Showing papers on "Surface plasmon resonance published in 1997"
TL;DR: The use of surface plasmon resonance biosensors to measure the binding affinities and the kinetic constants of reversible interactions between biological macromolecules is reviewed.
Abstract: Surface plasmon resonance biosensors have become increasingly popular for the qualitative and quantitative characterization of the specific binding of a mobile reactant to a binding partner immobilized on the sensor surface. This article reviews the use of this new technique to measure the binding affinities and the kinetic constants of reversible interactions between biological macromolecules. Immobilization techniques, the most commonly employed experimental strategies, and various analytical approaches are summarized. In recent years, several sources of potential artifacts have been identified: immobilization of the binding partner, steric hindrance of binding to adjacent binding sites at the sensor surface, and finite rate of mass transport of the mobile reactant to the sensor surface. Described here is the influence of these artifacts on the measured binding kinetics and equilibria, together with suggested control experiments.
623 citations
TL;DR: Experimental design appears to be the key to successful interaction analysis in terms of identifying conditions where a response related to changes in matrix conformation could be ignored and improving data quality.
571 citations
TL;DR: Advances in experimental design and data analysis methods are making it possible to accurately define the assembly mechanisms and rate constants associated with macromolecular interactions.
542 citations
TL;DR: In this paper, the authors used surface plasmon resonance to measure the affinity and kinetics of CD80 binding to CD28 and CTLA-4, and showed that these low affinities were the result of very fast dissociation rate constants (k(off)).
Abstract: The structurally related T cell surface molecules CD28 and CTLA-4 interact with cell surface ligands CD80 (B7-1) and CD86 (B7-2) on antigen-presenting cells (APC) and modulate T cell antigen recognition. Preliminary reports have suggested that CD80 binds CTLA-4 and CD28 with affinities (Kd values approximately 12 and approximately 200 nM, respectively) that are high when compared with other molecular interactions that contribute to T cell-APC recognition. In the present study, we use surface plasmon resonance to measure the affinity and kinetics of CD80 binding to CD28 and CTLA-4. At 37 degrees C, soluble recombinant CD80 bound to CTLA-4 and CD28 with Kd values of 0.42 and 4 microM, respectively. Kinetic analysis indicated that these low affinities were the result of very fast dissociation rate constants (k(off)); sCD80 dissociated from CD28 and CTLA-4 with k(off) values of > or = 1.6 and > or = 0.43 s-1, respectively. Such rapid binding kinetics have also been reported for the T cell adhesion molecule CD2 and may be necessary to accommodate-dynamic T cell-APC contacts and to facilitate scanning of APC for antigen.
531 citations
TL;DR: In this paper, alternating polyelectrolyte/protein layers were constructed in order to increase the binding layer capacity (i.e. sensitivity) of the thin film with respect to IgG detection.
Abstract: Alternating polyelectrolyte films constructed by the sequential adsorption of poly(allylamine hydrochloride) (PAH) and poly(styrenesulfonate) (PSS) have been used as substrates for the immobilization of immunoglobulin G (IgG) and anti-IgG. Anti-IgG has also been immobilized in multilayer films by the alternate deposition of PSS and anti-IgG. The assembly process of the multilayer films was monitored using a quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). Film growth was achieved up to at least nine (5 anti-IgG and 4 PSS) layers. The utility of these films for immunosensing has been investigated via their subsequent interaction with IgG. The alternating polyelectrolyte/protein layers were constructed in order to increase the binding layer capacity (i.e. sensitivity) of the thin film with respect to IgG detection. The sensitivity, determined using IgG mass uptake data from quartz crystal microgravimetry, was found to be linearly dependent on the number of anti-IgG layers (and hence th...
398 citations
TL;DR: This work investigates the binding of the protein catalase to gold surfaces modified by self-assembled monolayers (SAMs) of 3-mercaptopropanoic acid, 3-MPA, 11-MUA, and a mixture of the two acid thiols.
