Dissertations / Theses: 'Surface plasmon resonance imaging'

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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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Foley, Jennifer Olivia. "Design and development of surface plasmon resonance imaging microfluidic assays /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/7982.

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Beusink, J. B. "Label-free biomolecular interaction sensing on microarray using surface plasmon resonance imaging." Enschede : University of Twente [Host], 2009. http://doc.utwente.nl/60694.

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BELLASSAI, NOEMI. "Surface Plasmon Resonance Imaging Biosensors for Cancer Diagnosis: Detection of Circulating Tumor DNA." Doctoral thesis, Università degli studi di Catania, 2018. https://hdl.handle.net/20.500.11769/549419.

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This doctoral thesis focused on the realization of Surface Plasmon Resonance Imaging (SPRI) biosensor for the rapid, simple and label-free detection of single point mutations in the KRAS gene, standard actionable cancer biomarkers for colorectal cancer, in human plasma samples. Initially, the SPRI assay included the immobilization of specific peptide nucleic acid (PNA) probes onto the gold sensor to ensure the hybridization reaction of PNA-DNA complexes. The spatially controlled immobilization of PNA probes has been obtained by injecting PNA wild-type and PNA mutated solutions into a microfluidic system coupled to SPR sensor chip. The extremely low concentration of genomic DNA required an improvement of SPRI detection capabilities, by using functionalized gold nanoparticles to amplify the hybridization signal between target analytes and corresponding PNA probes. Three representative single-point mutations, gDNA G12D, G12V and G13D, have been successfully detected. After preliminary results of nanoparticle-enhanced SPRI assay, a mixed-charge polymer based on Poly-L-lysine (PLL) polypeptide backbone modified with an anionic peptide, connected via a nonionic OEG spacer, has been synthesized in order to achieve control over the charge distribution of PLL-coated surfaces, and thus the antifouling property. The PLL backbone has been functionalized with different percentages (y%) of maleimide-OEG-NHS ester chains (PLL-mal(y%), from 13% to 26%), and the anionic oligopeptide CEEEEE, composed of one cysteine (C) and five glutamic acids (E), with a short sequence to limit the thickness of the mixed-charge polymer antifouling coating, has been attached to the maleimide units through the thiol maleimide Michael-type addition. The grafting density has been varied to tune the balance of charged groups at polymer backbone. PLL-mal(y%)-CEEEEE surfaces have been characterized by water contact angle and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). Complementary acoustic (quartz crystal microbalance with dissipation, QCM-D) and plasmonic (surface plasmon resonance imaging, SPRI) techniques have been employed to monitor the adsorption of bovine serum albumin (BSA), used as standard protein solution, and diluted human plasma samples. Hence, a new nanoparticle-enhanced SPRI assay for circulating tumour DNA (ctDNA) detection in human plasma samples using PLL-mal(y%)-CEEEEE layer as the antifouling coating has been devised. The PNA probes and the anionic peptide have been attached to the maleimide units through the thiol maleimide reaction using a microfluidic system coupled to SPR sensor chip. The analysis of ctDNA G12D target in diluted human plasma samples (5 pg uL-1), collected from cancer patients and healthy donors, has been carried out using the conjugated AuNPs system, with a minimal sampling handling to avoid any contamination and disruption of the antifouling activity of PLL-mal(y%)-CEEEEE layer. The combined use of PLL-mal(y%)-CEEEEE as the antifouling layer with functionalized gold nanoparticles for the amplification of target detection overcomes the limiting factors related to the biosensor in the clinical field and offers an excellent ctDNA discrimination in the bloodstream at attomolar level.

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Bellassai, Noemi. "Surface Plasmon Resonance Imaging Biosensors for Cancer Diagnosis: Detection of Circulating Tumor DNA." Doctoral thesis, Università di Catania, 2018. http://hdl.handle.net/10761/4165.

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This doctoral thesis focused on the realization of Surface Plasmon Resonance Imaging (SPRI) biosensor for the rapid, simple and label-free detection of single point mutations in the KRAS gene, standard actionable cancer biomarkers for colorectal cancer, in human plasma samples. Initially, the SPRI assay included the immobilization of specific peptide nucleic acid (PNA) probes onto the gold sensor to ensure the hybridization reaction of PNA-DNA complexes. The spatially controlled immobilization of PNA probes has been obtained by injecting PNA wild-type and PNA mutated solutions into a microfluidic system coupled to SPR sensor chip. The extremely low concentration of genomic DNA required an improvement of SPRI detection capabilities, by using functionalized gold nanoparticles to amplify the hybridization signal between target analytes and corresponding PNA probes. Three representative single-point mutations, gDNA G12D, G12V and G13D, have been successfully detected. After preliminary results of nanoparticle-enhanced SPRI assay, a mixed-charge polymer based on Poly-L-lysine (PLL) polypeptide backbone modified with an anionic peptide, connected via a nonionic OEG spacer, has been synthesized in order to achieve control over the charge distribution of PLL-coated surfaces, and thus the antifouling property. The PLL backbone has been functionalized with different percentages (y%) of maleimide-OEG-NHS ester chains (PLL-mal(y%), from 13% to 26%), and the anionic oligopeptide CEEEEE, composed of one cysteine (C) and five glutamic acids (E), with a short sequence to limit the thickness of the mixed-charge polymer antifouling coating, has been attached to the maleimide units through the thiol maleimide Michael-type addition. The grafting density has been varied to tune the balance of charged groups at polymer backbone. PLL-mal(y%)-CEEEEE surfaces have been characterized by water contact angle and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). Complementary acoustic (quartz crystal microbalance with dissipation, QCM-D) and plasmonic (surface plasmon resonance imaging, SPRI) techniques have been employed to monitor the adsorption of bovine serum albumin (BSA), used as standard protein solution, and diluted human plasma samples. Hence, a new nanoparticle-enhanced SPRI assay for circulating tumour DNA (ctDNA) detection in human plasma samples using PLL-mal(y%)-CEEEEE layer as the antifouling coating has been devised. The PNA probes and the anionic peptide have been attached to the maleimide units through the thiol maleimide reaction using a microfluidic system coupled to SPR sensor chip. The analysis of ctDNA G12D target in diluted human plasma samples (5 pg uL-1), collected from cancer patients and healthy donors, has been carried out using the conjugated AuNPs system, with a minimal sampling handling to avoid any contamination and disruption of the antifouling activity of PLL-mal(y%)-CEEEEE layer. The combined use of PLL-mal(y%)-CEEEEE as the antifouling layer with functionalized gold nanoparticles for the amplification of target detection overcomes the limiting factors related to the biosensor in the clinical field and offers an excellent ctDNA discrimination in the bloodstream at attomolar level.

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Zhang, Jing. "High resolution solid immersion lens microscopy and its application to surface plasmon resonance imaging." Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431865.

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Aura, Angela Margherita. "Surface plasmon resonance imaging biosensors for the detection of pathogens and toxins in food." Doctoral thesis, Università di Catania, 2017. http://hdl.handle.net/10761/3746.

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The detection of pathogens and toxins in food represents an essential requirement for food quality control. Standard methods for pathogen detection rely on laborious and time-consuming growth of pathogens in different culture media followed by biochemical or serological identification. Such methods often operate with poor sensitivity and selectivity. In recent years, efforts have been made to provide rapid, reliable and sensitive detection platforms for foodborne pathogens detection. The demand for more rapid, sensitive and accurate methods has been push forward by the implementation of the Hazard Analysis and Critical Control Points (HACCP) protocols. In this context, biosensing platforms provide promising alternatives for the detection of pathogens and toxins with good selectivity and sensitivity. In particular, optical biosensors based on Surface Plasmon Resonance Imaging (SPRI) are attractive because they allow the sensitive detection of analytes from food matrices in real-time. SPRI can assays crude samples without purification and can exploits antibodies or single-stranded DNA (ssDNA) probes for the specific detection of pathogens and toxins with high sensitivity. My research activity has been aimed at developing SPRI biosensors able to detect pathogens and toxins in food matrices in a rapid, specific and sensitive way. In this perspective, specific oligonucleotide sequences and antibodies have been used for the detection of DNA and bacterial toxins, respectively. SPRI biosensor sensitivity benefited of the use of properly functionalized gold nanoparticles (AuNPs). The combination of the SPRI sensing apparatus with microfluidics devices reduces the amount of sample needed for the analysis and provides an efficient environment for the detection.

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Aura, Angela Margherita. "Surface plasmon resonamce imaging biosensors for the detection of pathognes and toxins in food." Doctoral thesis, Università di Catania, 2017. http://hdl.handle.net/10761/3668.

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The detection of pathogens and toxins in food represents an essential requirement for food quality control. Standard methods for pathogen detection rely on laborious and time-consuming growth of pathogens in different culture media followed by biochemical or serological identification. Such methods often operate with poor sensitivity and selectivity. In recent years, efforts have been made to provide rapid, reliable and sensitive detection platforms for foodborne pathogens detection. The demand for more rapid, sensitive and accurate methods has been push forward by the implementation of the Hazard Analysis and Critical Control Points (HACCP) protocols. In this context, biosensing platforms provide promising alternatives for the detection of pathogens and toxins with good selectivity and sensitivity. In particular, optical biosensors based on Surface Plasmon Resonance Imaging (SPRI) are attractive because they allow the sensitive detection of analytes from food matrices in real-time. SPRI can assays crude samples without purification and can exploits antibodies or single-stranded DNA (ssDNA) probes for the specific detection of pathogens and toxins with high sensitivity. My research activity has been aimed at developing SPRI biosensors able to detect pathogens and toxins in food matrices in a rapid, specific and sensitive way. In this perspective, specific oligonucleotide sequences and antibodies have been used for the detection of DNA and bacterial toxins, respectively. SPRI biosensor sensitivity benefited of the use of properly functionalized gold nanoparticles (AuNPs). The combination of the SPRI sensing apparatus with microfluidics devices reduces the amount of sample needed for the analysis and provides an efficient environment for the detection.

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Tan, Han-Min. "High resolution angle-scanning widefield surface plasmon resonance imaging and its application to bio-molecular interactions." Thesis, University of Nottingham, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556099.

