Dissertations / Theses on the topic 'Surface Enhanced Resonance Raman Spectroscopy'
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Cunningham, 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.
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Kier, 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.
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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/.
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Herein analysis of dye molecules has been carried out by means of surface enhanced Raman spectroscopy (SERS) and/or surface enhanced resonance Raman spectroscopy (SERRS) using citrate- and/or borohydride-reduced silver colloids employing laser exciting wavelengths equal to 514.5 and/or 632.8 nm. SERS and/or SERRS spectra are reported using, as model system probes, eight dye molecules which belong to several distinct chemical structural classes. Experimental protocols were developed and subsequently modified, as required, for each dye molecule examined. Vibrational spectroscopic profiles were obtained, where possible, with respect to concentration and pH dependence. SERS and/or SERRS vibrational bands provided unique fingerprint spectra for each dye molecule. In an attempt to develop novel applications of SERRS the technique has been used, in a kinetic investigation, to monitor and analyse the synthesis of the dye indigo carmine from indigo using a silver sol as the SERRS substrate/medium. In another study it was possible to differentiate between two structurally similar anthraquinones, alizarin and purpurin, using SERRS. It was also possible to demonstrate the existence of multiple molecular species of certain dye molecules, as a function of pH e.g. nuclear fast red, metanil yellow, purpurin and alizarin. For some dye molecules e.g. alcian blue it was possible to combine the linear regions of normal (non-resonance/non-enhanced) Raman and SERS/SERRS plots, thereby extending the dynamic range available for semi-quantitative analysis. The sensitivity of the SERS/SERRS technique for semi-quantitative trace analysis of eight dye molecules has been successfully demonstrated.
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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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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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McLaughlin, Clare. "Development and evaluation of Surface Enhanced Resonance Raman Scattering (SERRS) spectroscopy for quantitative analysis." Thesis, University of Strathclyde, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366867.
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Carella, Yvonne. "Development of SERS for the determination of environmental pollutants." Thesis, University of Strathclyde, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288745.
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Balagopal, Bavishna. "Advanced methods for enhanced sensing in biomedical Raman spectroscopy." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6343.
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Raman spectroscopy is a powerful tool in the field of biomedicine for disease diagnosis owing to its potential to provide the molecular fingerprint of biological samples. However due to the inherent weak nature of the Raman process, there is a constant quest for enhancing the sensitivity of this technique for enhanced diagnostic efficiency. This thesis focuses on achieving this goal by integrating advanced methods with Raman spectroscopy. Firstly this thesis explores the applicability of a laser based fluorescence suppression technique – Wavelength Modulated Raman Spectroscopy (WMRS) - for suppressing the broad luminescence background which often obscure the Raman peaks. The WMRS technique was optimized for its applications in single cell studies and tissue studies for enhanced sensing without compromising the throughput. It has been demonstrated that the optimized parameter would help to chemically profile single cell within 6 s. A two fold enhancement in SNR of Raman bands was demonstrated when WMRS was implemented in fiber Raman based systems for tissue analysis. The suitability of WMRS on highly sensitive single molecule detection techniques such as Surface Enhanced Raman Spectroscopy (SERS) and Surface Enhanced Resonance Raman Spectroscopy (SERRS) was also explored. Further this optimized technique was successfully used to address an important biological problem in the field of immunology. This involved label-free identification of major immune cell subsets from human blood. Later part of this thesis explores a multimodal approach where Raman spectroscopy was combined with Optical Coherence Tomography (OCT) for enhanced diagnostic sensitivity (>10%). This approach was used to successfully discriminate between ex-vivo adenocarcinoma tissues and normal colon tissues. Finally this thesis explores the design and implementation of a specialized fiber Raman probe that is compatible with surgical environments. This probe was originally developed to be compatible with Magnetic Resonance Imaging (MRI) environment. It has the potential to be used for performing minimally invasive optical biopsy during interventional MRI procedures.
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Brown, Rachel. "The chemical modification of DNA for analysis by surface enhanced resonance Raman scattering (SERRS) spectroscopy." Thesis, University of Strathclyde, 2002. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21166.
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The detection of specific DNA sequences is of increasing interest due to the sequencing of the human genome. This can be achieved by the use of covalently labelled oligonucleotide probes detected by sensitive analytical techniques. Surface Enhanced Resonance Raman Scattering (SERRS) spectroscopy is one such technique that provides molecularly specific information about probes at very low concentrations. The enhancement results from adsorption of a chromophore within the probe to a roughened metal surface. Specific SERRS probes were synthesised using benzotriazole as the metal complexing agent and azo dyes as the chromophore. They were coupled to the 5' end of DNA using two strategies. Firstly, coupling was achieved via an amino linker, achieved by reaction of the activated carboxylic acid derivative of the SERRS label with DNA containing a free amine at the 5'end. Secondly, the phosphoramidite of the SERRS label was synthesised and incorporated as the final monomer during the solid phase synthesis of the DNA sequence. Preliminary spectroscopic data was obtained for the labelled oligonucleotides. Ultraviolet melting studies of a DNA sequence labelled with an azobenzotriazole dye show an increase in melting temperature (TM) of 5.42 °C over the same sequence without modification, suggesting that the label confers stability to the double helix. Initial SERRS optimisation experiments allowed the optimum sample conditions to be determined for these novel oligonucleotides. SERRS spectra have been obtained for each labelled oligonucleotide with a detection limit determined at 5x 10⁻⁸ M. A potential application of the labelled oligonucleotides was investigated resulting in the first ever preparation of a SERRS labelled nanoparticle probe. This provides the basis for a specific sequence detection technique based on SERRS.
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Westley, Chloe. "Raman spectroscopy and its enhancement techniques for the direct monitoring of biotransformations." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/raman-spectroscopy-and-its-enhancement-techniques-for-the-direct-monitoring-of-biotransformations(4ff7ebac-048b-4d81-b13c-7087a2028464).html.
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Protein engineering strategies, such as directed evolution, generate large libraries of enzyme variants, typically in the range of 106-108 variants. However, the availability of rapid, robust high-throughput screening methods has often limited the impact of directed evolution in discovering enzymes with enhanced catalyst performance. Raman spectroscopy is an established analytical technique, providing molecular specific information, permitting analysis in aqueous solutions and as such is an attractive, alternative screening method for biological systems. Although an inherently weak physical phenomenon, enhanced Raman scattering techniques, such as surface enhanced Raman scattering (SERS) and ultraviolet resonance Raman (UVRR) spectroscopy, can be used to overcome the associated sensitivity issues. Herein, we successfully monitored xanthine oxidase (XO) catalysed conversions of xanthine to uric acid, before extending to hypoxanthine, using two contrasting Raman scattering enhanced approaches. Firstly, a SERS-based assay was developed utilising silver nanoparticles to measure analytes directly and quantitatively on micromolar scale, in the absence of chromogenic substrates or lengthy chromatography. Secondly, a UVRR approach was developed enabling monitoring of the XO-mediated reaction in real-time and without the need to quench the system. Significantly, both methods demonstrated over >30 fold reduction in acquisition times (when compared to conventional HPLC analysis), and offered excellent medium-term reproducibility and accuracy of results over significant time periods. Furthermore, investigations were made into developing this SERS-based assay into an enantiomeric screen using another vibrational spectroscopy approach, Raman optical activity (ROA), along with circular dichroism (CD). Successful chiral reduced nanoparticles were synthesised, with multiple characterisation techniques employed, affording enantiopure Au-cysteine and Ag-tyrosine colloids. However, it was not possible to generate consistent and reproducible SEROA responses, with these techniques ultimately being unsuccessful in analysing these chiral sensitive nanoprobes, and thus differentiating between the D- and L- forms. Finally, a novel SERS-based approach, in combination with the standard addition method (SAM), was developed for the routine analysis of uric acid (end product in XO catalysed reaction(s) and biomarker for various diseases), at clinically relevant levels in urine samples from patients. Results were highly comparable and in very good agreement with HPLC analyses, with an average < 9% difference in predictions between the two analytical approaches across all samples analysed, and a 60-fold reduction in acquisition time (when compared with HPLC). Together, the research presented in this thesis demonstrates the suitability of Raman enhanced techniques for quantitative analysis, measuring the analytes directly using a portable Raman instrument and, most importantly, offering significant reductions in acquisition times when compared to established analytical techniques.
