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Showing papers on "Surface plasmon resonance published in 1996"


Journal ArticleDOI
TL;DR: Surface plasmon resonance studies showed that His-tagged proteins adsorbed on the NTA-SAM retained a greater ability to participate in binding interactions with proteins in solution than protein immobilized in a thin dextran gel layer by covalent coupling.
Abstract: This paper reports the generation of a self-assembled monolayer (SAM) that selectively binds proteins whose primary sequence terminates with a His-tag: a stretch of six histidines commonly incorporated in recombinant proteins to simplify purification. The SAM was prepared by the adsorption onto a gold surface of a mixture of two alkanethiols: one thiol that terminated with a nitrilotriacetic acid (NTA) group, a group that forms a tetravalent chelate with Ni(II), and a second thiol that terminated with a tri(ethylene glycol) group, a group that resists protein adsorption. His-tagged proteins bound to the SAM by interaction of the histidines with the two vacant sites on Ni(II) ions chelated to the surface NTA groups. Studies with model proteins showed the binding was specific for His-tagged proteins and required the presence of Ni(II) on the surface. Immobilized His-tagged proteins were kinetically stable in buffered saline at pH 7.2 but could be desorbed by treatment with 200 mM imidazole. Surface plasmo...

597 citations


Journal ArticleDOI
02 Oct 1996-Langmuir
TL;DR: Using surface plasmon resonance (SPR) spectroscopy in the Kretschmann configuration, this paper followed the self-assembly of organic ultrathin films which resulted from exposure of gold surfaces to solutions of CH3(CH2)n-1SH (n = 8, 12, 16, and 18) in ethanol and heptane.
Abstract: Using surface plasmon resonance (SPR) spectroscopy in the Kretschmann configuration, we followed the self-assembly of organic ultrathin films which resulted from exposure of gold surfaces to solutions of CH3(CH2)n-1SH (n = 8, 12, 16, and 18) in ethanol and heptane We monitored film growth in situ and continuously for up to 72 h with an overall thickness resolution of <1 A Film dielectric constants, necessary for accurately calculating average film thicknesses from SPR spectra, were determined unambiguously for fully formed films by comparing spectra from organic films in different solvents In addition, we introduce a novel two-color SPR experiment with which we can obtain both film thickness and film dielectric constant without changing solvents We studied the chain length dependent and concentration dependent kinetics of film formation in ethanol and found that there are at least three distinct kinetics steps The kinetics of the first, most rapid, step and the third, slowest, step can be described w

443 citations


Journal ArticleDOI
TL;DR: Real time biospecific interaction analysis (surface plasmon resonance, SPR) shows that cholera toxin preferably binds to gangliosides in the following sequence: GM1 > GM2 > GD1A > GM3 > GT1B • GD1B > asialo-GM1.
Abstract: The present study determines the affinity of cholera toxin for the ganglioside series GM1, GM2, GM3, GD1A, GD1B, GT1B, asialo GM1, globotriosyl ceramide, and lactosyl ceramide using real time biospecific interaction analysis (surface plasmon resonance, SPR). SPR shows that cholera toxin preferably binds to gangliosides in the following sequence: GM1 > GM2 > GD1A > GM3 > GT1B > GD1B > asialo-GM1. The measured binding affinity of cholera toxin for the ganglioside sequence ranges from 4.61 x 10-12 M for GM1 to 1.88 x 10-10 M for asialo GM1. The picomolar values obtained by surface plasmon resonance are similar to Kd values determined with whole-cell binding assays. Both whole-cell assays and SPR measurements on synthetic membranes are higher than free solution measurements by several orders of magnitude. This difference may be caused by the effects of avidity and charged lipid head-groups, which may play a major role in the binding between cholera toxin, the receptor, and the membrane surface. The primary difference between free solution binding studies and surface plasmon resonance studies is that the latter technique is performed on surfaces resembling the cell membrane. Surface plasmon resonance has the further advantage of measuring apparent kinetic association and dissociation rates in real time, providing direct information about binding events at the membrane surface.

