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Monolithic metal dimer-on-film structure: new plasmonic properties introduced by the underlying metal
摘要： Dimers -two closely-spaced metallic nanostructures- are one of the primary nanoscale geometries in plasmonics, supporting high local field enhancements in their interparticle junction under excitation of their hybridized “bonding” plasmon. However, when a dimer is fabricated on a metallic substrate, its characteristics are changed profoundly. Here we examine the properties of an Au dimer on an Au substrate. This structure supports a bright “bonding” dimer plasmon, screened by the metal, and a lower energy magnetic charge transfer plasmon. Changing the dielectric environment of the dimer-on-film structure reveals a broad family of higher-order hybrid plasmons in the visible region of the spectrum. Both the localized surface plasmons resonances (LSPR) of the individual dimer-on-film structures as well as their collective surface lattice resonances (SLR) show a highly sensitive refractive index sensing response. Implementation of such all-metal magnetic-resonant nanostructures offers a promising route to achieve higher-performance LSPR- and SLR-based plasmonic sensors.
关键词： Plasmonics,localized surface plasmon resonance,surface lattice resonance,LSPR sensing,refractive index sensing
更新于2025-11-21 11:24:58
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Enhanced Single-Mode Lasers of All-Inorganic Perovskite Nanocube by Localized Surface Plasmonic Effect from Au Nanoparticles
摘要： Miniaturized laser sources recently attracted considerable interests as their potential applications in optical communication, data storage, and imaging. However, high cavity losses induced by size reduction from the gain medium would lead high lasing threshold. In this work, the enhanced optical properties of CsPbBr3 perovskite nanocubes by using localized surface plasmonic effect of Au nanoparticles (NPs) were investigated. The integration of Au NPs in the poly (3, 4-ethylenedioxy-thiophene): poly (styrenesulfonate) PEDOT: PSS layer induces obviously enhancement both in the absorption and photoluminescence (PL) of CsPbBr3 perovskite nanocubes. Importantly，the lasing threshold of CsPbBr3 perovskite nanocubes is significantly reduced by ~ 33%. This study suggests that the lead halide perovskites hybridized with plasmonic nanomaterials would be promising candidates for laser devices and other optoelectronic devices with high efficiency.
关键词： Low threshold,Perovskite nanocubes,LSPR,Au nanoparticles
更新于2025-11-14 15:32:45
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Blu-ray DVD as SERS substrate for reliable detection of albumin, creatinine and urea in urine
摘要： We report here the working of a simple reproducible surface enhanced Raman scattering (SERS) substrate by efficiently guiding localized plasmon resonance (LSPR) field of gold nanoparticles (AuNPs) through trapping it in the nano channels of a blu-ray digital versatile disc (BRDVD). SERS based sensing of the designed substrate has been performed. The trapped AuNPs in the channel of the BRDVD generate guided mode resonance (GMR) field and the photon lifetime of the coupled em field in the channel increases which accounts for overall enhancement of the local field intensity. These two factors are primarily responsible for enhancement of the scattered Raman signal from the substrate. The proposed SERS substrate yields reasonably stable signal intensity over a period of 45 days. With the designed substrate Raman signal intensities of three clinically important chemicals namely albumin, creatinine and urea in urine have been measured and quantified reliably. The minimum concentration of albumin, creatinine and urea which can be measured by Raman spectrometer are 0.1 μg/mL, 0.2 μg/mL and 0.6 μg/mL respectively. These values are well below the normal range and thus meet the requirement of detection and analysis of these chemicals for different clinical purposes.
