Langmuir最新文献

Conventional approaches for bacterial cell analysis are hindered by lengthy processing times and tedious protocols that rely on gene amplification and cell culture. Impedance spectroscopy has emerged as a promising tool for efficient real-time bacterial monitoring, owing to its simple, label-free nature and cost-effectiveness. However, its limited practical applications in real-world scenarios pose a significant challenge. In this review, we provide a comprehensive study of impedance spectroscopy and its practical utilization in bacterial system measurements. We begin by outlining the fundamentals of impedance theory and modeling, specific to bacterial systems. We then offer insights into various strategies for bacterial cell detection and discuss the role of impedance spectroscopy in antimicrobial susceptibility testing (AST) and single-cell analysis. Additionally, we explore key aspects of impedance system design, including the influence of electrodes, media, and cell enrichment techniques on the sensitivity, specificity, detection speed, concentration accuracy, and cost-effectiveness of current impedance biosensors. By combining different biosensor design parameters, impedance theory, and detection principles, we propose that impedance applications can be expanded to point-of-care diagnostics, enhancing their practical utility. This Perspective focuses exclusively on ideally polarizable (fully capacitive) electrodes, excluding any consideration of charge transfer resulting from Faradaic reactions.

Salinity gradient energy is a chemical potential energy between two solutions with different ionic concentrations, which is also an ocean energy at the junction of rivers and seas. In our original work, the device "activated carbon//(0.083 M Na₂SO₄, 0.5 M Na₂SO₄)//vanadium pentoxide" for the conversion of salinity gradient energy was designed, and the conversion value of 6.29 J g^-1 was obtained. However, the low specific surface area of the original V₂O₅ inevitably resulted in limited active sites and slow ionic transport rates, and the inherent lower conductivity and narrower layer spacing of the original V₂O₅ also resulted in poor electrode kinetic performance and cycle stability, hindering its practical application. To solve the above problems, the present work provides a strategy of using polyaniline (PANI) molecule chain intercalation to regulate the layer spacing of the original V₂O₅, and through the expansion and traction of the layer spacing, the composite PANI/V₂O₅ (PVO) with high specific surface area is prepared and used as an anode material for electrochemical conversion of salinity gradient energy application. The significantly increased layer spacing of the crystal plane (001) corresponding to the original V₂O₅ was confirmed with the PANI by the hydrogen bonding and the van der Waals force. The high specific surface area of the composite provides more electrochemical active sites to realize a fast Na⁺ migration rate and high specific capacitance. Meanwhile, the inserted PANI molecule chain, which acts not only as a pillar enlarging the Na⁺ diffusion channel but also as an anchor locking the gap between V₂O₅ bilayers, improves the structural stability of the V₂O₅ electrode during the electrochemical conversion process. The proposed insertion strategy for the conductive polymer PANI has created a new way to improve the cycle stability performance of the salinity gradient energy conversion device.

This research studied the role of DMSO in a binary system of Triton X and water in the hexagonal mesophase. One effect of DMSO addition, determined using polarized optical microscopy and small-angle X-ray scattering measurements, is to promote a decrease in the hexagonal to isotropic phase transition temperature, T_H-ISO, decreasing the range of temperatures of the hexagonal phase until the hexagonal phase completely disappears when DMSO is added up to 5.0 mol %. The periodicity and the lattice parameter of the hexagonal arrangement, calculated as a function of DMSO concentration, slight increased due to the insertion of DMSO molecules in the water region, causing a greater distance between the cylindrical micelles, while the radius of the apolar domains kept constant at 22 (1) Å.

Economic synthesis of amine-modified solid adsorbents is pivotal for the global-scale direct air capture (DAC) technologies required to realize net-zero emissions. To address the problems of the traditional reflux method using excessively costly amino silane, we propose introducing silane by impregnation into mesoporous silica with interconnected three-dimensional pores. X-ray diffraction, Fourier transform infrared spectroscopy, N₂ adsorption-desorption, transmission electron and scanning electron microscopies, magic-angle spinning nuclear magnetic resonance, and elemental analysis identified the spatial distribution of amino silane in the materials with different loading levels. The results of structure characterization and a comparison with a reference experiment (using a porous support with one-dimensional pores and/or the conventional reflux method) revealed that the proposed strategy provided a uniform amine distribution, together with a high utilization efficiency of the amino silane. We also demonstrate that the obtained material has a high adsorption capacity and good recycling stability comparable to those of the previously reported amino silane modified adsorbents under simulated DAC conditions.

The limited active sites and faster photogenerated electron-hole pair recombination rate of g-C₃N₄ restrict its application in photocatalytic H₂ production. Constructing heterojunctions has been shown to improve the spatial (directional) separation of photogenerated electrons and holes. However, due to interface mismatch in traditional heterojunction structures and a lack of precise electron transport channels, the photocatalytic efficiency is limited. Here, we developed a two-step calcination approach to create an Fe₂N/g-C₃N₄ heterojunction linked by Fe-O bonds (named as Fe-OCN). The newly formed Fe-O bonds within the heterojunction can act as atomic-level interface electron transfer channels, directly transferring the photogenerated electrons of g-C₃N₄ to the reactive center Fe₂N, significantly improving the charge transfer rate and utilization, thus promoting visible-light-driven photocatalytic H₂ production. The optimal Fe-OCN achieved a H₂ production rate of 5986.29 μmol g^-1 h^-1 under visible light, 13.44 times higher than that of the OCN due to efficient charge separation and transfer capabilities. This work provides a constructive reference for the design and synthesis of organic-inorganic heterojunction with chemically bonded interfaces, establishing quick electron transfer channels, and achieving targeted electron transfer.

