Dissertations / Theses on the topic 'Surface-enhanced Raman scattering'
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Maher, Robert Christopher. "Surface enhanced Raman scattering." Thesis, Imperial College London, 2007. http://hdl.handle.net/10044/1/7843.
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Xie, 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.
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Huang, 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.
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Diaz, J. A. D. "Nano-structured substrates for surface-enhanced Raman scattering." Thesis, Queen's University Belfast, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431606.
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McCabe, Ailie Fiona. "Remote detection using surface enhanced resonance Raman scattering." Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401340.
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Tsoutsi, Dionysia. "Inorganic Ions Sensing by surface-enhanced Raman scattering spectroscopy." Doctoral thesis, Universitat Rovira i Virgili, 2015. http://hdl.handle.net/10803/288213.
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En aquest projecte de tesi s'ha aconseguit desenvolupar un sistema de detecció, identificació i quantificació independent d'ions inorgànics. La detecció dels ions es basa en la diferent afinitat cap a diferents lligands orgànics mitjançant l'espectroscòpia de dispersió Raman augmentada per superfícies (surface-enhanced Raman scattering, SERS). En resum, com a substrat s'utilitzaran nanopartícules de plata o microesferes nanoestructurades que es prepararan mitjançant l'adsorció de nanopartícules d'or sobre la superfície de microesferes de sílice a partir del protocol de capa per capa i el seu posterior creixement epitaxial amb plata. Aquest últim pas es realitzarà a través de protocols desenvolupats en el nostre laboratori i té com a objectiu l'obtenció de superfícies plasmòniques discretes altament eficients en SERS. Els substrats es funcionalizaran posteriorment amb lligands orgànics tiolats amb alta afinitat per ions inorgànics (el fluoròfor orgànic, amino-MQAE i la terpiridina, pztpy-DTC). Com a pas següent, es realitzarà la detecció i quantificació simultània dels ions combinant, per a la seva detecció, espectroscòpia SERS. Els canvis espectrals SERS, en la manera de vibració dels lligands organics, estan correlacionats com a funció de la concentració de cada ió amb límits de detecció comparables als de diversos mètodes analítics convencionals.En 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.
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Khaywah, Mohammad Yehia. "New ultrasensitive bimetallic substrates for surface enhanced Raman scattering." Thesis, Troyes, 2014. http://www.theses.fr/2014TROY0041/document.
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Afin de développer des capteurs ultrasensibles des substrats fiables pour la diffusion Raman exaltée de surface (SERS) ont été fabriqués. Les deux meilleurs candidats de matériaux constituant les nanoparticules pour des substrats SERS sont l’argent et l’or. L’argent présente un meilleur facteur d’exaltation de l'intensité Raman et l’or est stable dans les milieux biologiques. C’est pourquoi la combinaison de ces deux métaux dans des nanostructures bimétalliques semble être une approche prometteuse qui combine les propriétés de surface de l’or et d’exaltation de l’argent. Le recuit thermique des couches métalliques minces est utilisé comme une technique simple et peu coûteuse. Cette dernière permet d’élaborer des substrats homogènes et reproductibles de nanoparticules bimétalliques or-argent ayant un facteur d’exaltation importante. Ces nanoparticules gardent leurs propriétés d’exaltation même après une année de fabrication. En jouant sur la composition de nanoparticules bimétalliques il est possible d’avoir une résonance de plasmons de surface localisés (LSPR) sur tout le spectre visible. Ces substrats sont caractérisés par une exaltation SERS supérieure lorsque la résonance plasmon est plus proche de la longueur d'onde d'excitation Raman. En outre, les nanoparticules bimétalliques de différentes tailles, compositions ont été réalisés par lithographie électronique. L’étude systématique de leurs propriétés plasmoniques et de leur exaltation SERS a révélé une conservation du lien entre résonance plasmon et signal SERSDriven by the interest in finding ultrasensitive sensors devices, reliable surface enhanced Raman scattering (SERS) based substrates are fabricated. Silver and gold nanoparticles are two of the best candidates for SERS substrates where Ag nanoparticles exhibit large enhancing ability in Raman intensity while Au nanostructures are stable in biological systems. Hence, combining the two metals in bimetallic nanostructures appeared to be a promising approach in order to sum the merits of Au surface properties and Ag enhancing ability. Thermal annealing of thin metallic films is used as a simple and relatively inexpensive technique to elaborate homogenous and reproducible Ag/Au bimetallic nanoparticles SERS substrates with high enhancing ability. The fabricated nanoparticles proved their enhancing stability even after one year of fabrication. Manipulating the composition of Ag/Au bimetallic NPs resulted in tuning the Localized Surface Plasmon Resonance (LSPR) over the whole visible spectrum, where the substrates are characterized with higher SERS enhancement when they exhibit LSPR closer to the Raman excitation wavelength. Additionally, bimetallic nanoparticles patterns with different size, composition and lattice constants have been conducted by electron beam lithography. The systematic study of their interesting plasmonic and SERS enhancing properties revealed maintenance in the LSPR-SERS relation by changing the nanoparticle size
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Sengupta, Atanu. "Detection of biological species by surface enhanced Raman scattering /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8523.
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Harper, Mhairi. "DNA diagnostic assays using Surface Enhanced Raman Scattering (SERS)." Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=22401.
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DNA is the prerequisite for all biological life and its discovery has revolutionised the understanding of biomolecular interactions and disease expression. This has enabled significant improvements in patient diagnosis and medical treatment to be carried out. The advancements in technology and instrumentation have continually progressed this knowledge and continue to push the boundaries of diagnostic and clinical advancements. One effective way to achieve this is through application of dye labelled DNA sequences and metallic nanoparticle suspensions. This research details an understanding of the interaction between dye labelled oligonucleotides and silver nanoparticle surfaces, which generate strong surface enhanced Raman scattering (SERS) responses through specific hybridisation events which correlate to the presence of targeted sequences. During this study, the attraction of oligonucleotides onto metal nanoparticles was shown to be driven through the DNA nucleobases. Therefore, the increased exposure of the base groups within single stranded DNA sequences generated a higher affinity for metal surfaces which in turn produced stronger SERS responses when compared to double stranded DNA. This principle was utilised within a DNA detection assay to successfully demonstrate the presence of target DNA sequences. Two novel DNA detection assays were also investigated which utilised SERS to determine the presence of sequences relating to the methicillin resistant Staphylococcus aureus (MRSA) strain. A solution based detection method was developed through coupling a TaqMan assay with SERS. This combination enabled highly specific detection of clinically relevant sequences of MRSA to be obtained with 7 fM limits of detection achievable. The multiple detection of different genomic S. aureus strains was achieved through the molecularly specific and narrow emission spectral profiles obtained. A contrasting DNA detection strategy which relies upon the hybridisation of comple mentary sequences on a solid substrate surface was shown. Silver nanoparticles were functionalised with specific DNA sequences and a variety of SERS active molecules, enabling the selective detection of target sequences from nitrocellulose membranes. This thesis has exploited SERS to enable the specific identification of DNA sequences to be achieved via utilisation of silver nanoparticles. Through SERS, an insight into the interactions of DNA and silver nanoparticles surfaces has been gained as well as enhancing the sensitivity and specificity achievable within SERS detection assays.
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Stewart, Shona Diane. "Surface enhanced Raman scattering on electrochemically prepared silver surfaces." Thesis, Queensland University of Technology, 1999.