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The work described in this thesis is to develop a microscope into a high resolution bio-molecular interaction sensor. A "prism less" widefield surface plasmon microscope has been constructed and applied to imaging of interactions of protein and its antibody in aqueous media through a high NA objective. There are two main parts in this thesis: (1) design and layout of a high resolution angle scanning widefield surface plasmon resonance microscope; and (2) the application to bio-molecular interactions. In the first part, an angle-scanning widefield surface plasmon imaging (AW-SPRI) system consisting of an optical system, a liquid handling system and a data processing system is described. In the optical system, surface plasmons are excited by objective coupling. A spatial light modulator in a conjugate back focal plane of the objective lens allows dynamic control of illumination angle. The reflected bright-field widefield images, encoded with SPR signals, are detected by a CCD. The SPR signals in the images are decoded by a signal processing algorithm. AW-SPRI also combines well-controlled liquid handling units in order to monitor bio-molecular interactions or detect analytes in water-based solvent. The system shows high sensor resolution ( 5 x 10-5 RIU) as a biosensor. In addition, the edge response of A W -SPRI images with the BSA grating vector parallel to the incident polarization direction is 6.5 flm in air and 7.6 urn in water and the edge response with the BSA grating vector perpendicular to the incident polarization direction is 4.3 urn in air and 4.8 urn in water. The system presents high spatial resolution, too. The second part introduces sensor chip preparation and bio-molecular interactions. The sensor chip is where the bio-molecular interaction takes place and where the biochemical binding event is transduced into SPR signals. There are three types of sensor chips mentioned in this thesis which are bare gold-coated coverslips, protein grating patterns on a gold surface created by micro-contact printing, and protein grating patterns covalently immobilised on a gold surface created by photolithography. The patterned proteins on gold surfaces as our sensor chips are used to perform bio-molecular interactions. The results show our system can be used for comparison or determination of the concentration of ligands on the sensor chip or the affinities of the analyte with different samples on sensor chips. In addition, the measurement of affinity and rate constants show that the AW-SPRI can be used to measuring binding processes and carry out kinetic analysis of macromolecular interactions with standard interaction cycle method. Although the errors are larger than with the commercial SPR machines (SR 7000DC), they are nevertheless of similar order of magnitudes. To the authors' knowledge, this is the first demonstration of such high spatial resolution for quantitative, label-free, real-time detection of bio-molecule interaction cycles.

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Golden, Mary S. "Use of angle-resolved surface plasmon resonance imaging (SPRi) for the characterization of protein binding dynamics." Thesis, Boston University, 2012. https://hdl.handle.net/2144/31560.

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Thesis (Ph.D.)--Boston University PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. Protein-protein interactions are essential to multiple cellular functions. However, the individual mechanisms that control protein-protein interactions are not clearly understood, and the transient dynamics of multi-protein complexes are challenging to study. The work presented in this thesis focuses on improvements to angle-resolved surface plasmon resonance imaging (SPRi) methods, including surface fabrication and patterning techniques, which enable multi-array kinetic and thermodynamic studies of protein binding events on surfaces. Because immobilization can significantly influence binding mechanisms, we investigated the effects of density and orientation of surface attached proteins on binding efficiency and kinetics. The activity of trimeric cytokine Tumor Necrosis Factor Alpha (TNFa), a model system, was highly dependent on immobilization conditions. Using a unique multi-wavelength SPRi approach to simultaneously determine dielectric constants and thicknesses of TNFa layers we were able to distinguish between different oligomeric states of a pre-associated multi-protein complex immobilized on the surface. For a different protein-protein system, IKKB binding to NF-kB Essential Modulator (NEMO), we generated a library of IKKB mutants and determined activity using both solution and surface assays. Results for IKKB mutants patterned on the biosensor surface agreed well with solution-phase fluorescence anisotropy measurements. We quantified the contribution of select IKKB residues on the specificity of NEMO binding and identified two new hot spot regions. These results may aid the development of inhibitors for IKKB:NEMO binding in targeted drug discovery. The experimental capabilities used for the above protein studies were optimized on an unrelated non-biological system. For that case, we developed a general methodology to characterize the wavelength dependent optical properties of noble-metal nanoparticles (NPs) in close proximity to a metal sensor surface. NPs are often used as labels to enhance the sensitivity of SPR measurements, however, the dependence of NP optical properties on the distance of the NP to a metal substrate is not fully understood. We report the optical properties of 10 nm gold NPs as a function of particle-to-metal substrate distance and excitation wavelength. These results may aid predictive theoretical models of the signal-enhancing capabilities of NPs. This new knowledge could lead to the development of higher sensitivity SPR biosensors. 2031-01-01

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Hook, Andrew Leslie, and andrew hook@flinders edu au. "Patterned and switchable surfaces for biomaterial applications." Flinders University. Chemistry, Physics and Earth Sciences, 2008. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20090210.161131.

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The interactions of biomolecules and cells at solid-liquid interfaces play a pivotal role in a range of biomedical applications and have hence been studied in detail. An improved understanding of these interactions results in the ability to manipulate biomolecules and concurrently cells spatially and temporally at surfaces with high precision. Spatial control can be achieved using patterned surface chemistries whilst temporal control is achieved by switchable surfaces. The combination of these two surface properties offers unprecedented control over the behaviour of biomolecules and cells at the solid-liquid interface. This is particularly relevant for cell microarray applications, where a range of biological processes must be duly controlled in order to maximise the efficiency and throughput of these devices. Of particular interest are transfected cell microarrays (TCMs), which significantly widen the scope of microarray genomic analysis by enabling the high-throughput analysis of gene function within living cells Initially, this thesis focuses on the spatially controlled, electro-stimulated adsorption and desorption of DNA. Surface modification of a silicon chip with an allylamine plasma polymer (ALAPP) layer resulted in a surface that supported DNA adsorption and sustained cell attachment. Subsequent high density grafting of poly(ethylene glycol) (PEG) formed a layer resistant to biomolecule adsorption and cell attachment. PEG grafted surfaces also showed significantly reduced attachment of DNA with an equilibrium binding constant of 23 ml/mg as compared with 1600 ml/mg for ALAPP modified surfaces. Moreover, both hydrophobic and electrostatic interactions were shown to contribute to the binding of DNA to ALAPP. Spatial control over the surface chemistry was achieved using excimer laser ablation of the PEG coating which enabled the production of patterns of re-exposed ALAPP with high resolution. Preferential electro-stimulated adsorption of DNA to the ALAPP regions and subsequent desorption by the application of a negative bias was observed. Furthermore, this approach was investigated for TCM applications. Cell culture experiments demonstrated efficient and controlled transfection of cells. Electro-stimulated desorption of DNA was shown to yield enhanced solid phase transfection efficiencies with values of up to 30%. The ability to spatially control DNA adsorption combined with the ability to control the binding and release of DNA by application of a controlled voltage enables an advanced level of control over DNA bioactivity on solid substrates and lends itself to biochip applications. As an alternative approach to surface patterning, the fabrication and characterisation of chemical patterns using a technique that can be readily integrated with methods currently used for the formation of microarrays is also presented. Here, phenylazide modified polymers were printed onto low fouling ALAPP-PEG modified surfaces. UV irradiation of these polymer arrays resulted in the crosslinking of the polymer spots and their covalent attachment to the surface. Cell attachment was shown to follow the patterned surface chemistry. Due to the use of a microarray contact printer it was easily possible to deposit DNA on top of the polymer microarray spots. A transfected cell microarray was generated in this way, demonstrating the ability to limit cell attachment to specific regions and the suitability of this approach for high density cell assays. In order to allow for the high-throughput characterisation of the resultant polymer microarrays, surface plasmon resonance imaging was utilised to study the adsorption and desorption of bovine serum albumin, collagen and fibronectin. This analysis enabled insights into the underlying mechanisms of cell attachment to the polymers studied. For the system analysed here, electrostatic interactions were shown to dominate cellular behaviour.

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De, Martin Eleonora. "Autoimmune hepatitis: clinical experience after liver transplantation and molecular study using surface plasmon resonance imaging-based strategy." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424166.

