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- 2019
- Photovoltaics
- Finite-difference
- Nanotechnology
- Absorption enhancement
- Plasmonics
- Time domain simulation
- Localized surface plasmon resonance
- Optoelectronic Information Materials and Devices
- Islamic Azad University
- Aerospace Research Institute
- Tehran University
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Multifunctional nanoclusters of NaYF4:Yb3+,Er3+ upconversion nanoparticle and gold nanorod for simultaneous imaging and targeted chemotherapy of bladder cancer
摘要： This paper reports successful synthesis of multifunctional nanoclusters of upconversion nanoparticle (UCNP) and gold nanorod (AuNR) through a PEGylation process. UCNPs emit visible luminescence under near-infrared excitation, producing high-contrast images with no background fluorescence. When coupled with AuNRs, the resulting UCNP-AuNR multifunctional nanoclusters are capable of simultaneous detection and treatment of bladder cancer. These UCNP-AuNR nanoclusters are further functionalized with antibodies to epidermal growth factor receptor (EGFR) to target bladder cancer cells known to overexpress EGFRs. This paper demonstrates, for the first time, efficient targeting of bladder cancer cells with UCNP-AuNR nanoclusters. In addition to high-contrast imaging and consequently high sensitivity detection of bladder cancer cells, highly selective optoporation-assisted chemotherapy was accomplished using a dosage of chemotherapy agent significantly lower than any previous reports, within a clinically relevant incubation time window. These results are highly relevant to the eventual human application in which the nanoclusters and chemotherapy drugs will be directly instilled in bladder via urinary catheter.
关键词： Luminescence upconversion,Surface Plasmon,Bladder Cancer,Gold Nanorod,Optoporation
更新于2025-09-23 15:23:52
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Gold Nanorod-Coated Capillaries for the SERS-Based Detection of Thiram
摘要： Surface enhanced Raman scattering (SERS)-based capillary system is a promising route towards fast, real-time and in-situ detection using a facile sampling process. Here, we demonstrate for the first time resonance-tunable SERS-active capillaries with high sensitivity, reproducibility and stability. The strong signal consistency independent of measurement spots or storage time supports the long-term storage and signal tracking of analytes in practical use. The capillaries were successfully applied to the in-situ detection of pesticide residues, and the sampling process provides operation conveniency compared to conventional methods. These results indicate that our SERS-active capillaries have great potentials in fast in-situ detection for many practical applications.
关键词： surface enhanced Raman scattering,stability,thiram detection,gold nanorod,capillary tube,tunable plasmon resonance
更新于2025-09-23 15:23:52
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Effects of Ge substrate on the structural and optical conductivity parameters of Bi2O3 thin films
摘要： In this article the structural, optical and dielectric properties of a 200 nm thick Bi2O3 thin films which are deposited onto amorphous germanium substrate are reported. Both of the Ge and Bi2O3 thin films are prepared by the thermal evaporation technique under vacuum pressure of 10^-5 mbar. Bi2O3 thin films are found to prefer the monoclinic nature of structure with larger values of microstrain, dislocation density, stacking faults and smaller grain sizes upon replacement of the glass substrate by germanium. Optically, significant redshift in the energy band gap is observed when the films are grown onto Ge. The Ge/Bi2O3 heterojunctions exhibit a conduction and valence band offsets of value of 0.81 and 1.38 eV, respectively. In addition to the enhancement in the dielectric constant near the IR region, the Drude-Lorentz modeling of the Ge/Bi2O3 heterojunctions has shown remarkable effect of the Ge substrate on the optical conductivity parameters of Bi2O3. Particularly, the drift mobility increased by about one order of magnitude, the free hole density decreased by ~24 times and the plasmon frequency ranges extended from 5.21 to 11.0 GHz to 2.59–12.80 GHz when germanium substrate is used. The optical features of the heterojunction nominate it for visible light communication technology.
