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Development of Plasmonic Photocatalyst by Sitea??selective Loading of Bimetallic Nanoparticles of Au and Ag on Titanium(IV) Oxide
摘要： Morphology-controlled rutile titanium(IV) oxide (TiO2) and anatase TiO2 were prepared by a hydrothermal method and their surfaces were selectively loaded with Au, Ag and AuAg bimetallic nanoparticles (NPs) by photo-deposition in order to obtain visible-light responsive photocatalysts. With the help of local surface plasmon resonance (LSPR) of noble metal NPs, the photocatalytic activity of noble metal-loaded TiO2 under visible-light irradiation was improved compared to that of bare TiO2. The enhancement of LSPR on the photocatalytic activity of rutile TiO2 was larger than that of anatase TiO2 with optimum amount of Au or AuAg. In addition, the reusability (stability) of AuAg-loaded TiO2 was much better than that of Ag-loaded TiO2. Double-beam photoacoustic results confirmed different trap energy level distribution lead to different electron transfer ways, resulting in different oxidizing capabilities and they gave one of important strategies for designing visible-light responsive TiO2.
关键词： morphology-controlled TiO2,visible-light responsive,electron transfer,surface plasmon resonance
更新于2025-09-23 15:19:57
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Actuated plasmonic nanohole arrays for sensing and optical spectroscopy applications
摘要： Herein, we report a new approach to rapidly actuate the plasmonic characteristics of thin gold films perforated with nanohole arrays that are coupled with arrays of gold nanoparticles. The near-field interaction between the localized and propagating surface plasmon modes supported by the structure was actively modulated by changing the distance between the nanoholes and nanoparticles and varying the refractive index symmetry of the structure. This approach was applied by using a thin responsive hydrogel cushion, which swelled and collapsed by a temperature stimulus. The detailed experimental study of the changes and interplay of localized and propagating surface plasmons was complemented by numerical simulations. We demonstrate that the interrogation and excitation of the optical resonance to these modes allow the label-free SPR observation of the binding of biomolecules, and is applicable for in situ SERS studies of low molecular weight molecules attached in the gap between the nanoholes and nanoparticles.
关键词： gold nanoparticles,responsive hydrogel,plasmonic nanohole arrays,surface plasmon resonance,SERS
更新于2025-09-23 15:19:57
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Determination of refractive index using surface plasmon resonance (SPR) and rigorous coupled wave analysis (RCWA) with a D-shaped optical fiber and a nano-gold grating
摘要： A D-shaped optical-fiber refractive index sensor based on surface plasmon resonance is reported. Rigorous coupled-wave analysis was used to simulate the numerical modeling. The influences of different metal grating parameters on the coupling efficiency were studied and an optimal phase match was obtained. The results show that wavelength sensitivity of the proposed optical fiber sensor is as high as 0.925 lm/RIU for refractive index values from 1.35 to 1.43 with a high linearity value of 0.997. The reported structure may promote the development of high-performance biochemical sensing devices.
关键词： metal grating,D-shaped optical fiber,surface plasmon resonance,sensor,rigorous coupled-wave analysis
更新于2025-09-23 15:19:57
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Photocurrent improvement of an ultra-thin silicon solar cell using the localized surface plasmonic effect of clustering nanoparticles
摘要： The cluster-shaped plasmonic nanostructures are used to manage the incident light inside an ultra-thin silicon solar cell. Here, for the first time, spherical, conical, pyramidal, and cylindrical nanoparticles as a form of a cluster in the rear side of a thin silicon cell are simulated using finite difference time domain (FDTD) method. By calculating the optical absorption and hence the photocurrent, it is shown that the clustering of nanoparticles significantly improves them. The photocurrent enhancement is the result of the plasmonic effects of clustering the nanoparticles. For more comparison, at first, a cell with a single nanoparticle at the rear side is evaluated. Then four smaller nanoparticles are put around it to make a cluster. The photocurrents of 20.478, 23.186, 21.427, and 21.243 mA/cm2 are obtained for the cells using clustering conical, spherical, pyramidal, cylindrical NPs at the backside, respectively. These values are 13.987, 16.901, 16.507, 17.926 mA/cm2 for the cell with one conical, spherical, pyramidal, cylindrical nanoparticle at the rear side, respectively. So, clustering significantly improves the photocurrents. Finally, the distribution of the electric field and the generation rate for the proposed structures are calculated.
