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隼人, 市橋, and Hayato Ichihashi. "Studies on optical spectroscopy techniques with surface plasmon resonance." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13127436/?lang=0, 2020. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13127436/?lang=0.
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表面プラズモン共鳴型超音波センサは高分解能な光音響顕微鏡用超音波受波器として期待されている．本研究では，サブナノ秒パルスレーザを利用したポンププローブシステムを構築してサブナノ秒域における表面プラズモン共鳴センサの熱・弾性的な過渡応答を光学的に評価した。特にプローブ光の反射率変化として観測される過渡応答の発生メカニズムについて，実験と理論の両方のアプローチから検討しており，観測される過渡応答は金属薄膜のプラズマ周波数の変化に起因することを明らかにした。Surface plasmon resonance (SPR) sensor has been expected as a ultrasonic sensor used in high resolution photoacoustic microscopy (PAM). In this thesis, thermoelastic transient responses in SPR sensor were evaluated by a pump probe system with a developed sub-nanosecond pulsed laser. Especially, the mechanism of the transient response to be observed as a reflectivity change of the probe light was studied by two approaches of the experiment and the theoretical estimation. As consequence of these approaches, it was revealed that the transient response was caused by the change of the plasma frequency in a thin metal film of SPR sensor.
博士(工学)
Doctor of Philosophy in Engineering
同志社大学
Doshisha University
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Shinall, Brian Darnell. "Using surface plasmon resonance spectroscopy to characterize thin composite films." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/10157.
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Mozsolits, Henriette 1971. "Surface plasmon resonance spectroscopy for the study of peptide-membrane interactions." Monash University, Dept. of Biochemistry and Molecular Biology, 2001. http://arrow.monash.edu.au/hdl/1959.1/8123.
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Baumeister, Carl Robert. "Electrochemical impedance spectroscopy and surface plasmon resonance for diagnostic antibody detection." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/31495.
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The successful use of biomarker antibody detection for disease diagnosis is currently
restricted to cases where the antibody affinity and specificity of interaction with
antigen is high. Evanescent field biosensing, e.g. Surface Plasmon Resonance (SPR),
and electrochemical detection, in particular Electrochemical Impedance Spectroscopy
(EIS), have been shown viable for detection of lower affinity antibodies, based on the
principle that these technologies allow the measurement of antibody binding to
immobilized antigen, i.e. without the need to wash away excess, non-bound
antibodies or using labelled antibodies. Proof of principle for this in the case of
detection of biomarker anti-mycolic acid antibodies for TB diagnosis has been
provided in the Mycolic acid Antibody Real-Time Inhibition assay (MARTI) by our
research group. Although already patented and published, MARTI is not yet a feasible
diagnostic test due to slow sample turn-around time, affordability and technical
vulnerability associated with unstable lipid antigen surface chemistry and the
difficulty of standardization of liposome carriers of mycolic acids used for measuring
the binding inhibition of serum antibodies to immobilized antigen. Here, these
challenges were addressed by investigating the use of a magnetic field for more stable
lipid antigen immobilization, new phospholipid compositions to generate more stable
liposome carriers for lipid antigen in solution and the use of screen-printed electrodes
(SPE) in EIS to address affordability of diagnosis and improve sample turn-around
time. The latter approach appeared quite promising in distinguishing a TB positive
and a TB negative patient serum and is amenable to automation by means of a flow
injection system.Dissertation (MSc)--University of Pretoria, 2012.
Biochemistry
MSc
Unrestricted
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Watkins, William L. "Study and development of localised surface plasmon resonance based sensors using anisotropic spectroscopy." Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS505.pdf.
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La résonance de plasmon de surface localisée (LSPR) est définie comme l’oscillation collective du nuage d’électrons de conduction induite par un champ électrique externe. Dans le cas de nanoparticules composé de métaux nobles tels que l’or, l’argent, ou le cuivre,la résonance est localisée dans le visible ou le proche UV. La polarisabilité d’une nanoparticule est directement proportionnelle à quatre paramètres clefs : son volume, sa composition, sa forme et son milieu environnant. Ce sont ces propriétés qui font que la LSPR peut être utilisée à des fin de capteur. Dans le cas d’une particule isotrope, tel que la sphère, le spectre LSPR montre un seul pic d’absorption. Dans le cas d’une particule anisotrope, tel qu’une ellipsoïde, le spectre d’absorption a deux maxima distincts. Si on calcule la section efficace d’absorption en considérant une lumière non polarisée, on obtient deux maxima. Le point clef de ce type de système est la possibilité de découpler les deux résonances en utilisant une lumière polarisée. Dans cette description le système anisotrope est considéré comme microscopique, c’est à dire qu’il ne s’agit que d’une ou deux particules. Dans le cas d’un échantillon macroscopique, tel qu’une solution colloïdale d’ellipsoïdes ou nanotiges, le spectre d’absorption aura toujours deux maxima d’absorption, mais ceux-ci ne pourront pas être découplés car l’échantillon n’est pas globalement anisotrope. En revanche, si l’échantillon présente une anisotropie globale telle que des nanotiges alignés, ou des nanosphères organisées en ligne, il est possible d’avoir un spectre de plasmon dépendant de la polarisation de la lumière. Être capable de découpler les résonances d’un échantillon anisotrope permet de mesurer un spectre différentiel en prenant la différence des deux spectres d’absorption. Cela est expérimentalement possible en utilisant la spectroscopie de transmis- sion anisotrope qui permet la mesure de l’anisotropie optique. L’avantage est d’obtenir un spectre relative et différentiel donc plus stable et reproductible. De plus il est maintenant possible de suivre l’évolution de la réponse optique des particules plasmoniques, non plus en mesurant un déplacement spectral, mais en mesurant le changement d’intensité du signal à une longueur d’onde fixe. Cette méthode est utilisée pour deux cas d’études qui sont la mesure de l’interaction du dihydrogène avec des nanoparticules d’or, ainsi que la détection de faible pression partielle de dihydrogène dans un gaz porteur (argon, et air) à l’aide de palladium, pour des applications de capteur d’hydrogèneLocalised surface plasmon resonance (LSPR) is defined as the collective oscillation of the conduction electron cloud induced by an external electric field. In the case of nanoparticles composed of noble metals such as gold, silver, or copper, the resonance is located in the visible or near UV range. The polarisability of a nanoparticle is directly proportional to four key parameters: its volume, its composition, its shape and its surrounding environment. It is these properties that make LSPR useful for sensor applications. In the case of isotropic particles, such as spheres, the LSPR spectrum shows only one absorption peak. In the case of an anisotropic particle, such as an ellipsoid, the absorption spectrum has two or more distinct peaks. If the absorption cross-section is measured with unpolarised light, multiple maxima are obtained. The key point for these type of systems is the possibility to decouple the resonances using polarised light. In this description the anisotropic system is considered microscopic, i.e. it is only made of one or two particles. In the case of a macroscopic sample, such as a colloidal solution of ellipsoids or nanorods, the absorption spectrum will always have multiple absorption maxima, and they cannot be decoupled because the sample is not globally anisotropic.On the other hand, if the sample has a global anisotropy such as aligned nanorods, or nanosphere organised in lines, it is possible to have a plasmon spectrum dependent on the light polarisation. Being able to decouple the resonances of an anisotropic sample makes it possible to measure a differential spectrum by taking the difference of the two absorption spectra. This is experimentally possible by using anisotropic transmission spectroscopy which measures the optical anisotropy. The advantage is to obtain a relative and differential spectrum more stable and reproducible. Moreover, it is now possible to follow the evolution of the optical response of the plasmonic particles no longer by measuring a spectral shift but by measuring the change in intensity of the signal at a fixed wavelength. This method is used on two case studies which are the measurement of the interaction of dihydrogen with gold nanoparticles, as well as the detection of low partial pressure of dihydrogen in a carrier gas (argon, and air) using palladium nanoparticles, for hydrogen sensing applications
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Kaya, Abdulaziz. "Studies of polysaccharide adsorption onto model cellulose surfaces and self-assembled monolayers by surface plasmon resonance spectroscopy." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/39296.
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Throughout the study of polymer adsorption at the air/water and solid/water interfaces, surface tension measurements and surface plasmon resonance (SPR) spectroscopy have been identified as key methods for the acquisition of structural and thermodynamic information. These techniques were used to determine air/water and cellulose/water interfacial properties of pullulan (P) and pullulan cinnamates (PCs), 2-hydroxypropyltrimethylammonium xylans (HPMAXs), and hydroxypropyl xylans (HPXs).
Hydrophobic modification of pullulan with cinnamate groups promoted adsorption onto model surfaces of regenerated cellulose. In order to understand the relative contributions of hydrophilic and hydrophobic interactions towards PC adsorption, PC adsorption onto self-assembled monolayers (SAMs) with different functional groups was also studied. As the degree of cinnamate substitution increased, greater adsorption onto cellulose, methyl-terminated SAMs (SAM-CH3), and hydroxyl-terminated SAMs (SAM-OH) was observed. This study showed that hydrogen bonding alone could not provide a complete explanation for PC adsorption onto cellulose.