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Norman, Rachel. "Simultaneous detection of multiple explosives using surface enhanced Raman scattering." Thesis, University of Strathclyde, 2016. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27074.
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There remains a continuing threat of terrorist/insurgent attacks on military/civilian personnel and key strategic infrastructures both within the UK mainland and in operational theatres. The development of a novel, innovative, low cost, field deployable bionanosensor, which will have the capability to detect low levels of explosive in a multiplexed fashion is required. The use of the specific interaction between small molecules and biological capture molecules such as antibodies coupled with the detection technique of surface enhanced Raman scattering (SERS) allows a ‘one shot’ analysis. This research makes use of antibody functionalised silver nanoparticles for the detection of the explosives TNT, RDX and PETN by surface enhanced Raman scattering (SERS). Commercially available antibodies specific for TNT and RDX have been modified to specifically orientate ‘flat’ on the surface of silver nanoparticles bringing the target close enough to the metal surface to allow an intrinsic SERS signal of the target molecule to be obtained. Quantitative detection of TNT and RDX explosives was achieved, with pM sensitivity demonstrated for RDX. Furthermore, TNT was detected in two different types of dirt, natural and synthetic dirt in order to mimic a more realistic matrix in which TNT would be found in the field. However, for the detection of PETN, it was required to develop a method to modify a PETN antibody in-house, to specifically orientate ‘flat’ on the nanoparticles surface similarly to the commercially available antibodies. This was achieved by using carbodiimide chemistry and the antibody was purified by cartridge centrifugation and HPLC. The PETN modified antibody was then functionalised onto silver nanoparticles and detection of PETN was achieved by SERS. In addition, PCA was used to allow multiplexed analysis based on unique Raman bands for the three different explosives which could be clearly identified in the SERS spectra. Finally, TNT was detected by using magnetic nanoparticles which were functionalised with a terminal amine group in combination with FITC modified TNT antibody functionalised silver nanoparticles. This assay was designed to allow for the formation of a Meisenheimer complex in the presence of TNT, between the amine functionalised magnetic nanoparticles and the TNT. Furthermore, the TNT antibody functionalised silver nanoparticles also binds to TNT, aggregating the nanoparticles. The magnetic nanoparticles were subsequently used to remove the nanoparticle assembly from the matrix, resulting in a concentrated sample on the magnet, resulting in an increase in SERS.
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Tay, Li-Lin. "Towards near-field single molecule surface enhanced Raman scattering detection." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0029/NQ53683.pdf.
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Zhu, Wenqi. "Plasmonics for surface-enhanced Raman scattering: from classical to quantum." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11451.
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Metallic nanostructures that employ localized surface plasmon resonances to capture or radiate electromagnetic waves at optical frequencies are termed "plasmonic optical antennas". These structures enhance light-matter interactions in an efficient manner, enabling unique linear and nonlinear optical applications. One such application is surface-enhanced Raman scattering (SERS), which employs plasmonic antennas to enhance Raman cross-section of molecules by orders of magnitude. SERS has attracted a significant amount of research attention since it enables molecules to be identified through their characteristic vibrational spectra, even at the single molecule level.Engineering and Applied Sciences
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Hughes, Mhairi Patricia Hughes. "Surface enhanced resonance Raman scattering as an in situ probe." Thesis, University of Strathclyde, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248287.
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Lierop, Danny van. "Surface enhanced Raman scattering based assays for DNA detection by." Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=19195.
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Surface enhanced Raman scattering (SERS) based molecular diagnostic assays for the detection of specific DNA sequences have been developed in recent years to compete with the more common fluorescence based approaches. Current SERS assays require either time consuming separation steps that increase assay cost and can also increase the risk of contamination, or are negative assays where the signal intensity decreases in the presence of target DNA. A new separation free SERS assay with an increase of signal intensity when target DNA is present using a specifically designed SERS primer has been developed in this thesis. The presence of specific bacterial DNA from Staphylococcus epidermidis was detected using Polymerase Chain Reaction (PCR) and SERS and indicates a new opportunity for exploration of SERS assays requiring minimal handling steps. SERS primers have been used to directly detect specific PCR products utilizing the difference in adsorption between single stranded and double stranded DNA onto nanoparticle surfaces. Seven parameters important for improved positive SERS assays for real applications were investigated using a model system for optimization experiments. This was followed by a PCR assay to detect pathogen DNA, and the introduction of a novel assay which utilizes the 5"3' exonuclease activity of Taq DNA polymerase to partly digest the SERS probe, generating dye labelled single stranded DNA increasing the SERS signals for detection of pathogen DNA. Applying the model system it was found that uni-molecular SERS primers perform better than bi-molecular SERS primers. However within the PCR assays it was found that uni- and bi-molecular SERS primers performed very similarly, the most reproducible results were obtained using the 5"3' exonuclease digestion assay. The SERS based assays developed in this thesis offer new routes over conventional fluorescence based techniques. SERS primers have been designed for multiplex pathogen detection. A selection of dyes for multiplex pathogen detection was made. Assay designs for the SERS primer digestion, and the SERS primer extension assay were made successfully, followed by cross reaction analysis of the oligonucleotides required for the multiplex detection. The results indicate that it is feasible to perform a multiplex detection using both types of assays. However it was decided to postpone the final multiplex detection part of the project and investigate assay systems that require less complex designs. Additionally, to simplify the SERS primer assay novel cationic silver nanoparticles were synthesised and tested for discrimination between double stranded and single stranded DNA. These silver nanoparticles with a positive surface charge produced poor discrimination between double and single stranded DNA. However these cationic silver nanoparticles provide a simplified SERS substrate for DNA detection.
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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.
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Surface- and tip-enhanced resonant Raman scattering (resonant SERS and TERS) by optical phonons in a monolayer of CdSe quantum dots (QDs) is demonstrated. The SERS enhancement was achieved by employing plasmonically active substrates consisting of gold arrays with varying nanocluster diameters prepared by electron-beam lithography. The magnitude of the SERS enhancement depends on the localized surface plasmon resonance (LSPR) energy, which is determined by the structural parameters. The LSPR positions as a function of nanocluster diameter were experimentally determined from spectroscopic micro-ellipsometry, and compared to numerical simulations showing good qualitative agreement. The monolayer of CdSe QDs was deposited by the Langmuir–Blodgett-based technique on the SERS substrates. By tuning the excitation energy close to the band gap of the CdSe QDs and to the LSPR energy, resonant SERS by longitudinal optical (LO) phonons of CdSe QDs was realized. A SERS enhancement factor of 2 × 103 was achieved. This allowed the detection of higher order LO modes of CdSe QDs, evidencing the high crystalline quality of QDs. The dependence of LO phonon mode intensity on the size of Au nanoclusters reveals a resonant character, suggesting that the electromagnetic mechanism of the SERS enhancement is dominant. Finally, the resonant TERS spectrum from CdSe QDs was obtained using electrochemically etched gold tips providing an enhancement on the order of 104. This is an important step towards the detection of the phonon spectrum from a single QDDieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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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.
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Shi, Chao. "Molecular fiber sensor probes based on surface enhanced Raman scattering (SERS) /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2009. http://uclibs.org/PID/11984.
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Morlà, Folch Judit. "Direct Label-free Surface-Enhanced Raman Scattering Analysis of Nucleic Acids." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/454761.