关键词： Clustering NPs,Localized surface plasmon resonance,light management,FDTD,Photocurrent,Plasmonic solar cell
更新于2025-09-23 15:19:57
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Facile and controllable synthesis of Zn-Al layered double hydroxide/silver hybrid by exfoliation process and its plasmonic photocatalytic activity of phenol degradation
摘要： Photocatalysts have attracted interest in the applications of green technology due to its efficiency to eliminate detrimental substances under light irradiation. Various design strategies to enhance the efficiency of photocatalytic processes under solar irradiation is actively searched. Building on the idea to provide a better synthesis method of photocatalyst, this study explores an effective and simple synthesis strategy of Layered Double Hydroxide (LDH) silver hybrid for photocatalyst phenol degradation. Unlike the common photodeposition method that incorporates noble metal nanoparticle on the LDH surface, this study discovered a pathway of intercalation of Ag nanoparticle into LDH interlayer space by exfoliation route. Notably, the synthesized ZnAl LDH/Ag contents of several phases: Zn2.5Al(OH)6.5O0.5(DS)0.5Ag0.3, Zn2.5Al(OH)7(HDS)0.5(DS)1.5, Zn2.5Al (OH)6.32O0.68(CO3)0.16Ag0.03, Zn2Al(OH)5.32O0.68 (CO3)0.16. A preliminary demonstration of the concept was given by the efficient photocatalytic degradation of phenol with a resulting conversion ratio of phenol under light (Xe lamp, > 340-nm cut-off filter) irradiation by 80 % in 210 min. These findings provide a new strategy to incorporate noble metal nanoparticles into LDH interlayer space as a great potential for photocatalyst.
关键词： Silver nanoparticle,Photocatalyst,Surface plasmon resonance,Layered double hydroxide,Exfoliation
更新于2025-09-23 15:19:57
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Impact of Tryptophan Oxidation in Complementarity-Determining Regions of Two Monoclonal Antibodies on Structure-Function Characterized by Hydrogen-Deuterium Exchange Mass Spectrometry and Surface Plasmon Resonance
摘要： Purpose Tryptophan’s (Trp) unique hydrophobic and structural properties make it an important antigen binding motif when positioned in complementarity-determining regions (CDRs) of monoclonal antibodies (mAbs). Oxidation of Trp residues within the CDR can deleteriously impact antigen binding, particularly if the CDR conformation is altered. The goal of this study was to evaluate the conformational and functional impact of Trp oxidation for two mAb subtypes, which is essential in determining the structure-function relationship and establishing appropriate analytical control strategies during protein therapeutics development. Methods Selective Trp oxidation was induced by 2,2′-Azobis(2-amidinopropane) dihydrochloride (AAPH) treatment in the presence of free methionine (Met). The native and chemically oxidized mAbs were characterized by hydrogen-deuterium exchange mass spectrometry (HDX-MS) for conformational changes and surface plasmon resonance (SPR) for antigen-antibody binding. Results Treatment of mAbs with AAPH selectively oxidized solvent accessible Trp residues. Oxidation of Trp within or in proximity of CDRs increased conformational flexibility in variable domains and disrupted antigen binding. Conclusions Trp oxidation in CDRs can adversely impact mAbs’ conformation and antigen binding. Trp oxidation should be carefully evaluated as part of critical quality attribute assessments. Oxidation susceptible Trp should be closely monitored during process development for mAbs to establish appropriate analytical control for manufacturing of drug substance and drug product.
关键词： Tryptophan oxidation,surface plasmon resonance,complementarity-determining region,hydrogen-deuterium exchange mass spectrometry,monoclonal antibody
更新于2025-09-23 15:19:57
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[Methods in Molecular Biology] Autoantibodies Volume 1901 (Methods and Protocols) || Determination of CRP Autoantibodies by SPR Immunoassay
摘要： Biosensors based on the principle of surface plasmon resonance (SPR) are surface-sensitive optical devices used for monitoring biomolecular interactions at the sensor surface in real time without any labeling. It is used in a wide variety of areas including proteomics, clinical diagnosis, environmental monitoring, drug discovery, and food analysis. C-reactive protein (CRP) is a marker of in?ammation, which undergoes conformation changes in local lesions, leading to the formation of mCRP. Autoantibodies against mCRP are frequently detected in systemic lupus erythematosus (SLE) and associated with disease activity and prognosis. An SPR immunoassay for CRP autoantibodies at complement factor H–CRP interface is described in this chapter.