Abstract: The attachment of biomolecules, in particular proteins, onto solid supports is fundamental in the development of advanced biosensors, bioreactors, affinity chromatographic separation materials, and many diagnostic techniques. In addition, the effective investigation of biomolecular structure and function with scanning probe microscopy often requires a strong attachment of the biomolecule to a substrate. Here, we investigate the binding of the protein catalase to gold surfaces modified by self-assembled monolayers (SAMs). The chemical and physical adsorption of the protein molecules onto SAMs of 3-mercaptopropanoic acid (3-MPA), 11-mercaptoundecanoic acid (11-MUA), and a mixture of the two acid thiols (mixed) was investigated by utilizing tapping mode atomic force microscopy, scanning tunneling microscopy, surface plasmon resonance (SPR), static secondary ion mass spectrometry, and X-ray photoelectron spectroscopy. The surface concentration of catalase adsorbed on the SAMs decreased in the following order:...
378 citations
TL;DR: Theoretical analysis of the sensitivity of surface plasmon resonance (SPR) sensors with spectral interrogation is presented in this article, where two basic configurations of SPR sensors are investigated for the measurement of variations in the refractive index of bulk media, and for the monitoring of variation in the thickness of thin films.
Abstract: Theoretical analysis of the sensitivity of surface plasmon resonance (SPR) sensors with spectral interrogation is presented. Two basic configurations of SPR sensors with spectral interrogation are investigated—for the measurement of variations in the refractive index of bulk media, and for the monitoring of variations in the thickness of thin films. In both cases, analytical expressions allowing the sensitivity of SPR sensors to be calculated are derived and validated. On the basis of the theoretical analysis, the optimization of a spectral SPR sensor in terms of the operation wavelength and the choice of metal layer is carried out. It is demonstrated that spectral SPR sensors may attain higher sensitivity if operating at longer wavelengths and if using metal layers with a higher modulus of the real part of the dielectric constant.
345 citations
TL;DR: In this paper, the electronic dynamics of gold nanocrystals, passivated by a monolayer of alkylthiol(ate) groups, were studied by transient spectroscopy after excitation with subpicosecond laser pulses.
Abstract: The electronic dynamics of gold nanocrystals, passivated by a monolayer of alkylthiol(ate) groups, were studied by transient spectroscopy after excitation with subpicosecond laser pulses. Three solution-phase gold samples with average particle size of 1.9, 2.6, and 3.2 nm with size distribution less than 10% were used. The photoexcitation in the intraband (surface plasmon region) leads to the heating of the conduction electron gas and its subsequent thermalization through electron−electron and electron−phonon interaction. The results are analyzed in terms of the contribution of the equilibrated “hot” electrons to the surface plasmon resonance of gold. A different spectral response was observed for different sizes of gold nanoparticles. The results were compared to the dynamics of the large (30 nm diameter) gold nanocrystals colloidal solution. The size-dependent spectral changes are attributed to the reduction of the density of states for small nanoparticles. The observed variation in the kinetics of the ...
306 citations
TL;DR: The subsequent attachment of streptavidin to the biotinylated complements provides a method of enhancing the SPR imaging signal produced as a result of the Hybridization and leads to a 4-fold improvement in the hybridization detection limit of the SPR Imaging apparatus.
Abstract: A combination of scanning and imaging surface plasmon resonance (SPR) experiments is used to characterize DNA hybridization adsorption at gold surfaces and the subsequent immobilization of streptavidin. Single-stranded oligonucleotides are immobilized at gold surfaces, and the hybridization of biotinylated complements from solution is monitored with SPR. The subsequent attachment of streptavidin to the biotinylated complements provides a method of enhancing the SPR imaging signal produced as a result of the hybridization and leads to a 4-fold improvement in the hybridization detection limit of the SPR imaging apparatus. In situ scanning SPR experiments are used to measure a 60 ± 20% hybridization efficiency between immobilized single-stranded DNA and biotinylated complements. From the information provided by both the in situ imaging and scanning SPR experiments, an absolute surface coverage of immobilized single-stranded DNA is estimated to be ∼3 × 1012 molecules/cm2. The SPR signal resulting from hybridi...