关键词： SERS,Nanochannel,LSPR,BRDVD,Guided mode resonance,Urine sample
更新于2025-09-23 15:23:52
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Plasmoelectronic-Based Ultrasensitive Assay of Tumor Suppressor microRNAs Directly in Patient Plasma: Design of Highly Specific Early Cancer Diagnostic Technology
摘要： It is becoming understood that microRNAs hold great promise for non-invasive liquid biopsies for screening for different types of cancer, but current state-of-the-art RT-PCR and microarray techniques have sensitivity limitations that currently restrict their use. Herein, we report a new transduction mechanism involving delocalization of photoexcited conduction electrons wavefunction of gold triangular nanoprism (Au TNP) in the presence of -ssDNA/microRNA duplexes. This plasmoelectronic effect increases the electronic dimension of Au TNPs and substantially affects their localized surface plasmon resonance (LSPR) properties that together allow us to achieve a sensitivity for microRNA assay as low as 140 zeptomolar concentrations for our nanoplasmonic sensors. We show that the position of a single base-pair mismatch in the -ssDNA/microRNA duplex dramatically alters the LSPR properties and detection sensitivity. The unprecedentedly high sensitivity of nanoplasmonic sensors has allowed us to assay four different microRNAs (microRNA-10b, -182, -143 and -145) from bladder cancer patient plasma (50 μL/sample). For the first time, we demonstrate the utility of a label-free, nanoplasmonic sensor in quantification of tumor suppressor microRNAs - the level of tumor suppressor microRNAs goes down in cancer patient as compared to normal healthy individuals - in metastatic and non-metastatic bladder cancer patient plasma. Our statistical analysis of patient samples unequivocally suggests that the tumor suppressor microRNAs are more specific biomarkers (p-value of <0.0001) than oncogenic microRNAs for differentiation between metastatic and non-metastatic bladder cancer, and non-metastatic cancer from healthy individuals. This work demonstrating the electron wavefunctions delocalization dependent ultrasensitive LSPR properties of noble metal nanoparticles has a great potential for fabrication of miniaturized and extremely powerful sensors to investigate microRNA properties in other cancers (for example breast, lung, and pancreatic) through liquid biopsy.
关键词： nanoplasmonic sensors,ultrasensitive detection,microRNAs,LSPR,liquid biopsy,bladder cancer,plasmoelectronic effect
更新于2025-09-23 15:22:29
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Enhanced Fluorescence Emission and Magnetic Alignment Control of Biphasic Functionalized Composite Janus Particles
摘要： Janus particles, particles that have two distinct aspects on their surface or interiors, have attracted much attention due to their potential for application. For the application of Janus particles to high-resolution displays, and as light sources for optical circuits and fluorescent probes, the Janus particles should be nanosize to ensure high-resolution display and analysis, responsive to external stimuli, and highly fluorescent. However, it is still a challenging issue to develop such highly fluorescent nanoscale Janus particles and control their alignment. Magnetoresponsive Janus particles, of which the orientation can be controlled by an external magnetic field, are prepared by the simple introduction of polymer-coated magnetic nanoparticles (NPs) into the hemispheres of Janus particles. If these magnetoresponsive Janus particles can be combined with a strong fluorescence system, then they could be ideal candidates as components of the previously mentioned applications. In the present study, Janus particles are prepared with a fluorescent dye and gold nanoparticles (Au NPs) on one side. The optical properties of the resulting particles are assessed and discussed. Furthermore, the response of composite Janus particles containing dyes, Au NPs, and iron oxide NPs to an external magnetic field is discussed.
关键词： fluorescence enhancement,LSPR,magnetic alignment,Janus particles
更新于2025-09-23 15:21:21
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Microfluidic Platform for Integrated Plasmonic Detection in Laminal Flow
摘要： In this work, we propose a novel approach to design robust microfluidic devices with integrated plasmonic nanoparticles. A strong electric field generated in the gaps between AuBPs – due to the generation of the so-called extrinsic ‘hot-spots’ – was subsequently proved by the volumetric SERS detection of molecules in continuous flow conditions by loading the analyte into the microfluidic channel via a syringe pump. In conclusion, our miniaturized portable microfluidic system aims to detect and identify in real-time with high accuracy analyte molecules in laminal flow, providing thus a groundwork for further complex biosensing applications.
关键词： Gold Bipyramids,Detection in Laminal Flow,LSPR,Microfluidic Chip,SERS
更新于2025-09-23 15:21:01
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Silver-Gold Bimetallic Alloy versus Core-Shell Nanoparticles: Implications for Plasmonic Enhancement and Photothermal Applications
摘要： Bimetallic plasmonic nanoparticles enable tuning of the optical response and chemical stability by variation of the composition. The present numerical simulation study compares Ag-Au alloy, Ag@Au core-shell, and Au@Ag core-shell bimetallic plasmonic nanoparticles of both spherical and anisotropic (nanotriangle and nanorods) shapes. By studying both spherical and anisotropic (with LSPR in the near-infrared region) shapes, cases with and without interband transitions of Au can be decoupled. Explicit comparisons are facilitated by numerical models supported by careful validation and examination of optical constants of Au-Ag alloys reported in literature. Although both Au-Ag core-shell and alloy nanoparticles exhibit an intermediary optical response between that of pure Ag and Au nanoparticles, there are noticeable differences in the spectral characteristics. Also, the effect of the bimetallic constitution in anisotropic nanoparticles is starkly different from that in spherical nanoparticles due to the absence of Au interband transitions in the former case. In general, the improved chemical stability of Ag nanoparticles by incorporation of Au comes with a cost of reduction in plasmonic enhancement, also applicable to anisotropic nanoparticles with a weaker effect. A photothermal heat transfer study confirms that increased absorption by the incorporation of Au in spherical Ag nanoparticles also results in an increased steady state temperature. On the other hand, anisotropic nanoparticles are inherently better absorbers, hence better photothermal sources and their photothermal properties are apparently not strongly affected by the incorporation of one metal in the other. This study of the optical/spectral and photothermal characteristics of bimetallic Au-Ag alloy versus core-shell nanoparticles provides a detailed physical insight for the development of new taylor-made plasmonic nanostructures.