The adsorption of cationic 2-hydroxypropyltrimethylammonium (HPMA) xylans with different degrees of substitution (DS) onto SAMs and regenerated cellulose was studied by SPR. Surface concentration (Ð ) exhibited a maximum (Ð max) for HPMAX adsorption onto carboxylic acid-terminated SAMs (SAM-COOH) at an intermediate HPMA DS of 0.10. This observation was indicative of a relatively flat conformation for adsorbed HPMAXs with higher HPMA DS because of higher linear charge densities along the polymer backbone. Ð observed for HPMAX adsorption onto regenerated cellulose and SAM-OH surfaces was relatively low compared to HPMAX adsorption onto SAM-COOH surfaces.
Surface tension measurements for aqueous solutions of HPX by the Wilhelmy plate technique showed that surface tension changes ("γ = γwater " γHPX(aq)) increased and critical aggregation concentrations generally decreased with increasing hydroxypropyl (HP) DS. Hence, even though HP substitution was necessary to induce aqueous solubility, excessive hydroxypropylation promoted aggregation in water. SPR studies indicated that HPXs did not adsorb significantly onto regenerated cellulose or SAM-OH surfaces (submonolayer coverage). In contrast, HPX did adsorb (~monolayer coverage) onto SAM-CH3 surfaces.
Collectively, these studies showed natural polymers could be chemically modified to produce surface modifying agents with sufficient chemical control, whereby the surface properties of the resulting systems could be explained in terms of chemical structure and intermolecular interactions.Ph. D.
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Samaimongkol, Panupon. "Surface plasmon resonance study of the purple gold (AuAl2) intermetallic, pH-responsive fluorescence gold nanoparticles, and gold nanosphere assembly." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/96549.
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In this dissertation, I have verified that the striking purple color of the intermetallic compound
AuAl2, also known as purple gold, originates from surface plasmons (SPs). This contrasts to a
previous assumption that this color is due to an interband absorption transition. The existence of
SPs was demonstrated by launching them in thin AuAl2 films in the Kretschmann configuration,
which enables us to measure the SP dispersion relation. I observed that the SP energy in thin films of purple gold is around 2.1 eV, comparable to previous work on the dielectric function of this
material. Furthermore, SP sensing using AuAl2 also shows the ability to measure the change in the refractive index of standard sucrose solution. AuAl2 in nanoparticle form is also discussed in terms of plasmonic applications, where Mie scattering theory predicts that the particle bears nearly
uniform absorption over the entire visible spectrum with an order magnitude higher than a lightabsorbing carbonaceous particle. The second topic of this dissertation focuses on plasmon enhanced fluorescence in gold nanoparticles (Au NPs). Here, I investigated the distance-dependent fluorescence emission of rhodamine green 110 fluorophores from Au NPs with tunable spacers. These spacers consist of polyelectrolyte multilayers (PEMs) consisting of poly(allylamine
hydrochloride) and poly(styrene sulfonate) assembled at pH 8.4. The distance between Au NPs and fluorophores was varied by changing the ambient pH from 3 to 10 and back, which causes the
swelling and deswelling of PEM spacer. Maximum fluorescence intensity with 4.0-fold enhancement was observed with 7-layer coated Au NPs at ambient pH 10 referenced to pH 3. The last topic of this dissertation examines a novel approach to assemble nanoparticles, in particular, dimers of gold nanospheres (NSs). 16 nm and 60 nm diameter NSs were connected using
photocleavable molecules as linkers. I showed that the orientation of the dimers can be controlled
with the polarization of UV illumination that cleaves the linkers, making dipolar patches. This type
of assembly provides a simple method with potential applications in multiple contexts, such as
biomedicine and nanorobotics.PHD
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Revell, David Jon. "Self-assembled monolayers : spectroscopic characterisation and molecular recognition." Thesis, University of East Anglia, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302080.
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Ou, Meigui. "Nanostructured gold surfaces as biosensors : surface-enhanced chemiluminescence and double detection by surface plasmon resonance and luminescence." Lyon, INSA, 2008. http://theses.insa-lyon.fr/publication/2008ISAL0057/these.pdf.
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This thesis is devoted to develop two biological detection systems based on nanostructured gold surfaces to detect the binding of streptavidin/biotin. In the first part, we have studied a multimodal detection system using local surface plasmon resonance of the gold substrate and the luminescence of labelling core-shell Gd2O3/SiOx nanoparticles, which profits from the plasmonic property of nanostructure gold. In a second part, we have focused in a surface-enhanced chemiluminescence system based on chemiluminescence of luminal/hydrogen peroxide (H2O2) enhanced by gold nanostructures in the vicinity, which benefits from the catalytic property of nanostructure gold. Several parameters influencing the chemiluminescence of luminal were investigated. Enhancing mechanism of luminal chemiluminescence was proved to be not related to Plasmon-assisted process but originates from catalytic properties of the metal induced by corrugationCette thèse est consacré à développer deux systèmes pour la détection biologique à la base de la surface d’or pour détecter la liaison entre les molécules de biotine et de streptavidine. Premièrement, nous avons étudié un système de détection multimodal utilisant la résonance des plasmons de surface localisé sur substrats d’or et la luminescence de nanoparticules labellisées de coeur-écorce Gd2O3/SiOx, qui bénéficie de la propriété plasmonic d’or en nanostructure. Deuxièmement, nous avons focalisé sur un système qui se fonde sur le phénomène d’exaltation de chimiluminescence par la surface. La chimiluminescence de luminophore/ peroxyde d’hydrogène (H2O2) est exaltée par nanostructure d’or à proximité, qui bénéficie de la propriété catalytique de nanostructure d’or. Plusieurs paramètres ont été étudiés de manière systématique. Finalement, il est prouvée que le mécanisme de l’exaltation de chimiluminescence est originaire de la propriété catalytique du métal induit par la rugosité
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Zhang, Sanjun. "Surface plasmon resonance and its applications to the probing of macromolecules on gold surfaces." Lyon, École normale supérieure (sciences), 2008. http://www.theses.fr/2008ENSL0450.
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Fenzl, Christoph [Verfasser], and Antje J. [Akademischer Betreuer] Bäumner. "Liposomes as Versatile Tools for Signal Enhancement in Surface Plasmon Resonance Spectroscopy / Christoph Fenzl ; Betreuer: Antje J. Bäumner." Regensburg : Universitätsbibliothek Regensburg, 2016. http://d-nb.info/1118846257/34.
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Midelet, Clyde. "Diélectrophorèse de nanoparticules en système microfluidique ˸ étude par vidéo-microscopie numérique et application à l'analyse par spectroscopie optique." Thesis, Rennes, École normale supérieure, 2019. http://www.theses.fr/2019ENSR0019.
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La manipulation de micro- et nano- particules en solution peut être réalisée grâce aux interactions de ces objets avec des champs électromagnétiques. La lumière ou bien encore les champs électriques continus (DC) ou alternatifs (AC) peuvent être utilisés. Dans le cas d’un champ électrique non uniforme appliqué entre deux électrodes séparées par quelques micromètres, des gradients de champs très intenses et localisés sont ainsi créés. Ces gradients de champ localisés au niveau des électrodes engendrent la création de mouvements de charges composant la solution (effets électro-hydrodynamique). Mais aussi des charges confinées au niveau des particules à l’interface liquide/solide. Les particules en suspension subissent alors une force attractive ou répulsive appelée diélectrophorèse. Cette force est décrite dans la littérature pour des particules isolantes de taille supérieure à 200 nm. Dans cette étude par détection optique (videomicroscopie par champ sombre ou spectroscopie en microfluidique) la gamme de taille de particules est élargie (40-150 nm) pour étudier leurs réponses diélectrophorètique. En effet la diélectrophorèse dépend de la taille des particules, de son environnement et des paramètres du champ appliqué (fréquence, amplitude, topologie) La diélectrophorèse est mise en compétition avec le mouvement Brownian pour des particules d’or d’aussi petites tailles. La réponse pour des nanoparticules d’or en solution alors connue, il est envisageable de faire varier les paramètres, comme l’environnement de la particule ou bien la complexité des systèmes étudiésThe manipulation of micro- and nano- particles in solution can be achieved through the interactions of these objects with electromagnetic fields. Emitted light, continuous (DC) or alternating (AC) electric fields can be used. In the case of a non-uniform electric field applied between two electrodes separated by a few micrometers, very intense and localized field gradients are created. These field gradients localised close to the electrodes generates a motion of the mass solution (electro-hydrodynamic effects). The charges confined onto particles at the liquid/solid interface are also subjected to motion. Suspended particles undergo an attractive or repulsive force called dielectrophoresis.This force is described in the literature for insulating particles larger than 200 nm. In this study optical detection was used (dark field videomicroscopy or microfluidic spectroscopy) to expand the range of particle size (40-150 nm) and to study their dielectrophoretic responses. Indeed, the dielectrophoresis is dependent on the size of particles, their environment and the parameters of the applied electric field (frequency, amplitude, topology). The dielectrophoresis is in competition with the Brownian motion of these gold nanoparticles. By, knowing the dielectrophoretic response of these particles in solution, it is possible to vary parameters, such as the suspension composition of the particles or the complexity of the systems studied
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Zhang, Han. "STUDY OF TRANSMEMBRANE PROTEIN ACTIVITY IN STABILIZED LIPID MEMBRANES AND DEVELOPMENT AND APPLICATIONS OF SURFACE SENSITIVE PLASMON WAVEGUIDE RESONANCE SPECTROSCOPY." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/195280.