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De novo autoimmune hepatitis in patients with HCV recurrence (HCV-R) after liver transplantation (LT) is of challenging diagnosis and the impact of autoimmune therapy (AT) is still a matter of debate. In the first part of this work the aim was to evaluate clinical, serological, histological characteristics of these patients and the impact of AT. Patients have been evaluated in two European transplant centers .Liver biopsies were retrospectively by experts pathologists. Three parameters, plasma cells infiltrate, interface hepatitis and central vein necrosis, were evaluated applying a new semi-quantitative method. Final diagnosis was of prevalent viral lesions: HCV-R, or prevalent immunological lesions: AIH. Forty patients, transplanted between 1983-2009, were included, 16 (40%) patients were HCV-R and 24 (60%) AIH. High grade of interface hepatitis and confluent central vein necrosis were significantly more represented in AIH patients, moreover AST/ALT were significantly higher in AIH group (p=0.05 and p=0.003, respectively). No difference was found regarding baseline immunosuppression, autoantibodies and gammaglobulin levels. No relationship between HCV antiviral therapy and AIH was observed. Ten years survival was lower for AIH compared to HCVâR patients (65%, versus 93%, p=0.050). The AT improved the cytolysis but did not modify long-term survival (50% treated versus 87.5% non treated patients, p=ns), which was impaired by severe HCV disease progression. Anti-dsDNA autoantibodies (Abs) are highly diagnostic for systemic lupus erythematosus (SLE), however, they can be found in autoimmune hepatitis (AIH) but it remains uncertain which antigen triggers the production of these antibodies. Moreover the characteristics of antigenâantibodies interaction are still a matter of concern. In the second part of this work the aim was to differentiate the binding characteristics of dsDNA and anti-dsDNA Abs obtained from AIH and SLE patient's sera using Surface Plasmon Resonance imaging (SPRi) strategy. Sera from AIH (n=14), SLE patients (n= 7) with anti-dsDNA Abs positive Farr test, as well as from healthy controls (n= 7) were collected. IgGs and IgMs were purified from sera. Ten different types of oligonucleotides (OG) were spotted over the chip surface of SPRi. Kinetic SPRi study was also performed. All sera from both patients and controls showed a reactivity signal on SPRi, nevertheless when monoclonal mouse anti-IgGs were injected after the sera injection, only for AIH patients the signal was still evident, being lower for SLE patients and controls. When purified IgGs from sera were injected an interaction signal with OG was observed only for AIH patients. Mean IgGs koff were comparable among patients, meaning they have the same dissociation kinetic. SPRi method identifies interactions between sera from AIH, SLE patients and controls and dsDNA of OG used. However using purified IgGs a binding signal is observed only for AIH. These results suggest that immunocomplex found in AIH and SLE patients are different, in SLE patients the complex might require a third partner, or probably, recognize a specific dsDNA conformation. Results from our work suggest that new promising methods can be applied both in clinical and laboratory field for the comprehension and monitoring of autoimmune hepatitis. L'epatite autoimmune de novo che insorge in pazienti con recidiva di epatitie C dopo trapianto di fegato è di difficile diagnosi e l'impatto della terapia autoimmune rimane oggetto di discussione. Nella prima parte di questo lavoro lo scopo è stato di valutare le caratteristiche cliniche, sierologiche e istologiche di questi pazienti e il beneficio della terapia autoimmune. I pazienti sono stati inclusi in due centri trapianto europei. Le biopsie epatiche sono state retrospettivamente revisionate da anatomopatologi esperti che hanno valutato tre aspetti, infiltrato plasmacellulare, epatite d'interfaccia e necrosi perivenulare centrale, applicando un nuovo metodo semiquantitativo. La diagnosi finale si è basata sulla prevalenza di lesioni virali: HCV-R, o di lesioni autoimmuni: AIH. Quaranta pazienti sono stati inclusi, 16 (40%) HCV-R e 24 (60%) AIH. L'epatite d'interfaccia di alto grado e la necrosi centrale confluente sono state gli aspetti significativamente più rappresentati nei pazienti AIH, inoltre AST e ALT sono risultate significativamente più elevate nei pazienti AIH. Nessuna differenza è stata riscontrata riguardo all'immunosuppressione di base, aumento delle gammaglobuline o positività autoanticorpale. Alcuna relazione è stata riscontrata tra la terapia antivirale e lo sviluppo di AIH. La spravvivenza è risultata inferiore per i pazienti AIH rispetto ai pazienti HCV-R (65% versus 93%, p=0.050). La terapia autoimmune migliora la citolisi ma non modifica la sopravvivenza (50% pazienti trattati versus 87.5% pazienti non trattati, p=ns), che è compromessa dalla progressione dell'epatite C. Gli anticorpi anti-dsDNA sono altamente diagnostici di lupus eritematoso sistemico (LES), tuttavia possono essere riscontrati anche in altre patologie come l'epatite autoimmune, rimane incerto quali antigeni inducano la produzione di questi autoanticorpi. Inoltre le caratteristiche dell'interazione antigene-anticorpo sono state solo parzialmente elucidate. Nella seconda parte di questo lavoro lo scopo è stato di differenziare le caratteristiche dell'interazione tra dsDNA e anti-dsDNA in pazienti con AIH e LES utilizzando la tecnica innovante Surface Plasmon Resonance imaging (SPRi). I sieri di pazienti con AIH (n=14), LES (n=7), con anti-dsDNA ad alto titolo, riscontrati con il test di Farr, e di controlli sani (n=7) sono stati raccolti. Le IgG e IgM sono state purificate dai sieri. Dieci diversi oligonucleotidi (OG) sono stati immobilizzati sulla superficie del prisma dell'SPRi. La cinetica d'interazione è stata inoltre valutata. I sieri di tutti i pazienti e dei controlli sani hanno mostrato un segnale di attivazione in SPRi, tuttavia una volta iniettate le IgGs monoclonali murine, il segnale è rimasto evidente solo per i pazienti AIH, divenendo debole e quasi inesistente rispettivamente per i pazienti LES e i controlli sani. Dopo l'iniezione delle IgGs purficate, il segnale è stato riscontrato solo per i pazienti AIH. La media delle costanti di dissociazione (koff) è risultata comparabile per tutti i pazienti, a significare che la cinetica di dissocazione era comparabile per tutti i sieri di pazienti AIH. La tecnica SPRi permette di identificare la presenza di interazioni tra dsDNA e anti-dsDNA in pazienti AIH e LES e controlli, utilizzando le IgG purificate il segnale rimane presente solo per i pazienti AIH. Secondo questi risultati è possibile affermare che esiste una differenza tra i complessi immuni presenti nei pazienti AIH rispetto ai pazienti LES che richiedono la presenza di un terzo componente per la forazione o stabilizzazione dei complesso, o, probabilmente riconoscono delle sequenze oligonucleotidiche precise.

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Kravets, V. V., Z. Almemar, A. V. Kotko, I. M. Dmytruk, and A. O. Pinchuk. "Fluorescent Glycine-Coated Silver Nanoparticles as Bio-Imaging Agents for the Neural Stem Cells." Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42509.

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We study experimentally the photoluminescence of small glycine-coated silver nanoparticles and their application as the bio-imaging markers of the neural stem cells. In addition we study nanoparticle’s toxic effects on the neural stem cells. Glycine-coated silver nanoparticles were synthesized using a thermal reduction of silver nitrate in a glycine matrix and size-separated via centrifugation. The properties of the nanoparticles were characterized using transmission electron microscopy, extinction and photoluminescence spectroscopy. Our results indicate that the nanoparticles have deleterious effects on the cells and showed an amplified increase in their death rates. In fixed cells the particles penetrate the membranes within an hour and 25 minutes of incubation, but do not penetrate into the body of the cell.

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Zimmerer, Cordelia. "Entwicklung eines optischen markierungsfreien Ionenkanalsensor-Arrays." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1193247156004-79633.

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Ligandgesteuerte Ionenkanäle sind Membranproteine, die an der Weiterleitung von Reizen und an der Kommunikation zwischen Zellen beteiligt sind. Große Bedeutung besitzt die Messung der Aktivierung der Ionenkanäle beispielsweise in der Medizin (z.B. Ionenkanalerkrankungen), der Pharmazie (z.B. Medikamenten-Screening) und in der Bionanotechnologie (z.B. molekulare Schalter). In all diesen Gebieten besteht die Forderung nach hohen Probendurchsätzen bei sehr hohem Informationsgehalt. Etablierte elektrochemische Detektionsmethoden erfüllen diese Forderung nicht. Um dieses Defizit zu überwinden, wurde ein Ionenkanalsensor-Array mit optischer, paralleler Detektion entwickelt. Eine mikrostrukturierte Polymethyl(meth)acrylat (PMMA)-Schicht dient als Grundgerüst des Arrays. Über die Mikroporen, die nur wenige Mikrometer Durchmesser aufweisen, wird eine Lipidmembran gespannt, in die Ionenkanäle eingebaut werden. Wird der Ionenkanal aktiviert, strömen Ionen in die Mikroporen und führen zu einer messbaren Veränderung des Brechungsindexes. Mittels Oberflächenplasmonen-Resonanz Imaging lässt sich die Aktivierung der Ionenkanäle markierungsfrei und direkt bestimmen. Stabile, die Mikrostruktur überspannende Lipidmembranen wurden durch eine neu entwickelte Stempeltechnik und durch eine Oberflächenmodifikation der PMMA-Mikrostruktur erzielt. Für die Charakterisierung und den Funktionsnachweis des Sensoraufbaus wurden das infrarot-spektroskopische Imaging und die Fluoreszenzmikroskopie eingesetzt. Schließlich konnte gezeigt werden, dass eine Verbesserung der Empfindlichkeit durch das lokale Aufkonzentrieren der durch den Ionenkanal geströmten Metallionen am Porengrund mit oberflächengebundener 2-(Benzylsulfid)-18-Krone-6 möglich ist.

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Malic, Lidija. "Electro-wetting-on-dielectric digital microfluidic platform with integrated nanostructured biosensor interface for enhanced two-dimensional Surface Plasmon Resonance imaging detection." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86687.

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The sensitive and specific detection of biomolecular interactions is at the heart of many routine analyses in fundamental research, medical diagnosis and environmental monitoring. In contrast to laborious and costly multiwell plate assays, recent years have witnessed a significant progress in miniaturized and integrated biosensors, such as surface plasmon resonance (SPR), tailored to these applications. While the design of various SPR biosensors has been described in literature, a robust, multichannel, low-cost and highly sensitive solution has not yet been presented. Specifically, an integrated system that can allow surface functionalization in array format, low-volume multichannel fluidic interfacing, and increased sensitivity is sought. This thesis describes a novel electro-wetting-on-dielectric (EWOD) digital microfluidic device with integrated nanostructured biosensor interface that addresses the aforementioned issues for enhanced surface plasmon resonance imaging (SPRi) detection. We have taken the opportunity of the most recent advances in microfabrication, nanotechnology and SPR technique to develop this integrated platform. EWOD device is employed for the dynamic immobilization of bioreceptors on SPRi biosensor surface in an array fashion from sub-µL volume solutions. Programmable EWOD electric interface allows the application of an electric field at the biosensor surface for active control of the immobilized probe density and orientation, enhancing SPRi detection. Two-dimensional SPRi detection is achieved by coupling the EWOD device to SPRi instrumentation. Parallel manipulation of individual droplets allows more efficient exploitation of the biosensor surface by separating different samples for simultaneous and selective SPRi detection. Periodic gold structures (nanoposts, nanogratings and nanogrooves) residing on a surface of glass and plastic substrates are investigated to improve the SPRi sensitivity. The corresponding electromagnetic field enhancements lead to up to a five-fold increase in SPRi response and provide an order of magnitude improvement in the limit of detection. This optimized nanostructure design is integrated with the EWOD platform to increase the capability and enhance SPRi detection. The integrated platform is successfully employed for parallel detection of multiple DNA hybridization reactions in 90 nL droplets. More than a two-fold SPRi signal amplification is achieved within 15 min, while the detection time could be further reduced to 2 min for a simple "yes" or "no" answers for the presence of the target DNA in a sample. The proposed system holds a great potential for ultra-low volume, sensitive and rapid detection of biomolecules, such as DNA and proteins, for clinical diagnosis and other bioanalysis applications. La détection sensible et spécifique des interactions biomoléculaires est au coeur de plusieurs analyses au niveau de la recherche fondamentale, du diagnostic médical et du contrôle de l'environnement. Les analyses conduites sur des plaques de multipuits sont généralement laborieuses et coûteuses. Pour remedier a ceci, ces dernières années ont été témoin d'un progrès significatif dans la production de biocapteurs miniaturisés et intégrés, tel que la résonance plasmonique de surface (SPR), conçus pour ces applications. Tandis que la conception du biocapteur de SPR a été bien décrite dans la littérature scientifique, une solution comprenant un multicanal peu coûteux et hautement sensible n'a pas été encore présentée. Spécifiquement, le système intégré recherché doit permettre la functionalization des surfaces dans le format de réseau, l'interface fluidique multicanale en petit volume et une augmentation de la sensibilité. Cette thèse décrit une nouvelle plateforme microfluidique numérique de l'Électro-mouillage-sur-diélectrique (EWOD) avec un biocapteur à interface nanostructureé intégrée qui aborde les critères mentionnés ci-dessus pour une meilleure détection de l'imagerie SPR (SPRi). Nous avons profité des récents progrès dans la microfabrication, la nanotechnologie et en la technique du SPR pour développer ce dispositif intégré. La plateforme EWOD est utilisée pour l'immobilisation dynamique des biorécepteurs sur la surface du biocapteur de SPRi sous forme de réseau de solutions dont le volume est sous les µL. L'interface électrique programmable d'EWOD permet l'application d'un champ électrique sur la surface du biocapteur pour contrôler activement la densité et l'orientation des sondes immobilisées, augmentant ainsi la détection du SPRi. La détection bidimensionnelle de SPRi est réalisée en couplant le dispositif microfluidique d'EWOD à l'instrument SPRi. La mise en action d'EWOD manoeuvre en parallèle différentes gouttelettes pour une exploitation plus efficace de la surface du biocapteur, permettant la séparation de différents échantillons pour la detection simultanés et spécifique par SPRi. Des structures d'or périodiques (nanoposts, nanogratings et nanogrooves) qui se trouvent sur des surfaces en verre et des substrats en plastique sont étudiées pour améliorer la sensibilité de la détection de SPRi. Le perfectionnement du champ électromagnétique correspondant mène jusqu'à une augmentation quintuple de la réponse du SPRi et augmente d'un seul ordre de grandeur le perfectionnement de sensibilité. Finalement, la conception optimisée de nanostructure est intégrée avec la plate-forme d'EWOD pour augmenter les possibilités et améliorer l'interface de biocapteurs de SPRi. La plateforme intégrée est utilisée avec succès pour la détection parallèle de multiples réactions d'hybridation d'ADN dans des gouttelettes de 90 nL. Plus d'une amplification double du signal sont réalisées en seulement 15 minutes. La période de détection peut être encore réduite à minute 2 pour des réponses simples « oui » ou « non » pour la présence d'ADN dans un échantillon. Le système proposé a un grand potentiel pour la détection de petit volume, sensible et rapide, des biomolécules tels que l'ADN et les protéines pour le diagnostic clinique et d'autres

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Pendery, Joel S. "Nanoscale Patterning and Imaging of Liquid Crystals and Colloids at Surfaces." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1396623443.