301 citations
TL;DR: In this paper, the surface plasmon damping induced by high excitation of the electron gas is studied in femtosecond pump-and-probe experiments on gold colloids embedded in a sol-gel matrix.
Abstract: The surface plasmon damping induced by high excitation of the electron gas is studied in femtosecond pump-and-probe experiments on gold colloids embedded in a sol-gel matrix. Optical excitation of single-particle interband transitions leads to a pronounced broadening of the surface plasmon line. A similar behavior is observed for resonant excitation of the surface plasmon. This broadening is the dominant optical nonlinearity of the system, and reflects the excitation-induced damping of the surface plasmon resonance. The time evolution of the damping rate follows that of the electronic scattering rate.
282 citations
TL;DR: A new method for constructing oligonucleotide arrays on gold surfaces has been developed, and these arrays have been used in DNA hybridization experiments with in situ surface plasmon resonance (SPR) imaging detection, able to differentiate between single- and double-stranded DNA regions on the gold surface.
Abstract: A new method for constructing oligonucleotide arrays on gold surfaces has been developed, and these arrays have been used in DNA hybridization experiments with in situ surface plasmon resonance (SPR) imaging detection. The detection technique was able to differentiate between single- and double-stranded DNA regions on the gold surface. The hybridization of both oligonucleotides and PCR-amplified DNA fragments was detectable, with the latter exhibiting slower hybridization kinetics. Temperature control of the in situ SPR cell was used to discriminate between perfectly matched duplexes and single-base-mismatched duplexes. The SPR detection technique requires no label on the DNA, but fluorescently labeled targets were also tested and detected by fluorescence imaging as an independent verification of the hybridization behavior of these DNA arrays. The in situ SPR imaging method for detection of DNA hybridization is expected to complement other existing methods for study of DNA interactions and might find futu...
TL;DR: A variant of surface plasmon resonance (SPR) spectroscopy has been developed that combines a greatly enhanced sensitivity and spectral resolution with the ability to directly measure anisotropies in refractive index and optical absorption coefficient in a dielectric film adsorbed onto the surface of the overcoating.
TL;DR: The nonspecific electrostatic adsorption of proteins onto negatively charged self-assembled monolayers (SAMs) of 11-mercaptoundecanoic acid (MUA) is found to depend on the protein pI, solution ionic strength, and solution pH.
Abstract: A combination of in situ and ex situ surface plasmon resonance (SPR) imaging experiments is used to characterize the differential electrostatic adsorption of proteins and synthetic polypeptides onto photopatterned monolayers at gold surfaces. The nonspecific electrostatic adsorption of proteins onto negatively charged self-assembled monolayers (SAMs) of 11-mercaptoundecanoic acid (MUA) is found to depend on the protein pI, solution ionic strength, and solution pH. The pH dependence of the electrostatic adsorption of the protein avidin onto a MUA SAM indicates that a full monolayer adsorbs at a solution pH greater than 5.0, and an “effective pKa” of 3.6 is determined for the avidin adsorption. This effective pKa is a combination of the pKa of the MUA monolayer and the ion pairing adsorption coefficient for the avidin. Additional SPR imaging experiments show that the electrostatic adsorption of the synthetic polypeptide poly-l-lysine (PL) onto a MUA SAM varies with molecular weight, forming a full PL monola...
TL;DR: The adsorption of a range of plasma proteins to metal and polymer surfaces has been examined using surface plasmon resonance (SPR) using a model polystyrene film spun coated directly onto this substrate which confirmed the presence of a closely packed protein layer for all three protein systems.
TL;DR: In this paper, surface plasmon resonance (SPR) was used for real-time analysis of toxin binding under conditions that mimic the natural cell surface venue of these interactions and without any requirement for labeling of toxin or receptor.
TL;DR: Analysis of neomycin B binding with three short synthetic RNA hairpins showed binding with submicromolar affinity and 1:1 stoichiometry in each case, which suggests that neomyin B may generally bind with this affinity to regular A-form RNA or hairpin loops.