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This dissertation covers a broad range of research topics all towards the ultimate goal establishing of a novel type of biosensor in which the biocompatible membrane structure reconstituted with functional transmembrane proteins is utilized as the sensing element. It focuses on 1) examining the activity of a model transmembrane protein, bovine rhodopsin (Rho) when reconstituted into stabilized lipid membranes and 2) the instrumentation of a novel type of optical spectroscopy, plasmon waveguide resonance (PWR), which is a surface sensitive technique and its application in sensing biological events.Lipid membrane play crucial roles in cell function. Their biophysical properties affect the activity of a large amount of transmembrane receptors. They are great candidates for biosensing/ biomedical coating. However, the intrinsic instability of natural or fluid membranes prevents them to be used in a device. Studies have been done to show indirect evidence that the activity of Rho maybe maintained in polymerized membrane composed of bis-SorbPC lipids. The activity of Rho reconstituted into vesicular membranes comprised of various lipids was studied by a more direct technique, UV-Vis. It was found Rho activity was maintained to 66% of that in natural Egg PC lipid in the mixture of Egg PC:(poly)bis-SorbPC (1:1 mol:mol) as opposed to minimal values in 100 % (poly)lipids.A new type of spectral PWR was developed. The working concept, technical characterization and comparisons with similar techniques were discussed and compared in this work. A modified version of angular PWR in which lipid bilayers were formed by vesicle fusion was also developed. This method excludes possible effects from a high boiling point organic solvent on either the lipid bilayer itself or the membrane proteins associated with it. A calculating program NphaseAll for PWR was developed to do predictions of waveguide properties can be made to provide guidance for waveguide design. Theoretical calculations were done for PWR and experimental results were compared with the theoretical predictions.PWR was used to detect the formation of a biological lipid membrane, the association of alpha synuclein with membranes and the binding activity of human melanarcortin to its ligands in fluid and polymerized/dried membranes.
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Shumaker-Parry, Jennifer Sue. "Quantitative aspects of SPR spectroscopy and SPR microscopy, applications in protein binding to immobilized vesicles and dsDNA arrays /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/11600.
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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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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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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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Rodriguez, Kenneth Ralph. "The extraordinary infrared transmission of metal microarrays for enhanced absorption spectroscopy of monolayers, nanocoatings, and catalytic surface reactions." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1189549712.
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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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Rye, Jan-Michael. "Spatial Modulation Spectroscopy Of Single Nano-Objects In A Liquid Environment For Biosensing Applications." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1053/document.
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Le développement de méthodes rapides, précises et ultra-sensibles pour la détection d'analytes cibles en solution est crucial pour la recherche et les applications potentielles en médecine ou biologie moléculaire. Une approche très prometteuse consiste à développer des nano-capteurs à partir de nano-objets métalliques (NOM) qui présentent une résonance d'extinction dans leur réponse optique. Cette résonance nommée résonance de plasmon de surface localisée (RPSL) peut être ajustée spectralement en jouant sur la nature, la morphologie et l'environnement du NOM. Mesurer des modifications sur la RPSL de nano-objets individuels en présence d'analytes cibles doit permettre de s'affranchir des effets de moyennes dans les mesures d'ensemble. De plus, cela ouvre la voie vers le développement d'échantillons micrométriques pour des tests multicibles sans étiquette (« label-free »).Dans ce travail on a développé un nouveau dispositif expérimental basé sur la technique de spectroscopie à modulation spatiale (SMS) permettant de sonder la réponse optique de NOM individuels en milieu liquide. En parallèle des méthodes de synthèse ont été mises au point pour obtenir des échantillons sondes stables permettant des mesures sur NOM unique, en particulier sur des bipyramides d'or qui présentent de nombreuses qualités intrinsèques faisant d'elles de bonnes candidates pour le « bio-sensing ».Des mesures ont été réalisées dans des environnements d'indice variable et les changements détectés sont en bon accord avec les simulations théoriques. De plus, de nombreuses études ont été réalisées pour comprendre l'influence des nombreux paramètres agissant sur la réponse optique des systèmes étudiésAdvances in the development of rapid, accurate and highly sensitive methods for detecting target analytes in solution will provide crucial tools for research and applications in medicine and molecular biology. One of the currently most promising approaches is the development of nanosensors based on the localized surface plasmon resonance (LSPR) of noble metal nano-objects (MNOs), which is an optical response that depends on their size, shape, composition and local environment. The ability to measure the modification of the reponse of a single MNO in the presence of a target analyte would allow each object to act as an independent probe with increased sensitivity as the signal would be isolated from the averaging effects of ensemble measurements. Furthermore it would allow the development of micrometric, functionalized multiprobe samples for multitarget label-free assays.In this work, a novel experimental setup based on the spatial modulation spectroscopy (SMS) technique has been developed to measure the optical response of individual nano-objects in a liquid environment. In parallel, a new technique has also been developed to elaborate stable probes for measurements with the new setup, with a focus on gold bipyramids due to numerous qualities that make them excellent candidates for biosensing probes. The setup has been used to measure the response of individual objects in environments of different real refractive indices and the detected changes have been shown to be in good agreement with theoretical calculations. Numerical studies have also been performed to investigate the influence on the optical response of numerous factors encountered in the studied systems
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Okabayashi, Yohei. "Synthesis of azide- and alkyne-terminated alkane thiols and evaluation of their application in Huisgen 1,3-dipolar cycloaddition ("click") reactions on gold surfaces." Thesis, Department of Physics, Chemistry and Biology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-20559.
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Immobilization of different bio- and organic molecules on solid supports is fundamental within many areas of science. Sometimes, it is desirable to obtain a directed orientation of the molecule in the immobilized state. In this thesis, the copper (I) catalyzed Huisgen 1,3-dipolar cycloaddition, referred to as a “click chemistry” reaction, was explored as a means to perform directed immobilization of small molecule ligands on gold surfaces. The aim was to synthesize alkyne- and azide-terminated alkanethiols that would form well-organized self assembled monolayers (SAMs) on gold from the commercially available substances orthoethylene glycol and bromo alkanoic acid. N-(23-azido-3,6,9,12,15,18,21-heptaoxatricosyl)-n-mercaptododekanamide/hexadecaneamide (n = 12, 16) were successfully synthesized and allowed to form SAMs of different compositions to study how the differences in density of the functional groups on the surface would influence the structure of the monolayer and the click chemistry reaction. The surfaces were characterized by different optical methods: ellipsometry, contact angle goniometry and infrared reflection-absorption spectroscopy (IRAS). The click reaction was found to proceed at very high yields on all investigated surfaces. Finally, the biomolecular interaction between a ligand immobilized by click chemistry on the gold surfaces and a model protein (bovine carbonic anhydrase) was demonstrated by surface plasmon resonance using a Biacore system.
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Heer, Joseph Michael. "FDTD Modeling of the Spectroscopy and Resonances of Thin Films and Particles on Plasmonic Nickel Mesh." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1293754711.
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Kholodtsova, Maria. "Spectral, spatial and temporal properties of multilayered epithelial tissue in vivo in presence of metal nanoparticles in multimodal spectroscopy." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0031/document.
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Le travail de thèse est consacré aux interactions spatio-, temporo- et spectro- résolue de laser avec des tissus biologiques. L'objectif de cette thèse était d'étudier l'influence des nanoparticules colloïdales embarqués dans les tissus biologiques multicouches sur leurs propriétés optiques afin de fournir plus profond et / ou plus précise de sondage. Pour ce faire, les paramètres spectroscopiques intégrales et durée de vie de fluorophore dans les environs de nanoparticules métalliques ont été analysées théoriquement et expérimentalement. L’autre partie de l'étude était de proposer de nouvelles solutions algorithmiques pour l'amélioration de la performance du processus d'estimation des valeurs des propriétés optiques de la résolution spatiale des mesures spectroscopiques. La dernière partie de la thèse est la modélisation expérimentale et théorique de la cinétique de fluorophores en présence des nanoparticules d'or colloïdales. La composante ultra-courte pico-seconde (environ 100 ps) a été résolue et a été corrélée à champ dipolaire forte des nanoparticules qui compense le dipôle de la moléculeThe thesis work is devoted to spatially-, temporally- and spectrally- resolved laser and biological tissue interactions. The aim of the present thesis was to investigate the influence of colloidal nanoparticles embedded into multilayered biological tissues on their optical properties in order to provide deeper and/or more precise probing. To do so, the integral spectroscopic parameters and lifetime of fluorophore in vicinity of metal nanoparticles were analyzed theoretically and experimentally. Another part of the study was to propose new algorithmic solutions for improving the performance of the estimation process of the optical properties values from spatially resolved spectroscopic measurements. The last part of the thesis was the experimental and theoretical modelling of fluorophore’s kinetics in presence of colloidal gold nanoparticles. The ultra-short pico-second component (around 100 ps) was resolved and correlated to strong nanoparticles dipole field which is compensating the molecule’s dipole
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Bergström, Anna. "SPR Sensor Surfaces based on Self-Assembled Monolayers." Thesis, Linköping University, Department of Physics, Chemistry and Biology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-16664.
