Herein we describe the fabrication and characterization of Ag and Au bimetallic plasmonic crystals as a system that exhibits improved capabilities for quantitative, bulk refractive index (RI) sensing and surface-enhanced Raman spectroscopy (SERS) as compared to monometallic plasmonic crystals of similar form. The sensing optics, which are bimetallic plasmonic crystals consisting of sequential nanoscale layers of Ag coated by Au, are chemically stable and useful for quantitative, multispectral, refractive index and spectroscopic chemical sensing. Compared to previously reported homometallic devices, the results presented herein illustrate improvements in performance that stem from the distinctive plasmonic features and strong localized electric fields produced by the Ag and Au layers, which are optimized in terms of metal thickness and geometric features. Finite-difference time-domain (FDTD) simulations theoretically verify the nature of the multimode plasmonic resonances generated by the devices and allow for a better understanding of the enhancements in multispectral refractive index and SERS-based sensing. Taken together, these results demonstrate a robust and potentially useful new platform for chemical/spectroscopic sensing.
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http://dx.doi.org/10.3762/bjnano.8.249 | DOI Listing |
Nat Commun
January 2025
NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
Membrane bound histidine kinases (HKs) are ubiquitous sensors of extracellular stimuli in bacteria. However, a uniform structural model is still missing for their transmembrane signaling mechanism. Here, we used solid-state NMR in conjunction with crystallography, solution NMR and distance measurements to investigate the transmembrane signaling mechanism of a paradigmatic citrate sensing membrane embedded HK, CitA.
View Article and Find Full Text PDFRegen Ther
March 2025
Department of Hepatobiliary Surgery, Affiliated Hospital of Youjiang Ethnic Medical University, Baise, 533000, China.
In this work, laponite (LAP) was used to develop the silver (Ag) based nanocomposite for improved anti-bacterial action and wound healing properties. The amphiphilic co-polymers such as PLGA polymer was embedded with the surface of LAP molecules and polyethyleneimine (PEI) through the interaction of hydrophobic binding and it was formed as LAP/PLA-PEG/PEI formulation through the coupling chemistry. The Ag nanoparticles was loaded into formulation to develop LAP/PLA-PEG/PEI/Ag nanocomposite and characterized by different analytical techniques.
View Article and Find Full Text PDFNanoscale Adv
December 2024
Department of Biological Sciences and Engineering, Indian Institute of Technology Palakkad Palakkad Kerala 678 623 India.
Since the initial publication on the first TiCT MXene in 2011, there has been a significant increase in the number of reports on applications of MXenes in various domains. MXenes have emerged as highly promising materials for various biomedical applications, including photothermal therapy (PTT), drug delivery, diagnostic imaging, and biosensing, owing to their fascinating conductivity, mechanical strength, biocompatibility and hydrophilicity. Through surface modification, MXenes can mitigate cytotoxicity, enhance biological stability, and improve histocompatibility, thereby enabling their potential use in biomedical applications.
View Article and Find Full Text PDFLangmuir
January 2025
Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe, Mizuho, Nagoya 467-8603, Aichi, Japan.
In this study, we demonstrate a novel and efficient fabrication methodology for nonclose-packed, two-dimensional (2D) colloidal crystals exhibiting square lattice structures. In our recent work, we detailed the formation of 2D colloidal crystals via the electrostatic adsorption of three-dimensional (3D) charged colloidal crystals onto oppositely charged substrates. These 3D colloidal crystals possessed a face-centered cubic (FCC) lattice structure with their (111) planes aligned parallel to the substrate, facilitating the formation of 2D crystals with triangular lattice arrangements upon adsorption.
View Article and Find Full Text PDFBiotechnol Rep (Amst)
March 2025
Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK.
Unlabelled: Ongoing research in biosensor technologies has led to advanced functional materials for healthcare diagnostics, and bacteriophages (phages), demonstrating exceptional utility due to their high specificity, accuracy, rapid, label-free, and wireless detection capabilities with minimal false-positive results. Phage-based-pathogen-detecting biosensors (PBPDBs) include surface plasmon resonance (SPR) biosensors, magnetoelastic (ME), electrochemical, and quartz crystal microbalance (QCM) biosensors. Commonly used substrates for PBPDBs are gold, silicon, glass, carbon-based materials, magnetic particles, and quantum dots.
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