Abstract: The specificity of neomycin B and related aminoglycoside antibiotics in their interaction with the Rev responsive element (RRE) of HIV-1 mRNA has been studied by directly observing the aminoglycoside-RNA complexes using surface plasmon resonance. Several different RNA sequences, each with a biotin tag, have been prepared using T7 RNA polymerase-catalyzed transcription of synthetic DNA templates and have been immobilized on a streptavidin-coated surface for the binding study. The results indicate that neomycin B is not specific for the G-rich bubble region in RRE. Rather, it appears to interact with three different sites, each with a submicromolar dissociation constant, within the 67-nucleotide domain II of RRE. Further analysis of neomycin B binding with three short synthetic RNA hairpins showed binding with submicromolar affinity and 1:1 stoichiometry in each case. This suggests that neomycin B may generally bind with this affinity to regular A-form RNA or hairpin loops. The approach described here is generally useful for understanding the fundamental interactions involved in the specific recognition of nucleic acids by small molecules which is the basis of rational drug design.
TL;DR: Improved analytical approaches include the application of global analysis and analytical corrections for the influence of mass transport and improved experimental procedures that allow for a more reliable determination of equilibrium and kinetic constants.
TL;DR: In all cases, ferritin was found to be irreversibly adsorbed to gold and to form a stable protein layer, thus making it well suited as a biological receptor layer for immunosensing applications.
TL;DR: It is demonstrated that minute changes in the refractive index of a medium close to the surface of a metal film can be detected owing to a shift in the resonance angle, and further improvement in sensitivity is possible.
Abstract: The shot noise limitation as well as other factors that influence the sensitivity of measurements with a surface plasmon resonance (SPR) sensor are considered. It is demonstrated that minute changes in the refractive index of a medium close to the surface of a metal film can be detected owing to a shift in the resonance angle. In particular, changes in the adsorption layer of only a fraction of a biomolecular monolayer could be measured. Data for SPRare presented with adjacent media of air, water, as well as aqueous solutions of ethanol and sodium chloride at different concentrations. The immobilization of the protein bovine serum albumin to a specially prepared surface was monitored with the SPR technique. Specific responses to changes in the concentration and thickness of the adsorption layer were determined. The angular resolution of the present apparatus is approximately 1 millidegree, corresponding to a detection limit for an adsorbed protein layer of 15pg/mm2, which is still 2 to 3 orders of magnitude larger than the shot-noise limit, and therefore a further improvement in sensitivity is possible.
TL;DR: In this paper, surface plasmon resonance (SPR) spectroscopy was used to measure the rates and extents of association of four detergentssodium dodecyl sulfate (SDS), β-octyl glucoside, Triton X-100, and Tween 20to self-assembled monolayers (SAMs) of alkanethiolates on gold.
Abstract: This paper describes the use of surface plasmon resonance (SPR) spectroscopy to measure the rates and extents of association of four detergentssodium dodecyl sulfate (SDS), β-octyl glucoside, Triton X-100, and Tween 20to self-assembled monolayers (SAMs) of alkanethiolates on gold. SAMs presenting hexaethylene glycol groups resisted the adsorption of all four detergents. These same detergents associated with hydrophobic SAMs presenting methyl groups; the concentration of detergent molecules on the surface was 120−280 pmol/cm2. The associations of the detergents with the hydrophobic SAM were described well by the Langmuir adsorption isotherm. The dissociation constants Kd (M) for the desorption of the detergents from the surface correlated with the critical micelle concentration (cmc, M) of the detergents in solution, and followed the relationship cmc ≈ 7 (±2)Kd. The efficacy of SDS in removing the protein fibrinogen adsorbed on a hydrophobic SAM depended strongly on the concentration of detergent. SDS at a...
TL;DR: The combined assay demonstrates the use of SPR-BIA to evaluate the relative stability of sequential solution-phase interactions, as well as, upon MALDI-TOF analysis, the ability to unambiguously confirm the presence of species retained during the interaction analysis.
