- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Hierarchical assembly of silver and gold nanoparticles in two-dimension: Toward fluorescence enhanced detection platforms
摘要： Two-dimensional (2D) metal nanoparticle platforms hold great potential in high-throughput point-of-care testing on basis of their excellent fluorescence enhancement effect. Self-assembly of metal nanoparticles (NPs) is versatile but simple for the preparation of 2D platforms; however, the surface charges on NPs would repel each other and induce large gaps on platforms, which hinder the generation of intense hotspots in electromagnetic fields and thus weaken the fluorescence enhancement effect. Here, we presented the hierarchical assembly of large-sized silver (Ag) NPs and small-sized gold (Au) NPs for constructing fluorescence enhanced platforms. The small Au NPs with weak fluorescence were chosen to complementarily fill into the larger gaps of the pre-assembled Ag platforms for increasing the electromagnetic hotspots. The resulting Ag/Au hybrid platforms (1-, 3- and 6-Ag/Au) exhibited growing fluorescence enhancement effects and the maximum enhanced factor reached 3.6-fold. The inserting of small Au NPs enhanced the fluorescence emission of fluorescent dye (cyanine-5) on the Ag platforms, especially on the monolayer 1-Ag platform, which increased by 161.6%. Moreover, the finite-difference time-domain (FDTD) calculations revealed the underlying cause of the improved electromagnetic fields in the Ag/Au hierarchical architecture in comparison to the Ag or Au NP. This work presents the hierarchical assembly is expected to be a powerful tool in the large-scale fabrication of fluorescence enhanced detection platforms.
关键词： Hotspot,Metal nanoparticles,Fluorescence enhancement,Self-assembly,Plasmon coupling
更新于2025-09-19 17:15:36
-
Plasmonic nanopapers: flexible, stable and sensitive multiplex PUF tags for unclonable anti-counterfeiting applications
摘要： Highly flexible and stable plasmonic nanopaper comprised of silver nanocubes and cellulose nanofibres was fabricated through a self-assembly-assisted vacuum filtration method. It shows significant enhancement of the fluorescence emission with an enhancement factor of 3.6 and Raman scattering with an enhancement factor of ~104, excellent mechanical properties with tensile strength of 62.9 MPa and Young’s modulus of 690.9 ± 40 MPa, and a random distribution of Raman intensity across the whole nanopaper. The plasmonic nanopapers were encoded with multiplexed optical signals including surface plasmon resonance, fluorescence and SERS for anti-counterfeiting applications, thus increasing security levels. The surface plasmon resonance and fluorescence information are used as the first layer of security and can be easily verified by the naked eye, while the unclonable SERS mapping is used as the second layer of security and can be readily authenticated by Raman spectroscopy using a computer vision technique.
关键词： cellulose nanofibres,fluorescence enhancement,silver nanocubes,anti-counterfeiting,SERS,plasmonic nanopaper
更新于2025-09-19 17:13:59
-
Enhanced modulation of magnetic field on surface plasmon coupled emission (SPCE) by magnetic nanoparticles
摘要： The obvious enhancement effect of magnetic nanoparticles (MNPs) introduced in Cr/Co/Cr/Au substrate on the pulsed magnetic field-modulated surface plasmon coupled emission (SPCE) was investigated, and the observed enhancement factor was 4 comparing with the magnetic field modulated SPCE without MNPs. This is the new observation for the magnetic field-modulated SPCE in fluorescence signal and helps to build the new SPCE based stimulus-response system.
关键词： Magnetic field modulation,Magnetic nanoparticle,Surface plasmon coupled emission (SPCE),Fluorescence enhancement,Biosensor
更新于2025-09-16 10:30:52
-
Direct enhancement of luminescence of CdxZn1?xSeyS1?y/ZnS nanocrystals with gradient chemical composition by plasmonic nanoantennas
摘要： Flat photonic materials such as thin films or metasurfaces form the basis of new optics and laser technology. However, their characteristics, for example, absorption and luminescence, are drastically limited in contrast to bulk materials. This problem can be overcome using plasmonic nanostructures. While the quantum dots absorption is enhanced by the plasmonic nanostructure near fields in almost all circumstances, more sophisticated approaches are needed to obtain the fluorescent enhancement because of the concurrent quenching by the metallic surface. Here we report on the results of an illustrative experiment demonstrating the luminescence enhancement of a new type of semiconductor nanocrystals CdxZn1?xSeyS1?y/ZnS (alloyed quantum dots) at their direct contact with a monolayer of silver nanoparticles. This type of nanocrystals consists of a CdSe core, a ZnS shell, and a transition layer in between where the composition smoothly changes, thus representing an alloy with variable x and y. We found that at the resonant plasmon–exciton coupling of such nanostructures, the fluorescence enhancement is accompanied by the reduction of the luminescence decay time – the main signature of the Purcell effect. Unlike previously studied compositions, these new hybrid structures do not require additional components to avoid fluorescence quenching which is promising for practical applications in flat optical devices.
关键词： Quantum dot,Fluorescence,Enhancement,Purcell effect,Plasmon
更新于2025-09-11 14:15:04
-
Fluorescence enhancement of a microbial rhodopsin via electronic reprogramming
摘要： The engineering of microbial rhodopsins with enhanced fluorescence is of great importance in the expanding field of optogenetics. Here we report the discovery of two mutants (W76S/Y179F and L83Q) of a sensory rhodopsin from the cyanobacterium Anabaena PCC7120 with opposite fluorescence behavior. In fact, while W76S/Y179F displays, with respect to the wild-type protein, a nearly ten-fold increase in red-light emission, the second is not emissive. Thus, the W76S/Y179F, L83Q pair offers an unprecedented opportunity for the investigation of fluorescence enhancement in microbial rhodopsins, which is pursued by combining transient absorption spectroscopy and multi-configurational quantum chemistry. The results of such an investigation point to an isomerization-blocking electronic effect as the direct cause of instantaneous (sub-picosecond) fluorescence enhancement.
关键词： fluorescence enhancement,multi-configurational quantum chemistry,transient absorption spectroscopy,optogenetics,electronic reprogramming,microbial rhodopsins
更新于2025-09-04 15:30:14