Imaging of Surfaces by Concurrent Surface Plasmon Resonance and Surface Plasmon Resonance-Enhanced Fluorescence

Surface plasmon resonance imaging and surface plasmon induced fluorescent are sensitive tools for surface analysis. However, existing instruments in this area have provided limited capability for concurrent detection, and may be large and expensive. We demonstrate a highly cost-effective system capable of concurrent surface plasmon resonance microscopy (SPRM) and surface plasmon resonance-enhanced fluorescence (SPRF) imaging, allowing for simultaneous monitoring of reflectivity and fluorescence from discrete spatial regions. The instrument allows for high performance imaging and quantitative measurements with surface plasmon resonance, and surface plasmon induced fluorescence, with inexpensive off-the-shelf components.     

Photocatalytic Reduction of CO2 into Methanol over Ag/TiO2 Nanocomposites Enhanced by Surface Plasmon Resonance

Ag-loaded TiO₂ (Ag/TiO₂) nanocomposites were prepared by microwave-assisted chemical reduction method using tetrabutyl titanate as the Ti source. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N₂ adsorption–desorption isotherms, UV–vis absorption spectrum, X-ray photoelectron spectrum, photoluminescence spectrum, and Raman scattering spectrum, respectively. Results revealed that Ag nanoparticles (NPs) were successfully deposited on TiO₂ by reduction of Ag⁺, and the visible light absorption and Raman scattering of TiO₂ were enhanced by Ag NPs based on its surface plasmon resonance effect. Besides, Ag NPs could also effectively restrain the recombination of photogenerated electrons and holes with a longer luminescence life time. In addition, photocatalytic reduction of CO₂ with H₂O on the composites was conducted to obtain methanol. Experimental results indicated that Ag-loaded TiO₂ had better photocatalytic activity than pure TiO₂ due to the synergistic effect between UV light excitation and surface plasmon resonance enhancement, and 2.5 % Ag/TiO₂ exhibited the best activity; the corresponding energy efficiency was about 0.5 % and methanol yield was 405.2 μmol/g-cat, which was 9.4 times higher than that of pure TiO₂. Additionally, an excitation enhancement synergistic mechanism was proposed to explain the experimental results of photocatalytic reduction of CO₂ under different reaction conditions.     

Surface Plasmon Resonance Enhanced Faraday Rotation in Fe3O4/Ag Nanoparticles Doped Diamagnetic Glass

Diamagnetic TeO₂-PbO-B₂O₃ glasses were melt-quenching fabricated and characterized for Fe₃O₄/Ag nanoparticles doping through radio-frequency sputtering and thermal treatment techniques. The surface plasmon resonance influenced structure, composition, optical, and magneto optical properties of Fe₃O₄/Ag doped glasses were investigated through XRD, SEM, XPS analysis, and Faraday rotation measurement. The optimized sputtering and thermal conditions Fe₃O₄ and Ag nanoparticles were obtained. Under the optimized conditions, a great enhancement of Faraday rotation, thermal property, and big UV cutoff red-shift due to the excited surface plasma’s resonance effect was achieved in diamagnetic glass.

     

表面等离子体共振技术在分子生物学中的应用

表面等离子体共振(SPR)技术可以实时、原位地测定生物分子间的相互作用而无需任何标记,可以连续监测吸附和解离过程,并可以进行多组分复合物的相互作用的研究。SPR技术在DNA的复制和转录、DNA的修复、核酸与药物的作用以及肽库和抗体库的筛选等分子生物学领域的应用研究取得了令人瞩目的进展,显示了常规技术无法比拟的优越性。     

Graphene-MoS2 Hybrid Structure Enhanced Fiber Optic Surface Plasmon Resonance Sensor

Plasmonics - In this paper, a fiber optic surface plasmon resonance sensor based on graphene-MoS2 hybrid structure is presented. The wavelength interrogation method is employed to analyze the...     

Enhanced Sensitivity of Surface Plasmon Resonance Phase-Interrogation Biosensor by Using Silver Nanoparticles

It is demonstrated that the sensitivity of surface plasmon resonance phase-interrogation biosensor can be enhanced by using silver nanoparticles. Silver nanoparticles were fabricated on silver films by using thermal evaporation. Sizes of silver nanoparticles on silver thin film can be tuned by controlling the deposition parameters of thermal evaporation. By using surface plasmon resonance heterodyne interferometey to measure the phase difference between the p and s polarization of incident light, we have demonstrated that sensitivity of glucose detection down to the order of 10⁻⁸ refractive index units can be obtained.     

SPR技术在免疫学研究中的应用

表面等离子共振(Surface Plasmon Resonance,SPR)技术是研究生物分子相互作用的强有力工具之一,该技术使生物分子之间相互作用的实时检测成为可能,并且灵敏度高、无需标记.通过分析传感图谱及分子相互作用的响应值获取分子相互作用的模式和动力学常数等方面的信息,并且获得的信息是能够定性和定量.SPR技术现在已广泛应用于生物、化学、免疫学研究及新药开发等领域.本文主要就SPR技术在免疫学研究中抗体活性检测、抗原表位预测等方面的应用进行了综述.     

