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Recent Progress in Surface Plasmon Resonance Biosensors (2016 to Mid-2018)
摘要： More than 50 papers on surface plasmon resonance biosensors, published between 2016 and mid-2018, are reviewed. Papers concerning the determination of large particles such as vesicles, exosomes, cancer cells, living cells, stem cells, and microRNA are excluded, as these are covered by a very recent review. The reviewed papers are categorized into five groups, depending on the degree of maturity of the reported solution; ranging from simple marker detection to clinical application of a previously developed biosensor. Instrumental solutions and details of biosensor construction are analyzed, including the chips, receptors, and linkers used, as well as calibration strategies. Biosensors with a sandwich structure containing different nanoparticles are considered separately, as are SPR (Surface Plasmon Resonance) applications for investigating the interactions of biomolecules. An analysis is also made of the markers determined using the biosensors. In conclusion, there is shown to be a growing number of SPR applications in the solution of real clinical problems.
关键词： antibodies,cancer markers,surface plasmon resonance,receptor immobilization,biosensors,nanoparticles
更新于2025-09-04 15:30:14
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[SpringerBriefs in Materials] Anisotropic Metal Chalcogenide Nanomaterials (Synthesis, Assembly, and Applications) || Applications
摘要： Interest in anisotropic 1D and 2D nanostructures has been steadily increasing due to their large surface area, quantum con?nement effect, and superior optoelectrical or thermoelectrical properties. Anisotropic geometry and size reduction comparable to the Debye length can alter the optical, electric, and magnetic properties of the bulk counterparts. Focusing on MCs prepared in solution the major interests for practical applications are thermoelectric power phases, generation or electronic device cooling, high performance electrodes for batteries, nanocrystal-based photovoltaic devices, and photodetectors. Recently, new potential uses of the solution-based MC nanocrystals are being investigated, which include localized surface plasmon resonance (LSPR) and oxygen reduction reaction (ORR). MC thin ?lms prepared by the vacuum process have shown the possibilities as new class of materials such as topological insulator, semiconductor with a high electron mobility, and superconductor. Although the organic surfactants indispensable in solution chemistry diminish such superior physical properties, solution-based approach has large room to achieve such physical properties. This chapter will introduce recent advances in the practical applications of the anisotropic MC nanocrystals, and introduce brie?y the potential applications.
关键词： thermoelectric,oxygen reduction reaction,photodetector,metal chalcogenides,localized surface plasmon resonance,photovoltaic,superconductor,topological insulator,anisotropic nanostructures
更新于2025-09-04 15:30:14
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[Advances in Imaging and Electron Physics] || AlN/GaN and InAlN/GaN DBRs
摘要： This chapter presents the high resolution monochromated STEM-EELS characterization of two distributed Bragg re?ector (DBR) multilayer heterostructures, composed of a periodic staking of III-nitride layers. These heterostructures were grown by the group of E. Calleja at the Instituto de Sistemas Optoelectrónicos y Microtecnología (ISOM), from Universidad Politéc- nica de Madrid. One of these DBR is composed of an alternate staking of AlN and GaN layers, and the other one, of InAlN lattice matched to GaN. EELS at sub-nanometric spatial resolution and < 200 meV energy resolution was used to assess the electronic properties of the structures. The EELS signal was treated using ZLP subtraction and deconvolution methods, and non-linear ?tting tools complemented with theoretical modeling of the electron scattering distribution. In this sense, the log-ratio formula was used to calculate the relative thickness, related to the electron inelastic mean free path. Moreover, ?tting of the bulk plasmon peak was performed using Lorentzian and Drude free-electron models. As we have seen, in group-III nitride alloys, the energy position of this peak can be related to the chemical composition variation through Vegard’s law. Also, within the context of the Drude plasmon model, information regarding the structural properties of the material can be obtained from the lifetime of the oscillation. This structural and chemical characterization of the layers was complemented with experimental and simulated high angle annular dark ?eld (HAADF) images. Finally, information related to the dielectric response of the mate- rials was extracted using Kramers–Kronig analysis. Our results signi?cantly improve the understanding of previous macroscopic characterizations of the electro-optical properties of these structures.