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Dorney, Kevin Michael. "A Chemical Free Approach for Increasing the Biochemical Surface-Enhanced Raman Spectroscopy (SERS)-Based Sensing Capabilities of Colloidal Silver Nanoparticles." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401206511.
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Geist, Brian Lee. "Properties of Nanoscale Biomaterials for Cancer Detection and Other Applications." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/27630.
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The first thermal cycling experiments of ionic self-assembled multilayer (ISAM) films have been reported examining their survivability through repeated thermal cycles from -20° C to 120° C in ambient atmospheric conditions. The films were constructed from alternating layers of Nile Blue A and gold nanoparticles which provided a strong absorbance in the optical wavelength range. No degradation of the optical characteristics of the ISAM films was observed [1]. Techniques for measuring the capacitance and resistivity of various ISAM films have also been developed allowing for a more complete electrical characterization of ISAM films. Capacitance measurements enabled a calculation of the dielectric function and breakdown field strength of the ISAM films. The capacitance measurement technique was verified by measuring the dielectric function of a spin-coated thin film PMMA, which has a well characterized dielectric function [2]. Surface-enhanced Raman spectroscopy (SERS) has been studied as a possible detection method for malignant melanoma revealing spectral differences in blood sera from healthy horses and horses with malignant melanoma. A SERS microscope system was constructed with the capability of resolving the Raman signal from biologically important molecules such as beta-carotene and blood sera. The resulting Raman signals from sera collected from horses with malignant melanoma were found to have additional peaks not found in the Raman signals obtained from sera collected from healthy horses. A systematic analysis of the combination of absorbance and fluorescence signals of blood sera collected from populations of healthy dogs and dogs with cancer has resulted in a rapid and cost-effective method for monitoring protein concentrations that could possibly be used as part of a cancer screening process. This method was developed using the absorbance and fluorescence signals from known serum proteins, the combinations of which were used to match the absorbance and fluorescence signals of blood sera allowing for an accurate determination of protein concentrations in blood sera [3]. Finally, a novel method for measuring the melting point of DNA in solution using capacitance measurements is presented. This method allows for the determination of the melting temperature as well as the melting entropy and melting enthalpy of DNA strands. Two different short strands of DNA, 5'-CAAAATAGACGCTTACGCAACGAAAAC-3' along with its complement and 5'-GGAAGAGACGGAGGA-3' along with its complement were used to validate the technique as the characteristics of these strands could be modeled using theoretical methods. This experimental technique allows for the precise determination of the melting characteristics of DNA strands and can be used to evaluate the usefulness of theoretical models in calculating the melting point for particular strands of DNA. Additionally, a micro-fluidic device has been proposed that will allow for a rapid and cost-effective determination of the melting characteristics of DNA [4].Ph. D.
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Danilov, Artem. "Design, characterisation and biosensing applications of nanoperiodic plasmonic metamaterials." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0110/document.
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Cette thèse considère de nouvelles architectures prometteuses des métamatériaux plasmoniques pour biosensing, comprenant: (I) des réseaux périodiques 2D de nanoparticules d'Au, qui peuvent supporter des résonances des réseaux de surface couplées de manière diffractive; (II) Reseaux 3D à base de cristaux plasmoniques du type d'assemblage de bois. Une étude systématique des conditions d'excitation plasmonique, des propriétés et de la sensibilité à l'environnement local dans ces géométries métamatérielles est présentée. On montre que de tels réseaux peuvent combiner une très haute sensibilité spectrale (400 nm / RIU et 2600 nm / RIU, ensemble respectivement) et une sensibilité de phase exceptionnellement élevée (> 105 deg./RIU) et peuvent être utilisés pour améliorer l'état actuel de la technologie de biosensing the-art. Enfin, on propose une méthode de sondage du champ électrique excité par des nanostructures plasmoniques (nanoparticules uniques, dimères). On suppose que cette méthode aidera à concevoir des structures pour SERS (La spectroscopie du type Raman à surface renforcée), qui peut être utilisée comme une chaîne d'information supplémentaire à un biocapteur de transduction optiqueThis thesis consideres novel promissing architechtures of plasmonic metamaterial for biosensing, including: (I) 2D periodic arrays of Au nanoparticles, which can support diffractively coupled surface lattice resonances; (II) 3D periodic arrays based on woodpile-assembly plasmonic crystals, which can support novel delocalized plasmonic modes over 3D structure. A systematic study of conditions of plasmon excitation, properties and sensitivity to local environment is presented. It is shown that such arrays can combine very high spectral sensitivity (400nm/RIU and 2600 nm/RIU, respectively) and exceptionally high phase sensitivity (> 105 deg./RIU) and can be used for the improvement of current state-of-the-art biosensing technology. Finally, a method for probing electric field excited by plasmonic nanostructures (single nanoparticles, dimers) is proposed. It is implied that this method will help to design structures for SERS, which will later be used as an additional informational channel for biosensing
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Sheremet, Evgeniya. "Micro- and Nano-Raman Characterization of Organic and Inorganic Materials." Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-188175.
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Die Raman-Spektroskopie ist eine der nützlichsten optischen Methoden zur Untersuchung der Phononen organischer und anorganischer Materialien. Mit der fortschreitenden Miniaturisierung von elektronischen Bauelementen und der damit einhergehenden Verkleinerung der Strukturen von der Mikrometer- zur Nanometerskala nehmen das Streuvolumen und somit auch das Raman-Signal drastisch ab. Daher werden neue Herangehensweisen benötigt um sie mit optischer Spektroskopie zu untersuchen. Ein häufig genutzter Ansatz um die Signalintensität zu erhöhen ist die Verwendung von Resonanz-Raman-Streuung, das heißt dass die Anregungsenergie an die Energie eines optischen Überganges in der Struktur angepasst wird. In dieser Arbeit wurden InAs/Al(Ga)As-basierte Multilagen mit einer Periodizität unterhalb des Beugungslimits mittels Resonanz-Mikro-Raman-Spektroskopie und Raster-Kraft-Mikroskopie (AFM) den jeweiligen Schichten zugeordnet.