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Sereda, Alexandra. "Imagerie multi-spectrale par résonance des plasmons de surface : développement et applications." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112321/document.

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Dépistage du VIH, test de grossesse, mais également surveillance des eaux, détection de contaminants agro-alimentaires : la biodétection est au coeur des problématiques de santé actuelles. Dans ce contexte, les biocapteurs plasmoniques connaissent depuis quelques années un essor particulièrement important : de plus en plus de sociétés, telles que HORIBA Scientific, proposent des prototypes commerciaux, destinés tant à des utilisateurs du domaine de la recherche que de l'industrie. Basée sur le phénomène de résonance des plasmons de surface (communément appelé SPR) la biodétection plasmonique repose sur l'extrême sensibilité d’une onde évanescente se propageant à l’interface entre un film d’or, la biopuce, et le milieu diélectrique couvrant, siège des interactions biomoléculaires étudiées. De manière plus concrète, toute adsorption de matériel biologique se produisant à cette interface entraîne une modification importante des propriétés optiques d’un faisceau de lumière réfléchi par la biopuce : le principe de transduction par SPR consiste alors à mesurer directement ces variations. A l'heure actuelle, différents modes d'interrogation, offrant des performances intéressantes, mais également des limitations propres à chaque configuration. Pour répondre aux exigences de précision et de dynamique de mesure posées par de nombreuses applications, un développement théorique et instrumental, présenté dans ce document, a été initié dans le but de proposer un nouveau un nouveau mode d'interrogation des biopuces plasmoniques : l'interrogation multi-spectrale. Les résultats obtenus par cette technique ont été exploités pour concevoir et réaliser une source multi-spectrale à base de LEDs, particulièrement avantageuse vis-à-vis des configurations existant à l'heure actuelle. La caractérisation du système développé dans le cadre du diagnostic génétique (mucoviscidose) et celui du cancer, ouvre la voie à une nouvelle génération de biocapteurs performants, compacts et de coût relativement raisonnable, présentant un potentiel industriel certain Biodetection is at the core of the current health concerns, as shown through the variety of applications to HIV screening, food contaminant analysis or water quality monitoring. In this field, plasmonic biosensing is a well-established label-free technique on the market: commercial systems from HORIBA Scientific are currently available for both research and industrial users.Based on the surface plasmon resonance (SPR) phenomenon, plasmonic biodetection uses the high sensitivity of an evanescent wave propagating along a metallic film (forming the biochip) and the surrounding dielectric medium interface. More specifically, the adsorption of biomolecules onto the metal surface induces a strong change in the optical properties of a light beam reflected by the biochip: the main principle of plasmonic transduction consists in measuring these physical changes. Several interrogation techniques have therefore been developed to access such optical information, but they fail in meeting the most demanding user requirements for precise, real-time, high-throughput measurement.Initiated by these issues, the instrumentation work presented in this document has led to the development of a novel SPR interrogation technique, referred to as multi-spectral interrogation. Moreover, the promising results obtained have been pushed forward to propose a multi-spectral illumination system based on LEDs, providing attractive performances compared to existing configurations. The biosensing potential of the developed system, demonstrated through applications to genetic diagnosis and cancer detection, opens the door to a new generation of compact, high-performance, low-cost SPR sensors

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Duperron, Matthieu. "Conception et caractérisation de nanoantennes plasmoniques pour la photodétection infrarouge refroidie." Thesis, Troyes, 2013. http://www.theses.fr/2013TROY0030/document.

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L’imagerie infrarouge refroidie est portée par une demande forte pour des applications dans les secteurs militaire, industriel et spatial. Les enjeux actuels de ce marché sont le fonctionnement à haute température et la fonctionnalisation spectrale des détecteurs.Ces enjeux peuvent être adressés grâce à l’utilisation de résonateurs optiques et leur faculté à concentrer le champ électromagnétique. Ce travail de thèse montre comment des résonateurs plasmoniques peuvent être intégrés dans la filière HgCdTe.La théorie temporelle des modes couplés a été utilisée, de manière analytique, pour optimiser à travers la condition de couplage critique, l’absorption dans un résonateur plasmonique chargé par un semiconducteur. La conception d’une photodiode HgCdTe ultramince plasmonique est ensuite détaillée. Elle repose sur l’utilisation d’un mode optique résultant du couplage entre un mode plasmon de surface et un mode gap plasmon de cavité The market for cooled infrared imaging technologies is growing fast due to a range of applications covering military, commercial and space. Current research for innovative systems focuses on high operating temperature and multispectral detectors.To achieve these aims, optical resonators can be used to concentrate electromagnetic fields in thin absorbing media. This thesis investigates the possibility of using plasmonic resonators for HgCdTe photodetection.Temporal coupled-mode theory is used to optimise analytically the absorption in a plasmonic resonator incorporating an absorbing semiconductor subject to the critical coupling condition. A design of a thin plasmonic HgCdTe diode is then described. This includes a hybrid plasmonic mode arising from the coupling between a surface plasmon and a cavity gap-plasmon mode

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Guo, Zhen. "Insights of Taste Masking from Molecular Interactions and Microstructures of Microspheres." Thesis, University of Bradford, 2017. http://hdl.handle.net/10454/17420.

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The effects of taste masking are determined by interactions between drug and excipients as well as the microstructures of the particulate drug delivery systems (DDS). Cyclodextrin (CD) is a widely used taste masking agent, to which the relationship between kinetic parameters (Ka and Kd) of a drug and taste masking remains unexplored, which is investigated for the first time in this study. A data base of the kinetic parameters for drug-CD was established by Surface Plasmon Resonance Imaging (SPRi) and High Performance Affinity Chromatography (HPAC). Combined with the electronic tongue, Ka and Kd based models for the taste masking effect of HP-β-CD were successfully established and applied to the prediction of taste masking effects. Paracetamol was used as a model drug for taste masking formulation optimization. As well as drug release the microstructure of solid DDS has considerable influence on drug taste. The microstructure of lipid microspheres and the molecular distribution of drug and excipients in lipid microspheres were investigated by Synchrotron radiation-based micro-computed tomography (SR-μCT) and Synchrotron radiation-based Fourier-transform infrared spectromicroscopy (SR-FTIR), respectively. The results demonstrated that the polymeric formulation components as well as shape and particle size of the drug were the key factors to taste masking of paracetamol by inhibiting bust release thereby reducing the interaction intensity of the bitterness. The FTIR absorption spectra confirmed the deposition and formation of chitosan and gelatin films on the drug microsphere surface by layer-by-layer coating. In conclusion, this research demonstrates the molecular kinetic basis of CD taste-masking as well as microstructural basis of particle systems for bitter taste masking.

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Banville, Frédéric. "Nanostructuration de surface pour l'imagerie à résonance de plasmons de surface de haute résolution." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLO005/document.