关键词： AlN/GaN,InAlN/GaN,Kramers–Kronig analysis,STEM-EELS,Vegard’s law,plasmon peak,DBRs
更新于2025-09-04 15:30:14
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Resonant Plasmon-Enhanced Upconversion in Monolayers of Core-Shell Nanocrystals: Role of Shell Thickness
摘要： The upconversion luminescence (UCL) of colloidal lanthanide-doped upconversion nanocrystals (UCNCs) can be improved either by precise encapsulation of the surface by optically inert shells around the core, by an alteration of the nearby environment via metal nanoparticles, or by a combination of both. Considering their potential importance in crystalline silicon photovoltaics,the present study investigates both effects for two-dimensional arrangements of UCNCs. Using excitation light of 1500 nm wavelength, we study the variation in the upconversion luminescence from an Er3+-doped NaYF4 core as a function of the thickness of a NaLuF4 shell in colloidal solutions as well as in spin-cast-assisted self-assembled monolayers of UCNCs. The observed UCL yields and decay times of Er3+ ions of the UCNCs increase with increasing shell thickness in both cases, and nearly no variation in decay times is observed in the transition of the UCNCs from solution to film configurations. The luminescence efficiency of the UCNC monolayers is further enhanced by electron-beam-lithographic-designed Au-nanodiscs deposited either on top or buried within of the monolayer. It is observed that the improvement by the nanocrystal shells is greater than that of the Au-nanodiscs.
关键词： shell thickness,core-shell nanocystals,monolayer,upconversion,Plasmon enhancement
更新于2025-09-04 15:30:14
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Theoretical study on surface plasmon properties of gold nanostars
摘要： With the rapid development of nanotechnology, the surface plasmon properties of metal nanostructures have become the focus of research. In this paper, a multi-tip gold nanostars (GNSs) structure is designed theoretically, and its surface plasmon properties are simulated by using the finite element method (FEM), which is practical and versatile. Compared with the traditional spherical and triangular plate particles, the results show that the tip structure of the GNSs has a stronger hot spots effect, resulting in greater local field enhancement properties. The relationship between the structure parameters of GNSs and their resonance peaks was also studied. The results indicate that the resonance peaks of GNSs depend strongly on the size, spacing between two GNSs, quantity and refractive index of the GNSs.
关键词： surface plasmon,finite element method,resonance peaks,gold nanostars,local field enhancement
更新于2025-09-04 15:30:14
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Comparative hyperthermia effects of silica–gold nanoshells with different surface coverage of gold clusters on epithelial tumor cells
摘要： Silica–gold nanoshell (SGNS), which is a silica core surrounded by a gold layer, was synthesized by seed-mediated coalescence of gold clusters in an electroless plating solution. SGNS variations with different surface coverage of gold clusters were prepared by adjusting the amounts of gold salts in the presence of formaldehyde-reducing agents. Fully covered SGNS (f-SGNS) with connected gold clusters exhibited stronger intensity and more redshift of plasmon bands located around 820 nm than those of partially covered SGNS (p-SGNS) with disconnected gold clusters. Upon irradiation with near-infrared light (30 W/cm2, 700–800 nm), f-SGNS caused a larger hyperthermia effect, generating a large temperature change (?T =42°C), as compared to the relatively small temperature change (?T =24°C) caused by p-SGNS. The therapeutic antibody, Erbitux? (ERB), was further conjugated to SGNS for specific tumor cell targeting. The f-ERB-SGNS showed excellent therapeutic efficacy based on the combined effect of both the therapeutic antibody and the full hyperthermia dose under near-infrared irradiation. Thus, SGNS with well-controlled surface morphology of gold shells may be applicable for near-infrared-induced hyperthermia therapy with tunable optical properties.
关键词： gold nanoshell,plasmon resonance,human epithelial cancer,Erbitux,hyperthermia
更新于2025-09-04 15:30:14
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Metasurface with pull
摘要： Using light to manipulate small particles has proven an indispensable tool for ‘tweezing’, sorting and force measurements. To achieve effective optical traps with high ‘stiffness’, researchers often go to great lengths to tailor light fields, for example by using holographic elements. Now, Aliaksandra Ivinskaya and colleagues from Russia, the USA, the UK and Israel predict that small particles can be manipulated using a plane wave of light and a simple flat surface of an anisotropic media supporting hyperbolic modes. Their hyperbolic metamaterial is composed of metal and dielectric layers and is potentially less affected by losses and offers more broadband capability than purely plasmonic approaches. In their theoretical study a small dielectric sphere near a hyperbolic metamaterial is considered. The particle is sufficiently small to provide the required momentum to excite both surface plasmon and bulk hyperbolic waves from incident plane waves. Strong optical pulling forces were predicted over the 400–800 nm wavelength range thanks to the broadband high density of states of hyperbolic modes.
关键词： metasurface,hyperbolic modes,plasmon,nano-optics,optical manipulation
更新于2025-09-04 15:30:14