340 citations


Journal ArticleDOI
TL;DR: In this article, a surface plasmon resonance sensing technique based on optical heterodyne phase detection is presented, and the theoretical sensitivity of this new method is compared with traditioal surface PLASM resonance technique.
Abstract: A surface plasmon resonance sensing technique based on optical heterodyne phase detection is presented. The theoretical sensitivity of this new method is compared with traditioal surface plasmon resonance technique. The results of phase detection modeling shows a strong dependence on sensor film thickness. With a practical configuration, the resolution of refractive index is predicted to be 5 × 10 −7 refractive index units. An experimental set-up is described and the initial results presented conincide with the theoretical prediction.

281 citations


Journal ArticleDOI
TL;DR: In this article, a fully integrated surface plasmon resonance transducer is described, which is based on the encapsulation of the required electro-optical components within the optical material, through a molding process.
Abstract: A novel, fully integrated surface plasmon resonance (SPR) transducer is described which is based on the encapsulation of the required electro-optical components within the optical material, through a molding process. Prototype sensors based on this approach have been successfully fabricated and tested. Results are shown for sensing of refractive index variations in alcohol solutions. Additionally, the SPR transducer is shown to function as a biological sensor.

229 citations


Journal ArticleDOI
TL;DR: In this paper, surface modification on the Ag plasmon resonance was studied in both colloidal suspensions and colloidal metal films and the conclusion was made that adsorption of I- and Br- ions results in charging of the Ag particle as a whole and a shift of its potential to more negative values.
Abstract: Silver colloids of 20 nm mean particle diameter were prepared by laser ablation and modified by adsorption of iodide and bromide ions. Addition of cytochrome c to this colloid resulted in the reduction of the protein, which was monitored by surface-enhanced resonance Raman scattering and absorption spectroscopies. Colloidal metal films, prepared from the same Ag colloid, were employed to minimize contributions from aggregation. Effects of surface modification on the Ag plasmon resonance were studied in both colloidal suspensions and colloidal metal films. The conclusion was made that adsorption of I- and Br- results in charging of the Ag particle as a whole and a shift of its potential to more negative values. The donated charge is delocalized in a thin surface layer and does not significantly affect the plasmon resonance frequency of the particle.

208 citations


Journal ArticleDOI
TL;DR: In this article, the use of surface plasmons on planar surfaces for the characterisation of those surfaces is analysed, and analytic expressions for the sensitivity of such characterisation to the variation of bulk refractive indices, and to the addition of thin dielectric layers on the plasmon supporting surface.

166 citations


Journal ArticleDOI
TL;DR: In this paper, a new fiber optic sensor for the detection of refractive index variations is presented based on the generation of surface plasma waves at the interface between a thin metallic layer deposited on the fibre core and a surrounding dielectric medium.
Abstract: A new fibre optic sensor for the detection of refractive index variations is presented. The principle of the sensor is based on the generation of surface plasma waves at the interface between a thin metallic layer deposited on the fibre core and a surrounding dielectric medium. Specific injection of monochromatic light into the fibre allows the detection of a refractive index variation as low as for dielectric media lying in the 1.33 - 1.40 refractive index range. Modelling of sensing signal and experiments are performed. Potential applications are aqueous solution analyses and detection of gases and solvents with a specific polymeric layer.

152 citations


Journal ArticleDOI
TL;DR: In this paper, a real-time, in situ non-perturbative all-optical approach for determining both the average thickness and the average dielectric constant of transparent thin films using surface plasmon resonance spectroscopy was proposed.

144 citations


Journal ArticleDOI
TL;DR: The kinetics of ligand binding by Se155-4, an antibody specific for the Salmonella serogroup B O-polysaccharide, were studied by surface plasmon resonance and indicated that the relatively low affinity of the antibody was due to rapid dissociation.