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En recherche pharmacologique, les cellules vivantes sont largement utilisées comme milieu d’analyse pour l’étude de phénomènes biologiques, par exemple l’apoptose et la réorganisation cellulaire. Différents outils de caractérisation sont développés pour analyser et traduire l’information biologique en information quantifiable. L’imagerie à résonance de plasmons de surface (SPR) est sensible aux variations d’indice de réfraction d’un milieu à l’interface d’une couche métallique. Elle trouve beaucoup d’applications en recherche pharmacologique, car elle permet l’acquisition d’images en temps réel et ne nécessite pas de marquage biologique comme en fluorescence. Cependant, la nature propagative des plasmons de surface (PSP) limite la résolution spatiale en entraînant un étalement de l’information dans la direction de propagation des PSP. Cela signifie qu’il est difficile de résoudre spatialement des détails inférieurs à la distance de propagation des PSP, généralement de l’ordre des dizaines de micromètres. Plusieurs groupes de recherche travaillent à améliorer la résolution spatiale en imagerie SPR. Toutefois, bien que des résolutions spatiales inférieures à celle de la propagation ont été obtenues, certains compromis ont été effectués, par exemple la diminution de la résolution temporelle ou d’indice de réfraction.Ce projet de thèse s’insère dans cette problématique en concevant et réalisant des dispositifs plasmoniques permettant d’améliorer la résolution spatiale en imagerie SPR, tout en minimisant les compromis avec les autres paramètres d’imagerie. Ces puces SPR sont composées de surfaces métalliques nanostructurées dont le mode guidé combine les propriétés des plasmons propagatifs et des plasmons localisés. Un logiciel de modélisation numérique a permis de démontrer comment la géométrie des surfaces nanostructurées peut être optimisée de manière à réduire la longueur d’atténuation du mode plasmonique tout en conservant un fort contraste d’imagerie. Une géométrie optimale a été identifiée et des structures de l’ordre du micromètre ont été observées à l’aide des puces SPR nanostructurées optimisées. Les résultats expérimentaux ont montré une réduction de la propagation d’un facteur de 6.3 comparativement à des surfaces métalliques uniformes.Les performances en imagerie des puces SPR nanostructurées ont été validées au cours d’études de réponses cellulaires causées par stimulation à l’aide d’agents pharmacologiques. Les puces ont été employées dans l’étude de changements d’intégrité de couches confluentes de cellules suivant stimulation. La quantification de trous intercellulaires dans la couche a montré une augmentation significative du nombre de petits trous détectés (~ 1-2 µm2) lors de l’utilisation des puces SPR nanostructurées. Cette augmentation de la sensibilité à l’activité cellulaire est le résultat de l’amélioration de la résolution spatiale. Finalement, l’étude de la morphologie de cellules au cytosquelette fortement linéaire a permis d’observer des structures subcellulaires et de suivre la réorganisation du cytosquelette de cellules individuelles. Les puces SPR nanostructurées conçues et réalisées au cours de cette thèse montrent un fort potentiel d’applications en imagerie sans marquage de cellules vivantes In pharmacological research, living cells are widely used as the sensing medium for biological studies, such as cell apoptosis and cellular reorganization. Different characterization systems are developed to analyze and quantify biological information. Surface plasmon resonance (SPR) imaging is sensitive to minute refractive index variations occurring in a medium at the proximity of a metal layer. It has found many applications in pharmacological research since it allows the real-time image acquisition and does not require biological labeling like for fluorescence. However, the propagative nature of surface plasmons (PSPs) limits the spatial resolution by spreading the information in the direction of propagation of the PSPs. This means that it is difficult to spatially resolve details smaller than the attenuation length of the PSPs, generally of the order of tens of micrometers. Several research groups have worked on this limitation in order to improve the spatial resolution in SPR imaging. However, although spatial resolutions lower than that of the propagation have been obtained, those techniques require compromises, such as loss in temporal resolution or in refractive index.In this thesis project, plasmonic devices were designed and characterized in order to improve spatial resolution in SPR imaging, while minimizing compromises with other imaging parameters. These SPR chips are composed of nanostructured metal surfaces where the guided mode combines the properties of propagative plasmons and localized plasmons. An in-house numerical modeling software has demonstrated how the geometry of nanostructured surfaces can be optimized to reduce the attenuation length of the plasmonic mode, while maintaining a high imaging contrast. An optimum geometry was identified, and micron-sized structures have been observed using the optimized nanostructured SPR chips. Experimental results showed a reduction in propagation by a factor of 6.3 compared to uniform metal surfaces.The imaging performances of nanostructured SPR chips were assessed by studying cellular responses following pharmacological stimulation. The chips were used in real-time monitoring of integrity changes in confluent endothelial cell layer following stimulation. Quantification of intercellular gaps in the monolayers showed a significant increase in the number of small holes detected (~ 1μm2) when using nanostructured SPR chips. This increase in sensitivity to cellular activity is the result of improved spatial resolution. Finally, the study of morphology in highly linear cytoskeleton cell enabled the observation of subcellular structures and the monitoring of cytoskeleton reorganization in individual cells. The nanostructured SPR chips designed and realized during this thesis show a strong potential label-free live cell imaging

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Klenkar, Goran. "Protein Microarray Chips." Doctoral thesis, Linköping : Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8904.

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Pillet, Flavien. "Développement d'un outil d'analyse d'interactions moléculaires basé sur la résonance plasmonique de surface (SPRi)." Thesis, Toulouse, INSA, 2010. http://www.theses.fr/2010ISAT0029/document.

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Ces dernières décennies, on a assisté à l’augmentation du nombre de technologies et de concepts permettant l’analyse des interactions intermoléculaires. Dans ce contexte, les puces à fluorescence restent les plus fréquemment utilisées. Cependant, cette technologie bien que très sensible et multiplexée, ne permet pas d’avoir accès aux paramètres cinétiques, indispensables au calcul des constantes d’affinité et la recherche de systèmes alternatifs s’impose. Dans cette optique, la résonance plasmonique de surface par imagerie (SPRi) est considérée comme une véritable option. Cette technologie se caractérise par l’absence de marquage et permet de suivre en temps réel d’infimes variations de masses consécutives à des interactions intermoléculaires sur la surface du prisme. L’obtention de constantes d’affinité est ainsi possible. En revanche, la SPRi présente un certain nombre de limites, principalement au niveau de la sensibilité et du multiplexage. Les objectifs de la thèse ont ainsi consisté à combler en partie ces différentes limites. La chimie de greffage basée sur l’utilisation d’oligonucléotides modifiés par un thiol a permis d’améliorer le multiplexage et de déposer plus de 1000 spots par cm² sur la surface d’or du prisme. Dans le même temps, la modification de la surface avec des colloïdes d’or et des dendrimères a permis pour des interactions ADN/ADN, d’atteindre une limite de détection de 2 nM (d’où un gain de 200%). En parallèle de ces travaux, diverses applications biologiques ont été effectuées. Une première étude a consisté à rechercher des ligands spécifiques des structures G-quadruplex des télomères. Une seconde étude s’est portée sur le complexe de partition bactérien. Par des études de criblage les bases impliquées dans l’interaction avec une protéine indispensable à la partition du plasmide F chez E.coli ont été identifiées. L’ensemble de ces travaux ont montré le fort potentiel de la SPRi et les applications potentielles qui en découlent sont nombreuses During the last decades a large number of technologies have been developed to analyze intermolecular interactions. In this context, the fluorescence biochips remain the most frequently used. Although this technology is very sensitive and multiplexed, it does not allow access to the kinetic parameters, essential to the calculation of the constants of affinity. Therefore, the research for alternative systems is essential. In this way, the Surface Plasmon Resonance imaging (SPRi) is considered as an opportunity. It is an optical detection process that can occur when a polarized light hits a prism covered by a thin metal layer. Under certain conditions free electrons at the surface of the biochip absorb incident light photons and convert them into surface plasmon waves. Perturbations at the surface of the biochip, such as an interaction between probes immobilized on the chip and targets, induce a modification of resonance conditions which can be measured. It is a label free technology which allows intermolecular interactions in real time and gives access to the kinetics parameters. However, SPRi is limited in sensitivity and multiplexing. The objectives of my PhD were to circumvent these various limits. Thus, we validated the immobilization of DNA probes on gold surface using thiol-modified oligonucleotide probes. Deposition carried out on non-modified gold surface, does not require electrical stimulation and expensive specific robotic devices. The thiol modification of the probes was shown to be very stable at room temperature, contrary to pyrrole and diazonium probes that need to be prepared just prior to their spotting. We demonstrate that thiol-modified oligonucleotide probes spotted on a gold surface of the SPRi-prisms are very robust and reproducible. We also demonstrated that this simple chemistry is compatible with high density arrays fabrication bearing more than 1000 spots using a classical spotter. Furthermore, the modification of the prism surface with gold colloids and dendrimers allowed for DNA/DNA interactions, to reach a detection limit of 2 nM. In parallel of this work, various biological applications were carried out and validate our previous developments. A first study was to screen G-quadruplex specific ligands to inhibit telomerase activity. We demonstrated that SPRi technology is particularly well adapted to the screening of interaction of small molecules with DNA probes and is sensitive enough to permit distinction between interactions with different DNA structures. The second study was on the bacterial partition complex. We study the DNA binding requirement involved in SopB-sopC specific interactions and analysed at the nucleotide level the bases involved in the binding efficiency and essential for the partition All this PhD work improved the SPRi technology and demonstrated its great potential in biological applications

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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 molécule The 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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Beltrami, Coline. "Développement d'un biocapteur plasmonique pour la détection en faibles concentrations de miARNs dans le cadre du don d'organes." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPAST196.

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La surveillance des conditions physiologiques de donneurs d'organes en état de mort cérébrale est cruciale pour prévenir la dégradation des tissus. Ce suivi peut être effectué en observant la réponse inflammatoire (tempête cytokinique) à travers des biomarqueurs spécifiques : les miARNs. Ce travail propose d'utiliser l'imagerie par résonance plasmonique de surface (SPRI) pour détecter quantitativement ces miARNs. Cette recherche vise à développer un biocapteur SPRI plus sensible et spécifique pour détecter les miARNs à des concentrations inférieures à la limite de détection de ces systèmes.Tout d'abord, une fonctionnalisation de la surface d'or de la biopuce mieux orientée a été développée afin d'améliorer l'accessibilité des biorécepteurs. Ensuite, des sondes modifiées avec des bases LNA ont été employées pour renforcer l'affinité avec le miARN cible. En parallèle, une stratégie d'amplification par sandwich du signal SPRI a été conçue en utilisant des nanoparticules d'or, et un modèle cinétique a été élaboré pour prédire le facteur d'amplification. Les AuNPs ont été synthétisées en une seule étape à température ambiante et fonctionnalisées pour être spécifiques vis-à-vis du miARN et solubles en solution saline. Ces approches combinées ont conduit à une amplification du signal de plus de deux ordres de grandeur et à une limite de détection de miARNs dans la gamme du picomolaire Monitoring the physiological conditions of brain-deceased organ donors is crucial to prevent tissue degradation. Tracking this degradation can be done by following the inflammatory response (i.e. cytokine storm) through specific biomarkers like miRNAs. This work proposes using Surface Plasmon Resonance Imaging (SPRI) to quantitatively detect those miRNAs. To achieve detection at concentrations below the usual SPRI limits, this research focuses on developing a more sensitive and specific SPRI biosensor for miRNA detection. Firstly, a new surface functionalization better oriented was developed for the SPRI gold biochip to improve bioreceptor accessibility. LNA-modified probes were then employed to enhance the affinity with the target miRNA. Secondly, a signal amplification strategy was designed using gold nanoparticles (AuNPs) in a sandwich-like assay, and a kinetic model predicting the amplification factor was developed. The AuNPs were synthesized in a one-step process at ambiant temperature and functionalized for miRNA specificity and solubility in saline solution.These combined approaches led to more than two orders of magnitude signal amplification and a detection limit in the picomolar range

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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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Kholodtsova, Maria. "Spectral, spatial and temporal properties of multilayered epithelial tissue in vivo in presence of metal nanoparticles in multimodal spectroscopy." Electronic Thesis or Diss., Université de Lorraine, 2016. http://www.theses.fr/2016LORR0031.

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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 molécule The 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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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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Stewart, Ciaran. "Phase differential surface plasmon imaging." Thesis, University of Exeter, 2010. http://hdl.handle.net/10036/3102.

