Modern track-etching methods allow the preparation of membranes containing a single charged conical nanopore that shows high ionic permselectivity due to the electrical interactions of the surface pore charges with the mobile ions in the aqueous solution. The nanopore has potential applications in electrically assisted single-particle detection, analysis, and separation of biomolecules. We present a detailed theoretical and experimental account of the effects of pore radii and electrolyte concentration on the current-voltage and current-concentration curves. The physical model used is based on the Nernst-Planck and Poisson equations. Since the validity of continuum models for the description of ion transport under different voltages and concentrations is recognized as one of the main issues in the modeling of future applications, special attention is paid to the fundamental understanding of the electrical interactions between the nanopore fixed charges and the mobile charges confined in the reduced volume of the inside solution.
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http://dx.doi.org/10.1063/1.2179797 | DOI Listing |
Anal Chem
January 2025
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Ligand binding to membrane proteins initiates numerous therapeutic processes. Surface plasmon resonance (SPR), a popular method for analyzing molecular interactions, has emerged as a promising tool for in situ determination of membrane protein binding kinetics owing to its label-free detection, high surface sensitivity, and resistance to intracellular interference. However, the excitation of SPR relies on noble metal films, typically gold, which are biologically incompatible and can cause fluorescence quenching.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Electrical and Electronic Engineering, Pabna University of Science and Technology, Pabna, Bangladesh.
Waterborne bacteria pose a serious hazard to human health, hence a precise detection method is required to identify them. A photonic crystal fiber sensor that takes into account the dangers of aquatic bacteria has been suggested, and its optical characteristics in the THz range have been quantitatively assessed. The PCF sensor was designed and examined as computed in Comsol Multiphysics, a program in which uses the method of "Finite Element Method" (FEM).
View Article and Find Full Text PDFJ Mol Model
January 2025
Nanjing Hydraulic Research Institute, Shanghai, China.
Context: This study systematically investigated the effects of single S-atom vacancy defects and composite defects (vacancy combined with doping) on the properties of MoS using density functional theory. The results revealed that N-doped S-vacancy MoS has the smallest composite defect formation energy, indicating its highest stability. Doping maintained the direct band gap characteristic, with shifts in the valence band top.
View Article and Find Full Text PDFNano Lett
January 2025
Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
The advent of two-dimensional van der Waals materials is a frontier of condensed matter physics and quantum devices. However, characterizing such materials remains challenging due to the limitations of bulk material techniques, necessitating the development of specialized methods. Here, we investigate the superconducting properties of BiSrCaCuO flakes by integrating them with a hybrid superconducting microwave resonator.
View Article and Find Full Text PDFBiol Aujourdhui
January 2025
Institut d'Écologie et des Sciences de l'Environnement de Paris (iEES Paris), Paris, France - Sorbonne Université, 4 place Jussieu, 75005 Paris, France.
The evolutionary success of angiosperms, which make up more than 95 percent of the world's terrestrial flora, is largely based on their interactions with animal pollinators. Indeed, it is estimated that, on average, 87.5 percent of flowering plants are pollinated by animals.
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