143 citations


Patent
06 Sep 1996
TL;DR: In this paper, a surface plasmon resonance-mass spectrometer system is proposed for the rapid, sensitive and accurate investigation of molecular interactions coupled with the identification and quantification of the same.
Abstract: The invention provides surface plasmon resonance-mass spectrometry for the rapid, sensitive and accurate investigation of molecular interactions coupled with the identification and quantification of the same. Methods of the invention include capturing an analyte present within a sample by an interactive surface layer on a real-time interaction analysis sensor, analyzing the analyte by surface plasmon resonance while the analyte is captured by the interactive surface layer, and identifying the captured analyte by desorbing/ionizing the analyte from the interactive surface layer while under vacuum within a mass spectrometer. Devices of the invention include a transparent material, a conductive material capable of supporting surface plasmon resonance affixed to the transparent material, an interactive surface affixed to the conductive material, and a means for exposing the interactive surface to the interior of a mass spectrometer without breaking the vacuum therein.

Journal ArticleDOI
TL;DR: It is found that, within a certain range of size, a hill on an otherwise flat surface can be a source of a micrometer wide plasmon beam, and the effective cross section of a defect can be substantially larger than its visible geometrical size.
Abstract: A new technique for direct-write ablation on a 100 nm scale has been implemented in a photon scanning tunneling microscope setup. This combination allows us, for the first time, to study surface plasmon scattering by in situ created individual surface defects, while the sizes and shapes of the defects are varied. It is found that, within a certain range of size, a hill on an otherwise flat surface can be a source of a micrometer wide plasmon beam. Another new observation is that the effective cross section of a defect can be substantially larger than its visible geometrical size. These results suggest possible practical applications of surface plasmons in two-dimensional optical arrangements.

Journal ArticleDOI
TL;DR: Cheskis et al. as discussed by the authors used surface plasmon resonance (SPR) to characterize the kinetics of both protein−protein and protein−DNA interactions by VDR and RXR in the presence and absence of their cognate ligands.
Abstract: Many nuclear hormone receptors, including the human 1,25-dihydroxyvitamin D3 receptor (VDR), bind cooperatively to DNA as either homodimers or heterodimers with the 9-cis-retinoic acid receptor (RXR). Protein−protein interactions mediated by residues within both the DNA- and ligand-binding domains contribute to this binding. We have previously reported that the ligands for VDR and RXR can modulate the affinity of the receptors' interaction with DNA [Cheskis, B., & Freedman, L. P. (1994) Mol. Cell. Biol. 14, 3329−3338]. To examine this in more detail, we report here the use of surface plasmon resonance (SPR) to characterize the kinetics of both protein−protein and protein−DNA interactions by VDR and RXR in the presence and absence of their cognate ligands. We find that 1,25 dihydroxyvitamin D3 binding favors both VDR−RXR heterodimerization and, as a result, DNA binding by the complex. Conversely, the ligand reduces VDR homodimerization in solution and the affinity of VDR−DNA interaction. 9-cis-Retinoic aci...

Journal ArticleDOI
15 Mar 1996-Virology
TL;DR: A sensitive microscale binding assay is developed to study the interaction between influenza hemagglutinin and its cell surface receptor sialic acid using real-time surface plasmon resonance to quantitate the tight binding achieved through the multivalent interaction between BHA rosettes and the fetuin-derivitized sensor surface.

Journal ArticleDOI
TL;DR: A technique that utilizes surface-plasmon resonance to intensify the fluorescence produced by multiphoton excitation by enhancing the electric field initially generated by the excitation laser light is demonstrated.
Abstract: We demonstrate a technique that utilizes surface-plasmon resonance to intensify the fluorescence produced by multiphoton excitation. By enhancing the electric field initially generated by the excitation laser light, the presence of plasmon resonance introduces a gain 90 times higher in the experimentally observed fluorescence intensity than that produced from total internal reflection fluorescence. We also analyze the enhancement efficacy of surface-plasmon resonance as a function of the excitation wavelength.