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Surface Plasmon Resonance (SPR) has been utilised in various forms in sensors for many years. It is usually based on angular or wavelength interrogation of the reflectivity minimum found with Transverse Magnetic (TM) light. However, as the SPR is traversed there is also a very rapid change in the phase of the reflected TM light there being no such change in the Transverse Electric (TE) light. Presented in the thesis a new SPR sensor has been developed that exploits this rapid change in optical phase. Linearly polarised light of mixed TM/TE polarisation is passed through a polarization modulator, which adds a small amplitude modulation to the polarisation. This modulated light is incident on a gold film 40 nm thick evaporated onto the base of a SF2 prism in the Kretschmann-Raether, configuration. The coupling of the TM polarised light to the SPR is dependant on the properties of the dielectric medium adjacent to the gold film. The SPR shifts when this sensed medium undergoes a change in refractive index (or index or thickness if it is a bound analyte layer). This in turn causes a change in the reflected elliptically polarised light. The change of the resultant modulated polarisation dither is interrogated through the use of a phase sensitive detectors. Initially a simple photo diode coupled with a lock-in amplifier was used to monitor the modulated signal. This was expanded into an imaging technique by using two cameras (64 by 64 pixels) fabricated with the equivalent of a lock-in amplifier on each of the 4096 pixels. The spatial map of the modulation amplitude gives an optical phase differential image. By imaging in this way it is possible to produce a multi channel differential sensor

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Templier, Vincent. "Exploration de méthodes alternatives pour la détection de bactéries dans le sang." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAS008/document.

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La présence de bactéries dans le sang, un milieu normalement stérile, peut avoir des conséquences graves voire fatales pour l’organisme atteint. Afin de diagnostiquer au plus tôt cette infection, appelée bactériémie, et ainsi administrer le traitement adéquat, il est nécessaire d’identifier les microorganismes isolés à partir du sang. Mais, la nature complexe de ce fluide biologique, associée à la faible charge bactérienne, parfois inférieure à 1 UFC par millilitre de sang ont des conséquences sur les méthodes pouvant être utilisées pour l’identification des bactéries. La plupart d’entre elles ont donc recours à une première étape, l’hémoculture, au cours de laquelle les microorganismes présents dans le prélèvement sanguin de volume important (20-30 mL) vont se multiplier. Leur croissance est facilitée par la dilution du sang dans des milieux de culture dédiés à cette étape particulière. C’est seulement ensuite que l’identification peut débuter. Elle nécessite encore entre 2 et 48 heures et parfois plus, selon les moyens à disposition et les microorganismes impliqués. Réduire considérablement le temps nécessaire à l’identification aurait pourtant des retombées bénéfiques à l’échelle du patient mais aussi plus globalement en réduisant les coûts associés à cette infection et en limitant la pression de sélection exercée par l’emploi d’antibiotiques à large spectre.Au cours de ce travail, l’évaluation d’une stratégie basée sur l’identification des bactéries lors de leur multiplication dans le milieu d’hémoculture est donc proposée. Elle repose sur l’observation en temps réel et sans marquage par Résonance Plasmonique de Surface par imagerie (SPRi) des interactions entre les bactéries et des ligands déposés à la surface d’un capteur. Dans un premier temps, des ligands alternatifs aux anticorps parmi lesquels figurent les aptamères, des protéines de l’immunité innée et la vancomycine sont testés. Suite à cette étude, les anticorps ont été retenus pour poursuivre ce travail. Leur emploi n’est cependant pas dénué de difficultés lorsqu’il s’agit de détecter spécifiquement Staphylococcus aureus, choisi comme l’un des modèles expérimentaux. En effet, la présence de protéine A chez cette bactérie est à l’origine d’interférences sur les immunoglobulines. Différentes stratégies pour s’affranchir de ces effets ont été évaluées, comme le clivage enzymatique des anticorps ou l’emploi d’anticorps de poule pour lesquels la protéine A n’a pas d’affinité. Ces essais aboutissent à des résultats encourageants en milieu de culture simple. L’ajout de sérum humain au milieu a soulevé de nouveaux problèmes pour la détection de cette bactérie. Les résultats montrent qu’en interagissant avec des constituants de l’échantillon sanguin, dont les anticorps, S. aureus devient indétectable par une biopuce à anticorps. Une discussion des moyens possibles pour lever cette inhibition est ensuite proposée. Des expériences de détection d’une autre bactérie, Salmonella enterica sérovar Enteritidis pour laquelle nous disposons d’un anticorps hautement affin et spécifique ont alors été entreprises afin de conclure sur l’employabilité du dispositif dans des conditions proches d’une hémoculture. Des interférences affectant différentiellement les anticorps selon leur point isoélectrique ont ainsi été mises en évidences et l’implication de l’anticoagulant (polyanéthole sulfonate de sodium, SPS) présent dans les milieux d’hémoculture a été démontrée. La résolution partielle de ce problème a finalement permis la détection de 1 UFC.mL-1 de sang dans 32 mL au total démontrant ainsi la possibilité de détecter spécifiquement une bactérie dans des conditions proches d’une hémoculture The presence of bacteria in the blood, a normally sterile environment, can cause dramatic consequences for an organism. In order to diagnose this infection, called bacteremia, the identification of the microorganism present in blood must be performed. Furthermore, proper diagnosis enables the administration of a suitable antibiotic therapy. Blood complexity as well as the low bacterial load, usually lower than 1 CFU.mL-1, make the diagnosis of this infection quite challenging. Indeed, most identification methods begin only after the blood culture turns positive due to their insufficient sensitivity. For this they require incubation of a large blood sample volume (20 – 30 mL) in specific culture media that allows bacterial growth above their detection limit. Therefore, its increases considerably the time of diagnosis, which usually takes between 2 and 48 hours and sometimes even more time after blood culture positivity depending on the method and the microorganism present in blood. A reduction of the time required for identification would have a positive impact for both the patient and the healthcare systems by reducing selective pressure on resistant bacteria and hospitalization costs by giving proper treatment faster.In this work, the evaluation of a new strategy based on the identification of bacteria during their multiplication in the blood culture is presented. This method is based on Surface Plasmon Resonance imaging (SPRi) which enables real time and label-free measurements of interactions occurring between bacteria and specific probes. Alternative ligands like aptamers, innate immune proteins and vancomycin have been tested. Following this study antibodies have been chosen as the major specific probes in this work. Nonetheless, the presence of the staphylococcal protein A leads to false-positive results in all immunoglobulin G (IgG). Enzymatic cleavage to remove the constant fragment of antibody where protein A interacts and the use of chicken antibodies (IgY) for which protein A has no affinity have been evaluated. Both methods allow to get rid of protein A interactions in pure culture media. But the presence of human serum in the media results in the total loss of signal. Our results show that interactions between blood components and staphylococcal proteins exposed at the bacterial surface, including the interactions between protein A and circulating antibodies, are responsible for this phenomenon. Solutions to alleviate this inhibition are discussed and tested. Detection experiments of another bacterial model, Salmonella enterica serovar Enteritidis in blood culture media are presented. The crucial role played by the anticoagulant Sodium Polyanethole Sulfonate in non-specific interactions on antibodies is demonstrated. These interactions leading to a total loss of specificity for some antibodies are influenced by the isoelectric point (pI) of the probes which interact with this anionic compound and then attract blood components. After the partial resolution of this issue, we show the feasibility of detecting less than one bacteria per blood milliliter in a total volume of 32 milliliters, conditions close to real blood culture

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Pardoux, Éric. "Détection à large spectre de pathogènes bactériens à l'aide de peptides antimicrobiens." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAV026/document.

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L’analyse microbiologique pour confirmer l’absence de bactéries dans des échantillons biologiques normalement sains, comme le sang, est une routine dans de nombreux laboratoires. En effet, la présence de bactéries dans le sang, appelée bactériémie, peut avoir des conséquences très graves, voire mortelles pour le patient. Le protocole standard pour la détection des bactériémies repose jusqu’ici sur l’enrichissement des échantillons sanguins prélevés sur les patients lors de l’hémoculture, afin d’obtenir une population suffisante pour analyse. La lenteur de ce procédé retarde ainsi de parfois plusieurs jours le diagnostic et donc l’adaptation du traitement antibiotique administré au patient. Ces dernières décennies, des techniques comme l’identification par spectrométrie de masse ou les analyses moléculaires, ont permis de diminuer le délai requis pour identifier les pathogènes en cause. Dans ce contexte, l’emploi de biocapteurs est également une alternative. Ce travail propose d’inclure des sondes à large spectre dans un capteur optique par imagerie SPR (résonance de plasmons de surface). Ce système est déjà développé pour la reconnaissance spécifique de pathogènes au cours de leur croissance dans le sang. Les nouveaux ligands proposés et évalués sont les peptides antimicrobiens (PAM). Ces courts peptides cationiques et amphiphiles, présentent l’avantage d’un large spectre d’interaction couplé à une haute stabilité (chimique, thermique et séchage) comparativement aux anticorps employés jusqu’ici. Leur immobilisation sur des prismes SPRI permet d’évaluer simultanément l’affinité de plusieurs PAM à la même souche bactérienne. Les biocapteurs ainsi préparés ont permis de détecter des souches pathogènes d’Escherichia coli et Staphylococcus aureus en milieu de culture simple, comme en plasma et en sang dilué au milieu d’hémoculture. Le système obtenu permet la détection des pathogènes présents à une concentration initiale de l’ordre de 1 UFC.ml-1, en moins de 24 heures et quel que soit le milieu. Enfin, la mise en place d’analyses statistiques multidimensionnelles a abouti à une classification cohérente des espèces ciblées en milieu simple, comme en sang. Ces résultats montrent le potentiel de ce système pour parvenir à développer un biocapteur à large spectre capable à la fois de détecter mais aussi d’identifier par affinité croisée des pathogènes bactériens Microbiological analysis to confirm the absence of bacteria in normally sterile biological samples, such as blood, is routine in many laboratories. The presence of bacteria in blood, called bacteremia, can have very serious, and even fatal consequences for the patient. So far, the standard protocol for their detection has been based on the enrichment of blood samples collected from patients, thanks to blood culture, in order to obtain a sufficient population for analysis. These procedures are time consuming which sometimes lead to delays in diagnosis and subsequent adaptation of antibiotic treatments by several days. In recent decades, techniques such as mass spectrometry identification or molecular analyses have reduced the time required to identify the pathogens involved. In this context, the use of biosensors is another promising alternative. This work proposes to include wide spectrum probes in an optical sensor using SPR imaging (surface plasmon resonance). This system is already developed for the specific recognition of pathogens during their growth in the blood. The new ligands we propose to evaluate are antimicrobial peptides (AMP). These short, cationic and amphiphilic peptides have the advantage of having a broad spectrum of interaction with bacteria, coupled with high stability (chemical, thermal and drying), especially compared to the antibodies used so far in this technique. Their immobilization on SPRI prisms allows the simultaneous evaluation of the affinity of several AMP to the same bacterial strain. The biosensors based on AMP were able to detect pathogenic strains of Escherichia coli and Staphylococcus aureus in simple culture medium, such as plasma and diluted blood in blood culture medium. The system obtained allows the detection of pathogens present at an initial concentration of about 1 CFU.ml-1, in less than 24 hours and in all assayed media. Finally, the implementation of multidimensional statistical analyses has resulted in a consistent classification of targeted species, in simple culture medium, such as blood. These results show the potential of this system to develop a wide-spectrum biosensor capable of both detecting and cross-referencing bacterial pathogens

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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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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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El, kazzy Marielle. "Etude fondamentale pour l'optimisation des performances d'un nez bioélectronique basé sur des protéines liant les odorants." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALV105.