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La recerca s'ha realitzat en el context de l'espectroscòpia “Surface-Enhanced Raman Scattering” (SERS) per a l'anàlisi d'àcids nucleics. SERS és una tècnica analítica de gran abast que combina l'especificitat estructural i alta flexibilitat experimental de l'espectroscòpia Raman amb l'extremada sensibilitat proporcionada per l'amplificació del senyal òptic per part de la nanoestructura metàl•lica.
La caracterització dels àcids nucleics (ANs) s'ha convertit en una meta important en molts camps. En general, els ANs es troben en baixes quantitats de manera que la sensibilitat representa un requisit clau per a la seva detecció. En aquest sentit, l'espectroscòpia SERS es pot considerar una poderosa eina per a l'anàlisi de ANs, donat a la seva extraordinària sensibilitat i a la rica informació estructural proporcionada.
Fins ara, l'anàlisi SERS de ANs ha estat en gran part restringit a enfocaments indirectes, perdent les informacions estructurals de l'adquisició directa de la petjada vibracional. En aquest sentit, nanopartícules de plata carregades positivament recobertes amb espermina, van ser dissenyades específicament per a l'anàlisi de ANs amb SERS directe. Mitjançant l'ús d'aquest substrat s'assegura la interacció electrostàtica entre els ANs i els col•loides produint espectres SERS intensos i altament reproduïbles a nivell ultrasensible.
Aquest mètode directe, sense necessitat d'afegir marcadors i altament sensible es va implementar amb èxit en diverses aplicacions d'interès biològic, incloent la identificació i quantificació de nucleobases amb modificacions, en simple i doble cadenes d'ADN, quantificació de la composició de nucleobases en ADN curts i en ADN genomic, i classificació vibracional de ARNs petits estructuralment similars.
En resum, aquesta tesi demostra el gran potencial analític d'aquest nou mètode directe, obrint noves vies pel futur desenvolupament d'una tècnica analítica ràpida, de baix cost i alt rendiment per l’anàlisi d'àcids nucleics.La investigación se ha realizado en el contexto de la espectroscopia “Surface-Enhanced Raman Scattering” (SERS) para el análisis de ácidos nucleicos. SERS es una técnica analítica de gran alcance que combina la especificidad estructural y alta flexibilidad experimental de la espectroscopia Raman con la extremada sensibilidad proporcionada por la amplificación de la señal óptica por parte de la nanoestructura metálica. La caracterización de los ácidos nucleicos (ANs) se ha convertido en una meta importante en muchos campos. En general, los ANs se encuentran en bajas cantidades de modo que la sensibilidad representa un requisito clave para su detección. En este sentido, la espectroscopia SERS se puede considerar una poderosa herramienta para el análisis de ANs, dado a su extraordinaria sensibilidad y la rica información estructural proporcionada. Hasta ahora, el análisis SERS de ANs ha sido en gran parte restringido a enfoques indirectos, perdiendo las informaciones estructurales de la adquisición directa de la huella vibracional. En este sentido, nanopartículas de plata cargadas positivamente recubiertas con espermina, fueron diseñadas específicamente para el análisis de ANs con SERS directo. Mediante el uso de este sustrato se asegura la interacción electrostática entre los ANs y los coloides produciendo espectros SERS intensos y altamente reproducibles a nivel ultrasensible. Este método directo, sin necesidad de añadir marcadores y altamente sensible se implementó con éxito en diversas aplicaciones de interés biológico, incluyendo la identificación y cuantificación de nucleobases modificadas, en simple y doble cadena de ADN, cuantificación de la composición de nucleobases en ADN cortos y en el ADN genómico, y clasificación vibracional de ARNs pequeños estructuralmente similares. En resumen, esta tesis demuestra el gran potencial analítico de este nuevo método directo, abriendo nuevas vías para el futuro desarrollo de una técnica analítica rápida, de bajo coste y alto rendimiento para análisis de ácidos nucleicos.
The research has been carried out in the context of Surface-Enhanced Raman Scattering (SERS) spectroscopy for nucleic acids analysis. SERS is a powerful analytical technique that combines the structural specificity and high experimental flexibility of Raman spectroscopy with the extremely high sensitivity provided by the metal nanostructure amplification of the optical signal. Characterization of nucleic acids (NAs) has become a major goal in fields such as genetics or drug discovery. NAs are usually found in low amounts which require extremely sensitive techniques to be detected. Sensitivity represents a key requirement for their implementation into easy-to-use, cost-effective, rapid and high accuracy NA sensors. In this regard, the extraordinary sensitivity, in combination with the rich structural information provided by the Raman spectra, turned SERS into a powerful tool for the analysis of NAs. SERS analysis of NAs has been largely restricted to indirect approaches, dismissing the exquisite structural information provided by the direct acquisition of the biomolecular vibrational fingerprint. In this regard, positively charged silver nanoparticles coated with spermine were specifically designed for direct label-free SERS analysis of nucleic acids. By using these cationic nanoparticles the electrostatic interaction between NAs and the colloids is ensured yielding intense and highly reproducible SERS spectra at the ultrasensitive level. This highly sensitive label-free approach was successfully implemented in various applications of biological interest including identification and quantification of chemically-modified nucleobases in single and double stranded DNA, quantification of nucleobase composition in short and genomic DNA, and vibrational classification of structurally similar small RNA. In summary, this thesis demonstrates the tremendous analytical potential of this novel direct SERS method for nucleic acids analysis, opening new ways for the future development of a fast, low-cost, and high-throughput analytical technique for nucleic acids analysis.
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Karabicak, Seher. "Application Of Surface-enhanced Raman Scattering (sers) Method For Genetic Analyses." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613130/index.pdf.
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Raman spectroscopy offers much better spectral selectivity but its usage has been limited by its poor sensitivity. The discovery of surface-enhanced Raman scattering (SERS) effect, which results in increased sensitivities of up to 108-fold for some compounds, has eliminated this drawback.
A new SERS active substrate was developed in this study. Silver nanoparticle-doped polyvinyl alcohol (PVA) coated SERS substrate prepared through chemical and electrochemical reduction of silver particles dispersed in the polymer matrix. Performances of the substrates were evaluated with some biologically important compounds.
The specific detection of DNA has gained significance in recent years since increasingly DNA sequences of different organisms are being assigned. Such sequence knowledge can be employed for identification of the genes of microorganisms or diseases. In this study, specific proteasome gene sequences were detected both label free spectrophotometric detection and SERS detection. In label free spectrophotometic detection, proteasome gene probe and complementary target gene sequence were attached to the gold nanoparticles separately. Then, the target and probe oligonucleotide-modified gold solutions were mixed for hybridization and the shift in the surface plasmon absorption band of gold nanoparticles were followed.
SERS detection of specific nucleic acid sequences are mainly based on hybridization of DNA targets to complementary probe sequences, which are labelled with SERS active dyes. In this study, to show correlation between circulating proteasome levels and disease state we suggest a Raman spectroscopic technique that uses SERGen probes. This novel approach deals with specific detection of elevated or decreased levels of proteasome genes&rsquotranscription in patients as an alternative to available enzyme activity measurement methods. First, SERGen probes were prepared using SERS active labels and specific proteasome gene sequences. Then DNA targets to complementary SERGen probe sequences were hybridized and SERS active label peak was followed.
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McNay, Graeme. "Advancing surface enhanced resonance Raman scattering (SERRS) techniques for biological detection." Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438129.