Enhanced Photonic Spin Hall Effect with a Bimetallic Film Surface Plasmon Resonance

Plasmonics - The surface plasmon resonance (SPR) with the bimetallic film can achieve minimum reflectivity and higher evanescent field enhancement than the SPR configuration with the single gold...     

Single-Step Synthesis and Surface Plasmons of Bismuth-Coated Spherical to Hexagonal Silver Nanoparticles in Dichroic Ag:Bismuth Glass Nanocomposites

Here, we report for the first time the synthesis of bismuth-coated silver nanoparticles in dichroic bismuth glass nanocomposites by a novel and simple one-step melt quench technique without using any external reducing agent. The metallic silver nanoparticles (Ag NPs) were generated first, and subsequently, metallic bismuth was deposited on the Ag NPs and formed a thick layer. The reduction of Bi³⁺ to Bi^o and subsequently its deposition on the Ag NPs (which were formed earlier than Bi^o) in the K₂O–Bi₂O₃–B₂O₃ (KBB) glass system have been explained by their standard reduction potentials. The UV–vis absorption spectra show a prominent surface plasmon resonance (SPR) absorption band at 575 nm at lower concentrations (up to 0.01 wt%); three bands at 569, 624 and 780 nm at medium concentration (0.02–0.03 wt%); and two weak bands at 619 and 817 nm at highest concentration (0.06 wt%) of silver. They have been explained by the electrodynamics theories. TEM images reveal the conversion of spheroidal (5–15 nm) to hexagonal (10–35 nm) shaped Ag NPs with the increase in concentration of silver (up to 0.06 wt%). SAED pattern confirms the crystalline planes of rhombohedral bismuth and cubic silver. Thermal treatment at 360 °C, which is the glass transformation temperature (T _g) of the sample containing lower concentration of silver (0.007 wt%), shows red-shifted SPR band due to increase in size of NPs. Whereas the sample containing higher concentration (0.06 wt%) of silver under similar treatment exhibited changes in SPR spectral profile happened due to conversion to spherical NPs from hexagonal shape and reduction in size (10–20 nm) of NPs after heat treatment for 65 h. HRTEM images corroborate the different orientations of the NPs. FESEM images reveal hexagonal disk like structure having different orientations. Dichroic nature of the nanocomposites has been explained with the size and shape of Ag nanoparticles. We believe that this work will create new avenues in the area of nanometal–glass hybrid nanocomposites and the materials have significant applications in the field of optoelectronics and nanophotonics.     

Surface Plasmon Resonance Enhanced the Transverse Magneto-optical Kerr Effect in One-dimensional Magnetoplasmonic Nanostructure

Plasmonics - The properties of the optics and transverse magneto-optical Kerr effect (TMOKE) of one-dimensional magnetoplasmonic nanostructures are experimentally investigated. It shows that the...     

表面等离子体激元共振与生物分子相互作用分析

对表面等离子体激元共振（surface plasmon resonance, SPR）的原理和在生物学研究方面的应用进行了综述.这种技术可以直接原位、实时地跟踪生物学实验研究系统,而不需要附加参数如进行标记等手段,具有高敏感性,也可以连续监测吸附或解吸附过程,目前有关的应用涉及到生物学结合分析、动力学及亲和力测定、免疫识别研究、结构与活性研究和核酸研究等多个领域.     

Metal-Dielectric-Graphene Hybrid Heterostructures with Enhanced Surface Plasmon Resonance Sensitivity Based on Amplitude and Phase Measurements

Metal-dielectric-graphene hybrid heterostructures based on oxides Al₂O₃, HfO₂, and ZrO₂ as well as on complementary metal–oxide–semiconductor compatible dielectric Si₃N₄ covering plasmonic metals Cu and Ag have been fabricated and studied. We show that the characteristics of these heterostructures are important for surface plasmon resonance biosensing (such as minimum reflectivity, sharp phase changes, resonance full width at half minimum and resonance sensitivity to refractive index unit (RIU) changes) can be significantly improved by adding dielectric/graphene layers. We demonstrate maximum plasmon resonance spectral sensitivity of more than 30,000 nm/RIU for Cu/Al₂O₃ (ZrO₂, Si₃N₄), Ag/Si₃N₄ bilayers and Cu/dielectric/graphene three-layers for near-infrared wavelengths. The sensitivities of the fabricated heterostructures were?~?5–8 times higher than those of bare Cu or Ag thin films. We also found that the width of the plasmon resonance reflectivity curves can be reduced by adding dielectric/graphene layers. An unexpected blueshift of the plasmon resonance spectral position was observed after covering noble metals with high-index dielectric/graphene heterostructures. We suggest that the observed blueshift and a large enhancement of surface plasmon resonance sensitivity in metal-dielectric-graphene hybrid heterostructures are produced by stationary surface dipoles which generate a strong electric field concentrated at the very thin top dielectric/graphene layer.