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La détection de molécules odorantes et de composés organiques volatils (COVs) fait l'objet d'une demande croissante dans divers domaines tels que l’industrie alimentaire, la parfumerie, le diagnostic médical, la surveillance environnementale, etc. Bien que précises et fiables, les méthodes les plus couramment employées - la chromatographie en phase gazeuse couplée à la spectrométrie de masse et les panels de nez humain ou encore des nez de chiens dressés- présentent un certain nombre d'inconvénients notamment en termes de coût et de temps. En réponse à ces contraintes, les nez électroniques (NEs) sont alors apparus comme des outils prometteurs pour l’analyse de COVs. Inspirés du nez biologique, ces dispositifs biomimétiques se composent généralement d'un ensemble de capteurs chimiques à réactivité croisée combinés à un système de reconnaissance des formes. Au cours des trois dernières décennies, les nez électroniques ont démontré leur potentiel significatif pour l'analyse des COV dans de nombreux domaines. Toutefois, l'une des principales faiblesses de la plupart des NEs existants est leur sélectivité limitée. Pour répondre à cette problématique, les efforts de recherche se sont multipliés au cours de la dernière décennie pour explorer l'utilisation de matériaux biologiques issu du système olfactif comme matériaux de détection afin d'améliorer les performances des NEs. Dans ce contexte, notre équipe au sein du laboratoire Systèmes Moléculaires et Nanomatériaux pour l'Energie et la Santé (SyMMES, UMR 5819), a conceptualisé un nez bioélectronique utilisant l’imagerie par résonance de plasmons de surface comme technique de transduction et employant de petits peptides comme matériaux de détection. Cette technologie a conduit à la création d'Aryballe, une société qui a réussi à miniaturiser et à commercialiser le dispositif. Ce projet de thèse fait partie du projet ANR OBP-Optinose (ANR-18-CE42-0012) et vise principalement à explorer le potentiel des protéines liant les odorants (OBPs) en tant que nouveaux matériaux de détection pour le développement de nez bioélectroniques.Au cours de la thèse, nous avons utilisé une combinaison d'OBPs de type sauvage et d’OBPs plus sélectives, qui ont été conçues et génétiquement modifiées pour avoir des propriétés de liaison spécifiques pour certains COVs cibles. Notre approche expérimentale consistait à étudier les divers paramètres susceptibles d’impacter les performances des biocapteurs à base d'OBP pour la détection de COVs en phase gazeuse. Ainsi, dans un premier temps, nous avons entrepris une caractérisation complète des couches d'OBP immobilisée en surface. Nous avons commencé par évaluer la stabilité des protéines en phase gazeuse, un élément crucial pour assurer leur activité. Ensuite, nous avons approfondi notre analyse en examinant la densité et l'orientation des OBPs après leur dépôt sur la surface d’or de la puce. Car ces facteurs peuvent impacter la sensibilité de notre système. Nous avons également examiné l’impact du glycérol sur les couches d’OBPs. En outre, nous avons réalisé des recherches approfondies sur le mécanisme d'hydratation des couches d'OBP qui nous ont permis de mieux comprendre comment les conditions d'humidité influencent la réactivité des biocapteurs. Enfin, nous avons démontré les bonnes performances du nez bioélectronique à base d’OBP en phase gazeuse en termes de sélectivité, stabilité et répétabilité The detection of odorant molecules and volatile organic compounds (VOCs) is the subject of growing demand in various fields such as food industry, perfumery, medical diagnostics, environmental monitoring and so on. Although accurate and reliable, the most commonly used methods - gas chromatography coupled with mass spectrometry and panels of human noses or trained dogs- have a number of drawbacks, particularly in terms of cost and time. In response to these limitations, electronic noses (eNs) have emerged as promising tools for the analysis of VOCs. Inspired by the biological nose, these biomimetic devices generally consist of a set of cross-reactive chemical sensors combined with a pattern recognition system. Over the past three decades, eNs have demonstrated their great potential for VOC analysis in many areas. However, one of the main weaknesses of most existing eNs is their limited selectivity. In response to this problem, research efforts have multiplied over the last decade to explore the use of biological materials from the olfactory system as sensing materials in order to improve the performance of eNs. In this context, our team at the Molecular Systems and Nanomaterials for Energy and Health laboratory (SyMMES, UMR 5819), has conceptualized a bioelectronic nose using surface plasmon resonance imaging as a transduction technique and employing small peptides as sensing materials. This technology led to the creation of Aryballe, a company that has successfully miniaturized and commercialized the device. This thesis project is a part of the ANR project OBP-Optinose (ANR-18-CE42-0012), which aims to explore the potential of odorant binding proteins (OBPs) as novel sensing materials for the development of bioelectronic noses.During the thesis, we used a combination of wild-type and more selective OBPs, which were designed and genetically modified to have specific binding properties for target VOCs. Our experimental approach was to study various parameters that could have an impact on the performance of OBP-based biosensors for the detection of VOCs in the gas phase. First, a complete characterization of the OBP layers after immobilization on surface was carried out. The stability of the proteins in the gas phase was assessed, which is crucial to ensure their activity. The density and orientation of the OBPs were also studied since they may have impact on the sensitivity of the system. In addition, the impact of glycerol and humidity on the OBP layers was investigated. In particular, in-depth research into the hydration mechanism of the OBP layers was carried out, which enabled us to gain a better understanding of how humidity influences the reactivity of the biosensors. Finally, we demonstrated the good performance of OBP-based bioelectronic nose in the gas phase in terms of selectivity, stability, and repeatability

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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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38

Prabhu, G. Radhakrishna. "Studies On Surface Plasmon Resonance And Related Experimental Methods Using Fixed Plasmon Angle." Thesis, Indian Institute of Science, 2000. https://etd.iisc.ac.in/handle/2005/205.

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Abstract:

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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39

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.

Full text

Abstract:

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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40

Guo, Jing. "MULTI-MODE SELF-REFERENCING SURFACE PLASMON RESONANCE SENSORS." UKnowledge, 2013. http://uknowledge.uky.edu/ece_etds/13.

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Surface-plasmon-resonance (SPR) sensors are widely used in biological, chemical, medical, and environmental sensing. This dissertation describes the design and development of dual-mode, self-referencing SPR sensors supporting two surface-plasmon modes (long- and short-range) which can differentiate surface binding interactions from bulk index changes at a single sensing location. Dual-mode SPR sensors have been optimized for surface limit of detection (LOD). In a wavelength interrogated optical setup, both surface plasmons are simultaneously excited at the same location and incident angle but at different wavelengths. To improve the sensor performance, a new approach to dual-mode SPR sensing is presented that offers improved differentiation between surface and bulk effects. By using an angular interrogation, both surface plasmons are simultaneously excited at the same location and wavelength but at different angles. Angular interrogation offers at least a factor of 3.6 improvement in surface and bulk cross-sensitivity compared to wavelength-interrogated dual-mode SPR sensors. Multi-mode SPR sensors supporting at least three surface-plasmon modes can differentiate a target surface effect from interfering surface effects and bulk index changes. This dissertation describes a tri-mode SPR sensor which supports three surface plasmon resonance modes at one single sensing position, where each mode is excited at a different wavelength. The tri-mode SPR sensor can successfully differentiate specific binding from the non-specific binding and bulk index changes.

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41

Nehru, Neha. "Reference Compensation for Localized Surface-Plasmon Resonance Sensors." UKnowledge, 2014. http://uknowledge.uky.edu/ece_etds/41.

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Noble metal nanoparticles supporting localized surface plasmon resonances (LSPR) have been extensively investigated for label free detection of various biological and chemical interactions. When compared to other optical sensing techniques, LSPR sensors offer label-free detection of biomolecular interactions in localized sensing volume solutions. However, these sensors also suffer from a major disadvantage – LSPR sensors remain highly susceptible to interference because they respond to both solution refractive index change and non-specific binding as well as specific binding of the target analyte. These interactions can severely compromise the measurement of the target analyte in a complex unknown media and hence limit the applicability and impact of the sensor. In spite of the extensive amount of work done in this field, there has been a clear absence of efforts to make LSPR sensors immune to interfering effects. The work presented in this document investigates, both experimentally and numerically, dual- and tri-mode LSPR sensors that utilize the multiple surface plasmon modes of gold nanostructures to distinguish target analyte from interfering bulk and non-specific binding effects. Finally, a series of biosensing experiments are performed to examine various regeneration assays for LSPR sensors built on indium tin oxide coated glass substrate.

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42

Badjatya, Vaibhav. "TUNABLE LASER INTERROGATION OF SURFACE PLASMON RESONANCE SENSORS." UKnowledge, 2009. http://uknowledge.uky.edu/gradschool_theses/588.

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Surface plasmons are bound TM polarized electromagnetic waves that propagate along the interface of two materials with real dielectric constants of opposite signs. Surface plasmon resonance (SPR) sensors make use of the surface plasmon waves to detect refractive index changes occurring near this interface. For sensing purposes, this interface typically consists of a metal layer, usually gold or silver, and a liquid dielectric. SPR sensors usually measure the shift in resonance wavelength or resonance angle due to index changes adjacent to the metal layer. However this restricts the limit of detection (LOD), as the regions of low slope (intensity vs. wavelength or angle) in the SPR curve contain little information about the resonance. This work presents the technique of tunable laser interrogation of SPR sensors. A semiconductor laser with a typical lasing wavelength of 650nm was used. A 45nm gold layer sputtered on a BK7 glass substrate served as the sensor. The laser wavelength is tuned to always operate in the region of highest slope by using a custom-designed LabVIEW program. It is shown that the sensitivity is maximized and LOD is minimized by operating around the region of high slope on the SPR curve.

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43

Green, Rebecca J. "Protein/polymer interactions investigated by surface plasmon resonance." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336926.

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44

Berg, S. (Sonja). "Characterization and activity of surface plasmon resonance materials." Master's thesis, University of Oulu, 2017. http://urn.fi/URN:NBN:fi:oulu-201711083053.