Abstract: The use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) in concert with surface plasmon resonance-based biomolecular interaction analysis (SPR-BIA) is reported. A chip-based biosensor unit was used to simultaneously monitor biomolecular interactions taking place on four different regions of the sensor chip (flow cells). Species retained during SPR-BIA were then identified by performing MALDI-TOF directly from within the area of the flow cells. Analyses were performed on an antibody/antigen/antibody system with detection limits in the low-femtomole range. The combined assay demonstrates the use of SPR-BIA to evaluate the relative stability of sequential solution-phase interactions, as well as, upon MALDI-TOF analysis, the ability to unambiguously confirm the presence of species retained during the interaction analysis.
TL;DR: In this paper, a direct write ablation technique has been implemented in a photon scanning tunneling microscope setup, which allows us to study surface-plasmon (SP) scattering by in situ created individual surface defects, while the sizes and shapes of the defects are varied continuously.
Abstract: A direct-write ablation technique has been implemented in a photon scanning tunneling microscope setup. This combination allows us to study surface-plasmon (SP) scattering by in situ created individual surface defects, while the sizes and shapes of the defects are varied continuously. It is found that within a certain range of its size, a ``hill'' on an otherwise flat surface can be the source of a very narrow plasmon beam. This effect is explained using the Huygens-Fresnel principle. Shadowing and refraction of the SP field by smaller defects has also been observed. In order to explain these results we introduce an effective SP refractive index for two classes of surface defects: shallow topographical defects and areas covered with absorbed molecular layers. This concept allows us to achieve a qualitative understanding of plasmon scattering in many practical cases. Some simple optical elements for the control of SP propagation are suggested and demonstrated. Our observations suggest numerous practical applications in multichannel chemical sensing, biosensing, and integrated optics.
TL;DR: An integrated optical sensor based on the resonant coupling between a surface plasmon wave and a guided mode of an integrated optical waveguide is reported in this paper, where detailed theoretical analysis of the proposed sensor based upon the modal approach and upon the mode expansion and propagation method is presented.
Abstract: An integrated optical sensor based on the resonant coupling between a surface plasmon wave and a guided mode of an integrated optical waveguide is reported. Detailed theoretical analysis of the proposed sensor based upon the modal approach and upon the mode expansion and propagation method is presented. The performance of a realized sample of the waveguide sensor is investigated. It is demonstrated that by measuring the optical power transmitted through the sensing element, variations in the refractive index of the analyte as small as 2×10 −5 may be resolved.
TL;DR: The surface plasmon resonance curves have been shown to be influenced by both NO 2 and H 2 S as discussed by the authors, with lower detection limits of about 50 vapour parts per million at room temperature.
Abstract: The technique of surface plasmon resonance has been used to characterize Langmuir-Blodgett films of polyaniline. The thickness per layer obtained by curve fitting was 5.5 ± 0.6 nm. The surface plasmon resonance curves have been shown to be influenced by both NO 2 and H 2 S. The effects were partly reversible, with lower detection limits of about 50 vapour parts per million at room temperature.
TL;DR: A novel strategy for real-time analysis of oligonucleotide probe hybridization based on detection by surface plasmon resonance that allowed detection of single nucleotide substitutions in a target template, suggesting that procedures for confirmatory DNA sequencing can be envisioned.
TL;DR: Surface plasmon resonance (SPR) detection using the BIAcore biosensing system was employed for the detection of blood group-associated antigens (BGAA) on whole erythrocytes and a quantitative relationship between the cell binding response and ERYthrocyte concentration was confirmed.
TL;DR: In this paper, a novel ethylenediamine plasma-polymerized film matrix was proposed for surface plasmon resonance immunosensing, which was applied on gold surfaces.
Abstract: We propose a novel ethylenediamine plasma-polymerized film matrix that is deposited on gold surfaces for use in surface plasmon resonance immunosensing. The films formed on the gold surfaces are extremely thin (∼100 nm), are homogeneous, demonstrate good adhesion, have a flat profile, and incorporate amino groups to introduce a chemical functionality. A sensor chip made with the film has many advantages when compared with conventionally used designs such as carboxylated dextran hydrogels. For example, a sensor chip made with the film shows a better sensor response than a conventional design partly because antibodies are densely and two-dimensionally immobilized onto the surface of the plasma-polymerized film.