关键词： Ge/Bi2O3,Band offsets,X-ray,Heterojunction,Plasmon,Dielectric
更新于2025-09-23 15:23:52
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Electrochemical surface plasmon resonance (EC-SPR) aptasensor for ampicillin detection
摘要： Surface plasmon resonance technique is highly sensitive to various processes taking place on a metal film and it has emerged as a powerful label-free method to study molecular binding processes taking place on a surface. Another important but less explored area of applications is the use of hybrid methods which combine electrochemistry with optical methods for better monitoring and understanding of biochemical processes. A detection method based on surface plasmon resonance was developed for ampicillin, applying electrochemical techniques for the elaboration and characterization of the aptasensing platform used in this study. Ampicillin is a broad-spectrum β-lactam antibiotic, used both in human and veterinary medicine for the treatment and prevention of primary respiratory, gastrointestinal, urogenital, and skin bacterial infections. It is widely used because of its broad spectrum and low cost. This widespread use can result in the presence of residues in the environment and in food leading to health problems for individuals who are hypersensitive to penicillins. The gold chip was functionalized through potential-assisted immobilization, using multipulse amperometry, first with a thiol-terminated aptamer, as a specific ligand and secondly, using the same procedure, with mercaptohexanol, used to cover the unoccupied binding sites on the gold surface in order to prevent the nonspecific adsorption of ampicillin molecules. After establishing the optimal conditions for the chip functionalization, different concentrations of ampicillin were detected in real time, in the range of 2.5–1000 μmol L?1, with a limit of detection of 1 μmol L?1, monitoring the surface plasmon resonance response. The selectivity of the aptasensor was proven in the presence of other antibiotics and drugs, and the method was successfully applied for the detection of ampicillin from river water.
关键词： Multipulse amperometry,Electrochemical surface plasmon resonance (EC-SPR),Ampicillin,QCM,Antibiotic detection,SPR aptasensor
更新于2025-09-23 15:23:52
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Numerical study of nanoscale biosensor based on surface plasmon polariton propagation in Mach-Zehnder interferometer structure
摘要： In this paper, we numerically investigate a nanoscale plasmonic biosensor based on Mach-Zehnder interferometry. The operation of Mach-Zehnder interferometer (MZI) biosensor is examined based on two methods. In the first method, in which the transmission of surface plasmon polariton (SPP) modes is investigated under different refractive indices of sample medium as well as different dimensions, the best transmission rate achieved about 56.6% which is resulted by refractive index variation about 0.045 for the length 12 μm and width 80 nm of the gold layer. Also, the sensitivity, figure of merit (FOM) and quality factor (Q-factor) of MZI are examined for different geometries by utilizing the alternative method. It is realized that for the constant length, increasing the thickness of gold layer has significantly led to increased Q-factor and FOM. On the other hand, considering fixed thickness of the Au layer and three different lengths, the major outcome is that as the length of biosensor increases, the sensitivity, Q-factor as well as FOM follow an upward trend. Finally, inserting two distinct additional gold layers on top of the main gold layer, resulted in an extreme increase for the sensitivity and FOM of the plasmonic MZI biosensors with respect to the MZI biosensor without additional layer.
关键词： Plasmonic biosensor,Surface plasmon polariton (SPP),Mach-Zehnder interferometer (MZI),Finite difference time domain (FDTD)
更新于2025-09-23 15:23:52
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A compact leaky-wave antenna using a planar spoof surface plasmon polariton structure
摘要： This article presents and validates a leaky-wave antenna by using the spoof surface plasmon polariton (SSPP) technique. By properly designing the proposed SSPP unit, the SSPP wave can be switched between the confinement and radiation modes. A large radiation efficiency can be achieved by properly designing the modulation depth, which ensures that a compact SSPP leaky-wave array can be realized by using a small number of SSPP radiation units. To verify the design, a prototype which consists of a SSPP feeding network and a 4 by 4 SSPP radiation units has been fabricated by using a low cost FR-4 substrate. A good agreement between simulated and measured results has been obtained. The proposed array antenna shows the promising capability of the SSPP technique for leaky-wave antenna applications.
关键词： dispersion curve,the spoof surface plasmon polariton (SSPP),SSPP antenna array,SSPP power divider
更新于2025-09-23 15:23:52
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Electron energy-loss spectroscopy (EELS) with a cold-field emission scanning electron microscope at low accelerating voltage in transmission mode
摘要： A commercial electron energy-loss spectrometer (EELS) attached to a high-resolution cold-field emission scanning electron microscope in transmission mode (STEM) is evaluated and its potential for characterizing materials science thin specimens at low accelerating voltage is reviewed. Despite the increased beam radiation damage at SEM voltages on sensitive compounds, we describe some potential applications which benefit from lowering the primary electrons voltage on less-sensitive specimens. We report bandgap measurements on several dielectrics which were facilitated by the lack of Cherenkov radiation losses at 30 kV. The possibility of volume plasmon imaging to probe local composition changes in complex materials was demonstrated using energy-filtered STEM, either via spectrum imaging or elemental mapping using the 'three-windows' method. As plasmonic materials are increasing used for energy, electronics or biomedical applications, the ability of reliably evaluate their properties at low accelerating voltage in a SEM is very appealing and is demonstrated. The energy resolution of the spectrometer, taken as the full width at half maximum of the zero-loss peak, was routinely measured at around 0.55 eV and it is demonstrated that t/λ ratios up to 1.5 allowed practical EEL spectroscopy at 30 kV.