Journal ArticleDOI
TL;DR: A review of the state-of-the-art of ion-implanted glasses can be found in this paper from the perspective of the nonlinear optical properties of ionimplants.
Abstract: Implantation of metal ions (e.g., silver, copper, gold, lead) in glass substrates leads under certain circumstances to the formation of nanometer-radius colloidal particles in a thin surface layer. These particles exhibit an electron plasmon resonance which depends on the optical constants of the implanted metal and on the refractive index of the glass host. The nonlinear optical properties of such colloids, in particular the enhancement of optical Kerr susceptibility by both dielectric and quantum-confinement effects, suggest that the ion implantation technique may play an important role for the production of all-optical switching devices. A review of the state-of-the-art of the research in this field will be presented from the perspective of the nonlinear optical properties of ion-implanted glasses.

Journal ArticleDOI
TL;DR: Real-time optical biosensors based on surface plasmon resonance (SPR) are greatly facilitating the biochemical analysis of the molecular interactions that mediate cell adhesion, but researchers have discovered the potential pitfalls of SPR, which can lead to inaccurate affinity and kinetic measurements.

Journal ArticleDOI
TL;DR: Addition of free antigen induced the desorption of bound antibodies and allowed accurate measurements of the dissociation rate constant, which can be explained if the accessibility of the antigenic epitopes depends on the peptide density.

Journal ArticleDOI
TL;DR: Gold surfaces coated with monolayers of alkyl thiols are significant in the field of biosensors and chromatography and there is a general concern about the quality of coatings in terms of surface densities as mentioned in this paper.
Abstract: Gold surfaces coated with monolayers of alkyl thiols are significant in the field of biosensors and chromatography. There is a general concern about the quality of coatings in terms of surface dens...

Journal ArticleDOI
TL;DR: In this paper, a blue shift and sharpening of the peak corresponding to the plasmon resonance was observed as the distance between particles decreased to a value comparable to, or less than, their diameter.
Abstract: Two-dimensional arrays of 1000 A silver particles were prepared by adsorption from colloidal suspensions onto glass slides derivatized with (3-mercaptopropyl)trimethoxysilane. By variation of the concentration of the colloidal suspensions, slides with different interparticle distances were obtained, and their extinction spectra were measured in water. A blue shift (up to 90 nm) and sharpening of the peak corresponding to the plasmon resonance was observed as the distance between particles decreased to a value comparable to, or less than, their diameter. The angular dependence of the extinction spectra was studied for s- and p-polarized light. The data are interpreted to result from coherent coupling of the plasmon resonances in closely spaced silver particles upon irradiation with light.

Journal ArticleDOI
TL;DR: The surface plasmon resonance (SPR) technique was used to study the formation kinetics of a de novo designed coiled-coil (E/K coil) and the preference for heterodimer formation is due to a combination of moderately fast association and slow dissociation rates.
Abstract: The surface plasmon resonance (SPR) technique was used to study the formation kinetics of a de novo designed coiled-coil (E/K coil). The E/K coil is made up of two distinct peptides (E and K) each with five heptad (g-a-b-c-d-e-f) repeats. The E peptide's heptad sequence is E-V-S-A-L-E-K, and the K peptide's heptad sequence is K-V-S-A-L-K-E. A linker C-nL-G-G-G (nL = norleucine) is present at the C-terminus of the E peptide and at the N-terminus of the K peptide for the SPR studies. Heterodimer formation involves both electrostatic and hydrophobic interactions at the dimer interface. Under conditions that favor the heterodimer formation, the CD signal ([theta]222) varied as a function of peptide concentration. The estimated dissociation constant (Kd) was 2.45 +/- 0.71 nM. Denaturation studies with guanidine-HCI (GdnHC11/2 = 3.9 M) suggested a value of 3.53 +/- 0.48 nM. For the SPR investigation, the peptides were biotinylated and linked to streptavidin in order to increase their effective molecular weight and consequently enhance the signal intensity. Biotinylation in itself did not impede coiled-coil formation based on CD measurements. The biosensor study revealed a slow dissociation rate constant for the heterodimer (kd approximately 2 x 10(-4) s-1) and a moderately fast association rate constant [ka approximately (4.27-4.53) x 10(5) M-1 s-1). This gives a calculated Kd of 0.47-0.50 nM, which agrees reasonably well with the equilibrium CD studies. Therefore, based on the SPR data, the preference for heterodimer formation is due to a combination of moderately fast association and slow dissociation rates.