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Faulds, Karen Jade. "Detection of drugs of abuse by surface enhanced Raman scattering (SERS)." Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288636.
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McCarney, Karen Michelle. "A flow cell surface enhanced resonance Raman scattering (SERRS) detection system." Thesis, University of Strathclyde, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426325.
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Sow, Idrissa. "Surface enhanced Raman Scattering : from fundamental aspects to single molecule detection." Paris 7, 2013. http://www.theses.fr/2013PA077171.
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Au cours des deux dernières décennies, il y a eu un intérêt accru pour la recherche de nouveaux dispositifs de type capteurs pour la détection de très petites quantités de molécules, par exemple, d'intérêt biologique. Les critères importants de tels capteurs sont principalement la grande sensibilité et la sélectivité. Dans ce contexte, la diffusion Raman exaltée de surface (DRES) est considérée comme une technique spectroscopique très sensible et spécifique pour détecter la signature vibrationnelle de molécules, à condition que celles-ci soient absorbées à la surface de nanoparticules métalliques tels que l'or, l'argent ou le cuivre. De telles nanoparticules présentent une résonance plasmon de surface localisée. Les nanoparticules métalliques peuvent être fabriquées par lithographie par nanosphère (LN), par lithographie par faisceau d'électrons (LFE), et par synthèse chimique en solution acqueuse. Les méthodes lithographiques, LN et LFE, permettent de définir précisément la géométrie de la particule. Cependant, l'étape d'évaporation du métal fournit une structure métallique polycristalline, contrairement à la plupart des particules monocristallines fabriquées par synthèse chimique. L'influence de la structure cristalline et de la rugosité de la surface de nanoparticules métalliques sur leurs propriétés optiques reste ainsi une question ouverte, alors que son impact a été clairement établi dans certains cas, par la comparaison de structures fabriquées par synthèse chimique et LFE. Dans ce travail, nous allons présenter une étude détaillée sur l'influence des nano-rugosités de surface de nanoparticules fabriquées par lithographie lectronique sur leurs propriétés optiques (sondé par spectroscopie d'extinction UV-visible), et sur leur réponse optique en champ proche par effet DRES. Bien que les échantillons lithographiques soient de très bons modèles pour l'étude des mécanismes DRES, ils ne sont pas le meilleur candidat pour la détection de molécules uniques. Pour être en mesure de détecter quelques molécules, voire la molécule unique, celles-ci doivent être situées à des endroits de forte exaltation du champ électrique, dits points chauds. Les points chauds sont par nature, très inhomogènes. Généralement moins de 1 % des molécules sont observés, ce qui n'est pas adapté pour les applications de détection. Dans ce travail, nous proposons une stratégie, basé sur l'adsorption sélective de la molécule cible uniquement sur les points chauds, qui nous permet de montrer qu'il est possible de faire de la détection de la molécule unique par effet DRESOver the two last decades, there has been an increased interest in finding new devices that provide ultrasensitive sensors detection of very small amounts of molecules. Important criteria on such sensors mainly deal with sensitivity and selectivity. In this context, Surface enhanced Raman scattering (SERS) is considered as a very sensitive and selective technique for the detection of the vibrational signature of the molecules provided they are adsorbed at the surface of metallic nanoparticles such as gold, silver or copper. Such kind of nanoparticles differs strongly from the respective bulk material in their optical response for they can exhibit localized surface plasmon resonance (LSPR). Fabrication methods for metal nanoparticles include nanosphere lithography (NL), electron beam lithography (EBL) and the chemical synthesis in liquid media. The lithographie methods, NL and EBL, employ a masking structure to first define the geometry of the nanoparticles that are then grown by, e. G. , vacuum deposition of the metal. This process results in a polycrystalline metal structure, in contrast to the mostly single-crystalline particles fabricated by chemical synthesis. The influence of the crystalline structure and surface roughness of metal nanoparticles on their optical properties remains however to some extent a matter of speculation, while its drastic impact was made clear in some cases by the comparison between chernically synthesized and EBL fabricated structures. In this work, we will present a detailed study on the influence of the nanometric surface roughness (NSR) on the far-field optical response of "realistic" lithographie particles, probed by UV-visible extinction spectroscopy, and the near-field response monitored by SERS intensity. Although the lithographie samples are very good models for the investigation of the SERS mechanisms, they are not the best candidate when single (or few) molecules detection is required. To be able to detect only a few molecules, they have to be located at the position of highest enhancements, so¬called hot-spots (HS). HS are by nature, very inhomogeneous. As a result, typically less than 1% of molecules are observed, which is of course not suitable for sensing applications. In this work, we propose a simple scheme based on selective adsorption of the analyte at the hot-spots only, which in principle allows the detection of every single target molecules
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Nwahara, Nnamdi. "Photophysicochemical properties and surface-enhanced Raman scattering of phthalocyanine-nanoparticle conjugates." Thesis, Rhodes University, 2019. http://hdl.handle.net/10962/71647.
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This work presents the synthesis, photophysical and photochemical characterization of a series of metallophthalocyanines (MPcs) and boron dipyrromethene (BODIPY) and their conjugates with either gold or silver nanoparticles (AuNPs or AgNPs) or graphene quantum dots (GQDs). The rich π-electron systems of GQDs and MPcs employed in this work enabled the coordination of MPcs to GQDs (either as pristine or modified) via the non-covalent (π-π stacking) method. GQDs, AuNPs and AgNPs were also functionalized with L-glutathione (GSH) in order to assist coupling to the Pcs or BODIPY dye. Spectroscopic and microscopic studies confirmed the formation of the respective nanoparticles (NPs) as well as the conjugates which exhibited enhanced photophysicochemical properties in comparison to the phthalocyanines (Pcs) or BODIPY alone. This work also shows that the incorporation of folic acid (FA) into Pcs-NPs composites leads to further enhancements in the singlet oxygen generation capabilities of the resulting conjugates, and so experimentally demonstrates for the first time, a synergy between FA and the respective nanoparticles (GQDs, AuNPs and AgNPs) in affecting the photophysical properties of Pcs complexes. GQDs and Pcs/GQDs hybrids were also herein decorated with AuNPs – metallic nanostructures that employ localized surface plasmon resonances to capture or radiate electromagnetic waves at optical frequencies. These nanostructures herein reported, have been shown to possess enhanced light-matter properties, enabling unique surface-enhanced Raman scattering (SERS) behaviours, with unprecedented enhancement factors of up to 30-fold. This work therefore, reports on the fabrication of Pc/GQDs/AuNPs hybrids and experimentally demonstrates their incredible potential as novel Raman-active PDT agents.
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McAnally, Gerard David. "Analysis of polymer surfaces and thin-film coatings with Raman and surface enhanced Raman scattering." Thesis, University of Strathclyde, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248360.
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Seballos, Leo B. "Raman and surface enhanced raman scattering of biomolecules and materials for hydrogen storage and delivery /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2007. http://uclibs.org/PID/11984.
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Lu, En Tzu. "Measuring and predicting model and uranyl species using normal Raman and surface-enhanced Raman scattering." Diss., University of Iowa, 2017. https://ir.uiowa.edu/etd/5559.