     

基于表面等离子共振的适配体传感器应用研究进展

基于表面等离子共振的适配体传感器是利用适配体进行高特异性、高灵敏度、高通量检测的新型生物传感器。我们在简要阐述适配体的筛选方法、偶联技术及适配体传感器工作原理的基础上,结合最新的研究结果,对基于表面等离子共振的适配体传感器在生物活性小分子检测、传染病检测、肿瘤标志物检测、食品安全监测等方面的应用研究进展进行了综述。     

Plasmon Resonance and Clustering of Silver Nanoclusters Embedded in Glass

Silver nanoclusters growth in AR Schott glass was investigated by transmission electron microscopy (TEM) and optical absorption. The studied samples were Ag–Na ion-exchanged and annealed at ambient air in a furnace. Optical absorption was performed to visualize the size effect on the spectra and compared to the Drude model. TEM was used to evaluate the distribution size of the silver particles so as to confirm the precipitation of the metallic nano-aggregates, to observe their morphological evolution with time, and to correlate it to the absorption curves which makes the interest and the aim of this study. The TEM observations prove that we are in a confinement regime with a particle size below the mean free path of the bulk metal. Growth of the clusters is ascribed first to the diffusion of the silver ions due to annealing and in a second time to an Oswald process.     

Surface Plasmon Resonance Field-Enhanced Fluorescence Properties of Gold Quantum Dots on Polyelectrolyte Multilayers and Their H2O2 Sensor Application

Plasmonics - In this work, we investigate surface plasmon field-enhanced fluorescence (SPF) emission from gold quantum dots (AuQDs) on a polyelectrolyte multilayer ultrathin film deposited onto an...     

Visible-Light Photocatalytic Application of Hierarchical Au-ZnO Flower-Rod Heterostructures via Surface Plasmon Resonance

The semiconductor metal oxide, ZnO, is limited to application in photocatalysis because of large bandgap. Metallic nanostructures are utilized to enhance visible-light absorption and improve photocatalytic activity via surface plasmon resonance (SPR). In this work, through a facile thermal decomposition method, the Au nanoparticles (NPs) were successfully loaded on oriented hierarchical ZnO flower-rod (ZFRs) heterostructures, which have a higher areal proportion of exposed active (001) crystal faces. The results indicate that ZFRs are wurtzite phase grown along the [001] direction and the Au NPs spread on the surface of ZFRs in metallic form. It reveals that there is an electronic interaction between Au NPs and ZFRs, and more oxygen molecules are adsorbed on the surface of Au-ZnO flower-rod heterostructures (AZFRs). The AZFRs show a strong absorbance in visible region due to the SPR and enhance the separation of electron–hole pair, resulting in an improvement of photocatalytic activity under visible-light irradiation. During 80 min, the degradation efficiency of rhodamine B for AZFRs-20 is about 3.7 times as the pure ZFRs. Moreover, the AZFRs exhibit predominant photoelectrochemical properties, and the photocurrent can reach 1.2?×?10^?4?A. Finally, the as-prepared photocatalytic device composed of AZFRs based on indium doped tin oxide glass is convenient to recycle without centrifugation.     

Sensitivity Enhanced by MoS2–Graphene Hybrid Structure in Guided-Wave Surface Plasmon Resonance Biosensor

Plasmonics - Compared with surface plasmon resonance (SPR) biosensor, guided-wave surface plasmon resonance (GWSPR) biosensor has a higher sensitivity. In order to further enhance the sensitivity...     

Characterization of Glycoprotein Oligosaccharides Using Surface Plasmon Resonance

Surface plasmon resonance was used to characterize the carbohydrate moieties of bovine fetuin. This technique, requiring no sample derivitization or labeling, identified the presence and composition of both N- and O-linked oligosaccharides, using a combination of lectin probes and in situ glycosidase digestion. A complete analysis was achieved using 1.4 μg of pure bovine fetuin, and was fully automated using Pharmacia′s BIAcore. The presence or absence of specific oligosaccharide structures was determined by the binding of a panel of unlabeled lectins. Monosaccharide order and linkages were determined by sequential digestion using a range of specific exoglycosidases. This novel method implementing in situ digestion was achieved using a modification to the BIAcore software, allowing the flow of reagent over the sensor chip to be stopped for variable lengths of time, thereby permitting enzymatic digestion to occur. This technique can be applied to other commercial SPR biosensors currently available. Glycoanalysis by SPR uses approximately 100- to 1000-fold less protein than comparable analyses using alternative techniques such as gel permeation chromatography of released oligosaccharides, labeled lectin binding, or mass spectrometry.     

Lifetime of Enhanced Graphene Surface Plasmon and Superstrate Sensitivity

Plasmonics - We investigated the field enhancement and lifetime of tuning surface plasmon in zero-thickness nanostructured graphene patches. The graphene surface plasmon (GSP) resonance mechanism...     

Tunable Properties of Surface Plasmon Resonance of Metal Nanospheroid: Graphene Plasmon Interaction

Plasmonics - Graphene plasmonic resonances play a significant role for enhancing the photon absorption inside thin film solar devices. We investigate the field rising at the intersection of...