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The goal of this study was to obtain new information about possibilities to utilize carbon dioxide (CO₂) with photocatalytic activation and reduction by using surface plasmon resonance titanium dioxide based materials decorated with platinum group metals. Carbon dioxide is known to be one of the most common greenhouse gases (GHG) and having a major impact on ongoing global warming. By utilizing CO₂ it is possible to mitigate CO₂ emissions and produce new sustainable fuels. This study included characterization of the prepared palladium (Pd) and platinum (Pt) decorated catalysts and testing their photocatalytic properties in carbon monoxide (CO) oxidation and CO₂ activation reactions under visible light and under irradiation of specific wavelength. In addition to different irradiation also different feed gas combinations were tested in both reactions. Characterization of prepared materials was done with XRD to study the crystalline structure and composition, BET-BJH to get information about the surface area and pore sizes, and TEM for surface structure analyses and distribution of metal decoration. Photocatalytic activity was studied with FT-IR DRIFT analyses with external solar light source and equipped with filters to control the wavelength of irradiation. The results of the characterization showed that preparation of the catalysts was successful. Photocatalytic activity results showed that some of the tested materials are able to oxidise CO and activate CO₂ in the presence of irradiation. Obtained results show that palladium and platinum decorated TiO₂ based materials could possibly be used in surface plasmon enhanced photocatalytic CO₂ reduction successfully Työn tarkoituksena on selvittää hiilidioksidin (CO₂) hyödyntämisen mahdollisuutta valokatalyyttisellä aktivoinnilla ja pelkistämisellä käyttäen pintaplasmonisesti resonoivia jalometalleja sisältäviä titaanidioksidimateriaaleja. Hiilidioksidin tiedetään olevan yksi yleisimmistä kasvihuonekaasuista ja näin ollen sillä on suuri vaikutus meneillään olevaan ilmaston lämpenemiseen. Hyödyntämällä hiilidioksidia on mahdollista vähentää hiilidioksidipäästöjä ja kehittää uusia kestäviä polttoaineita. Tämä tutkimus sisältää valmistettujen platina- ja palladium-titaanidioksidi-katalyyttien karakterisointia ja niiden valokatalyyttisten ominaisuuksien tutkimista hiilimonoksidin (CO) hapettamisessa ja hiilidioksidin (CO₂) aktivoinnissa näkyvällä valolla ja valituilla valon aallonpituuksilla. Käytettyjen säteilyalueiden lisäksi myös erilaisia syöttökaasun yhdistelmiä tutkittiin molemmissa reaktioissa. Valmistettujen katalyyttien karakterisoinnit tehtiin XRD:llä, jolla saatiin tietoa materiaalien kiderakenteesta ja koostumuksesta, BET/BJH-menetelmällä jolla määritettiin pinta-alat ja huokostilavuudet sekä TEM mikroskopialla, jolla tarkasteltiin pinnan rakenteita ja metallin jakautumista katalyytin pintaan. Valokatalyyttistä aktiivisuutta tutkittiin DRIFT-mittauksin, joissa käytettiin ulkoista valonlähdettä ja erillisiä valosuodattimia, jotta eri aallonpituuksien vaikutusta reaktioon voitiin tutkia tarkemmin. Karakterisointien tulokset osoittivat materiaalien valmistuksen olleen onnistunut. Valokatalyyttisten aktiivisuuskokeiden tutkimustuloksista saatiin selville, että osa palladiumia tai platinaa sisältävistä titaanidioksidimateriaaleista kykeni hapettamaan hiilimonoksidia sekä aktivoimaan hiilidioksidia valosäteilyn avulla. Saadut tutkimustulokset osoittavat, että TiO₂ pohjaisia katalyyttejä platina- ja palladiumlisäyksillä voidaan mahdollisesti käyttää pintaplasmonisella värähtelyllä tehostetussa valokatalyysissä hiilidioksidin pelkistämiseksi

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45

"Pixel-referencing phase-sensitive surface plasmon resonance imaging sensor." 2011. http://library.cuhk.edu.hk/record=b5894708.

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Yu, Tsz Tat. "December 2010." Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. Includes bibliographical references (leaves 143-147). Abstracts in English and Chinese. Abstract --- p.2 摘要 --- p.4 Acknowledgements --- p.5 List of Figures --- p.6 List of Tables --- p.12 List of Abbreviations --- p.13 Table of Contents --- p.14 Chapter Chapter 1 --- Introduction --- p.17 Chapter Chapter 2 --- Literature Review Chapter 2.1 --- Surface Plasmon Wave --- p.19 Chapter 2.2 --- Excitation of Surface Plasmon --- p.23 Chapter 2.3 --- Surface Plasmon Coupling --- p.24 Chapter 2.4 --- Surface Plasmon Resonance Detection Techniques --- p.33 Chapter 2.5 --- Applications of SPR biosensors --- p.39 Chapter Chapter 3 --- Theory of irradiance modulator Chapter 3.1 --- Polarization --- p.44 Chapter 3.2 --- Optical polarizer --- p.45 Chapter 3.3 --- Liquid Crystal Modulator --- p.49 Chapter 3.4 --- Irradiance Modulator --- p.52 Chapter Chapter 4 --- LCM characterization Chapter 4.1 --- Single LCM Transmittance driven by pure square wave --- p.66 Chapter 4.2 --- Single LCM Reflectance driven by 50:50 STAM wave --- p.70 Chapter 4.3 --- Multiple LCMs Reflectance driven by 90:10 STAM wave --- p.73 Chapter Chapter 5 --- Background of phase measurement Chapter 5.1 --- From holography to shearography --- p.77 Chapter 5.2 --- From static Mach-Zehnder interferometer to differential-phase Mach-ZehnderZ interferometer --- p.81 Chapter 5.3 --- From differential-phase imaging to pixel-referencing imaging --- p.86 Chapter Chapter 6 --- Pixel-referencing data processing Chapter 6.1 --- Background --- p.89 Chapter 6.2 --- Procedures --- p.94 Chapter 6.3 --- Experimental results --- p.98 Chapter 6.4 --- Sensor resolution --- p.116 Chapter 6.5 --- Performance comparison between single-beam LCM and Mach Zehnder configuration --- p.119 Chapter Chapter 7 --- Discussions Chapter 7.1 --- Experiment precautions --- p.136 Chapter 7.2 --- Linear curve fitting --- p.137 Chapter 7.3 --- Hardware limitation: Low frame rate --- p.138 Chapter 7.4 --- Matching oil and glass slide --- p.139 Chapter Chapter 8. --- Conclusions --- p.141 References --- p.143 Appendix Chapter A1 --- "Concentration, Refractive Index and Dielectric constant of Sodium Chloride Solution (20°C)" --- p.148 Chapter A2 --- Liquid Crystal Modulator Specification --- p.149 Chapter A3 --- "Digital-to-analogue Converter Device (NI, PCI6036E) Datasheet" --- p.150 Chapter A4 --- "CCD Camera (Lumenera, Infinity) Datasheet" --- p.151 Chapter A5 --- Flow chart of SPR phase extraction --- p.152 Chapter A6 --- Codes of SPR phase extraction in modules --- p.153

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46

Chen, Chi-Xian, and 陳祈先. "Investigation of Phase-Shift Interferometry Surface Plasmon Resonance Imaging System." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/wnv4z2.

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碩士 國立虎尾科技大學 光電與材料科技研究所 100 The study is to conduct the phase response of the sensitivity of SPR. The researcher used nanoimprint lithography to imprint a grating and plated AU by Thermal Evaporation on the top of the grating to make a grating-coupled SPR. A cylindrical lens in an optical path can help the incident light to focus and to produce multiple incident angles. At the same plane, it can get the luminous intensity of the reflected light in different incident angle to become the intensity of the SPR image system. To detect phase changes, the researcher used a phase-shift method, LCD, and a LCD controller to make polarization produce certain phase differential, which can automatically capture the images with Labview, a webcam, and a computer. First, the researcher used Labview to call a dynamic link library and connected a webcam to capture five interference images. Then, with the image process, the researcher used a self-designed med-filter and a curve fitting to lower noise; then, made an algorithm to get a phase response diagram, by analyzing the five images.

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47

ERMINI, MARIA LAURA. "Surface plasmon resonance imaging for the detection of single nucleotide polymorphisms." Doctoral thesis, 2013. http://hdl.handle.net/2158/794372.

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The application of the surface plasmon resonance imaging biosensor was studied for the determination of single nucleotide polymorphisms with the ultimate goal of developing a system applicable for molecular diagnostics, directly on clinical samples, such as blood. The influence of nanoparticles on SPRi system has been studied with the aim of improving the sensitivity.

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48

Li, Yuan. "Surface enzymatic reactions for ultrasensitive surface plasmon resonance imaging with DNA and RNA microarrays." 2006. http://www.library.wisc.edu/databases/connect/dissertations.html.

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49

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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50

Reiter, Kyle. "Analysis of Enzymatic Degradation of Cellulose Microfibrils by Quantitative Surface Plasmon Resonance Imaging." Thesis, 2012. http://hdl.handle.net/10214/4895.

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Cellulose is the most plentiful biopolymer on the planet, and as such, is a large potential energy source. Converting cellulose into ethanol first requires the disruption of the crystallinity of cellulose fibers and subsequent hydrolysis into glucose. The glucose can then be fermented, producing ethanol. The conversion of cellulose fibers to glucose is an energy intensive and costly step, which is a barrier to industrial production of cellulosic ethanol. The use of enzymes to facilitate this conversion is a promising approach. In the present study, the action of individual enzymes and combinations of enzymes from the Hypocrea jecorina secretome on bacterial cellulose fibers has been studied, to better understand their individual and synergistic action. I have used a custom Surface Plasmon Resonance imaging (SPRi) device to measure changes in the thickness of cellulose fiber coverage of a thioglucose-functionalized gold substrate upon exposure to enzymes. The cellulose fibers were deposited using a Langmuir-Blodgett technique, resulting in non-uniform cellulose coverage of the substrate. By defining local Regions of Interest (ROIs) of the cellulose-covered gold film, and by measuring the SPR curves at elevated temperature for the ROIs as a function of time, we are able to determine the rate and extent of degradation of the cellulose fibers within individual ROIs. We have fit the change in SPR angle over time after exposure to enzyme to an exponential decay function that allows us to determine the average time constant of action of these enzymes on the deposited cellulose fibers. We have used the above procedure to measure the average time constants of action and the average degradation fraction (the change in average thickness divided by the initial average thickness) of cellulose fibers exposed to CBH-1, CBH-2, and EG-1, as well as combinations of these enzymes. We have measured an increase in the average degradation fraction and a decrease in the average time constants of action for cellulose fibers exposed to 23 μg/mL CBH-2 compared to fibers exposed to the same concentration of CBH-1. Additionally, for concurrent exposure of CBH-1 and EG-1 (with individual concentrations of 23 μg/mL), as well as concurrent introduction of CBH-1, CBH-2 and EG-1, we observed increases in the average degradation fraction and decreases in average time constants relative to the values measured for the individual enzymes. These measurements allow us to determine the relative activity of these enzymes and they demonstrate cooperativity and complementarity of action of the different enzymes.

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