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This dissertation seeks to accurately and sensitively detect and estimate changes in molecule orientation of model and uranium species in complex samples. Currently available methods for detecting these molecules lack sensitivity, specificity, and/or require days to weeks to report trace chemical information. To overcome these limitations, normal Raman and surface-enhanced Raman scattering (SERS) are employed to gain molecular speciation. For instance, changes in uranium speciation depends on the pH and the ions present in solution. These ions form coordination complexes with uranyl, which influence the symmetric uranyl stretch that is Raman-active and can be used for the near real-time identification and relative abundance of uranium speciation in environmental samples. To accomplish this task, a strategy to extract uranyl speciation from Raman spectroscopy was developed. Important analysis methods were assessed using speciation modeling and protocols reported that minimize human subjectivity in spectral analysis. To improve detection limits of normal Raman spectroscopy, nanomaterials are employed for SERS. The adsorption of small aromatic molecules to gold coated silver nanoparticles encapsulated by internally etched silica membranes balances limitations of nanoparticle instability and orientation-dependent vibrational modes orientation relative to the plasmon resonance (electric field). Additionally, adsorption is monitored using localized surface plasmon resonance (LSPR) spectroscopy, SERS, and isotherm modeling. These combined approaches indicate that slight variations in molecular functional groups influence the free energies of adsorption of the target molecules. This provides an understanding of molecule-dependent SERS signals for sensitive, selective, and near real-time detection of small molecules in dynamic conditions. These findings support that nanomaterial surface chemistry greatly impacts molecular detection. As a result, gold nanostars functionalized with carboxyl groups are applied for uranyl detection. The distance dependent SERS response for uranyl is revealed by increasing the carbon chain length from 3-11 in the self-assembled monolayer. The shortest alkanethiol facilitated sensitive uranyl detection down to 120 nM. Finally, SERS detection is combined with electrospun amidoximated polyacrylonitrile (AO-PAN) mats to provide robust and reproducible detection of uranyl in complex matrices. AO-PAN mats are employed to initially extract and isolate uranyl while functionalized gold nanostars facilitate direct SERS detection. Characterization of AO-PAN mats uranyl uptake is examined by SEM, FT-IR and Raman spectroscopy. SERS measurements on the AO-PAN mats are obtained from matrices containing calcium and carbonate ions and synthetic urine with minimized matrix effects. Consequently, selective and sensitive detection of uranyl in environmental samples can be achieved thus broadening the scope of SERS for practical use.
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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.
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Surface enhanced Raman scattering (SERS) has achieved much attention since its conception in 1974. The analytical technique overcomes many difficulties associated with conventional Raman whilst also increasing sensitivity. However, the increased interest and work in the field has also identified flaws, many of which are centred on the irreproducibility of the SERS enhancement effect. The majority of the work described in this thesis focusses on the ‘optimisation’ of solid-state and solution based SERS systems. Optimisation plays a crucial role in maximising both enhancement effects and reproducibility. Here criteria are outlined for the synthesis of high performance solid-state SERS substrates and the synthesis of a range of substrates is assessed, each with associated pros and cons. The most successful substrate was synthesised by exploiting redox potentials which allow for the direct deposition of silver onto copper foil. The deposition times and temperatures were optimised sequentially to generate a high performance substrate capable of detecting Rhodamine 6G at trace levels. Reproducibility comparisons of the silver on copper (SoC) substrate were carried out against commercial substrates: Klarite and QSERS, multiple univariate and multivariate methods were used to assess the substrates performance. The results confirmed that the SoC substrate performed better than both the commercial substrates. The work also highlights the importance of using multiple data analysis methods in order to assess the performance of a solid-state SERS substrate. Deposition of the silver surface was also successful on British 2p coins allowing the for the detection and discrimination of illegal and legal drugs when coupled with multivariate data analysis methods such as PCA and PLS. Solution based SERS analyses were also carried out successfully using different optimisation strategies. The initial investigation involved careful control of the individual components of a SERS system (nanoparticles, aggregating agents and analyte) in order to establish a low limit of detection for the increasingly abused ‘legal high’ MDAI. The use of a reduced factorial design was then successfully employed to explore a greater number of SERS variables and define a low limit of detection for the class B drug mephedrone. The robust experimental design also allowed an insight into the importance of each of the individual components within a solution based SERS system. The final piece of work carried out was the SERS discrimination of antibiotics: ampicillin, ticarcillin and carbenicillin. Optimisation of the solution based experiment allowed the in-situ hydrolysis of the β-lactam moiety present in ampicillin rendering it pharmacologically inactive to be followed under acidic conditions at concentrations of 10 ppm.
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Lundahl, Johan. "Optimisation of surface enhanced Raman scattering from gold and silver nanoparticle solutions." Thesis, University of Strathclyde, 2008. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21945.
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The efficiency of Surface enhanced resonance Raman spectroscopy (SERS or SERRS) as a technique is entirely dependent on controlling the parameters responsible for the enhancement effects. In this thesis, some of the critical parameters have been investigated. It is concluded that it is possible to predict and to some degree manipulate the maximum enhancement of the Raman scattering in an experimental setup. By applying the findings presented in this thesis it is possible to optimise an experimental setup according to a desired purpose where silver or gold nanoparticle solutions are used as the source of surface enhancement. Many of the findings herein are also expected to be applicable to other SER(R)S-systems, and also to be of interest in related techniques, such as metal enhanced fluorescence and surface plasmon resonance. Methods for the controlled synthesis of silver and gold nanoparticles, are presented and techniques for the characterisation of their physical properties are evaluated. Further, a technique enabling the separation of the relative contribution of absorption and scattering to the extinction profile is presented. Further, the effect of the nanoparticles physical properties on their suitability as SERS substrates is investigated. In particular, the effect of nanoparticle size and nanoparticle solution state of aggregation is investigated in order to optimise the SERS intensity at the detector. The results show that the SERS intensity is critically dependent on these properties, and that it is possible to predict the optimal combination of nanoparticle size, wavelength of the excitation source and aggregation state of the nanoparticle solution. Finally, the effect of a molecular resonance on the SERRS intensity is demonstrated and confirmed as a significant effect.
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Mallinder, 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.
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Boddu, 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.
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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.
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Thesis (PhD) - Swinburne University of Technology, Centre for Atom Optics and Ultrafast Spectroscopy, 2007.Thesis 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.
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GUY, ANITA LOUISE. "THE EFFECT OF UNDERPOTENTIALLY DEPOSITED LEAD THIN FILMS ON SURFACE ENHANCED RAMAN SCATTERING AT SILVER ELECTRODES." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183882.
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This dissertation details the effect of underpotentially deposited (UPD) Pb on the surface enhanced Raman scattering (SERS) ability of roughened polycrystalline Ag electrodes. The deposition of monolayer and submonolayer amounts of Pb results in a quenching of the SERS response for pyridine and Cl⁻ adsorbed at Ag electrodes. Various factors which may contribute to the loss of SERS intensity are investigated. The most significant factors include changes in surface roughness features brought about by Pb UPD, changes in surface electronic properties of Pb-modified Ag and changes in a chemical contribution to surface enhancement. Possible changes in surface roughness properties of the Ag electrode due to Pb deposition are examined using scanning electron microscopy (SEM) and SERS reversibility studies. SEMs of roughened Ag electrodes before and after Pb monolayer deposition show no significant change in the morphology of the larger roughness features. However, the deposition and stripping of 60 - 70% of a Pb monolayer results in a loss of ca. 50% of the original SERS intensity for both adsorbate bands. This irreversible loss of SERS intensity is attributed to the destruction of atomic scale roughness (ASR). These results suggest that ca. 50% of the observed SERS response arises from a mechanism involving ASR. In addition, the destruction of ASR is shown to be largely responsible for the quenching of SERS at higher Pb coverages. The morphology of the SERS quenching profiles at lower Pb coverages for pyridine and Cl⁻ varies as a function of excitation wavelength. Experimental quenching profiles are compared with theoretical quenching profiles based on an electromagnetic contribution to SERS. Theoretical quenching profiles are calculated using a model for electromagnetic enhancement at a overlayer-covered ellipsoids proposed by Murray. The experimental results for both adsorbates are in agreement with the theoretical predictions for laser excitation in the blue. Experimental results in the green and red wavelength regions are best explained in terms of photoassisted charge-transfer mechanisms for surface enhancement.