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The study and understanding of molecular interactions is fundamentally important in today's field of life sciences and there is a demand for well designed surfaces for biosensor applications. The biosensor has to be able to detect specific molecular interactions, while non-specific binding of other substances to the sensor surface should be kept to a minimum. The objective of this master´s thesis was to design sensor surfaces based on self-assembled monolayers (SAMs) and evaluate their structural characteristics as well as their performance in Biacore systems. By mixing different oligo (ethylene glycol) terminated thiol compounds in the SAMs, the density of functional groups for bimolecular attachment could be controlled. Structural characteristics of the SAMs were studied using Ellipsometry, Contact Angle Goniometry, IRAS and XPS. Surfaces showing promising results were examined further with Surface Plasmon Resonance in Biacore instruments.
Mixed SAM surfaces with a tailored degree of functional COOH groups could be prepared. The surfaces showed promising characteristics in terms of stability, immobilization capacity of biomolecules, non-specific binding and kinetic assay performance, while further work needs to be dedicated to the improvement of their storage stability. In conclusion, the SAM based sensor surfaces studied in this thesis are interesting candidates for Biacore applications.
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Du, Xiaosong. "Adsorption Studies of Polysaccharides and Phospholipids Onto Cellulose." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/30161.
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Interactions between biomolecules and cellulose films at solid/liquid interfaces was studied by surface plasmon resonance spectroscopy (SPR), quartz crystal microbalance with dissipation monitoring (QCM-D) and in situ atomic force microscopy (AFM) measurements. This dissertation shows the porous character of nanocrystalline cellulose films as the key feature for enhanced adsorption of chemically modified polysaccharides and provides quantitative analysis of polymer supported phospholipid structures as a stable platform for studying membrane-related processes.
Smooth cellulose I films were prepared by spincoating cellulose nanocrystal suspensions onto positively charged self-assembled monolayers on gold. The adsorption of pullulan cinnamate (PC) onto cellulose surfaces increased with increasing degree of cinnamate substitution. The interactions between PCs with higher degree of substitution (DS) and porous nanocrystalline cellulose (NC) films presumably generated looped multilayer PC structures that adsorbed more than twice as much onto NC films than onto regenerated cellulose (RC) films. PC chains not only covered the NC surface but also penetrated into the porous film. The porous features of NC film are responsible for the greater adsorption of polymer chains relative to tightly packed RC films.
Adsorption of phospholipid vesicles onto RC and NC films was also studied. Aggregates of intact vesicle were observed on NC surfaces with high water content ~ 84 % by mass. Phospholipid patches with smooth features were found to assemble onto RC surfaces with a lower degree of hydration ~ 30 % by mass. Vesicle membrane breakage was triggered by a destabilizing agent, LysoPC. The great mass decrease, and changes in dissipation and degree of hydration for phospholipid structures after exposure to LysoPC corresponded to the transformation from vesicles to layered structures. Initial binding of LysoPC micelles to unruptured vesicles was clearly resolved in SPR, whereas the huge mass decrease associated with bound water hides the initial adsorption of LysoPC onto vesicles in QCM-D experiments. The intitial binding of LysoPC micelles onto vesicle membranes lasted for 200 seconds with a maximal increase of 14 % by mass prior to vesicle collapse.
The role of cholesterol in phospholipid interactions with model cellulose surfaces was also considered. Supported vesicle layers over RC surfaces were observed for vesicle membranes containing â ¥ 6.3 % by mole cholesterol, whereas phospholipid or phospholipid with lower cholesterol content formed disconnected lipid islands on RC surfaces. Meanwhile, intact vesicles were always observed on NC surfaces for phospholipid/cholesterol blends regardless of the cholesterol content. The intact vesicles on cellulose surfaces were attributed to the ability of cholesterol to accommodate vesicle deformation.
These studies showed the impact of mesoscale structure of cellulose films on adsorbates. It sheds light on the role of the lignin-carbonhydrate-complex in plant cell wall structure and will inform the next generation of biomimetic nanocomposites. The designed polymer supported biomimetic membranes provide a perfect platform to develop intact and ruptured protoplast systems for the study of plant cell wall self-assembly.Ph. D.
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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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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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Mershin, Andreas. "Tubulin in vitro, in vivo and in silico." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/1635.
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Tubulin, microtubules and associated proteins were studied theoretically, computationally and experimentally in vitro and in vivo in order to elucidate the possible role these play in cellular information processing and storage. Use of the electric dipole moment of tubulin as the basis for binary switches (biobits) in nanofabricated circuits was explored with surface plasmon resonance, refractometry and dielectric spectroscopy. The effects of burdening the microtubular cytoskeleton of olfactory associative memory neurons with excess microtubule associated protein TAU in Drosophila fruitflies were determined. To investigate whether tubulin may be used as the substrate for quantum computation as a bioqubit, suggestions for experimental detection of quantum coherence and entanglement among tubulin electric dipole moment states were developed.
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Geiss, Frank Andreas [Verfasser]. "Proteo-Lipobeads : a novel platform to investigate strictly oriented membrane proteins in their functionally active form. Bio-UV-SPR: exploring the ultraviolet spectral range for water-bound analytes in surface plasmon resonance spectroscopy / Frank Andreas Geiss." Mainz : Universitätsbibliothek Mainz, 2019. http://d-nb.info/1175027928/34.
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Nilebäck, Erik. "A novel biotinylated surface designed for QCM-D applications." Thesis, Linköping University, Department of Physics, Chemistry and Biology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-19250.
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Control of protein immobilization at sensor surfaces is of great interest within various scientific fields, since it enables studies of specific biomolecular interactions. To achieve this, one must be able to immobilize proteins with retained native structure, while minimizing non-specific protein binding. The high affinity interaction between streptavidin (SA) and biotin is extensively used as a linker between a surface, where SA is immobilized, and the (biotinylated) molecule of interest. Self- assembled monolayers (SAMs) of poly- and oligo ethylene glycol (PEG and OEG) derivatives have been proven in literature to minimize non-specific protein binding, and biotin-exposing SAMs have been shown efficient for immobilization of SA.
The aim of this master's thesis project was to develop biotinylated gold surfaces for quartz crystal microbalance with dissipation monitoring (QCM-D) applications through the self-assembly of mixed monolayers of thiolated OEG (or PEG) derivatives with or without a terminal biotin head group. For this, different thiol compounds were to be compared and evaluated. For the systems under study, the required biotin density for maximum specific SA immobilization was to be established, while keeping the non-specific serum adsorption at a minimum. Model experiments with biotinylated proteins immobilized to the SA-functionalized surfaces were to be performed to evaluate the possibilities for commercialization.
A protocol for the preparation of a novel biotinylated surface was developed based on the immersion of gold substrates in an ethanolic incubation solution of dithiols with OEG chains (SS-OEG and SS-OEG-biotin, 99:1) and found to give reproducible results with respect to low non-specific protein binding and immobilization of a monolayer of SA. The modified surfaces allowed for subsequent immobilization of biotinylated bovine serum albumin (bBSA) and biotinylated plasminogen (bPLG). PLG was the subject of a challenging case study, using a combination of QCM-D and surface plasmon resonance (SPR), where the immobilized protein was subjected to low molecular weight ligands that were believed to induce conformational changes. The high control of the surface chemistry allowed for the interpretation of the increased dissipation shift upon ligand binding in terms of conformational changes.
An obstacle before commercialization of the described biotinylated surfaces is that they do not seem stable for storage > 7 days. The reasons for this have to be investigated further.
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Corten, Cathrin Carolin. "Synthese und Charakterisierung dünner Hydrogelschichten mit modulierbaren Eigenschaften." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1209463829168-95283.