关键词： Damage,Plasmon resonance,Silver,STEM,Lithium,Zero-loss,Bandgap
更新于2025-09-23 15:23:52
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Physical principle and advances in plasmon-enhanced upconversion luminescence
摘要： In this review, we introduced the principle and advances in plasmon-enhanced upconversion luminescence. Firstly, we focus on the physical mechanism and principle of plasmon-enhanced upconversion luminescence, based on quantum electrodynamics. Secondly, we introduce in detail the advances in plasmon-enhanced upconversion luminescence, including plasmon-enhanced UC luminescence by metal/films, core-shell upconversion nanocrystals, plasmonic arrays/cavity and metal tip. Our review can not only promote deeper understanding quantum electrodynamics based plasmon-enhanced upconversion luminescence, but also can enlighten the potential applications of plasmon-enhanced upconversion luminescence.
关键词： Plasmon,Physical principle,Upconversion luminescence,Advances
更新于2025-09-23 15:23:52
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Electrochemiluminecence nanogears aptasensor based on MIL-53(Fe)@CdS for multiplexed detection of kanamycin and neomycin
摘要： A dual gears electrochemiluminecence (ECL) aptasensing strategy for multiple selective determination of kanamycin and neocycin was designed on the basis of the combination of kannamycin and neocycin induced dual gears conversion, the loading platform of metal-organic frameworks (MOFs), surface plasmon resonance (SPR) and ECL resonance energy transfer (ERET) between CdS QDs and AuNPs (or PtNPs). In the absence of target, the dual gears were "off". Then the B1-AuNP (gear B) and aptamer 1-PtNPs acted as signal quenching elements to quench ECL intensity due to ERET process. Upon addition of kanamycin, the aptamer 1-PtNPs were removed from the gear gradually, the ECL was enhanced due to SPR process between AuNPs and CdS QDs. After the incubation of aptamer 2, the dual gears were "off" again and ECL intensity was decreased by ERET process between AuNPs and CdS QDs. In the presence of neomycin, dual gears were "on" again, the ECL signal was enhanced by SPR process between AuNPs and CdS QDs. Under optimal condition, the proposed aptasensor exhibited wide linear ranges of kanamycin (10-10- 10-6 M) and neomycin (10-9 -10-5 M), and relatively low detection limits to kanamycin (1.7×10-11 M) and neomycin (3.5×10-10 M). The developed aptasensor realized the multiple ECL detection of kanamycin and neomycin with single luminophore, and was successfully applied to the detection of kanamycin and neomycin in food samples.
关键词： electrochemiluminecence resonance energy transfer,electrochemiluminescence,antibiotic,nanogears,surface plasmon resonance
更新于2025-09-23 15:23:52
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Ultrasensitive detection of miRNA with an antimonene-based surface plasmon resonance sensor
摘要： MicroRNA exhibits differential expression levels in cancer and can affect cellular transformation, carcinogenesis and metastasis. Although fluorescence techniques using dye molecule labels have been studied, label-free molecular-level quantification of miRNA is extremely challenging. We developed a surface plasmon resonance sensor based on two-dimensional nanomaterial of antimonene for the specific label-free detection of clinically relevant biomarkers such as miRNA-21 and miRNA-155. First-principles energetic calculations reveal that antimonene has substantially stronger interaction with ssDNA than the graphene that has been previously used in DNA molecule sensing, due to thanking for more delocalized 5s/5p orbitals in antimonene. The detection limit can reach 10 aM, which is 2.3–10,000 times higher than those of existing miRNA sensors. The combination of not-attempted-before exotic sensing material and SPR architecture represents an approach to unlocking the ultrasensitive detection of miRNA and DNA and provides a promising avenue for the early diagnosis, staging, and monitoring of cancer.
关键词： surface plasmon resonance,biosensor,antimonene,cancer diagnosis,miRNA detection
更新于2025-09-23 15:23:52