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Shi, Jian. "Horizontal zinc oxide nanomaterials growth and their application for surface enhanced raman scattering." Diss., Columbia, Mo. : University of Missouri-Columbia, 2008. http://hdl.handle.net/10355/6682.
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Thesis (M.S.)--University of Missouri-Columbia, 2008.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 19, 2009) Includes bibliographical references.
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Tuschel, David Daniel 1957. "A CHARACTERIZATION OF THE OXIDATION-REDUCTION CYCLE AND SURFACE MORPHOLOGY OF ELECTROCHEMICAL SURFACE ENHANCED RAMAN SCATTERING." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/277026.
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Wei, Haoran. "Surface-Enhanced Raman Spectroscopy for Environmental Analysis: Optimization and Quantitation." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/93204.
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Fast, sensitive, quantitative, and low-cost analysis of environmental pollutants is highly valuable for environmental monitoring. Due to its single-molecule sensitivity and fingerprint specificity, surface-enhanced Raman spectroscopy (SERS) has been widely employed for heavy metal, organic compound, and pathogen detection. However, SERS quantitation is challenging because 1) analytes do not stay in the strongest enhancing region ("hot spots") and 2) SERS reproducibility is poor. In this dissertation, gold nanoparticle/bacterial cellulose (AuNP/BC) substrates were developed to improve SERS sensitivity by increasing hot spot density within the laser excitation volume. Environmentally relevant organic amines were fixed at "hot spots" by lowering solution pH below the analyte pKa and thus enabling SERS quantitation. In addition, a new SERS internal standard was developed based upon the electromagnetic enhancement mechanism that relates Rayleigh (elastic) and Raman (in-elastic) scattering. Rayleigh scattering arising from the amplified spontaneous emission of the excitation laser was employed as a normalization factor to minimize the inherent SERS signal variation caused by the heterogeneous distribution of "hot spots" across a SERS substrate. This highly novel technique, hot spot-normalized SERS (HSNSERS), was subsequently applied to evaluate the efficiency of SERS substrates, provide in situ monitoring of ligand exchange kinetics on the AuNP surface, and to reveal the relationship between the pKa of aromatic amines and their affinity to citrate-coated AuNPs (cit-AuNPs). Finally, colloidally stable stable pH nanoprobes were synthesized using co-solvent mediated AuNP aggregation and subsequent coating of poly(ethylene) glycol (PEG). These nanoprobes were applied for pH detection in cancer cells and in phosphate buffered aerosol droplets. The latter experiments suggest that stable pH gradients exist in aerosol droplets.PHD
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Yan, Bo. "Rationally designed substrates for SERS biosensing." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12894.
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Thesis (Ph.D.)--Boston UniversityThe large electromagnetic field enhancement provided by nanostructured noble metal surfaces forms the foundation for a series of enabling optical analytical techniques, such as surface enhanced Raman spectroscopy (SERS), surface enhanced IR absorption spectroscopy (SEIRA), surface enhanced fluorescent microscopy (SEF), to name only a few. Critical sensing applications have, however, other substrate requirements than mere peak signal enhancement. The substrate needs to be reliable, provide reproducible signal enhancements, and be amenable to a combination with microfluidic chips or other integrated sensor platforms. These needs motivate the development of engineerable SERS substrate "chips" with defined near- and far-field responses. In this dissertation, two types of rationally designed SERS substrates - nanoparticle cluster arrays (NCAs) and SERS stamp - will be introduced and characterized. NCAs were fabricated through a newly developed template guided self-assembly fabrication approach, in which chemically synthesized nanoparticles are integrated into predefined patterns using a hybrid top-down/bottom-up approach. Since this method relies on chemically defined building blocks, it can overcome the resolution limit of conventional lithographical methods and facilitates higher structural complexity. NCAs sustain near-field interactions within individual clusters as well as between entire neighboring clusters and create a multi-scale cascaded E-field enhancement throughout the entire array. SERS stamps were generated using an oblique angle metal deposition on a lithographically defined piston. When mounted on a nanopositioning stage, the SERS stamps were enabled to contact biological surfaces with pristine nanostructured metal surfaces for a label-free spectroscopic characterization. The developed engineered substrates were applied and tested in critical sensing applications, including the ultratrace detection of explosive vapors, the rapid discrimination of bacterial pathogens, and the label-free monitoring of the enzymatic degradation of pericellular matrices of cancer cells.
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Gisbert, Quilis Patricia. "Optical detection and structural analysis of DNA via direct surface-enhanced Raman scattering." Doctoral thesis, Universitat Rovira i Virgili, 2018. http://hdl.handle.net/10803/586257.
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Un nou mètode basat en la espectroscopia Raman intensificada per superfície (SERS) és implementat en aquesta tesi per a la detecció òptica i anàlisi estructural d'àcids nucleics. Aquest mètode es basa en la utilització de partícules de plata carregades positivament, com a substrats plasmònics per a l'anàlisi d'ADN en solució per SERS. Aquesta estratègia s'ha aplicat amb èxit per a la detecció ultrasensible de mutacions puntuals en el gen K-Ras, les quals són habitualment analitzades amb objectius diagnòstics, especialment en el càncer colorectal. En paral·lel amb aquest estudi, l'impacte estructural d'aquestes partícules amb l'ADN s'analitza amb profunditat.Un nuevo método basado en la espectroscopía Raman intensificada por superficie (SERS) se implementa en esta tesis para la detección óptica y análisis estructural de ácidos nucleicos. Este método se basa en la utilización de partículas de plata cargadas positivamente, como sustratos plasmónicos para el análisis de ADN en solución por SERS. Esta estrategia se ha aplicado con éxito para la detección ultrasensible de mutaciones puntuales en el gen K-Ras, las cuales son comúnmente analizadas con objetivos diagnósticos, especialmente en el cáncer colorectal. En paralelo con este estudio, el impacto estructural de estas partículas con el ADN se analiza con profundidad.
A novel approach based on surface-enhanced Raman scattering (SERS) for the label-free optical detection and structural analysis of nucleic acids is implemented in this dissertation. The method relies on the use of positively-charged silver nanoparticles as plasmonic substrates for SERS analysis of DNA in solution. This strategy is successfully applied for the sensitive detection of clinically relevant point mutations in the K-Ras gene, which are routinely screened for diagnostic purposes, especially in colorectal cancer. Along this study, the impact of the cationic nanoparticles on the structural features of the interacting DNA molecules is extensively investigated.
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Jackson, Joseph Bryan. "Surface enhanced Raman scattering with metal nanoshells." Thesis, 2004. http://hdl.handle.net/1911/18648.