Ein effizienterer Weg um die Raman-Sensitivität zu erhöhen ist die Verwendung der oberflächenverstärkten Raman-Streuung (SERS). Sie beruht hauptsächlich auf der Verstärkung der elektromagnetischen Strahlung aufgrund von lokalisierten Oberflächenplasmonenresonanzen in Metallnanostrukturen.
Beide oben genannten Signalverstärkungsmethoden wurden in dieser Arbeit zur oberflächenverstärkten Resonanz-Raman-Streuung kombiniert um geringe Mengen organischer und anorganischer Materialien (ultradünne Cobalt-Phthalocyanin-Schichten (CoPc), CuS und CdSe Nanokristalle) zu untersuchen. Damit wurden in beiden Fällen Verstärkungsfaktoren in der Größenordnung 103 bis 104 erreicht, wobei bewiesen werden konnte, dass der dominante Verstärkungsmechanismus die elektromagnetische Verstärkung ist.
Spitzenverstärkte Raman-Spektroskopie (TERS) ist ein Spezialfall von SERS, bei dem das Auflösungsvermögen von Licht unterschritten werden kann, was zu einer drastischen Verbesserung der lateralen Auflösung gegenüber der konventionellen Mikro-Raman-Spektroskopie führt. Dies konnte mit Hilfe einer Spitze erreicht werden, die als einzelner plasmonischer Streuer wirkt. Dabei wird die Spitze in einer kontrollierten Weise gegenüber der Probe bewegt. Die Anwendung von TERS erforderte zunächst die Entwicklung und Optimierung eines AFM-basierten TERS-Aufbaus und TERS-aktiver Spitzen, welche Gegenstand dieser Arbeit war. TERS-Bilder mit Auflösungen unter 15 nm konnten auf einer Testprobe mit kohlenstoffhaltigen Verbindungen realisiert werden. Die TERS-Verstärkung und ihre Abhängigkeit vom Substratmaterial, der Substratmorphologie sowie der AFM-Betriebsart wurden anhand der CoPc-Schichten, die auf nanostrukturierten Goldsubstraten abgeschieden wurden, evaluiert. Weiterhin konnte gezeigt werden, dass die hohe örtliche Auflösung der TERS-Verstärkung die selektive Detektion des Signals weniger CdSe-Nanokristalle möglich macht.
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Schreiber, Benjamin, Dimitra Gkogkou, Lina Dedelaite, Jochen Kerbusch, René Hübner, Evgeniya Sheremet, Dietrich R. T. Zahn, Arunas Ramanavicius, Stefan Facskoa, and Raul D. Rodriguez. "Large-scale self-organized gold nanostructures with bidirectional plasmon resonances for SERS." Technische Universität Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A23477.
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Efficient substrates for surface-enhanced Raman spectroscopy (SERS) are under constant development, since time-consuming and costly fabrication routines are often an issue for high-throughput spectroscopy applications. In this research, we use a two-step fabrication method to produce self-organized parallel-oriented plasmonic gold nanostructures. The fabrication routine is ready for wafer-scale production involving only low-energy ion beam irradiation and metal deposition. The optical spectroscopy features of the resulting structures show a successful bidirectional plasmonic response. The localized surface plasmon resonances (LSPRs) of each direction are independent from each other and can be tuned by the fabrication parameters. This ability to tune the LSPR characteristics allows the development of optimized plasmonic nanostructures to match different laser excitations and optical transitions for any arbitrary analyte. Moreover, in this study, we probe the polarization and wavelength dependence of such bidirectional plasmonic nanostructures by a complementary spectroscopic ellipsometry and Raman spectroscopy analysis. We observe a significant signal amplification by the SERS substrates and determine enhancement factors of over a thousand times. We also perform finite element method-based calculations of the electromagnetic enhancement for the SERS signal provided by the plasmonic nanostructures. The calculations are based on realistic models constructed using the same particle sizes and shapes experimentally determined by scanning electron microscopy. The spatial distribution of electric field enhancement shows some dispersion in the LSPR, which is a direct consequence of the semi-random distribution of hotspots. The signal enhancement is highly efficient, making our SERS substrates attractive candidates for high-throughput chemical sensing applications in which directionality, chemical stability, and large-scale fabrication are essential requirements.
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Ludemann, Michael. "In situ Raman-Spektroskopie an Metallphthalocyaninen: Von ultradünnen Schichten zum organischen Feldeffekttransistor." Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-206568.
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Im ersten Teil der Arbeit werden Signalverstärkungsmechanismen für Raman-Spektroskopie erschlossen und evaluiert. Die als geeignet bewerteten Methoden finden im zweiten Teil ihre Anwendung zur Untersuchung der vibronischen Eigenschaften von dünnen Manganphthalocyaninschichten, die anschließend mit Kalium interkaliert werden. Hierbei sind verschiedene Phasen identifizierbar, die ein ganzzahliges Verhältnis von Kaliumatomen zu Manganphthalocyaninmolekülen besitzen. Im dritten Teil werden die elektrischen Eigenschaften durch die Verwendung dieses Materialsystems als aktives Medium eines Feldeffekttransistors untersucht.
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Rastogi, Rishabh. "Engineered Electromagnetic Hot-spots for Highly Sensitive (Bio)molecular Detection by Plasmonic Specytroscopies." Thesis, Troyes, 2020. http://www.theses.fr/2020TROY0018.
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La détection nanoplasmonique repose sur des champs électromagnétiques exaltés à proximité de la surface des métaux nanostructurés pour détecter les molécules à des concentrations ultra-faibles. Les exaltations de champ sont fortement prononcées aux jonctions entre les nanostructures adjacentes, ce qui entraîne des points chauds. Les exaltations de champ en ces points chauds augmentent de façon non linéaire en fonction des distances jusqu’au régime inférieur à 10nm. Les analytes présents à ces lacunes peuvent tirer parti de ces exaltations de champ, résultant en une sensibilité ultra-élevée dans la détection. Toutefois, ces lacunes de champ confiné affectent la capacité des grands analytes tels que les biomolécules d’entrer et de tirer ainsi parti des champs EM dans les lacunes. Cela présente des besoins spatiaux pour exalter les champs em en contradiction avec ceux pour accueillir les interactions biomoléculaires. Cette thèse démontre la conception rationnelle des configurations de réseaux qui permet aux hotspots EM d’être mieux exploités par le témoin de l’événement de liaison biomoléculaire. La thèse utilise l’approche moléculaire basée sur l’auto-assemblage pour fabriquer des nanoréseaux plasmoniques reproductibles sur des plaquettes complètes. Plusieurs paramètres sont envisagés, y compris la dimension, la forme et la densité des points chauds, la fonctionnalisation de surface, et le choix des substrats, pour démontrer la détection quantitative des molécules jusqu’aux concentrations picomolairesNanoplasmonic sensing relies on enhanced electromagnetic fields at the vicinity of nanostructured metal surface to detect molecules at ultra-low concentrations. The EM enhancements are strongly pronounced at junctions between adjacent nanostructures resulting in gap hot-spots. EM enhancements at these hot-spots increase non-linearly as a function of gap distances down to sub-10 regime. Analyte present at these gaps can leverage these EM enhancements, resulting in ultra-high sensitivity in detection. However, such confining gaps affect the ability of large analytes such as biomolecules to enter and thereby leverage EM fields within the gaps. This presents spatial needs to enhance EM fields at odds with those for accommodating biomolecular interactions. This thesis demonstrates the rational design of array configurations that allows the EM hotspots to be better leveraged by the reporter of biomolecular binding event. The thesis uses molecular self-assembly based approach to fabricate reproducible plasmonic nanoarrays on full wafers. Multiple parameters are considered including the dimension, shape, and density of hotspots, surface functionalization, and the choice of substrates, to demonstrate quantitative detection of molecules down to picomolar concentrations
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Hernandez-Santana, Aaron. "Surface-enhanced resonance Raman coded beads." Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443118.
