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Spectroscopic and Microscopic Analyses of Fe3O4/Au Nanoparticles Obtained by Laser Ablation in Water
摘要： Magneto-plasmonic nanoparticles constituted of gold and iron oxide were obtained in an aqueous environment by laser ablation of iron and gold targets in two successive steps. Gold nanoparticles are embedded in a mucilaginous matrix of iron oxide, which was identified as magnetite by both microscopic and spectroscopic analyses. The plasmonic properties of the obtained colloids, as well as their adsorption capability, were tested by surface-enhanced Raman scattering (SERS) spectroscopy using 2,2'-bipyridine as a probe molecule. DFT calculations allowed for obtaining information on the adsorption of the ligand molecules that strongly interact with positively charged surface active sites of the gold nanoparticles, thus providing efficient SERS enhancement. The presence of iron oxide gives the bimetallic colloid new possibilities of adsorption in addition to those inherent to gold nanoparticles, especially regarding organic pollutants and heavy metals, allowing to remove them from the aqueous environment by applying a magnetic field. Moreover, these nanoparticles, thanks to their low toxicity, are potentially useful not only in the field of sensors, but also for biomedical applications.
关键词： SERS,magnetite,gold,2,2'-bipyridine,laser ablation
更新于2025-09-19 17:13:59
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Nanoplasmonic sensor for foodborne pathogens detection. Towards development of ISOa??SERSa??PCA methodology of taxonomic affiliation of Campylobacter spp
摘要： According to EU summary report on zoonoses, zoonotic agents and food-borne outbreaks in 2017, Campylobacter was the most commonly reported gastrointestinal bacterial pathogen in humans in the EU. Unfortunately, the standard methods for detection of thermotolerant Campylobacter spp. in foods are time-consuming. Additionally, the qualified staff is obligatory. For this reason, the new methods of pathogens detection are needed. The present work demonstrates that surface-enhanced Raman scattering (SERS) is a reliable and fast method for detection of Campylobacter spp. in food samples. The proposed method combines the SERS measurements performed on an Ag/Si substrate with two initial steps of the ISO standard procedure. Finally, the principal component analysis (PCA) allows for statistical classification of the studied bacteria. By applying the proposed ISO-SERS-PCA method in the case of Campylobacter bacteria the total detection time may be reduced from 7-8 days required by ISO method to 3-4 days in the case of SERS-based approach.
关键词： PCA,ISO,foodborne bacteria,surface-enhanced Raman spectroscopy,SERS,Campylobacter spp.
更新于2025-09-19 17:13:59
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Plasmon-coupled Charge Transfer in FSZA Core-shell Microspheres with High SERS Activity and Pesticide Detection
摘要： A commercial SeRS substrate does not only require strong enhancement, but also can be reused and recycled in actual application. Herein, fe3o4/Sio2/Zno/Ag (fSZA) have been synthesised, which consisted of fe3o4 core with strong magnetic field response and an intermediate SiO2 layer as an electronic barrier to keep the stability of magnetite particles and outer ZnO and Ag as the effective layers for detecting pollutants. The SERS enhancement factor (EF) of the FSZA was ~8.2 × 105. the enhancement mechanism of the fSZA core-shell microspheres were anatomized. the electromagnetic enhancement of surface deposited Ag, charge transfer, and molecular and exciton resonances act together to cause such high enhancement factors. for practical application, the fSZA core-shell microspheres were also used to detect thiram, moreover, which was collected and separated by an external magnetic field, and maintained the SERS activity without significant decline during multiple tests. So the good enhancement performance and magnetic recyclability make the fSZA core-shell microspheres a promising candidates for practical SeRS detection applications.