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A systematic investigation of surface enhanced Raman scattering (SERS) was performed using metal nanoshells as the substrate. Nanoshells are a dielectric sphere coated with a thin metal shell, which have a well understood, geometrically tunable plasmon resonance. This tunability allows for the engineering of the optical near field for SERS. A simple model connecting the nanoshell electromagnetic near field at the incident frequency to that at the Raman shifted frequency is discussed. This theory is compared to the measured SERS response of the nonresonant molecule para-mercaptoaniline (pMA) adsorbed on silver and gold nanoshells.
Using a solution of silver nanoshells, at an excitation wavelength of 1064 nm enhancements on the order of 106 to 108 were observed. Accounting for reabsorption of the Raman scattered light as it traverses the solution suggests enhancements of 1012.
To mitigate the reabsorption, film geometries were investigated. For film measurements a 782 nm excitation laser was used. The SERS response of a dense film of silver nanoshells followed the calculated single nanoshell response of the nanoshells whose plasmon resonance was tuned near the excitation wavelength. In contrast, for nanoshells blue shifted from the excitation laser, the film Raman response followed an estimated dimer response.
The Raman response as a function of nanoshell density was studied using films of gold nanoshells dispersed on the surface of polyvinylpyridine (PVP) coated glass slides. A linear dependence of the Raman modes on the nanoshell density was observed confirming that the single nanoshell plasmon dominates the SERS response. The SERS enhancements for nanoshell films calculated by direct comparison to an unenhanced measurement were on the order of 10 10 to 1012.
The Raman response as a function of incident intensity was measured for dense silver nanoshell films. An optical pumping model allowing for stimulation of the Raman emission is proposed. Using this model, an effective unenhanced Raman cross section of the order of 10-27 cm2 is found. This is comparable to cross sections obtained in unenhanced Raman measurements. Evidence for two photon photoluminescence by nanoshells is presented. It is proposed the Raman emission is stimulated by the two photon photoluminescence.
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He, Yan-Ting, and 何彥廷. "Surface enhanced Raman scattering investigation of nanodiamonds." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/06623796108508405837.
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碩士國立東華大學
應用物理研究所
94
In this thesis, the effect of surface enhanced Raman scattering (SERS) on diamond nanostructure was investigated. Ag and Au thin films were used as SERS-active substrates. The part of the experiment includes three series altogether. In the first series of SERS experiments were prepared with sputtered metals nano-island on the nanodiamond surfaces. In the second one, nano-dots of silver thin films were deposited with thermal evaporation under the environment of the high vacuum. In both series, metallic nano-structure thin films were obtained. In the third one, the diamond nanoparticles were positioned on silver surface by using laser acceleration method. These three different methods determine the interaction of the carbon nanostructure with SERS-active substrate and allow us to observe different surface enhancement effect. The intensity and spectral shape of SERS spectra occurs significant variations with time, due to enhanced field effect of electromagnetic coupling and chemical effect. When the surface electron of metallic nano-cluster with different arrangement were excited by laser, resonant of the local surface plasmon took place in various degree. The enhancement of Raman scattering signals and “Blinking effect” of SERS spectra were also observed, and some branch lines were attributed to the interstitial defect of diamond or metallic clusters. Observed enhancement of SERS signals both for 100 nm and 5 nm nanodiamond can reach up to two orders of magnitude and upward in our experiment. It was observed in this research that SERS is regarded as an extremely useful technique for the analysis of the near-surface of nano-structure metal. Our work confirms that SERS can contribute to an obvious enhancement of the surface sensitivity for investigation of nano diamond.
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李振銘. "Surface enhanced Raman scattering of ZnO Nanocrystals." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/01952674869145511890.
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碩士國立彰化師範大學
光電科技研究所
101
This thesis is devoted to the study of surface enhanced Raman scattering of ZnO nanocrystals. The ZnO nanocrystals were synthesized by a sol-gel method. Their sizes were controlled by the pH value and temperature of synthetic solutions. The results of transmission electron microscope analysis showed that the particle sizes ranged between 2.5 and 4.9 nm. The synthesized ZnO nanocrystals were further used to grown ZnO/Ag aggregated nanostructures. The results of Raman measurement of these nanostructures showed that the signal intensity of ZnO was significantly enhanced by a factor of 1000 as the concentration of silver nitrate was 1.0 mM. The E2-low Raman signal shifted as the ZnO particle size decreased. A relationship between particle size and signal shift was obtained. It agreed well with the theoretical prediction.
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PENG, BIN, and 彭斌. "Surface enhanced Raman scattering in sandblast roughened metal surface." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/57103346848640516814.
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Wen, Ching-Chong, and 文靖中. "Long Distance Stimulated Raman Scattering and Surface Enhanced Raman Detection." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/34042090409041898634.
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碩士國立陽明大學
生醫光電工程研究所
99
Raman scattering is widely used in measuring the specific vibrational bonds of a (organic) sample to reveal its chemical structure. Stimulated Raman scattering (SRS) can enhance the signal through the mechanism of stimulated emission. Both Raman and stimulated Raman scattering are a third-order nonlinear optical process. SRS is highly sensitive and its strength depends on both incident light beams. This study is aimed to take advantage of the coherence stimulated Raman scattering in improving the working distance and the efficiency in scanning a large area. The long distance detection setup is using low numerical aperture optics in detecting SRS, at the cost of high spatial -resolution available for optical microscope. In this way, the working distance is stretched in achieving a much wider field of view and the efficiency of scanning a large area is greatly enhanced. This study demonstrates the feasibility of applying long distance stimulated Raman scattering. An oil-water mixture and polystyrene beads are used to illustrate the feasibility. To further enhance the SRS, the effect of surface plasmon enhancement is adopted by adding gold nanoparticles to the sample. The electron plasma of gold nanoparticles resonates with the incident electric field and thus increase the intensity of the incident and scattered light.
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Chou, He-Chun. "Enhancement of Raman signals : coherent Raman scattering and surface enhanced Raman spectroscopy." Thesis, 2012. http://hdl.handle.net/2152/ETD-UT-2012-05-5476.
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Raman spectroscopy is a promising technique because it contains abundant vibrational chemical information. However, Raman spectroscopy is restricted by its small scattering cross section, and many techniques have been developed to amplify Raman scattering intensity. In this dissertation, I study two of these techniques, coherent Raman scattering and surface enhanced Raman scattering and discuss their properties. In the first part of my dissertation, I investigate two coherent Raman processes, coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS). In CARS project, I mainly focus on the molecular resonance effect on detection sensitivity, and I find the detection sensitivity can be pushed into 10 [micromolar] with the assistance of molecular resonance. Also, I am able to retrieve background-free Raman spectra from nonresonant signals. For SRS, we develop a new SRS system by applying spectral focusing mechanism technique. We examine the feasibility and sensitivity of our SRS system. The SRS spectra of standards obtained from our system is consistent with literature, and the sensitivity of our system can achieve 10 times above shot-noise limit. In second part of this dissertation, I study surface enhanced Raman scattering (SERS) and related plasmonic effects. I synthesize different shapes of nanoparticles, including nanorod, nanodimer structure with gap and pyramids by template method, and study how electric field enhancement effects correlate to SERS by two photon luminescence (TPL). Also, I build an optical system to study optical image, spectra and particle morphology together. I find that SERS intensity distribution is inhomogeneous and closely related to nanoparticle shape and polarization direction. However, TPL and SERS are not completely correlated, and I believe different relaxation pathways of TPL and SERS and coupling of LSPR and local fields at different frequencies cause unclear correlation between them.text
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Chen, Le-Wei, and 陳立偉. "The Surface Enhanced Raman Scattering Of Silver Nanoparticle." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/03906245648023601649.