Journal ArticleDOI
TL;DR: In this paper, an optical fiber sensor based on resonant coupling between a mode of a monomode optical fiber and a surface plasmon is presented. But it is not shown that very small changes in the refractive index of the sensed medium can be determined.
Abstract: An optical fibre sensor based on resonant coupling between a mode of a monomode optical fibre and a surface plasmon is reported. It is demonstrated that, by measuring the optical power transmitted through the sensing element, very small changes in the refractive index of the sensed medium can be determined.

Journal ArticleDOI
TL;DR: The ability of SPR spectroscopy to monitor interactions among the proteins associated with signal transduction in membrane-bound systems is demonstrated.

Journal ArticleDOI
TL;DR: A rapid direct assay for polymerase-induced elongation along a given template is an obligate requirement for understanding the processivity of polymerization and the mode of action of drugs and inhibitors on this process.
Abstract: A rapid direct assay for polymerase-induced elongation along a given template is an obligate requirement for understanding the processivity of polymerization and the mode of action of drugs and inhibitors on this process. Surface plasmon resonance can be used to follow the association and the dissociation rates of a given reverse transcriptase on DNA.RNA and DNA.DNA hybrids immobilized on a biotin-streptavidin surface. The addition of nucleotides complementary to the template strand produces an increase in the local mass, as deduced from an increase in the measured signal, due to elongation of the primer strand that allows an estimation of both the extent and rate of the polymerization process. The terminator drug 3'-deoxy-3'-azidothymidine triphosphate completely abolishes the increase in signal as would be expected from an inhibition of elongation. This technique provides a sensitive assay for the affinities of different polymerases for specific templates and for the effects of terminators of the elongation process.

Journal ArticleDOI
TL;DR: It is concluded that the flow chamber technology can be an useful complement to atomic force microscopy for studying interactions between isolated biomolecules, with a resolution of about 20 ms and sensitivity of a few piconewtons.
Abstract: We studied single molecular interactions between surface-attached rat CD2, a T-lymphocyte adhesion receptor, and CD48, a CD2 ligand found on antigen-presenting cells. Spherical particles were coated with decreasing densities of CD48–CD4 chimeric molecules then driven along CD2-derivatized glass surfaces under a low hydrodynamic shear rate. Particles exhibited multiple arrests of varying duration. By analyzing the dependence of arrest frequency and duration on the surface density of CD48 sites, it was concluded that (i) arrests were generated by single molecular bonds and (ii) the initial bond dissociation rate was about 7.8 s−1. The force exerted on bonds was increased from about 11 to 22 pN; the detachment rate exhibited a twofold increase. These results agree with and extend studies on the CD2–CD48 interaction by surface plasmon resonance technology, which yielded an affinity constant of ≈104 M−1 and a dissociation rate of ≥6 s−1. It is concluded that the flow chamber technology can be an useful complement to atomic force microscopy for studying interactions between isolated biomolecules, with a resolution of about 20 ms and sensitivity of a few piconewtons. Further, this technology might be extended to actual cells.

Patent
25 Oct 1996
TL;DR: In this paper, a surface plasmon resonance (SPR) sensor and a chemical electrode sensor are used to detect redox-active analytes in aqueous solutions.
Abstract: This disclosure describes new methods and devices for sensing redox-active analytes in solution The invention combines a surface plasmon resonance (SPR) sensor and a chemical electrode sensor A conducting layer which supports SPR is attached to a voltage source The voltage source is also connected to a reference electrode, which is in the aqueous solution with the SPR sensor As the voltage is varied, the analytes undergo oxidation and reduction at the surface of the conducting film The current is measured, just as it would be in a standard chemical electrode, with current peaks appearing at different potentials indicating different ions in the solution Unlike a standard chemical electrode, the surface of the conducting film is also used to excite a surface plasmon wave (SPW) The SPW provides new information which is not available from any standard chemical electrode, such as the effective index of refraction at the surface of the conducting film as the analytes are being oxidized and/or reduced This additional source of information can be used to minimize the effects of overlapping stripping peaks and interspecies compound formation as well as determine the thickness of surface layers during measurements Additionally, the simultaneous determination of reaction properties and optical properties of reaction products can provide additional information about the aqueous support solution such as the quantity and types of natural oxidants in solution, such as oxygen or hydroxides The formation of oxides and hydroxides will lead to measurably different optical properties