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Im Mittelpunkt dieser Arbeit stand die Darstellung sensitiver Blockcopolymere und deren Gele, die als Ausgangsmaterialien in Sensor- und Aktorsystemen einsetzbar sind. Die Vereinigung verschiedener Ansprechparameter stellt erhöhte Anforderung an die Synthese. Geringe Ansprechzeiten lassen sich mit einer Gelgröße im µm-Bereich erreichen. Hydrogele dieser Größenordnungen können durch nachträgliche Vernetzung funktioneller linearer Polymere ermöglicht werden. Die Makroinitiatormethode ermöglichte den Aufbau verschiedener linearer photovernetzbarer Blockcopolymere. Zum Einen wurde das temperatursensitive P(n-BuAc)-block-P(PNIPAAm-co-DMIAAm) erhalten, des Weiteren gelang die Darstellung der multi-sensitiven Blockcopolymere P2VP-block-P(NIPAAm-co-DMIAAm) und P4VP-block-P(NIPAAm-co-DMIAAm). Die Blockcopolymere wurden mit variierenden Blocklängen und Verhältnissen sowie mit unterschiedlichem Vernetzergehalt dargestellt. Die Charakterisierung der Blockcopolymere erfolgte mittels 1H-NMR-Spektroskopie, GPC-Messungen (Zusammensetzung) und DSC-Messungen (thermische Eigenschaften). Das Löslichkeitsverhalten in wässrigen Medien wurde durch Dynamische Lichtstreuung bestimmt. Die Beschreibung des Quellverhaltens der vernetzten Schichten erfolgte durch vornehmlich durch optische Methoden (SPR/OWS, WAMS, Ellipsometrie). Die Veränderung des E-Moduls in Abhängigkeit äußerer Parameter konnte mittels AFM untersucht werden. Die Reaktion der Schichten wurde gegenüber Temperatur, pH-Wert und Salzkonzentrationen getestet. Die charakterisierten Filme konnten im Anschluss als sensitive Schichten in piezoresistiven Sensorsystemen verwendetet werden.
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Freixas, Angel Luis. "Surface plasmon resonance experiments." FIU Digital Commons, 2007. http://digitalcommons.fiu.edu/etd/3417.
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In this study, a Surface Plasmon Resonance (SPR) optical sensor, based on Kretschmann configuration, was designed and constructed. SPR is a useful tool for obtaining quantitative kinetic and affinity information on biomolecular interactions.
The resolution and the sensitivity of our homemade SPR system was determined and optimized by using thiols and sucrose solutions. The data were normalized and processed to increase the resolution of the system. The sensograms were obtained and the kinetic constants were analyzed. The sensogram of the thiols solutions illustrated the process of association of the thiols on gold surface. The sensogram of the sucrose solutions shown, that the sucrose doesn't have association on gold surface.
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Andersson, Olof. "Imaging surface plasmon resonance." Doctoral thesis, Linköpings universitet, Sensorvetenskap och Molekylfysik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-14923.
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The central theme of this thesis is the use of imaging Surface Plasmon Resonance (iSPR) as a tool in the characterization of surfaces with laterally varying properties. Within the scope of this work, an instrument for iSPR analysis was designed and built. SPR is a very sensitive technique for monitoring changes in optical properties in the immediate vicinity of a sensor surface, which is very useful in biosensing and surface science research. We have employed SPR in the Kretschmann configuration, wherein surface plasmons are excited by means of an evanescent field arising from total internal reflection from the backside of the sensor surface. In iSPR, the signal is the reflectivity of TM-polarized light which is measured using an imaging detector, typically a CCD camera. Advantages of this technique include extreme surface sensitivity and, because detection is done from the backside, compatibility with complex samples. In addition, SPR is a non-labeling technique, and in imaging mode, a lateral resolution in the µm range can be attained. The imaging SPR instrument could be operated in either wavelength interrogation mode or in intensity mode. In the former case, the objective is to find the SPR wave-length, λSPR, which is the wavelength at which the reflected intensity is at a minimum. In intensity mode, a snapshot of the intensity reflectance is taken at a fixed wavelength hand incidence angle. In biosensor science, the use of an imaging technique offers a major advantage by enabling parallelization and thereby increasing throughput. We have, for example, used iSPR in biochemical interaction analysis to monitor immobilization and specific binding to protein and synthetic polypeptide micro arrays. The primary interest has been the study of soft matter surfaces that possess properties interesting in the field of biomimetics or for applications in biosensing. Specifically, the surfaces studied in this thesis include patterned self-assembled monolayers of thiolates on gold, a graft polymerized poly(ethylene glycol) (PEG) based hydrogel, a dextran hydrogel, and a polyelectrolyte charge gradient. Our results show that the PEG-based hydrogel is very well suited for use as a platform in protein immobilization in an array format, owing to the very low unspecific binding. In addition, well defined microarray templates were designed by patterning of hydrophobic barriers on dextran and monolayer surfaces. A polypeptide affinity microarray was further designed and immobilized on such a patterned monolayer substrate, in order to demonstrate the potential of analyte quantification with high sensitivity over a large dynamic range. Furthermore, iSPR was combined with electrochemistry to enable laterally resolved studies of electrochemical surface reactions. Using this combination, the electrochemical properties of surfaces patterned with self assembled monolayers can be studied in parallel, with a spatial resolution in the µm regime. We have also employed electrochemistry and iSPR for the investigation of potential and current density gradients on bipolar electrodes. The imaging SPR instrument could be operated in either wavelength interrogation mode or in intensity mode. In the former case, the objective is to find the SPR wave-length, λSPR, which is the wavelength at which the reflected intensity is at a minimum. In intensity mode, a snapshot of the intensity reflectance is taken at a fixed wavelength hand incidence angle.In biosensor science, the use of an imaging technique offers a major advantage by enabling parallelization and thereby increasing throughput. We have, for example, used iSPR in biochemical interaction analysis to monitor immobilization and specific binding to protein and synthetic polypeptide micro arrays. The primary interest has been the study of soft matter surfaces that possess properties interesting in the field of biomimetics or for applications in biosensing. Specifically, the surfaces studied in this thesis include patterned self-assembled monolayers of thiolates on gold, a graft polymerized poly(ethylene glycol) (PEG) based hydrogel, a dextran hydrogel, and a polyelectrolyte charge gradient. Our results show that the PEG-based hydrogel is very well suited for use as a platform in protein immobilization in an array format, owing to the very low unspecific binding. In addition, well defined microarray templates were designed by patterning of hydrophobic barriers on dextran and monolayer surfaces. A polypeptide affinity microarray was further designed and immobilized on such a patterned monolayer substrate, in order to demonstrate the potential of analyte quantification with high sensitivity over a large dynamic range.Furthermore, iSPR was combined with electrochemistry to enable laterally resolved studies of electrochemical surface reactions. Using this combination, the electrochemical properties of surfaces patterned with self assembled monolayers can be studied in parallel, with a spatial resolution in the µm regime. We have also employed electrochemistry and iSPR for the investigation of potential and current density gradients on bipolar electrodes.
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Yazidi, Senda. "Structure et propriétés optiques de nanoparticules couplées : application à la spectroscopie Raman exaltée de surface." Thesis, Poitiers, 2018. http://www.theses.fr/2018POIT2279/document.
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Ce travail vise à utiliser des surfaces d'alumine nanostructurées pour guider la croissance et l'organisation de particules métalliques (Ag, Au et AgxAu1-x), et à les tester en tant que substrats SERS-actifs robustes et réutilisables. Nous avons utilisé la spectrophotométrie pour la caractérisation des propriétés optiques résultantes, l'ellipsométrie spectroscopique pour l'extraction des indices optiques et la microscopie électronique en transmission pour les caractérisations structurales. La diffusion Raman exaltée de surface (SERS) a été utilisée pour la détection de molécules de bipyridine adsorbées sur la surface des échantillons, en collaboration avec l’Institut des Matériaux Jean Rouxel de Nantes. Nous étudions d'abord des systèmes de nanoparticules monométalliques et bimétalliques afin de comprendre les modes de croissance de telles assemblées. Nous montrons que des arrangements différents de nanoparticules bimétalliques sont obtenus selon la séquence de dépôt utilisée et qu'un alliage est obtenu à l'issue de recuits ex situ sous vide. Les propriétés optiques en champ proche et lointain de nanoparticules d'alliage AgxAu1-x noyées dans une matrice d'Al2O3 sont comparées numériquement à celles des métaux purs, par la méthode de calcul des différences finies dans le domaine temporel. Les résultats indiquent que l’amplification du champ pour les nanoparticules de métal pur est plus élevée que pour les nanoparticules d’alliage. Enfin, les expériences SERS menées sur un système dichroïque de nanoparticules d’Ag plus ou moins couplées montrent que l'on peut obtenir un signal SERS intense avec des nanoparticules recouvertesThe aim of this work is to use nanostructured alumina surfaces to guide the growth and to optimize the organization of metallic particles (Ag, Au and AgxAu1-x), and to test those systems as reusable SERS-active substrates. We used spectrophotometry to characterize the resulting optical properties, spectroscopic ellipsometry for the determination of the optical index and transmission electron microscopy for the structural characterizations. Surfaced-enhanced Raman spectroscopy (SERS) was used for the detection of adsorbed bipyridine molecules on the sample surface, in collaboration with the Institut des Matériaux Jean Rouxel at Nantes. We first study systems consisting of monometallic and bimetallic nanoparticles in order to understand the growth modes of such particle assemblies. A particular attention is paid to the influence of the sequential deposition of Au and Ag on the structural and optical properties. We show that different arrangements of bimetallic nanoparticles are obtained according to the deposition sequence used and that an alloy is obtained after ex situ annealing under vacuum. The near-field and far-field optical properties of AgxAu1-x nanoparticle alloys embedded in an alumina matrix are compared numerically by the finite difference time domain method, with those of pure metal nanoparticles. Our results indicate that pure metal nanoparticles exhibit a greater field enhancement than alloy nanoparticles. Finally, SERS experiments conducted with a dichroic system made of coupled Ag nanoparticles show that an intense SERS signal can be obtained with coated nanoparticles
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Juvé, Vincent. "Spectroscopie linéaire et ultra-rapide de nanoparticules métalliques : de l’ensemble au nano-objet individuel." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10163/document.