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碩士國立中央大學
物理研究所
93
Abstract Sliver nanoparticles have been broadly used as SERS excitation media. In this studies, Ag nanoparticle filmspace(AGNF) were prepared by the standard thermal evaporation method, and the mean particle diameter was determined by X-ray diffraction and AFM, to be at 25nm. The optical properties and the SERS behavior of the resultant AGNF were investigated. The absorption spectra show that the most efficient band for exciting SPR in Ag nanoparticle lies in the UV regime, which agrees with the predicted result according to Mie theory. The penetrated intensity was found to be exponentially decreasing with the increasing of film thickness. The strongest integrated SERS intensity occurred at a film thickness of 4μm. Annealing of the AGNF results in a dramatic decrease in the SERS intensity, while a 30% increase in the SERS intensity was found when the temperature was cooling to 77K.
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Lu, Hui-Hsin, and 呂慧歆. "Surface Enhanced Raman Scattering Quantitative Analysis on Biomolecule." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/03893574980330489029.
Full textAbstract:
碩士國立陽明大學
醫學工程研究所
92
In this thesis, we investigated the use of surface-enhanced Raman scattering technique as the tool to quantify some biomolecules in human bodily fluid. SERS-active substrates in our research are colloidal gold and silver-doped sol-gel, which contain metal nanoparticles. The components of bodily fluid provide the important information of healthy state and disease diagnosis. Urine is easily available and non-invasive to evaluate the health of human body. Compared with regular clinical chemical urinalysis, optical methods have some spectacular features, including less specimen contact, non-destructive specimen and multiple components analysis. We develop SERS-technique to detect the biomolecule of human urine. In the present initial investigation, the nitrogen compounds in urine can be detected by using normal Raman spectroscopic method. The creatinine and uric acid in urine can be detected by SERS method. For the mixture sample, the correlation coefficient (R) between the creatinine concentration and SERS band intensity was found to 0.99. For human subject analysis, ten normal human urine samples were analyzed by the SERS technique. Partial least square cross-validation (PLSCV) method was utilized to obtain the estimated creatinine concentration in clinically relevant (55.9mg/dl to 208mg/dl) concentration range. The correlation coefficient (R) between reference concentration and PLS predicted concentration was 0.93 and the root-mean square error of cross validation (RMSECV) is 26.1mg/dl.This research demonstrates the feasibility of using SERS for human subject urine creatinine detection, and establishes the SERS platform technique for bodily fluids measurement.
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Huang, Chia-Chi, and 黃家琪. "Surface-Enhanced Raman Scattering Appied In Natural Pigment." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/51641160743255031566.
Full textAbstract:
碩士國立嘉義大學
應用化學系碩士班
93
Surface - enhanced Raman scattering can enhance Raman signal , this technology provide for rich molecular vibrational information . The last year , scientists discover catechin and anthocyanin which can make people more health , many teams study these special properties and characters very hard . As a result of chromophore that makes Raman spectra reveal unclear information and the correlation research in Raman spectra is very poor . Therefore we point these questions and study catechin and anthocyanin in Raman spectra as well as discuss them . In this experiment , we use citrate to reduce Ag nanoparticles and let it to mix sodium chloride and sample which maybe catechin or anthocyanin . After three hours , we use Raman spectra to detect this mixture and we get rich molecular vibrational information successfully . When this technology is through the mature period , we start to detect super micro – concentration .With changing the volume of the mixture , for this reason , we are successful again . However , we think about the question which is heavy metal maybe contaminate environment . So , we approach to detect micro – volume with zeolite in SERS . In this section , we also use citrate to reduce Ag nanoparticles and then mix micro – volume of sample with sodium chloride , furthermore , the mixture can be absorbed on the surface of the zeolite . By the way of micro - Raman detection , we obtain good results . And this experiment will be turn into a new SERS technology .
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Zhong, Muyang. "Evaluation of substrates for surface-enhanced Raman scattering." Thesis, 2016. http://hdl.handle.net/1828/7431.
Full textAbstract:
Surface-enhanced Raman scattering (SERS) has long been the interest of researchers in chemistry, physics and engineering, especially since the discovery that SERS can probe into the system down to the single molecule (SM) level. Despite the large number of publications regarding the fabrication of SERS substrates, it has been a challenge in the field to quantify the SERS signal and universally compare substrates. Traditionally, enhancement factor (EF) is used as an indicator of substrate quality, but the EF calculation is hugely dependent on the estimation of the surface coverage and other factors that are determined largely subjectively. Therefore, this thesis aims at discussing other parameters that can also be used to evaluate different substrates.
Six different SERS substrates of Ag or Au nanoparticles of different sizes were fabricated by nanosphere lithography (NSL) and characterized by electron microscopy and UV-vis spectroscopy. SERS substrates were mapped for different concentrations of a probe molecule. Through subsequent baseline correction and principle component analysis (PCA), the "intensity" of individual spectrum was obtained and the shapes of intensity histograms of each substrate were acquired.
Instead of calculating EF, five criteria (six quantification methods in total) were employed to comprehensively evaluate the six substrates. These were density of hot spots (characterized by the number of zero-intensity events), enhancement (represented by mean intensity), spatial variation (calculated by RSD of intensity), repeatability (realized by cross correlation) and histogram shape (quantified by skewness and kurtosis). These new methods provide insights to the understanding of the properties of SERS substrates in terms of hot spots. Different substrates may exhibit better performance in terms of one criterion but worse in terms of others. Those variations in performance can be explained by their surface morphology.
These more elaborated methods are believed to provide a more comprehensive approach to evaluate and compare substrates than the traditional EF values. The thesis also paves the way for future study on SM-SERS and fabricating better SERS substrates.Graduate
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Yu, Long-Yo, and 余隆佑. "Surface-enhanced Raman Scattering Biosensors with Plasmonic Structures." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/75753926967358259410.
Full textAbstract:
碩士國立成功大學
光電科學與工程研究所
95
Raman spectrum is becoming an important tool for biomolecular interaction analysis.It is not only to be utilized to analyze various biomolecular structures, but also provides a possibility to grab biomolecule structural images. However, most of biomolecules are non-active Raman molecules, and hence how to enhance their tiny Raman signals is a great challenge. With the helps of metal nanoparticles and surface structures to enhance local electric fields, the Raman signals will be detectable. Surface-enhanced Raman scattering (SERS) with an inducement mechanism by exciting surface plasmons (SPs) could result in a several order electric field magnified effects and then enhance surface biomolecular detection signals detectable. In this thesis, prepared metal nanoparticles is first arranged and immobilized on metal film surface by using a self assembly monolayer (SAM) technique to enhance the localized electric fields. Silver nanoparticles are not easy to form a larger uniform active area like gold nanoparticles, so an electron-beam lithographic process and a focused ion beam (FIB) direct writing are utilized to develop more controllable and various plasmonic structures. With the enhancement of these plasmonic particles and structures,an attenuated-total-reflection (ATR) Raman excitation is operated to detect the Raman signals of DNA molecules preliminarily.