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Scherzer, Ryan D. "Degradation Resistant Surface Enhanced Raman Spectroscopy Substrates." UNF Digital Commons, 2017. http://digitalcommons.unf.edu/etd/760.
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Raman spectroscopy is employed by NASA, and many others, to detect trace amounts of substances. Unfortunately, the Raman signal is generally too weak to detect when very small, but non-trivial, amounts of molecules are present. One way around this weak signal is to use surface enhanced Raman spectroscopy (SERS).
When used as substrates for SERS, metallic nanorods grown using physical vapor deposition (PVD) provide a large enhancement factor to the Raman signal, as much as 1012. However, Silver (Ag) nanorods that give high enhancement suffer from rapid degradation as a function of time and exposure to harsh environment. Exposure to harsh environments is an enormous issue for NASA; considering all environments experienced during space missions will be drastically different from Earth regarding atmosphere pressure, atmosphere composition, and environmental temperature. Au and Ag nanorods suffer from a thermochemical kinetic phenomenon where the surface atoms diffuse and cause the nanostructures to coalesce towards bulk structure. When in bulk, SERS enhancement is lost and the substrate becomes useless.
A stable structure for SERS detection is designed through engineering the barriers to surface diffusion. Aluminum (Al) nanorods are forced to undergo surface diffusion through thermal annealing and form rough mounds with a stable terminating oxide layer. When Ag is deposited on top of this Al structure, it becomes kinetically bound and changes to physical structure become impeded. Using this paradigm, samples are grown with varied lengths of Ag and are then characterized using scanning electron microscopy (SEM) and Ultraviolet-Visible spectroscopy. The performance of the samples are then tested using SERS experiments for the detection of trace amounts of rhodamine 6G, a ‘gold standard’ analyte. Characterization shows the effectiveness of the Raman substrates remains stable up to 500°C.
Transitioning to basic scientific investigation, next is to strive to isolate the individual impacts of chemical and physical changes to the Ag nanostructure and how they affect the Raman signal. Substrates are compared over the course of a month long experiment to determine the effects of vacuum storage and addressing the effects of chemical adsorbance. Additionally, this was attempted by comparing the signal degradation of Ag nanorods to that of Au, which is known to be chemically inert, allowing for the separation of chemical and physical effects. Although Ag and Au have similar melting points, Ag physically coarsened significantly more. FTIR also showed significant chemical contamination of the Ag, but not Au. A hypothesis is proposed for future investigations into the chemical changes and how they are coupled with and promote the physical changes in nanostructures.
Overall, the novel SERS substrate engineered here may enable the detection of trace amounts of molecules in harsh environments and over long timescales. Conditions such as those found on space missions, where substrates will experience months or years of travel, high vacuum environments, and environments of extreme temperatures.
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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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Segervald, Jonas. "Fabrication and Optimization of a Nanoplasmonic Chip for Diagnostics." Thesis, Umeå universitet, Institutionen för fysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-163998.
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To increase the survival rate from infectious- and noncommunicable diseases, reliable diagnostic during the preliminary stages of a disease onset is of vital importance. This is not trivial to achieve, a highly sensitive and selective detection system is needed for measuring the low concentrations of biomarkers available. One possible route to achieve this is through biosensing based on plasmonic nanostructures, which during the last decade have demonstrated impressive diagnostic capabilities. These nanoplasmonic surfaces have the ability to significantly enhance fluorescence- and Raman signals through localized hotspots, where a stronger then normal electric field is present. By further utilizing a periodic sub-wavelength nanohole array the extraordinary optical transmission phenomena is supported, which open up new ways for miniaturization. In this study a nanoplasmonic chip (NPC) composed of a nanohole array —with lateral size on the order of hundreds of nanometer— covered in a thin layer of gold is created. The nanohole array is fabricated using soft nanoimprint lithography on two resists, hydroxypropyl cellulose (HPC) and polymethyl methacrylate (PMMA). An in depth analysis of the effect of thickness is done, where the transmittance and Raman scattering (using rhodamine 6G) are measured for varying gold layers from 5 to 21 nm. The thickness was proved to be of great importance for optimizing the Raman enhancement, where a maximum was found at 13 nm. The nanohole array were also in general found beneficial for additionally enhancing the Raman signal. A transmittance minima and maxima were found in the region 200-1000 nm for the NPCs, where the minima redshifted as the thickness increased. The extraordinary transmission phenomena was however not observed at these thin gold layers. Oxygen plasma treatment further proved an effective treatment method to reduce the hydrophobic properties of the NPCs. Care needs be taken when using thin layers of gold with a PMMA base, as the PMMA structure could get severely damaged by the plasma. HPC also proved inadequate for this projects purpose, as water-based fluids easily damaged the surface despite a deposited gold layer on top.
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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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Gant, Virgil Alexander. "Detection of integrins using surface enhanced raman spectroscopy." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/2304.
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Integrins are transmembrane heterodimer protein receptors that mediate adherence to both the intracellular cytoskeleton and extracellular matrix. They play a major role in cellular adhesion and the breadth of their importance in biology is only recently being understood. The ability to detect concentrations of integrins on the cell surface, spatially resolve them, and study the dynamics of their behavior would be a significant advance in this field. Ultimately, the ability to detect dynamic changes of integrins on the surface of a cell maybe possible by developing a combined device such as an atomic force microscope (AFM) and surface enhanced Raman spectroscopy (SERS) system. However, the focus of this research is to first determine if integrins can be detected using SERS. Surface enhanced Raman spectroscopy (SERS) is technique used to detect the presence of analytes at the nanomolar level or below, through detection of inelastically scattered light. This thesis discusses the detection of integrins employing SERS as the detection modality. Integrins have been detected, in solution, using two silver colloids as the enhancing surface. Two silver colloid preparation methods are compared by ease of formulation and degree of enhancement in this thesis. Citrate and hydroxylamine hydrochloride (HA-HCl) reduced silver colloids were prepared through wet chemistry,compared using UV-Vis light spectroscopy, and tested for surface enhancement using adenine (a strong SERS active molecule), and two different integrins, (alpha)V(beta)3 and (alpha)5(beta)1. Results indicated that both colloids demonstrate SERS activity for varying concentrations of adenine as compared to standard non-enhanced Raman, however, only the citrate reduced colloid showed significant enhancement effect for the integrins.
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Sockalingum, 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.
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Sharma, Narayan. "Solution Processable Surface Enhanced Raman Spectroscopy (SERS) Substrate." Bowling Green State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1434375587.
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Touzalin, Thomas. "Tip-enhanced Raman spectroscopy on electrochemical systems." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS364.
