente dal tipo di nanostruttura metallica investigata. Le misure di fotoacustica effettuate su soluzioni colloidali di nanoshell d’oro si sono rivelate in accordo con le predizioni teoriche di letteratura. Nella seconda parte del lavoro, i substrati plasmonici, realizzati principalmente con nanoparticelle e nanoshell d’oro, sono stati impiegati per la realizzazione di sensori SERS per la rivelazione di specie chimiche e biologiche. É stato realizzato un sensore di composti tossici aromatici volatili, accoppiando un substrato plasmonico con un film poroso di sol gel ibrido organico-inorganico. La componente organica della matrice sol gel è stata appositamente scelta per la sua alta affinità a composti aromatici, quali lo Xilene. È stata dimostrata l’amplificazione dei segnali della matrice da parte della componente plasmonica, ma si sono riscontrati alcuni problemi nella rivelazione delle molecole di analita attraverso il SERS. La difficoltà nella rivelazione è probabilmente dovuta al veloce deadsorbimento dello Xilene dalla matrice a causa del forte riscaldamento locale causato dalla radiazione laser. Nonostante questo, si è comunque dimostrata l’aumentata efficienza del sensore progettato, rispetto ai suoi componenti singoli. La seconda applicazione studiata ha riguardato la realizzazione di un sistema analita-accettore innovativo, che può essere utilizzato per diverse applicazioni bioanalitiche; esso è basato sull’interazione tra un cromoforo diazobenzenico (HABA) e il suo anticorpo specifico. Alla base dell’applicazione si trova una proprietà interessante del suddetto cromoforo, che è quella di cambiare la sua struttura molecolare, passando da una forma azo alla forma idrazo, dopo aver interagito con il suo anticorpo specifico. Questa variazione nella struttura molecolare può essere sfruttata per la rivelazione dell’avvenuta interazione analita-accettore, mediante SERS. Alcuni derivati di questo cromoforo sono stati sintetizzati e caratterizzati in modo da poter essere adsorbiti su un substrato SERS, che viene successivamente incubato in una soluzione di anticorpo. I segnali SERS della molecola di HABA sono risultati ben visibili sia sui substrati di nanoparticelle che di nanoshell d’oro. Purtroppo non è stato possibile rivelare la variazione strutturale del cromoforo, in quanto gli anticorpi, estratti in vivo da due coniglietti, inducono solo un parziale cambio di struttura, rendendo la rivelazione SERS alquanto difficile.
Stewart, Shona Diane. "Surface enhanced Raman scattering on electrochemically prepared silver surfaces." Thesis, Queensland University of Technology, 1999.
Find full textNergui, Navchtsetseg, and 倪娜. "Raman and Surface-Enhanced Raman Spectroscopy of Purine Derivatives." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/89694890714554310529.
Full text國立臺灣大學
化學研究所
104
The thesis proves an experimental basis for the featured characteristics of adenine and demonstrates the conditions for excitation wavelength dependency on vibrational modes to observe the spectral contributions by relative intensities. Purine derivative, adenine is the most ubiquitous of all the heterocyclic compounds in nature. Raman spectroscopy, which provides the signature of molecular vibrational fingerprints, is an emergent method to help identify a substrate and to examine compounds in nature. Raman spectra of adenine powder were acquired using excitation sources with 532 nm, 633 nm and 785 nm wavelengths. In comparison to the most distinct peak at 720 cm-1, the intensities of the peaks between 1200 cm-1 and 1500 cm-1exhibited a characteristic increase with decreasing excitation wavelength. This trend can be reproduced by different density functional theory (DFT) calculations for the adenine molecule. We showed that the above trend can also be seen in the aqueous solution of adenine. If the assumption of any peak intensity dependence on attenuated power , the Raman spectra remains to have no evidence on the spectra but could illustrate that well agreement of peak assignments despite power changes. The gained knowledge of spectroscopy potential and the characteristic of the compound, we tried to monitor a reaction in situ with the help of enormous enhancement, surface-enhanced Raman scattering (SERS). The most prominent peak of the compound, the adenine at 733 cm-1 can be exploited as signatures to identify the reaction in situ and the reaction product, hypoxanthine can also have splited prominent peak at 721 cm-1 and 740 cm-1 respectively. Despite the prominent peaks, the Raman spectrum provides distinctive peaks to integrate its area to function the reaction changes.