关键词： Localized Surface Plasmon Resonance (LSPR),Au@Ag core-shell,Ag-Au alloy,Ag@Au core-shell,Bimetallic plasmonic nanoparticles,Photothermal applications
更新于2025-09-23 15:21:01
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Self-assembled monolayer film of concave star-shaped Au nanocrystals as highly efficient SERS substrates
摘要： In this work, various geometries of Au nanocrystals with sharp tips including decahedra, concave star, and spindle were synthesized through Ag underpotential deposition-dominated growth approach based on utilizing a novel type of Au nanoseed (i.e., pentatwinned Au nanospheres). These as-prepared Au nanocrystals exhibited a broad localized surface plasmon resonance (LSPR) tunability from visible to near-infrared region. Furthermore, we fabricated the monolayer film based on Au nanocrystals with different morphologies through liquid/liquid interface self-assembly technique, which displayed strong shape-dependent surface enhanced Raman scatting (SERS) performance. More significantly, concave star-shaped Au nanocrystals with ten sharp tips endowed them with 12-fold higher SERS enhancements than Au nanospheres, which was in line with the simulation results by finite difference time domain (FDTD) method. Our study provides a novel route for fabrication of Au nanocrystals with diversified structures, and the efficient SERS substrates have great prospect for the applications in ultrasensitive chemical and biological sensing.
关键词： Au nanocrystals,SERS,Self-assembly,LSPR,Underpotential deposition
更新于2025-09-23 15:21:01
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Recent advances of plasmonic nanoparticle-based optical analysis in homogeneous solution and at the single-nanoparticle level
摘要： Plasmonic nanoparticles with special localized surface plasmon resonance (LSPR) characters have been widely applied for optical sensing of various targets. With the combination of single nanoparticle imaging techniques, dynamic information of reactions and biological processes is obtained, facilitating the deep understanding of their principle and design of outstanding nanomaterials. In this review, we summarize the recently adopted optical analysis of diverse analytes based on plasmonic nanoparticles in both homogeneous solution and single-nanoparticle level. A brief introduction of LSPR is first discussed. Colorimetric and fluorimetric homogeneous detection examples by using different sensing mechanisms and strategies are provided. Single plasmonic nanoparticle-based analysis is concluded in two aspects: visualization of chemical reactions and understanding of biological processes. The basic sensing mechanisms and performances of these systems are introduced. Finally, this review highlights the challenges and future trend of plasmonic nanoparticle-based optical analysis system.
关键词： Plasmonic nanoparticles,Single-nanoparticle level,Fluorimetric assays,Chemical reactions,Localized surface plasmon resonance (LSPR),Optical analysis,Homogeneous solution,Colorimetric assays,Biological processes
更新于2025-09-23 15:21:01
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Cuvette-based microfluidic device integrated with nanostructures for measuring dual Localized Surface Plasmon Resonance (LSPR) signals
摘要： A spectrophotometer that uses a localized surface plasmon resonance phenomenon is a powerful measurement tool in the biotechnology and bioanalysis fields. We propose a novel cuvette design type that can be used for universal spectrophotometers. The novel cuvette design needs a few μl reagent for measuring, and also two chips for measurement can be loaded and measured at the same time. A new cuvette can easily be used several times because of sample chips to be loaded and unloaded since they are mechanically mounted by screws. Therefore, it can offer advantages to users in terms of cost and time. We verify its possibility for use in the biotechnology and bioanalysis fields by a signal enhancement and dual signal detection.
关键词： spectrophotometer,bioanalysis,nanostructures,microfluidic device,biotechnology,Localized Surface Plasmon Resonance,LSPR
更新于2025-09-23 15:21:01