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L'analyse in situ d'interfaces électrochimiques à l'échelle nanométriques est un enjeu majeur pour la compréhension des mécanismes de transferts de charges et d'électrons dans les domaines du stockage d'énergie ou de l'électrocatalyse. Ce travail a permis le développement de la spectroscopie Raman exaltée de pointe (TERS) en milieu liquide et en conditions électrochimiques. Le TERS permet l'analyse de la structure de molécules ou de matériaux à l'échelle nanométrique du fait de l'exaltation localisée du champ électrique à l'extrémité d'une sonde de microscope à effet tunnel (STM) en or ou en argent. Un dispositif reposant sur l'illumination d'une pointe au travers d'un solvant organique a démontré la possibilité d'imager les inhomogénéités d'une monocouche auto-assemblée sur or. Une seconde approche reposant sur l'exaltation du signal Raman à l'apex d'une pointe de taille nanométrique utilisée comme microélectrode (spectroscopie Raman exaltée de surface de pointe, tip SERS) a permis de suivre la réduction d'une monocouche auto-assemblée et d'améliorer la compréhension de son mécanisme. Afin d'imager la surface d'une électrode polarisée, le couplage d'un STM utilisant une pointe TERS en conditions électrochimiques a montré une résolution latérale de moins de 8 nm pour sonder de variations locales de l'exaltation du champ électromagnétique induites par des singularités géométriques de surface. Par ailleurs, l'analyse TERS de couches organiques formées à partir de sels d'aryldiazoniums a permis de montrer des différences de structures selon type de greffage. Ce travail constitue donc une avancée majeure pour l'analyse locale de surfaces modifiéesThe 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
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Tanaka, Tomoyoshi. "Resonance raman and surface enhanced raman studies of hemeproteins and model compounds." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/27678.
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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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Yang, Mingwei. "In Situ Arsenic Speciation using Surface-enhanced Raman Spectroscopy." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3387.
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Arsenic (As) undergoes extensive metabolism in biological systems involving numerous metabolites with varying toxicities. It is important to obtain reliable information on arsenic speciation for understanding toxicity and relevant modes of action. Currently, popular arsenic speciation techniques, such as chromatographic/electrophoretic separation following extraction of biological samples, may induce the alternation of arsenic species during sample preparation. The present study was aimed to develop novel arsenic speciation methods for biological matrices using surface-enhanced Raman spectroscopy (SERS), which, as a rapid and non-destructive photon scattering technique. The use of silver nanoparticles with different surface coating molecules as SERS substrates permits the measurement of four common arsenicals, including arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV). This speciation was successfully carried out using positively charged nanoparticles, and simultaneous detection of arsenicals was achieved. Secondly, arsenic speciation using coffee ring effect-based separation and SERS detection was explored on a silver nanofilm (AgNF), which was prepared by close packing of silver nanoparticles (AgNPs) on a glass substrate surface. Although arsenic separation using the conventional coffee ring effect is difficult because of the limited migration distance, a halo coffee ring was successfully developed through addition of surfactants, and was shown to be capable of arsenicals separation. The surfactants introduced in the sample solution reduce the surface tension of the droplet and generate strong capillary action. Consequently, solvent in the droplet migrated into the peripheral regions and the solvated arsenicals to migrated varying distances due to their differential affinity to AgNF, resulting in a separation of arsenicals in the peripheral region of the coffee ring. Finaly, a method combining experimental Raman spectra measurements and theoretical Raman spectra simulations was developed and employed to obtain Raman spectra of important and emerging arsenic metabolites. These arsenicals include monomethylarsonous acid (MMAIII), dimethylarsinous acid (DMAIII), dimethylmonothioarinic acid (DMMTAV), dimethyldithioarsinic acid (DMDTAV), S-(Dimethylarsenic) cysteine (DMAIIICys) and dimethylarsinous glutathione (DMAIIIGS). The fingerprint vibrational frequencies obtained here for various arsenicals, some of which have not reported previously, provide valuable information for future SERS detection of arsenicals.
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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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He, 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.
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Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 23, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Mengshi Lin. Vita. Includes bibliographical references.
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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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SACCO, ALESSIO. "Metrological Approach to Tip-enhanced Raman Spectroscopy." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2827709.
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Marshall, 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.
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The aim of this thesis is to design plasmonic nano-gaps capable of detecting materials down to sufficiently low concentrations such that single molecule characteristics are observed. We begin first, by discussing the theory of plasmonics. Then, we assess the recent literature on the subject to develop an understanding in the field of plasmonics and to describe the fundamental concepts behind how plasmonic nano-sensors operate. Also, this allows us to show where our research fits in. The aim of this thesis is to design plasmonic nano-gaps capable of detecting materials down to sufficiently low concentrations such that single molecule characteristics are observed. We begin first, by discussing the theory of plasmonics. Then, we assess the recent literature on the subject to develop an understanding in the field of plasmonics and to describe the fundamental concepts behind how plasmonic nano-sensors operate. Also, this allows us to show where our research fits in. The second area of research involves practical Surface Enhanced Raman Spectroscopy (SERS) experiments from our optimized nano-gaps. The nano-gaps were doped with the molecular dyes Rhodamine 6G and Crystal Violet at concentrations of 2x10−7 M. SERS measurements revealed differences in the relative intensities of their respective SERS peaks at low concentrations when compared to the SERS spectra measured from gaps doped the same dye at higher concentrations of 2x10−5 M. Time dependent SERS measurements showed that the SERS signal is stable over a long period of time, indicating the observed relative intensity changes are due to changes in molecular orientation from one gap to another, demonstrating that our optimized nano-gaps have single molecule sensitivity. When exciting at 532 nm, the 118 nm silver spheres used to form the nanogap with the silver film below were shown to enhance the Raman signal by 4:2x relative to the 200 nm silver nano-spheres, and up to 7:73x relative to the 60 nm silver nanospheres. When compared to our simulation results for the same structures excited with a Gaussian source with NA = 0:55, we showed the information collected from the Raman study correlated well with the theoretical data. Following our work investigating single molecule characterisation of fluorescent materials, we began looking at trace levels of a conjugated polymer (F8-PFB). The previous investigation had been from a purely electromagnetic enhancement perspective using a secondary polymer matrix buffer which was optically transparent in the region of interest for the Raman spectra of our target molecule. This polymer provided a barrier between the target material and the metallic nanostructure, thereby minimizing the potential of photo-induced chemical processes in the Raman signal. In this study, the material itself forms the basis of the cavity between the particle and the film below. This system classifies the single molecule regime via the observation of intensity blinking events, which are characteristic of Single Molecule SERS (SM-SERS). We also demonstrated the biosensing applications of our research, where nanoparticle clusters on a metallic film were used to produce spectra from bio-molecules undergoing conformation changes as a result of UV light exposure. The SERS spectra revealed decreased intensity from the Tryptophan (Trp) modes and appearance of disulphide bonds as time under UV light exposure progresses for lysozyme. Our final chapter shows that by using nanoparticles coupled to different substrates such as Distributed Bragg Reflectors (DBRs) and dielectric slabs, the hybrid modes improved the Quality-factor (Q-factor) of the scattering spectra. Therefore, these systems theoretically have great potential for refractive index sensing with high sensitivity to binding activity of molecular targets. The highest Q-factor of the systems we investigated was the 200 nm gold particle coupled to the 2 μm dielectric slab at 22:48, followed by the same particle deposited on a 700 nm stop-band DBR at 7:41.