TL;DR: An optical tabletop system based on surface plasmon resonance (SPR) for refractive index determination has been developed to demonstrate the feasibility of a miniaturized and integrated concept which is also described.
Abstract: An optical tabletop system based on surface plasmon resonance (SPR) for refractive-index determination has been developed to demonstrate the feasibility of a miniaturized and integrated concept which is also described. The tabletop system is constructed from the ‘miniaturizable’ components required to realize a manufacturable, integrated minisensor utilizing the SPR phenomenon for transduction. The tabletop system exhibits adequate sensitivity, stability, and reproducibility while maintaining overall system simplicity. The sensor system is excited by a near-infrared light-emitting diode (LED) available in die form, since a laser source is impractical for the miniaturized sensor. The light is optically coupled into a plastic prism because the minisensor optics are readily molded using plastics or epoxy, rather than glass. The angular composition of the diverging reflected radiation is then separated and quantified by a photodiode array (also available in die form) consisting of pixels on a 63 μm pitch. A sputtered gold film is used as the SPR excitation layer. The sensor system performance is qualified using aqueous solutions containing ethylene glycol. The response to changes in concentration of the ethylene glycol is found to be on the order of one part in 10 4 . This translates to a refractive-index change of approximately 10 −5 . The stability of the system response has been investigated by quantifying the response change in water over a two-day period. The stability is excellent when temperature compensation is implemented. The components utilized in the tabletop system are consistent with the development of a low-cost miniature integrated surface plasmon sensor. Such a device has been constructed. A sketch of a minisensor is shown, along with preliminary response data.
TL;DR: A direct immunosensor has been developed using an acoustic wave device as a transducer and it was concluded that the phospholipid bilayer showed a good suppression of nonspecific binding.
Abstract: A direct immunosensor has been developed using an acoustic wave device as a transducer. The device is based on an acoustic waveguide geometry that supports a Love wave. The biorecognition surface, formed on a gold layer, consisted of a biotinylated supported lipid layer which specifically bound streptavidin and, subsequently, biotinylated goat IgG. The modified surface was used as a model immunosensor and successfully detected rabbit anti-goat IgG in the concentration range 3 × 10-8−10-6 M. Using the anti-goat IgG binding isotherm and the time-resolved measurements of antibody binding, both the binding and rate constants of the reaction were determined. The specificity of each binding step was studied with the acoustic wave device, and it was concluded that the phospholipid bilayer showed a good suppression of nonspecific binding. Comparative measurements using surface plasmon resonance allowed the response of the immunosensor to be quantitatively correlated with mass binding to the surface.
TL;DR: In this article, the Mie-Drude equation was interpreted by taking into consideration of a spilling out of electrons from the Au particle to the alumina matrix, and the measured values of χm(3) of the doped films are in the range of 9.2×10−6−4.0×10 −5 esu in the neighborhood of plasmon resonance wavelength of 530-570 nm.
Abstract: The precursor Au-doped alumina gel film was prepared by a sol-gel method using HAuCl4⋅4H2O and alumina sol derived from AlCl3⋅6H2O. The precursor gel was heat treated in a H2 gas flow at 300–800 °C. Average particle diameters of the Au particle of doped films were in the range of 4.6–12.7 nm. In the absorption spectra of the film, plasmon resonance absorption was strongly dependent on the heat treatment temperature of the alumina matrix, showing more sharp spectra and significant red shift with decreasing particle size. It was interpreted by a modified Mie–Drude equation by taking into consideration of a spilling out of electrons from the Au particle to the alumina matrix. The measured values of χm(3) of the doped films are in the range of 9.2×10−6–4.0×10−5 esu in the neighborhood of plasmon resonance wavelength of 530–570 nm. These are larger than those reported for the other doped systems. A dominant nonlinear response on the 1–3 ps time scale was obtained, reflecting higher thermoconductivity of alumin...