Shale contains numerous organic micropores with significant potential for CO₂ storage. To precisely evaluate the CO₂ storage potential of shale reservoirs, it is essential to accurately quantify the adsorption of CO₂ within these pores. This study used Grand Canonical Monte Carlo (GCMC) molecular simulations to analyze the CO₂ adsorption behavior in organic micropores of varying sizes. The study clarified the number and width of the CO₂ adsorption layers in micropores of various sizes and proposed a method for segmenting the multilayer adsorption structure. Additionally, the classic Ono-Kondo lattice (OK) model was extended to characterize pore-filling adsorption, incorporating solid-gas and gas-gas interactions. Accurate characterization of CO₂ multilayer adsorption and precise calculation of CO₂ absolute adsorption in micropores were achieved. Results indicate that CO₂ exhibits pore-filling adsorption behavior in organic micropores, forming a multilayer adsorption structure governed by the pore size. Following symmetry principles, the adsorption layer structure in organic micropores can be simplified to a maximum of three layers. When only one adsorption layer forms, its width equals the gas-accessible pore size. For two or more layers, the width of the original layer stabilizes as additional layers form. The stable adsorption layer widths, from nearest to farthest from the pore wall, are 0.33, 0.45, and 0.39 nm. The improved OK model accurately describes CO₂ excess and absolute adsorption isotherms across different pore sizes and calculates the CO₂ density in each adsorption layer, showing high consistency with GCMC simulation results. These findings highlight the importance of understanding the CO₂ multilayer adsorption structure for accurately estimating CO₂ adsorption in organic micropores.

Proteins exhibit diverse structures, including pockets, cavities, channels, and bumps, which are crucial in determining their functions. This diversity in topography also introduces significant chemical heterogeneity, with polar and charged domains often juxtaposed with nonpolar domains in proximity. Consequently, accurately assessing the hydropathy of amino acid residues within the intricate nanoscale topology of proteins is essential. This study presents quantitative hydropathy data for 277,877 amino acid residues, computed using the Protocol for Assigning a Residue's Character on a Hydropathy (PARCH) scale. Leveraging this data set comprising 1000 structurally diverse proteins sourced from the Protein Data Bank, we examined residues situated in various nanoscale environments and analyzed hydropathy in relation to protein topography. Our findings indicate that the hydropathy of a residue is intricately linked to both its individual characteristics and the geometric features of its neighboring residues in response to water. Changes in the number and chemical identity of the neighbors, as well as the nanoscale topography surrounding a residue, are mirrored in its hydropathy profile. Our calculations reveal the intricate interplay of hydrophilic, hydroneutral, and hydrophobic residues distributed across the surface and core of proteins. Notably, we observe that protein surfaces can be ten times more hydrophilic than their cores.

In this work, silk was selected as the substrate, and formic acid was utilized to create a rough texture on the silk. The conductive fabrics made from AgNWs and silk were created by applying multiple layers of silver nanowire dispersion onto the textured silk fabrics (SFs). The silk was immersed in a dispersion containing polydopamine (PDA), sericin (SE), tannic acid (TA), and silver nanowire under specific temperature conditions. After being cured at 120 °C, the three silver nanowire/silk fabrics (AgNWs/SFs), PDA/AgNWs/SF, SE/AgNWs/SF, and TA/AgNWs/SF, exhibited square resistances of 7.37, 540, and 200 Ω/sq, respectively. The method used to prepare the AgNW conductive SF is straightforward, resulting in fabrics that possess excellent thermal stability and resistance to washing. These fabrics also exhibit a range of useful properties, including conductivity, electrothermal capabilities, electrochemical functionality, human body sensing, hydrophobicity, and antimicrobial properties. These characteristics make them highly promising for various applications, such as human body motion detection, electronic textiles, electrothermal textiles, and antimicrobial applications.

Superhydrophobic materials have been widely applied in oil-water separation, self-cleaning, antifouling, and drag reduction; however, their role in liquid evaporation and drying remains unexplored. Inspired by the microstructure of the nonwetting legs of water striders, we designed a low-adhesion superhydrophobic cylindrical barrel (CB) derived from stainless-steel mesh (SSM) to enhance liquid thermal evaporation and drying. The CB was created by hydrothermally depositing zinc oxide (ZnO) with multilevel morphologies onto metal wires, followed by modification with low-surface-energy stearic acid (SA). We investigated the impact of the SSMCB on water evaporation and analyzed the decline in the liquid levels under varying porosities and temperatures through numerical normalization. A functional relationship was established between decline height, porosity, and temperature, revealing that the drop height increased from 3.7 to 25 mm as porosity increased from 0 to 0.5263. Moreover, the superhydrophobic coating demonstrated excellent resistance to friction and peeling, indicating improved mechanical stability.