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En passant de l’état massif à la nanoparticule les matériaux métalliques voient certaines de leurs caractéristiques modifiées de manière notable comme par exemple les propriétés optiques avec l’apparition d’une résonance dans le spectre optique, la Résonance Plasmon de Surface Localisée (RPSL) responsable du changement de couleur des nanoparticules métalliques. Les propriétés vibrationnelles et thermiques de nanoparticules métalliques ont été étudiées à l’aide d’une technique de Spectroscopie Femtoseconde. Nous avons montré qu’il était possible d’exciter et de détecter optiquement des fréquences de vibrations mécaniques dans le domaine térahertz pour des nanoparticules de platine composées de moins de cent atomes. D’autre part l’augmentation des effets dus aux interfaces a été mis en évidence sur les propriétés thermiques de nanoparticules d’or et d’argent. La résistance thermique à l’interface, résistance de Kapitza, voit son rôle augmenter lors du transfert thermique à l’échelle nanométrique. Une corrélation entre les valeurs mesurées et les impédances acoustiques des matériaux composants les interfaces a été mise en évidence. Nous avons aussi montré qu’elle augmente quand la température diminue de 300K à 70K. Les propriétés optiques de nanoparticules non sphériques ont été étudiées à l’aide de la Spectroscopie à Modulation Spatiale. Cette technique a permis de repérer puis de caractériser des nano-bâtonnets d’or individuels. Nous avons montré que la largeur spectrale de la RPSL est fortement dépendante de la géométrie des nanoparticules (diamètre et longueur). Cette double dépendance n’est pas prédite par les modèles classiques ou quantique existantsThe size reduction of metals, from bulk to nanoparticles, induces significant modifications of their properties. For instance, the optical properties evolve and a new resonance, the localized surface plasmon resonance, appears in the optical spectrum and is responsible for the change of colors of metallic nanoparticles. This work is focused on studies of metals’ properties at the nanometric scale. In the first part, the vibrational and thermal properties are studied with a femtosecond spectroscopy technique. It is shown that it is possible to excite and detect optically vibrational frequencies in the terahertz domain by studying platinum nanoparticles formed by less than 100 atoms. The study of the thermal properties of the metallic nanoparticles (gold and silver) has shown that the boundary effect increases. This thermal boundary resistance, known as the Kapitza resistance, plays a dominant role in the heat transfer at the nanometric scale. A correlation between the experimental values of the thermal boundary resistance and the acoustic impedances of the boundary’s materials has been found. We have also shown that the Kapitza resistance is a decreasing function of the temperature in the 70-300K range. In the second part, the effect of the size reduction on the optical properties of non-spherical nanoparticles is observed. The Spatial Modulation Spectroscopy technique is used in order to locate and study individual gold nanorods. It is shown that the two geometrical parameters (the length and the diameter) of the nanorods influence the spectral linewidth of the localized surface plasmon resonance. This effect is not predicted by existing classical or quantum models
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Ljungblad, Jonas. "Antibody-conjugated Gold Nanoparticles integrated in a fluorescence based Biochip." Thesis, Linköping University, Department of Physics, Chemistry and Biology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-50619.
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Gold nanoparticles exhibit remarkable optical properties and could prove useful in sensitive biosensing applications. Upon illumination gold nanoparticles produce localized surface plasmons, which influence nearby fluorophores and an enhancement in their fluorescence intensity can be observed. This property makes gold nanoparticles attractive for enhancing optical signals.
In this project gold nanoparticles were functionalized with an antibody and immobilized to the surface of an existing biochip platform based on fluorescence. The aim was to investigate the possibility of obtaining an increased fluorescence signal from the gold nanoparticles. Two different conjugation procedures were investigated, direct physisorption and covalent attachment of the antibodies to the particles. Activity of bound antibodies was confirmed in both cases.
The on-chip fluorescence intensity produced by the different conjugates was monitored by use a specialized fluorescence reader designed for point-of-care use. AFM and SEM were used to determine the surface concentration of particles. A correlation between the produced fluorescence intensity and the surface concentration could be seen.
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Harris, Richard David. "Waveguide surface plasmon resonance biosensor." Thesis, University of Southampton, 1996. https://eprints.soton.ac.uk/398739/.
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This thesis reports the design and development of the first waveguide surface plasmon resonance (SPR) biosensor for pesticide analysis. The integrated optical format allows the fabrication of a compact sensor that may be connected to optical fibre; necessary steps towards a portable optical biosensor. A major advantage of the integrated optical approach is the possibility of fabricating multiple sensors on one substrate, and hence testing for multiple analytes in one basic assay. The SPR structure incorporates a metal film that may be employed as an electrode to study the electrochemical control of sensing reactions. The performance of such devices requires analysis of the waveguide modes supported by the metal-clad waveguide, of their excitation by an input waveguide and of the resultant power coupled into an output waveguide. For the first time a rigorous numerical waveguide model to study the power transmission of such general multilayer absorbing structures has been developed. The model allows the determination of the modulation in output power of the sensor due to the adsorption of a thin organic layer to the sensor surface, which in turn leads to a measure of sensitivity. Designs for practical, sensitive, waveguide SPR sensors for an aqueous environment, optimised for specific sensing films are reported. The fabrication of gold-coated, potassium ion-exchanged, waveguide SPR sensors in soda-lime and Pyrex glass is reported. Three types of experiment were performed to validate the waveguide model using these devices. The first involved measuring changes in the output power of the sensor as a function of gold film length. The second measured the SPR response of sensors as a function of gold film parameters. Third, the effect on the SPR response of binding a dual layer of biotin-avidin to the sensor surface was observed as a function of gold film thickness. Predictions of the waveguide model were compared to the experimental data. Optimisation of the sensor design through these experimental procedures is also described. The transformation of the basic waveguide SPR sensor into a specific biosensor for the triazine herbicides simazine and atrazine is reported. The assay procedure was based on anti-simazine and anti-atrazine IgG antibodies and their Fab fragments developed by co-workers at GEC Marconi Materials Technology Ltd., UK Chemical modification of the sensor surface was developed by co-workers at the University of Tubingen, Germany, to bind the antibodies to the sensor surface. Laboratory characterisation of the sensor as a simazine sensor was performed and is reported in this thesis. Extended validation identified a detection limit of 0.22µg/l for the herbicide simazine in the aqueous environment. The biosensor gave a significant correlation with HPLC measurements on natural water samples when the cross-reactivity of the sensor with other triazine herbicides was taken into account.
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Nakkach, Mohamed. "Imagerie multidimensionnelle en mode de résonance de plasmons de surface de structures de biopuces : expérience et modélisation." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00734650.
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Dans cette thèse nous avons ajouté le contrôle du paramètre spectral pour donner plus de degré de liberté à l'instrument basé sur l'Imagerie par Résonance des Plasmons de Surface (SPRI), développant un système instrumental à interrogation angulo-spectrale. Pour valider notre travail, nous avons pris comme modèle d'étude un milieu diélectrique absorbant à unelongueur d'onde visible. La fonction diélectrique complexe est traitée par le modèle de Lorentz et la relation entre la partie réelle et imaginaire de l'indice optique est assurée par la relation de Kramers-Kronig. Nous avons commencé par injecter dans la cellule de mesure un colorant absorbant à 630 nm et mesuré la réflectivité angulo-spectrale avec ce milieu. Ensuite, un programme d'ajustement, que nous avons développé, a été utilisé pour le calcul inverse et la détermination des paramètres optiques à partir des données de l'expérience. Cet ajustement permet d'extraire la partie réelle et la partie imaginaire de l'indice de réfraction démontrant la possibilité d'applications de type spectroscopique. Nous avons également intégré successivement à la surface des molécules d'ADN marquées par différents chromophores pour voir l'effet de la position d'absorption sur la variation de réflectivité angulo-spectrale. En plus des milieux absorbants, nous avons fabriqué des réseaux diélectriques et métalliques et les avons intégrés à la surface du prisme. Les structures utilisées avaient une période de 250 nm et une épaisseur de 300 nm en PMMA. Cette condition nous a permis de voir un plasmon bandgap centré à 735 nm. Cette étude expérimentale est validée par une étude théorique en utilisant la méthode RCWA pour simuler la réponse des réseaux périodiques.