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Nicolson, 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.
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In the fields of security and biomedical imaging there is a significant need to non-invasively probe through barriers, e.g. plastic, glass or tissue. Raman spectroscopy provides a means to solving this challenge since it provides a unique chemical fingerprint without the need to destroy the sample. In spite of this, conventional Raman can be limited by sample volume and thickness, often failing to probe beneath the surface or through samples obscured by an opaque barrier. Spatially offset Raman spectroscopy provides a means of overcoming the limitation associated with conventional Raman spectroscopy since it is capable of providing a unique chemical fingerprint of the analyte understudy, even when obscuring barriers such as plastic or tissue are present. Furthermore, by combining the depth penetration benefits of SORS with the signal enhancing capabilities of SERS, SESORS is capable of achieving sample interrogation at even greater depth. Therefore, the focus of this research is to probe through barriers, specifically plastic and tissue, using both handheld CR and SORS instruments. The ability of both techniques to detect Raman and SERS analytes through barriers is explored and compared for applications involving security and biomedicine. The use of conventional Raman and SORS to detect ethanol through varying thicknesses of plastic is investigated. Raman signals from an ethanol solution through plastic was detected through thicknesses of up to 21 mm using SORS in combination with multivariate analysis. SORS was compared to conventional Raman, where through barrier detection of ethanol took place through depths up to 9 mm. Using a handheld SORS spectrometer, the detection of ex vivo breast cancer tumour models containing SERRS active nanotags through 15 mm of porcine tissue is demonstrated. In addition, SERRS-active nanotags were tracked through porcine tissue to depths of up to 25 mm. To date, this is the largest thickness that SERRS nanotags have been tracked through using a backscattering approach. This unprecedented performance is due to the use of red-shifted chalcogenpyrylium-based Raman reporters to demonstrate the novel technique of surface enhanced spatially offset resonance Raman spectroscopy (SESORRS) for the first time. The same ex vivo tumour models are also used to demonstrate a multiplexed imaging system through depths of 10 mm using back scattering SESORRS. The benefit of using red-shifted chalcogenpyrylium based Raman reporters for probing through large thicknesses of plastic and tissue barriers using SERS is also highlighted. Raman signals were collected from SERRS active nanotags through plastic thicknesses of up to 20 mm. The detection of SERRS-active nanotags taken up into ex vivo tumour models through depths of 5 mm of tissue is also shown. The advantages of applying multivariate analysis for through barrier detection when discriminating analytes with similar spectral features as the barrier is also clearly demonstrated. Finally, resonant chalcogenpyrylium nanotags were used to demonstrate the benefit of using a resonant Raman reporter for superior low-level limits of detection using SESORS. Nanotags containing chalcogenpyrylium dye were observed at concentrations as low as 1 pM through 5 mm of tissue. This is compared to the non-resonant small molecule Raman reporter BPE which could only be detected at concentrations of 11 pM. Calculated limits of detection suggest that these SERRS nanotags can be detected at concentrations as low as 104 fM using SESORRS.
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Panagoulia, Danai. "Surface enhanced Raman spectroscopy of the ionic liquid-metal interface." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/422133/.
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When a charge is applied to an electrode in the metal – Ionic Liquid (IL) interface, an electrochemical double layer is expected to form due to the arrangement of ions to counter the charge on the electrode surface. However, this arrangement of ions in ILs can be complicated by effects such as specific adsorption, ion re-orientation and superoxide ion and Au oxide formation. Traditional techniques used in the study of metal-IL interfaces, have provided a good indication of underlying processes. However, additional proof from new methods is required, as interpretations of the results sometimes vary. In this work, surface enhanced Raman (SERS) spectra have been acquired from the electrochemically controlled interface between Au and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMP TFSI). By analysing the intensity and positions of peaks in the spectra corresponding to specific vibrations in the different ions of the IL, useful information has been obtained about the processes occurring at the interface at a molecular level. By using impedance spectroscopy, the potential of zero charge (PZC) was tentatively assigned to -0.85 V vs. PQRE. Cathodic features in cyclic voltammograms and in current-potential data of the SERS experiment, at potentials negative to the PZC, have been assigned to the re-orienting of the BMP cations, increase in axial BMP conformers and superoxide ion formation, tying together varying interpretations from the literature. Au oxide formation from trace water was detected in the SERS spectra and corresponded to a small increase in current at positive potentials. Due to the high concentration of ions in ILs, the effect of the bulk signal on Raman and SERS spectra of ILs has also been examined. The depth resolution of the spectrometer, the SERS signal decay with distance from the substrate and the concentration of molecules in the analyte, have all been taken into account.
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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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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.
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Due to deteriorating water quality and the world’s increasing demand for clean water, the need for cheap, easy and portable techniques to characterize and quantify pollutants in waters is urgent. Hence, surface-enhanced Raman spectroscopy (SERS) have gained considerable attention in this field. Atrazine and bentazon are two of the most occurring pesticides causing pollution in Sweden, and where therefore examined in this study, along with 4-mercaptopyridine (mpy) as a reference molecule. In this project, silver and gold nanoparticles where synthesised and used as SERS substrates for detection of contaminants in water by using a handheld Raman device provided by Serstech AB. Sodium chloride (NaCl) and magnesium sulfate (MgSO4) where used as aggregation agents allowing the nanoparticles to form hot spots. Mpy was detected to 0.5 nM and an enhancement factor of 108 using silver nanoparticles aggregated with NaCl was obtained. No Raman signal was obtained from atrazine nor bentazon using the handheld Raman device with silver nanoparticles aggregated with NaCl. Therefore the Raman cross-section of the probe molecules where investigated using the handheld Raman device and a conventional Raman device. Bentazon was not detectable using the handheld Raman device but detectable using a conventional Raman device. Atrazine was detectable at high concentrations i.e. atrazine powder using the handheld Raman device and detectable at 100 nM using a conventional Raman device. Since bentazon was not detectable with the handheld Raman device, more focus was put on getting a detectable signal from atrazine using the handheld Raman device. Investigation of the adsorption of atrazine and bentazon to the silver nanoparticle surface was performed. Due to the weaker adsorption to the nanoparticle surface, MgSO4 was used aggregation agent instead of NaCl with mpy, atrazine and bentazon. Mpy was detectable using MgSO4 as aggregation agent, atrazine and bentazon was not. Measurements of mpy, atrazine and bentazon without any salt was performed. For these measurements, no detectable signal from neither molecule was obtained, indicating that the formation of hot spots is necessary to obtained a detectable Raman signal. Measurements of mpy and atrazine with gold nanostars where performed. Enhancement factor using the gold nanostars was calculated to 107, and a detectrable signal from mpy was obtained, not from atrazine. Measurements of atrazine and mpy simultaneously was performed, where mpy peaks was observed but no atrazine peaks. The affinity of the probe molecule and the nanoparticle is crucial to obtain a detectable signal. This study inducates that both the chemical enhancement and electromagnetic enhancement are needed to obtain a detectable signal. For that, strongly binding species is necessary. Considering the simplicity of this method and the limited optimization efforts, there is plenty of room for improvements, including different probe molecules and different SERS substrates. With the right conditions, the evaluated technique reveals a promising and accessible method using a commercially available handheld Raman spectrometer for detection and quantification of contaminants in water.
