Fluorescence intensity changes were investigated theoretically and experimentally using self-assembled colloidal structures on silver semitransparent mirrors. Using a simplified quasi-static model and finite element method, we demonstrate that near-field interactions of metallic nanostructures with a continuous metallic surface create conditions that produce enormously enhanced surface plasmon resonances. The results were used to explain the observed enhancements and determine the optimal conditions for the experiment. The theoretical parts of the studies are supported with reports on detailed emission intensity changes which provided multiple fluorescence hot spots with 2-3 orders of enhancements. We study two kinds of the fluorophores: dye molecules and fluorescent nanospheres characterized with similar spectral emission regions. Using a lifetime-resolved fluorescence/reflection confocal microscopy technique, we find that the largest rate for enhancement (~1000-fold) comes from localized areas of silver nanostructures.
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http://dx.doi.org/10.1117/1.3500463 | DOI Listing |
Sci Rep
January 2025
Ecology and Allergology Lab, Department of Zoology, Golapbag Campus, The University of Burdwan, Burdwan, 713104, West Bengal, India.
The jute hairy caterpillar, Spilosoma obliqua (Lepidoptera: Erebidae) is considered as one of the major threats to jute cultivation. The best eco-friendly methods to combat these jute pests involve administration of nano-biopesticides, as a successful alternative to the toxic chemicals. In this study, a nano-biopesticide formulation containing green synthesized silver nanoparticles (Ag NPs) using Ocimum sanctum leaf extract has been proposed.
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January 2025
Department of Chemistry, Devchand College, Arjunnagar, Kolhapur, MH, 591237, India.
Acoustical properties are essential for understanding the molecular interactions in fluids, as they influence the physicochemical behavior of liquids and determine their suitability for diverse applications. This study investigated the acoustical parameters of silver nanoparticles (Ag NPs), reduced graphene oxide (rGO), and Ag/rGO nanocomposite nanofluids at varying concentrations. Ag NPs and Ag/rGO nanocomposites were synthesized via a Bos taurus indicus (BTI) metabolic waste-assisted method and characterized using advanced techniques, including XRD, TEM, Raman, DLS, zeta potential, and XPS.
View Article and Find Full Text PDFAnal Chim Acta
February 2025
Engineering Research Center of Optical Instrument and System, Ministry of Education and Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, No.516 Jungong Road, Shanghai, 200093, China.
Background: Surface-enhanced Raman scattering (SERS) has attracted much attention as a powerful detection and analysis tool with high sensitivity and fast detection speed. The intensity of the SERS signal mainly depended on the highly enhanced electromagnetic field of nanostructure near the substrate. However, the fabrication of high-quality SERS nanostructured substrates is usually complicated, makes many methods unsuitable for large-scale production of SERS substrates.
View Article and Find Full Text PDFAnal Chim Acta
February 2025
The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, No. 28 Xianning West Road, Xi'an, 710049, China. Electronic address:
Background: Plasmonic core-shell nanostructures with embedded internal markers used as Raman probes have attracted great attention in surface-enhanced Raman scattering (SERS) immunoassay for cancer biomarkers due to their excellent uniform enhancement. However, current core-shell nanostructures typically exhibit a spherical shape and are coated with a gold shell, resulting in constrained local field enhancement.
Results: In this work, we prepared a core-shell AuNR@BDT@Ag structure by depositing silver on the surface of Raman reporter-modified gold nanorods (AuNR).
Polymers (Basel)
January 2025
Centro de Investigación y Desarrollo Tecnológico en Electroquímica SC, Parque Tecnológico Querétaro s/n Sanfandila, Pedro Escobedo, Querétaro 76703, Mexico.
Our work describes the green synthesis of silver sulfide nanoparticles (AgS NPs) and their formulation into polycaprolactone fibers (PCL), aiming to improve the multifunctional biological performance of PCL membranes as scaffolds. For this purpose, an extract of rosemary () was employed as a reducing agent for the AgS NPs, obtaining irregular NPs and clusters of 5-60 nm, with a characteristic SPR absorption at 369 nm. AgS was successfully incorporated into PCL fibers by electrospinning using heparin (HEP) as a stabilizer/biocompatibility agent, obtaining nanostructured fibers with a ca.
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