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An integrated approach for trace detection of pollutants in water using polyelectrolyte functionalized magneto-plasmonic nanosorbents
摘要： Resistance of pathogenic micro-organisms to conventional antibiotics is an essential issue for public health. the presence of such pharmaceuticals in aquatic ecosystems has been of major concern for which remediation and ultra-sensitive monitoring methods have been proposed. A less explored strategy involves the application of multifunctional nanosorbents for the uptake and subsequent detection of vestigial contaminants. in this study, colloidal nanoparticles (nps) of iron oxide and gold were encapsulated in multi-layers of a charged polyelectrolyte (pei: polyethyleneimine), envisaging the effective capture of tetracycline (TC) and its subsequent detection by Surface Enhanced Raman Scattering (SeRS). Adsorption studies were performed by varying operational parameters, such as the solution pH and contact time, in order to evaluate the performance of the nanosorbents for the uptake of tc from water. While the magnetic nanosorbents with an external pei layer (fe3o4@pei and fe3o4@PEI-Au@PEI particles) have shown better uptake efficiency for TC, these materials showed less SERS sensitivity than the fe3o4@pei- Au nanosorbents, whose SeRS sensitivity for tc in water has reached the limit of detection of 10 nM. Thus, this study highlights the potential of such magneto-plasmonic nanosorbents as multi-functional platforms for targeting specific contaminants in water, by taking into consideration both functionalities investigated: the removal by adsorption and the SeRS detection across the nanosorbents’ surfaces.
关键词： tetracycline,SERS detection,water pollutants,adsorption,magneto-plasmonic nanosorbents
更新于2025-09-16 10:30:52
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Faraday Effect and Magnetic Circular Dichroism in Media with Magneto-Plasmonic Nanoparticles and Two-Particle Clusters
摘要： The Faraday rotation and magnetic circular dichroism (MCD) in media containing spherical layered nanoparticles with a ferromagnetic core and a plasmon shell or two-particle clusters consisting of ferromagnetic and plasmonic nanoparticles are studied theoretically. Optical absorption spectra, MCD spectra, the orientation angle of the polarization ellipse, and the ellipticity of the light wave are calculated for these systems in the quasistatic approximation of electrodynamics. It is shown that the magneto-optical response of media with magneto-plasmon inclusions depends on the size of the ferromagnetic component of the inclusion. Moreover, this dependence is more pronounced for layered particles, and the response in the region of plasmon resonance of the noble metal is greater than for two-particle clusters.
关键词： magnetic circular dichroism,Faraday rotation,two-particle cluster,magneto-optical phenomena,magneto-plasmonic nanoparticle,dipole dynamic polarizability
更新于2025-09-12 10:27:22
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Enhanced Resonant Faraday Rotation in Multilayer Magnetoplasmonic Nanohole Arrays and Their Sensing Application
摘要： The optical and magneto-plasmonic properties of Ag/Co and Ag/Co/Ag multilayer nano-hole arrays have been investigated. By including a top- and bottom-Ag plasmonic layer onto a Co ferromagnetic perforated film, strong extraordinary optical transmission peaks and Wood’s anomalies (transmission minima) at both film-air and film-glass interfaces of the film are observed. The coupling between plasmonics and magneto-optics in the arrays gives rise to several resonantly enhanced Faraday rotation peaks that are much sharper than the plasmonic peaks/dips. The rotation peaks appeared exactly at the transmission minima have widths as narrow as 13 nm, which are much narrower than the transmission peaks (> 100 nm) and the accompanying transmission dips (~ 52 nm). The narrow line width of this enhanced Faraday rotation peak allows at least 2 times enhancement of the sensing performance, which is characterized by figure of merit, in compare to any other features of the optical transmission spectra.
关键词： Magnetic,Nano-Hole Arrays,Sensing Application,Hybrid Materials,Plasmonics,Magneto-Plasmonic,Faraday Rotation,Optical
更新于2025-09-12 10:27:22