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Smith, Susan James. "A resonance Raman and surface enhanced resonance Raman study of cytochrome P450s and their substrate/inhibitor interactions." Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288604.
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Kaya, Zeynep. "Controlled and localized synthesis of molecularly imprinted polymers for chemical sensors." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2220.
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Les polymères à empreintes moléculaires (MIP), également appelés "anticorps en plastique", sont des récepteurs biomimétiques synthétiques qui sont capables de reconnaître et lier une molécule cible avec une affinité et une spécificité comparables à celles des récepteurs naturels tels que des enzymes ou des anticorps. En effet, les MIP sont utilisés comme éléments de reconnaissance synthétiques dans les biocapteurs et biopuces pour la détection de petits analytes et les protéines. La technique d'impression moléculaire est basée sur la formation de cavités de reconnaissance spécifiques dans des matrices polymères par un procédé de moulage à l'échelle moléculaire. Pour la conception de capteurs et biopuces, une cinétique d'adsorption et une réponse du capteur rapide, l'intégration des polymères avec des transducteurs, et une haute sensibilité de détection sont parmi les principaux défis. Dans cette thèse, ces problèmes ont été abordés par le développement de nanocomposites MIP / d'or via le greffage du MIP sur les surfaces en utilisant des techniques de polymérisation dédiées comme l'ATRP qui est une technique de polymérisation radicalaire contrôlée (CRP). Ces techniques CRP sophistiquées sont en mesure d'améliorer considérablement les matériaux polymères. L'utilisation de l'ATRP dans le domaine de MIP a été limitée jusqu'à présent en raison de son incompatibilité inhérente avec des monomères acides comme l'acide méthacrylique (MAA), qui est de loin le monomère fonctionnel le plus largement utilisé dans les MIP. Ici, un nouveau procédé est décrit pour la synthèse de MIP par ATRP photo-initiée utilisant fac-[Ir(Ppy)3] comme catalyseur. La synthèse est possible à température ambiante et est compatible avec des monomères acides. Cette étude élargit considérablement la gamme de monomères fonctionnels et de molécules empreintes qui peuvent être utilisés lors de la synthèse de MIP par ATRP. La méthode proposée a été utilisée pour la fabrication de nanocomposites hiérarchiquement organisés sur des surfaces métalliques nanostructurés avec des nano-trous et nano-ilots, présentant des effets plasmoniques pour l'amplification du signal. La synthèse de films de MIP à l'échelle du nanomètre localisés sur la surface d'or a été démontrée. Des méthodes de transduction optiques, à savoir la résonance de plasmons de surface localisée (LSPR) et la spectroscopie Raman exaltée par effet de surface (SERS) ont été exploitées. Ces techniques se sont montrées prometteuses pour l'amélioration de la limite de détection dans la détection d'analytes biologiquement pertinents, y compris les protéines et le médicament propranololMolecularly imprinted polymers (MIPs), also referred to as plastic antibodies, are synthetic biomimetic receptors that are able to bind target molecules with similar affinity and specificity as natural receptors such as enzymes or antibodies. Indeed, MIPs are used as synthetic recognition elements in biosensors and biochips for the detection of small analytes and proteins. The molecular imprinting technique is based on the formation of specific recognition cavities in polymer matrices by a templating process at the molecular level. For sensor and biochip development, fast binding kinetics of the MIP for a rapid sensor response, the integration of the polymers with transducers, and a high sensitivity of detection are among the main challenges. In this thesis, the above issues are addressed by developing MIP/gold nanocomposites by grafting MIPs on surfaces, using dedicated techniques like atom transfer radical polymerization (ATRP) which is a versatile controlled radical polymerization (CRP) technique. Theses ophisticated CRP techniques, are able to greatly improve the polymeric materials. The use of ATRP in the MIP field has been limited so far due to its inherent incompatibility with acidic monomers like methacrylic acid (MAA), which is by far the most widely used functional monomer. Herein, a new method is described for the MIP synthesis through photo-initiated ATRP using fac-[Ir(ppy)3] as ATRP catalyst. The synthesis is possible at room temperature and is compatible with acidic monomers. This study considerably widens the range of functional monomers and thus molecular templates that can be used when MIPs are synthesized by ATRP. The proposed method was used for fabrication of hierarchically organised nanocomposites based on MIPs and nanostructured metal surfaces containing nanoholes or nanoislands, exhibiting plasmonic effects for signal amplification. The fabrication of nanometer scale MIP coatings localized on gold surface was demonstrated. Optical transduction methods, namely Localized Surface Plasmon Resonance (LSPR) and Surface Enhanced Raman Spectroscopy (SERS) were exploited and shown that they hold great promise for enhancing the limit of detection in sensing of biologically relevant analytes including proteins and the drug propranolol
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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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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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Chowdhury, 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 textAbstract:
Recent advances in nanotechnology and the biotechnology revolution have
created an immense opportunity for the use of noble metal nanoparticles as Surface
Enhanced Raman Spectroscopy (SERS) substrates for biological sensing and diagnostics.
This is because SERS enhances the intensity of the Raman scattered signal from an
analyte by orders of 106 or more. This dissertation deals with the different aspects
involved in the application of SERS for biosensing. It discusses initial studies performed
using traditional chemically reduced silver colloidal nanoparticles for the SERS
detection of a myriad of proteins and nucleic acids. It examines ways to circumvent the
inherent aggregation problems associated with colloidal nanoparticles that frequently
lead to poor data reproducibility. The different methods examined to create robust SERS
substrates include the creation of thermally evaporated silver island films on microscope
glass slides, using the technique of Nanosphere Lithography (NSL) to create
hexagonally close packed periodic particle arrays of silver nanoparticles on glass
substrates as well as the use of optically tunable gold nanoshell films on glass substrates. The three different types of SERS surfaces are characterized using UV-Vis absorption
spectroscopy, Electron Microscopy (EM), Atomic Force Microscopy (AFM) as well as
SERS using the model Raman active molecule trans-1,2-bis(4-pyridyl)ethylene (BPE).
Also discussed is ongoing work in the initial stages of the development of a SERS based
biosensor using gold nanoshell films for the direct detection of b-amyloid, the causative
agent for Alzheimer's disease. Lastly, the use of gold nanoshells as SERS substrates for
the intracellular detection of various biomolecules within mouse fibroblast cells in cell
culture is discussed. The dissertation puts into perspective how this study can represent
the first steps in the development of a robust gold nanoshell based SERS biosensor that
can improve the ability to monitor biological processes in real time, thus providing new
avenues for designing systems for the early diagnosis of diseases.