关键词： Surface plasmon resonance,CRP,Immobilization,Complement factor H,CRP autoantibody
更新于2025-09-23 15:19:57
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[Methods in Molecular Biology] Autoantibodies Volume 1901 (Methods and Protocols) || Detection of Autoantibodies to Complement Components by Surface Plasmon Resonance-Based Technology
摘要： The innate immune complement system is a powerful defense cascade against pathogens, but can induce host tissue damage when overactivated. In pathological conditions, mainly but not restricted to renal diseases, such as lupus nephritis, atypical hemolytic uremic syndrome, and C3 glomerulopathies, complement is overactivated or dysregulated by autoantibodies directed against its components and regulators. Among the key autoantibody targets are the initiator of the classical complement pathway C1q, the alternative pathway regulator Factor H, the components of the alternative pathway C3 convertase complex C3 and Factor B and the convertase complex itself. This methodological article describes our experience with a method for detection of anti-complement autoantibodies in real time using surface plasmon resonance-based technology. It allows label-free evaluation of the binding efficacy and stability of the formed antigen–antibody complexes.
关键词： Surface plasmon resonance,Complement components,Autoantibodies
更新于2025-09-23 15:19:57
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Au Nanobottles with Synthetically Tunable Overall and Opening Sizes for Chemo-Photothermal Combined Therapy
摘要： Highly asymmetric Au nanostructures, such as split Au nanorings and Au nanocups, exhibit attractive plasmonic properties due to their asymmetric geometries. To facilitate their plasmonic applications, effective and facile synthetic methods for producing asymmetric Au nanostructures with controllable sizes and uniform shapes are highly desirable. Herein we report on an approach for the synthesis of largely asymmetric colloidal Au nanobottles with synthetically tunable overall and opening sizes. Au nanobottles with overall sizes in the range of ~100–230 nm are obtained through the sacrificial templating with differently sized PbS nanooctahedra. The opening sizes of the produced Au nanobottles can be tailored from ~10 to ~120 nm by either adjusting the Au/PbS molar ratio in the growth process or controlling the oxidation degree. The achieved size tunability allows the plasmon resonance wavelength of the Au nanobottles to be varied in the range of ~600–900 nm. Our uniform Au nanobottles, which possess controllable sizes, large cavity volumes and tunable plasmon resonance wavelengths in the visible to near-infrared range, have been further applied for anticancer drug delivery and photothermal therapy. The effects of the surface coating and opening size of the Au nanobottles on the drug encapsulation efficiency and initial burst drug release are systemically evaluated. A high doxorubicin encapsulation efficiency and low initial burst drug release are realized with the dense silica-coated Au nanobottles having the opening size of 44 nm. In addition, chemo-photothermal combined therapy has been demonstrated with the doxorubicin-loaded Au nanobottles. Our results will be helpful for the design of the Au nanobottles with different sizes and plasmonic properties as well as ample opportunities for exploring various plasmon-enabled applications out of the Au nanobottles.
关键词： asymmetric metal nanostructures,plasmon resonance,gold nanobottles,magnetic plasmon resonance,photothermal therapy,drug delivery
更新于2025-09-19 17:15:36
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Surface Plasmon Enhanced Light Scattering Biosensing: Size Dependence on the Gold Nanoparticle Tag
摘要： Surface plasmon enhanced light scattering (SP-LS) is a powerful new sensing SPR modality that yields excellent sensitivity in sandwich immunoassay using spherical gold nanoparticle (AuNP) tags. Towards further improving the performance of SP-LS, we systematically investigated the AuNP size effect. Simulation results indicated an AuNP size-dependent scattered power, and predicted the optimized AuNPs sizes (i.e., 100 and 130 nm) that afford extremely high signal enhancement in SP-LS. The maximum scattered power from a 130 nm AuNP is about 1700-fold higher than that obtained from a 17 nm AuNP. Experimentally, a bio-conjugation protocol was developed by coating the AuNPs with mixture of low and high molecular weight PEG molecules. Optimal IgG antibody bioconjugation conditions were identified using physicochemical characterization and a model dot-blot assay. Aggregation prevented the use of the larger AuNPs in SP-LS experiments. As predicted by simulation, AuNPs with diameters of 50 and 64 nm yielded significantly higher SP-LS signal enhancement in comparison to the smaller particles. Finally, we demonstrated the feasibility of a two-step SP-LS protocol based on a gold enhancement step, aimed at enlarging 36 nm AuNPs tags. This study provides a blue-print for the further development of SP-LS biosensing and its translation in the bioanalytical field.
关键词： signal amplification,surface plasmon resonance,gold nanoparticles,surface plasmon enhanced light scattering,gold enhancement
更新于2025-09-19 17:15:36