关键词： pesticide Detection,plasmon-coupled charge transfer,High SeRS Activity,fSZA core-shell Microspheres
更新于2025-09-19 17:13:59
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Suba??10 nm Aua??Ag Heterogeneous Plasmonic Nanogaps
摘要： Controlling the formation of bimetallic heterogeneous nanogaps structures have many applications in the plasmonics and catalysis fields. Here, a simple and systematic method is developed to fabricate tunable and stable Au–Ag nanowire-based plasmonic metamaterials. The sub-10 nm Au–Ag bimetallic heterogeneous nanogaps with desirable optical properties are fabricated by a simple, ultrarapid, and robust nanoskiving technique. Compared to the monometallic linear Ag–Ag and Au–Au nanogaps, the Au–Ag bimetallic heterogeneous nanogaps exhibit remarkable surface enhanced Raman spectroscopy (SERS) enhancement properties due to the nanogaps between the adjacent Au/Ag nanowires, and the Ag/Au bimetallic composite film. In addition, 3D bimetallic heterogeneous nanogaps are built and produce much stronger electric fields than those of the 1D linear nanogaps. The sub-10 nm Au–Ag heterogeneous nanogaps are promising to be used in SERS substrate, plasmon devices, catalysis, and printed electronics.
关键词： surface-enhanced Raman spectroscopy (SERS),surface plasmon resonance,nanoskiving,heterogeneous nanogaps
更新于2025-09-19 17:13:59
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Redox-State-Mediated Regulation of Cytochrome?c Release in Apoptosis Revealed by Surface-Enhanced Raman Scattering on Nickel Substrates
摘要： The interaction of cytochrome c (Cyt c) with cardiolipin (CL) is believed to play an important role in the initial events of apoptosis. Herein, we investigate the structural changes of CL-bound Fe2+Cyt c and the correlation with Cyt c release through surface-enhanced Raman spectroscopy (SERS) on nickel substrates. The SERS results together with molecular dynamics simulation reveal that Fe2+Cyt c undergoes autoxidation and a relatively larger conformational alteration after binding with CL, inducing higher peroxidase activity of Cyt c and higher permeability of the CL membrane compared with those induced by the Fe3+Cyt c. The proapoptotic activity and SERS effect of the Ni nanostructures allow the in situ study of the redox-state-dependent Cyt c release from isolated mitochondria, which reveals for the first time that the ferrous state of Cyt c most likely plays a more important role in triggering apoptosis.
关键词： redox state,apoptosis,cytochrome c,nickel,SERS
更新于2025-09-19 17:13:59
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3D Ultrasensitive Polymers-Plasmonic Hybrid Flexible Platform for In-Situ Detection
摘要： This paper introduces a three-dimensional (3D) pyramid to the polymers-plasmonic hybrid structure of polymethyl methacrylate (PMMA) composite silver nanoparticle (AgNPs) as a higher quality flexible surface-enhanced Raman scattering (SERS) substrate. Benefiting from the effective oscillation of light inside the pyramid valley could provide wide distributions of 3D 'hot spots' in a large space. The inclined surface design of the pyramid structure could facilitate the aggregation of probe molecules, which achieves highly sensitive detection of rhodamine 6G (R6G) and crystal violet (CV). In addition, the AgNPs and PMMA composite structures provide uniform space distribution for analyte detection in a designated hot spot zone. The incident light can penetrate the external PMMA film to trigger the localized plasmon resonance of the encapsulated AgNPs, achieving enormous enhancement factor (~6.24 × 108). After undergoes mechanical deformation, the flexible SERS substrate still maintains high mechanical stability, which was proved by experiment and theory. For practical applications, the prepared flexible SERS substrate is adapted to the in-situ Raman detection of adenosine aqueous solution and the methylene-blue (MB) molecule detection of the skin of a fish, providing a direct and nondestructive active-platform for the detecting on the surfaces with any arbitrary morphology and aqueous solution.