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Syed, 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 textAbstract:
The prospect of ultra-sensitive detection of molecular species, particularly those of energetic materials, has prompted the present research initiative. The combination of metal surface nano-technology and Raman spectroscopy has given rise to ‘Surface Enhanced Raman Spectroscopy’ (SERS). This is a very sensitive technique and has proved to be capable of detecting a single molecule. SERS was demonstrated by recording Raman spectra of the sample molecules adsorbed on various specially prepared SER-active surfaces both in the form of a colloidal suspension and on the solid roughened surfaces. Using a gold colloidal suspension, pyridine has been detected down to 10-11 molar (M) concentration. A silver slab was roughened to a dimension of a nano-scale by etching in nitric acid solution to make SER-active surface. Pentaerythritol Tetranitrate (PETN) explosive was detected using this surface after its 10-2 M solution was dropped, dried and washed (of any residue) from the surface. Lithographically engineered silver structures in the form of nanoarrays having a number of silver structures of approximately 106 in a region of 0.1 mm2 have been used for SERS. The major noise contribution to the scattering from impurities in an ordinary glass substrate has been eliminated by replacing glasses as substrates with pure quartz discs. The headspace vapours from peroxide explosives, Triacetone Triperoxide (TATP) and Hexamethylene Triperoxide Diamine (HMTD), were detected at approximately 70 parts per million (ppm) and 0.3 ppm concentrations respectively using a portable commercial Raman Spectrometer. PETN was also detected from its headspace vapour at about 18 parts per trillion (ppt) in spite of it having a much lower vapour pressure. The possibility of desorption of adsorbed molecules from a nano-structured surface by laser irradiation has been demonstrated experimentally with the aim of reusability of SER-active surfaces. Also demonstrated was the enhancement in Raman intensity through resonance Raman effect spectroscopy for the future use in surface enhanced resonance Raman spectroscopy (SERRS).
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Wigginton, Krista Rule. "Surface Enhanced Raman Spectroscopy as a Tool for Waterborne Pathogen Testing." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29330.
Full textAbstract:
The development of a waterborne pathogen detection method that is rapid, multiplex, sensitive, and specific, would be of great assistance for water treatment facilities and would help protect water consumers from harmful pathogens. Here we have utilized surface enhanced Raman spectroscopy (SERS) in a sensitive multiplex pathogen detection method. Two strategies are proposed herein, one that utilizes SERS antibody labels and one that measures the intrinsic SERS signal of organisms. For the SERS label strategy, gold nanoparticles are conjugated with antibodies specific to Cryptosporidium parvum and Giardia lamblia and with organic dye molecules. The dye molecules, rhodamine B isothiocyanate (RBITC) and malachite green isothiocyanate (MGITC) were surface enhanced by the gold nanoparticles resulting in unique fingerprint SERS spectra. The SERS label method was successful in detecting G. lamblia and C. parvum simultaneously. The method was subsequently coupled with a filtration step to both concentrate and capture cysts on a flat surface for detection. Raman mapping across the filter membrane detected ~95% of the spiked cysts in the optimized system.
In the second type of strategy, intrinsic virus SERS signals were detected with silver nanoparticles for enhancement. Principal component analysis performed on the spectra data set resulted in the successful differentiation of MS2 and PhiX174 species and also for the differentiation of viable virus samples and inactivated virus samples.Ph. D.
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Jain, Ishan. "Paper-Based Sensors for Contaminant Detection Using Surface Enhanced Raman Spectroscopy." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/53946.
Full textAbstract:
Surface enhanced Raman spectroscopy (SERS) is highly promising analytical technique for trace detection of analytes. It is particularly well suited for environmental analyses due to its high sensitivity, specificity, ease of operation and rapidity. The detection and characterization of environmental contaminants, using SERS is highly related to the uniformity, activity and reproducibility of the SERS substrate.
In this thesis, SERS substrates were produced by gold nanoparticle formation on wax patterned chromatography paper. In situ reduction of hydrogen tetrachloroaurate (gold precursor) by trisodium citrate dihydrate (reducing agent) was used to produce gold nanoparticles within a paper matrix. These gold nanoparticle based SERS substrates were analyzed by FE-SEM, UV-Vis and Raman spectroscopy. This work discusses the SERS signal enhancements for Raman active MGITC dye for a series of substrates prepared by in situ reduction of gold salt and pre-produced gold nanoparticles. UV-Vis analysis was performed to understand the effect of different molar ratio (reducing agent to gold precursor) and reaction time on the size and shape of the localized surface plasmon resonance (LSPR) band that dictates the SERS enhancements. It was concluded that lower molar ratio (1:1 and 2:1) of citrate-to gold produced better SERS signal enhancements and broader LSPR band. Therefore, use of lower molar ratio (MR) was recommended for paper-based substrates using in situ-based reduction approach.Master of Science
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Syed, 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 textAbstract:
The prospect of ultra-sensitive detection of molecular species, particularly those of
energetic materials, has prompted the present research initiative. The combination of
metal surface nano-technology and Raman spectroscopy has given rise to ‘Surface
Enhanced Raman Spectroscopy’ (SERS). This is a very sensitive technique and has
proved to be capable of detecting a single molecule.
SERS was demonstrated by recording Raman spectra of the sample molecules adsorbed
on various specially prepared SER-active surfaces both in the form of a colloidal
suspension and on the solid roughened surfaces. Using a gold colloidal suspension,
pyridine has been detected down to 10-11 molar (M) concentration. A silver slab was
roughened to a dimension of a nano-scale by etching in nitric acid solution to make
SER-active surface. Pentaerythritol Tetranitrate (PETN) explosive was detected using
this surface after its 10-2 M solution was dropped, dried and washed (of any residue)
from the surface. Lithographically engineered silver structures in the form of nanoarrays
having a number of silver structures of approximately 106 in a region of 0.1 mm2
have been used for SERS. The major noise contribution to the scattering from
impurities in an ordinary glass substrate has been eliminated by replacing glasses as
substrates with pure quartz discs. The headspace vapours from peroxide explosives,
Triacetone Triperoxide (TATP) and Hexamethylene Triperoxide Diamine (HMTD),
were detected at approximately 70 parts per million (ppm) and 0.3 ppm concentrations
respectively using a portable commercial Raman Spectrometer. PETN was also detected
from its headspace vapour at about 18 parts per trillion (ppt) in spite of it having a much
lower vapour pressure.
The possibility of desorption of adsorbed molecules from a nano-structured surface by
laser irradiation has been demonstrated experimentally with the aim of reusability of
SER-active surfaces. Also demonstrated was the enhancement in Raman intensity
through resonance Raman effect spectroscopy for the future use in surface enhanced
resonance Raman spectroscopy (SERRS).
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Israelsen, Nathan. "Surface-Enhanced Raman Spectroscopy-Based Biomarker Detection for B-Cell Malignancies." DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4605.
Full textAbstract:
This thesis presents a light scattering-based method for biomarker detection, which could potentially be used for the quantification of multiple biomarkers specific to B-cell malignancies. This method uses fabricated gold nanoparticle probes to amplify inelastic light scattering in a process referred to as surface-enhanced Raman scattering. These gold nanoparticle probes were conjugated to antibodies for specific and targeted molecular binding. The spectrum of the amplified inelastic light scattering was detected using a spectrometer and a detector. To detect the light scattering signal from the gold nanoparticle probes, several commercial Raman spectrometer instruments were evaluated. Initial results from these evaluations are presented in this thesis. After system evaluation, a custom Raman microscope system was designed, built, and tested. This system was used for the development of a surface-enhanced Raman spectroscopy-based immunoassay. The development of this assay confirms the successful design of gold nanoparticle probes for the specific targeting and detection of immunoglobulins. The immunoassay also shows promise for the simultaneous detection of multiple biomarkers specific to B-cell malignancies.
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CARA, ELEONORA. "Tailored fabrication of nanostructured substrates for surface-enhanced Raman spectroscopy applications." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2735516.
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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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