Journal ArticleDOI
TL;DR: In this paper, a humidity sensor was fabricated by coating a surface plasmon waveguide with a thin layer of Nafion fluoropolymer, which is able to measure relative humidity over a range of at least 20% to 50%, while exhibiting good linearity.
Abstract: A humidity sensor has been fabricated by coating a surface plasmon waveguide with a thin layer of Nafion fluoropolymer. The refractive index of Nafion varies as a function of humidity, causing a shift in the plasmon resonance wavelength. The present device is able to measure relative humidity over a range of at least 20% to 50%, while exhibiting good linearity. Furthermore, humidity-induced index changes to Nafion occur rapidly and appear to be fully reversible.

Journal ArticleDOI
TL;DR: In this paper, an approach to the read-out problem of the shift of surface plasmon resonance (SPR) dip and an experimental arrangement for its realization are considered.
Abstract: An approach to the read-out problem of the shift of surface plasmon resonance (SPR) dip and an experimental arrangement for its realization are considered. The principle of the proposed registration method is based on the measurement of the ratio of the p- and s-polarized components in reflected light, giving a sensitive enhancement of up to two orders of magnitude. The described set-up can be employed to monitor biospecific interactions, producing refractive-index changes near the detection limit of the SPR technique using only p-polarized light.

Journal ArticleDOI
TL;DR: In this article, a simple and inexpensive refractive-index sensor is described, which is based on surface plasmon excitation at the metal/dielectric interface, using monochromatic incident light.
Abstract: A simple and inexpensive refractive-index sensor is described. The transducer is a multimode optical fibre which has been metallized with gold on the sensing area. The principle of this sensor is based on surface plasmon excitation at the metal/dielectric interface. This set-up, which uses monochromatic incident light, can work as an optical-fibre refractometer or as a refractive-index-variation optical-fibre sensor, in a range between 1.33 and 1.40. This sensor can detect a refractive-index variation around 10 −4 and can measure a refractive index with an accuracy around 2 × 10 −4 .

Journal ArticleDOI
TL;DR: In this article, a miniaturized fiber optical sensor based on surface plasmon resonance spectroscopy is investigated in view of the detection of organic solvent vapours, particularly tetrachloroethene.
Abstract: A miniaturized fibre optical sensor based on surface plasmon resonance spectroscopy is investigated in view of the detection of organic solvent vapours, particularly tetrachloroethene. Surface plasmons are excited on a silver coated multimode fibre by polychromatic light, and the resonant excitation is detected as a resonant absorption band in the measured output spectrum. When the analyte is absorbed in a thin gas-sensitive polysiloxane film deposited on the silver layer the polymer film changes its thickness and its refractive index. These changes result in a wavelength shift of the resonant curve depending on the analyte gas concentration. Theoretical considerations about the sensing effect are made and resonance curves were computer-simulated. Based on these simulations the layout of all sensor parameters was optimized. The sensor shows an excellent response to tetrachloroethene with a response time of two seconds and high reproducibility. When using self-assembling monolayers on the silver surface a long-term stability of more than 3 months can be obtained. Very low cross sensitivities of less than 1% to other solvent vapours like acetone and ethanol are obtained, furthermore, the influence of humidity is very low. This miniaturized fibre optical sensor in combination with an easy-to-handle and non-sophisticated measuring and evaluation unit is excellently suitable for the remote sensing of special organic solvent vapours.