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Jakob, Thomas. "High pressure surface plasmon spectroscopy." [S.l. : s.n.], 2002. http://ArchiMeD.uni-mainz.de/pub/2002/0084/diss.pdf.
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Nenninger, Garet Glenn. "High-resolution surface plasmon resonance biosensing /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/5840.
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Du, Yao. "Particle-modified surface plasmon resonance biosensor." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/289388.
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Surface plasmon resonance (SPR) biosensors have attracted great attention in scientific research in the past three decades. Extensive studies on the immobilisation of biorecognition elements have been conducted in pursuit of higher sensitivity, but trialled formats have focussed on a thin layer modification next to the plasmon film, which usually requires in situ derivatization. This thesis investigates an 'off-chip' immobilisation strategy for SPR biosensing using silica particles and considers the implications of a particle-modified evanescent field on the signal amplitude and kinetics, for an exemplar affinity binding between immobilised IgG and its anti-IgG complement. Submicron silica particles were synthesized as carriers for the bio-recognition elements. They were then immobilised to form a sub-monolayer on the gold film of an SPR biosensor using two methods: thiolsilane coupling and physical adsorption aided by mechanical pressure. The bio-sensitivity towards an antigen/antibody interaction was lower than an SPR biosensor with an alkanethiolate SAM due to the difference in ligand capacity and position in the evanescent field. The binding kinetics of antigen/antibody pair was found to follow the Langmuir model closely in a continuous flow configuration but was heavily limited by the mass transport from the bulk to the sensor surface in a stop-flow configuration. A packed channel configuration was designed with larger gel particles as ligand carriers, packed on top of a gold film to create a column-modified SPR biosensor. This sensor has comparable bio-sensitivity to the previous sub-monolayer particle-modified systems, but the binding and dissociation of the analyte was heavily dependent on mass transport and binding equilibria across the column. A bi-directional diffusion mechanism was proposed based on a two-compartment mass transport model and the expanded model fitted well with the experimental data. The column-modified sensor was also studied by SPR imaging and analyte band formation was observed and analysed. Using the lateral resolution, a multiplexing particle column configuration was explored, and its potential in distinguishing a multicomponent analyte.
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Vukusic, Peter. "Sensing thin layers using surface plasmon resonance." Thesis, University of Exeter, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358142.
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Chinowsky, Timothy Mark. "Optical multisensors based on surface plasmon resonance /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/5857.
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Lu, Hongbo. "Surface plasmon resonance biosensors : development and applications /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/8069.
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Fratzke, Scott B. "INTEGRATION OF MICROFLUIDICS WITH SURFACE PLASMON RESONANCE." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/366.
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This thesis successfully integrates laminate microfluidic devices with an analytic Surface Plasmon Resonance (SPR) instrument. Integration was accomplished at low-cost using materials such as polydimethylsiloxane (PDMS), Poly(methyl methacrylate) (PMMA), Tygon tubing, and a 3-way stopcock. The main components of this thesis are the design and fabrication of the low-cost, in-house fluidics that can integrate with upstream microfluidics and the validation of the in-house fluidics using the Biosensing Instruments BI-2000 SPR instrument. The low-cost fluidics was designed and fabricated “in-house” using a novel investment casting technique that required the use of laser cutting technology to make a master cast, and candle wax to make the fluidic flow gasket.
Integration of upstream microfluidic devices is the next step towards fully integrated point-of-care (POC) diagnostics. Development of low-cost POC diagnostics will enable physicians to diagnosis patients outside of clinical settings, granting treatment access to a much wider population. Surface Plasmon Resonance is used for its detection abilities combined with its ability to perform real-time sample analysis.
Validation of the in-house fluidics was accomplished by conducting (2) experiments: (1) to compare the angular shift elicited by ethanol solutions between in-house fluidics, factory fluidics, and the literature, and (2) to compare the angular shift between in-house fluidics and factory fluidics caused by the cleaving of fibroblasts from the SPR sensor chip. Successful comparisons made in both experiments proved successful development of low-cost fluidics that could integrate upstream microfluidic devices.
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Boutin, Elodie. "Mécanisme d'inhibition de la fusion membranaire du virus de l'hépatite C par différents composés : l'arbidol, la silymarine et les molécules la composant." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10244.
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L'infection par le virus de l'hépatite C (VHC) est un problème de santé publique majeur car en absence de vaccin et de thérapie suffisamment efficace, l’infection peut dégénérer en carcinome hépatocellulaire. Il est alors important d’identifier de nouvelles cibles thérapeutiques et de développer de nouveaux antiviraux. Ainsi, nous avons étudié l'activité anti-VHC de différents composés : l'arbidol (Arb), la silymarine (SM) et les molécules la composant, notamment la silibinine (SbN). Ces composés ont l'avantage d'être déjà utilisés en médecine humaine depuis de nombreuses années et ont ainsi prouvé leur innocuité. Ils présentent un large spectre antiviral et inhibent plusieurs étapes du cycle viral, dont la fusion membranaire. Cette étape du cycle est intéressante à cibler car le virus serait bloqué précocement, avant de provoquer des dommages cellulaires.Nous avons approfondi notre connaissance du mécanisme d'inhibition de la fusion par Arb en montrant par différentes stratégies qu'il s'associe avec les phospholipides à l'interface membranaire et interagit avec des résidus aromatiques. Cela suggère que Arb pourrait former durant le processus de fusion un complexe entre glycoprotéine virale et membrane, permettant d'inhiber les changements conformationnels de la glycoprotéine, nécessaires à la fusion. De même SM et ses composés inhibent la fusion de pseudoparticules de HCV, probablement en stabilisant les membranes impliquées dans le processus. Enfin, nous avons observé une activité antivirale et anti-inflammatoire très différente entre deux formulations de SbN. Tous ces résultats sont discutés dans le contexte actuel d'un arsenal thérapeutique anti-HCV qui reste limitéInfection by the hepatitis C virus (HCV) is a major public health problem since the infection can lead to hepatocellular carcinoma in the current absence of vaccine and effective treatment. It is therefore important to identify new therapeutic targets and to develop novel antiviral drugs. Here we studied the anti-HCV activity of two compounds : arbidol (Arb), the herbal extract silymarin (SM) and molecules therein, including silibinin (SbN). These compounds are already in use in human medicine for several years and have proven safety. They display a broad antiviral spectrum and inhibit several steps of the virus life cycle, including membrane fusion. This step is very interesting to target, since the virus could be blocked upstream the cellular damages it could induce. Using different biophysical strategies, we showed that Arb associates with phospholipids at the membrane interface and interacts with aromatic residues. This suggests that Arb could form during the fusion process a complex between viral glycoprotein(s) and membrane, leading to the inhibition of the conformational changes within the glycoprotein that are required during the fusion process. SM and its components inhibit fusion of HCV pseudoparticles, probably by stabilizing the membranes involved in this process. Finally, we observed different antiviral and anti-inflammatory activities between two different formulations of SbN. Knowledge of these antiviral mechanisms should lead to innovative therapeutic strategies against HCV
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Ring, Josh. "Novel fabrication and testing of light confinement devices." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/novel-fabrication-and-testing-of-light-confinement-devices(51572720-0c49-482e-8523-e44ca877117f).html.
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The goal of this project is to study novel nanoscale excitation volumes, sensitive enoughto study individual chromophores and go on to study new and exciting self assemblyapproaches to this problem. Small excitation volumes may be engineered using light con-finement inside apertures in metal films. These apertures enhance fluorescence emissionrates, quantum yields, decrease fluorescence quenching, enable higher signal-to-noiseratios and allow higher concentration single chromophore fluorescence, to be studied byrestricting this excitation volume. Excitation volumes are reported on using the chro-mophore's fluorescence by utilising fluorescence correlation spectroscopy, which monitorsfluctuations in fluorescence intensity. From the correlation in time, we can find the res-idence time, the number of chromophores, the volume in which they are diffusing andtherefore the fluorescence emission efficiency. Fluorescence properties are a probe ofthe local environment, a particularly powerful tool due to the high brightness (quantumyield) fluorescent dyes and sensitive photo-detection equipment both of which are readilyavailable, (such as avalanche photodiodes and photomultiplier tubes). Novel materialscombining the properties of conducting and non-conducting materials at scales muchsmaller than the incident wavelength are known as meta-materials. These allow combi-nations of properties not usually possible in natural materials at optical frequencies. Theproperties reported so far include; negative refraction, negative phase velocity, fluorescenceemission enhancement, lensing and therefore light confinement has also been proposed tobe possible. Instead of expensive and slow lithography methods many of these materialsmay be fabricated with self assembly techniques, which are truly nanoscopic and otherwiseinaccessible with even the most sophisticated equipment. It was found that nanoscaled volumes from ZMW and HMMs based on NW arrays wereall inefficient at enhancing fluorescence. The primary cause was the reduced fluorescencelifetime reducing the fluorescence efficiency, which runs contrary to some commentatorsin the literature. NW based lensing was found to possible in the blue region of the opticalspectrum in a HMM, without the background fluorescence normally associated with a PAAtemplate. This was achieved using a pseudo-ordered array of relatively large nanowireswith a period just smaller than lambda / 2 which minimised losses. Nanowires in the traditionalregime lambda / 10 produced significant scattering and lead to diffraction, such that they werewholly unsuitable for an optical lensing application.