关键词： PMMA,AgNPs,adenosine,SERS,methylene-blue,in-situ
更新于2025-09-19 17:13:59
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Waste to wealth translation of e-waste to plasmonic nanostructures for surface-enhanced Raman scattering
摘要： Here we report, for the first time, a simple one-step recycling of discharged batteries, a major constituent of electronic waste (e-waste), into value-added fluorescent nanomaterials-carbon quantum dots (CQDs). The e-waste derived CQDs (eW-CQDs) were systematically characterized for their optical properties, including absorption, photoluminescence, quantum yield, and emission lifetime. The morphology of these nanomaterials was determined by high-resolution transmission electron microscopy, selected area electron diffraction, and X-ray diffraction, whereas Raman spectroscopy was used to confirm their carbonaceous architecture. To broaden the range of applications, the eW-CQDs were employed in the synthesis of plasmonic nanostructures (eW-Au@CQDs) via a one-step chemical reduction strategy. Both eW-CQDs and eW-Au@CQDs were further tested for their suitability to be used as surface-enhanced Raman (SERS) substrates for the detection of methylene blue (MB), a model dye and Raman reporter. Our results show that while eW-CQDs are not ideal for SERS applications, eW-Au@CQDs, when deposited on a gold-modified screen-printed carbon electrode (SPE), produce strong MB SERS signals. With further optimization, these eW-Au@CQDs-modified SPEs could find applications in SERS-based sensing. This study demonstrates a new, promising, and sustainable approach of converting e-waste such as discharged batteries into value-added products with potential for a wide range of applications.
关键词： E-waste,Discharged batteries,Recycling,SERS,Carbon quantum dots,Methylene blue
更新于2025-09-19 17:13:59
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Extending Surface‐Enhanced Raman Spectroscopy to Liquids using Shell‐Isolated Plasmonic Superstructures
摘要： Plasmonic superstructures (PS) based on Au/SiO2 were prepared for Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS) in liquid phase applications. These superstructures are composed of functionalized SiO2 spheres with plasmonic Au nanoparticles (NPs) on their surface. Functionalization was performed with (3-aminopropyl)-trimethoxysilane, and poly(ethylene-imine) (PEI). Of these three, PEI-functionalized spheres showed the highest adsorption density of Au NPs in TEM, UV/Vis and dynamic light scattering (DLS) experiments. Upon decreasing the Au NP/SiO2 sphere size ratio, an increase in adsorption density was also observed. To optimize plasmonic activity, 61 nm Au NPs were adsorbed onto 900 nm SiO2-PEI spheres and these PS were coated with an ultrathin layer (1–2 nm) of SiO2 to obtain Shell-Isolated Plasmonic Superstructures (SHIPS), preventing direct contact between Au NPs and the liquid medium. Zeta potential measurements, TEM and SHINERS showed that SiO2 coating was successful. The detection limit for SHINERS using SHIPS and a 638 nm laser was around 10?12 m of Rhodamine (10?15 m for uncoated PS), all with acquisition settings suitable for catalysis applications.
关键词： Raman spectroscopy,plasmonic nanoparticles,reaction monitoring,heterogeneous catalysis,SERS
更新于2025-09-19 17:13:59
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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
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An Assembled Ordered W18O49 Nanowire Film with high SERS Sensitivity and Stability for the detection of RB
摘要： In this work, a novel ordered nanowire film composed of non-stoichiometric semiconductor metal oxide, W18O49, was assembled by a three-phase-interface approach. The prepared W18O49 nanowires possess relatively uniform morphologies with average diameter of about 10 nm. When employed as the SERS substrate for the detection of rhodamine B (RB), the ordered W18O49 nanowire film calcined in Ar/H2 (W18O49-H2) exhibited stronger SERS signal than W18O49 nanowire films which resulted from the existence of more oxygen vacancies due to the reduction effect of H2. The SERS detection limit of RB on W18O49-H2 nanowire films reached 10-7 M. And more importantly, the W18O49-H2 nanowire film SERS substrate possessed outstanding reproducibility for detecting RB because of the ordered as well as stable morphology, reflecting in the low relative standard deviation (RSD) (9.7%). Therefore, as a new non-noble metal SERS substrate, the W18O49-H2 nanowire film provides an important inspiration for its wide application in the detection of pollutants.
关键词： reproducibility,ordered W18O49 nanowire film,SERS substrate,RB detection
更新于2025-09-19 17:13:59