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Prabhu, G. Radhakrishna. "Studies On Surface Plasmon Resonance And Related Experimental Methods Using Fixed Plasmon Angle." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/205.
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Surface plasmon waves are transverse magnetic electromagnetic waves propagating along a dielectric-metal interface. These waves can be excited by resonant absorption of electromagnetic radiation leading to surface plasmon resonance (SPR) at the interface. The resonance is characterised by a reduction in the intensity of the reflected light at the interface due to strong coupling of incident optical radiation to surface plasmons. This gives rise to a minimum at a sharply defined angle of incidence, referred to as SPR angle or plasmon angle. The phenomenon of SPR has been extensively used in the past to develop reflective type optical devices for sensing applications on account of the high dielectric function dependent sensitivity of the SPR angle. Basically, devices which exhibit this phenomenon have a structure consisting of a metal film sandwiched between two dielectrics. The reflectivity of such a device is theoretically modelled based on either theory of thin films (Fresnel's model) or theory of resonance (Lorentzian model). These models have very effectively predicted the behaviour of such devices based on the shift in SPR angle due to the dielectric function variations.
We have been investigating the SPR device for intensity based metrological applications utilising its high angular sensitive reflectivity, with fixed SPR angle. In these intensity based applications or measurements, direct and simple expressions connecting intensity variation to angular change are unavailable in the literature and quantitative estimation or data inversion is based on either curve fitting or iterative methods. Fresnel and Lorentzian models have commonly been used in the experiments but data inversion through the Fresnel model is computationally complex and the Lorentzian model, although less complicated, gives erroneous results due to its approximate nature. In order to obtain a simple expression between intensity variation and the angular change, we have re-looked at the two existing models in order to derive an expression which has the simplicity of the Lorentzian model and the accuracy of the Fresnel model in the experiments with fixed plasmon angles. These efforts have been particularly directed to understand the relationship between intensity variation and meteorologically important properties of such devices. This thesis is an attempt to summarize the computational results which have led us to some novel experimental methodologies which have been used to exploit these devices for inverse type, illumination specific, SPR based applications.
The work presented in this thesis is organised in six chapters. Chapter 1, gives an overview of optical sensing, theory of surface plasmons, excitation schemes for surface plasmons, development of the SPR device and its characterisation. It also includes a brief literature review in the area of surface plasmon resonance, covering both the theoretical and experimental aspects. The objectives of the work and the scope of the thesis are also presented.
Chapter 2 presents the existing models of SPR device, based on Fresnel's and the Lorentzian models. These models allow reflectance calculations from knowledge of either the optical parameters that describe the layers or the parameters of the waves that propagate through them. Using these models, the inverse problem of estimating either the angle of incidence or the optical constants of the layers of the sensors utilizing the intensity based measurements is generally difficult. In order to solve this problem where the plasmon angles are fixed, a modified formalism for the angle scanned SPR spectrum of a three-layered SPR sensor is presented in this chapter. The new formalism regroups the wave vector parameters of Lorentzian resonance theory into a set of non-dimensional parameters 1, 4K and R. The new reflectivity index (1), which is the ratio of reflectance to the absorptance, has been introduced to help explain the physical processes underlying the device operation in the high sensitivity region of the characteristics. The parameter 4Kis a constant of the device and it depends on the dielectric constants of the device. This is a new SPR index and is identified at a point where reflectance and absorptance match. Parameter R is related to the loss mechanisms in the device and will be explained in detail in Chapter 3. This simple model links the new reflectivity index (1) to the angular detune from SPR angle (ΔƟ) and it brings out a parabolic variation of ΔƟ with 1. In this chapter the mathematical derivation of the proposed model is presented and the significance of the new parameters 1, 4Kand Rare discussed.
Chapter 3 evaluates the characteristic nature of errors associated with the predictions from the proposed model and presents methods for neutralizing them. It is demonstrated with the help of the function K which is linearly dependant on 1, that the proposed model predicts the reflectance from the wave vector parameters as accurately as the Fresnel's model. This R parameter explains the slowly varying nature of the radiative loss with the angle of incidence and
this variation contributes significantly to the SPR characteristics. As a consequence, it is found that the SPR characteristics can be represented as a sum of two primary functions which are parabolic and linear, respectively, and this leads to the easy explanation of the SPR characteristics. The present chapter also discusses a new observation that the angle-scanned SPR spectrum can be accurately described using a straight line in intercept form. The intercept value depends on 4Kand the slope depends on K. In addition to this, this chapter discusses practical methods for estimation of the intercept and the slope of such a straight line which are functions of the key wave vector parameters. A detailed discussion on the proposed model highlighting its advantages for inverse type, illumination specific, SPR-based applications with fixed SPR angle is also presented.
Chapter 4 describes the applications of the proposed model for optical constant measurements. The first part highlights a new approach for the determination of the dielectric constants of the metal film used for the optimised- or nearly-optimised SPR sensors using the proposed model. In the complex dielectric constant, the real part is calculated from the SPR angle and the imaginary part from 4K. A discussion on the dielectric constant study of silver and gold metal film is presented. The advantages of the proposed approach such as its simplicity and direct methodology are then discussed. The second part of the chapter also proposes a new approach to carry out measurements on the absorbance of the medium with enhanced sensitivity utilising the parameter 4K It describes a computational study on the variation of 4K values with the dielectric function and highlights the relationship of 4K variation due to the imaginary part of the dielectric function (absorption) of the samples. The physical processes causing a change in the value of 4Kdue to absorption is also discussed along with some computational results.
Chapter 5 reports the study carried out to bring out the importance of the new index,4K in metrological applications. Based on the new model, the effect of the laser beam divergence on SPR curve is studied. This chapter first of all discusses the design of the SPR device and the new methods for the development and characterisation of such a device. Details of the experimental procedure for laser divergence evaluation are proposed along with some of the significant computational results. Furthermore, a few applications such as focal length measurement of optical lenses, micro-displacement measurement based on the divergence of the laser beam are also reported. Since the SPR characteristics can be represented easily using the new model, the angular dependent intensity variation can be utilised for some metrological applications with simple data processing. In this context, the high angular sensitivity of the SPR device is studied and some applications such as micro-displacement measurement, pressure measurement and optical wedge angle measurement are included to highlight the above advantages.
The last chapter, Chapter 6, gives a summary and conclusions of the work presented in the thesis. The scope for future investigations is also included in this chapter.
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Vokac, Elizabeth Anne. "Localized surface plasmon resonance spectroscopy of gold and silver nanoparticles and plasmon enhanced fluorescence." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-12-4511.
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This thesis presents spectroscopic studies of metallic nanoparticle localized surface plasmons and plasmon enhanced fluorescence. We investigated the dielectric sensitivity of silver nanoprisms to an external electric field and gold nanorods to the formation of a self-assembled surface monolayer. Dark field microscopy was used to image plasmonic scattering from single nanoparticles, and a liquid crystal tunable filter was used to construct corresponding spectra. The plasmon resonances of silver nanoprisms displayed both reversible red shifts and irreversible blue shifts along with drastic intensity changes upon exposure to an applied bias. The plasmon resonances of gold nanorods showed sensitivity to the presence of alkanethiol molecules adhered to the particle surface by a moderate red shift. An increase in the effective external dielectric caused a shift toward longer wavelengths. We imaged plasmon enhanced fluorescence in order to optimize experimental parameters for a developing project that can characterize nanoparticle structure on sub-wavelength dimensions. Preliminary controls were performed to account for the effect of O₂ plasma treatment, solvent and alkanethiol monolayer formation on surface plasmon resonances. We found that O₂ plasma treatment for different time intervals did not result in a plasmon shift compared to untreated nanoparticles exposed to N₂; however when exposed to solvent the surface plasmons of the treated particles shifted five times as far toward the red. Interestingly, the solvent effect only resulted in a plasmon shift when the particles were N₂ dried after solvent incubation. Gold nanorods incubated in ethanol showed no wavelength maximum shift in pure solvent over time, but shifted moderately to the red after incubation in a solution of alkanethiol molecules. Conditions for the plasmon enhanced fluorescence study were optimized using a dye conjugate of the same alkanethiol molecule used previously by formation from solution in a monolayer on the gold nanorod surface. The appropriate synthesis for dye functionalization, molecular concentrations, solvents and optical settings were determined.text
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Fang, Shiping. "Surface enzyme kinetics and enzymatically amplified biosensing of nucleic acid arrays studied by surface plasmon resonance imaging and surface plasmon fluorescence spectroscopy." 2006. http://www.library.wisc.edu/databases/connect/dissertations.html.
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