Surface Charge Research Articles (Page 1)

Chloride-induced electron enrichment strategy: Stabilization mechanism and efficacy of calcium/magnesium modified biochar against chromium contamination in soil.

To combat the issue of pathogenic infections, the current work successfully synthesized a nanocomposite, which is based on the aqueous extract of Alkanna tinctoria (ATE) and silver-zinc oxide nanoparticles (ATE@Ag-ZnO NPs), using a green technique. Analytical methods were used to characterize the synthesized nanocomposite to verify its size, shape, distribution, surface charge, and crystallinity. The resulting nanocomposite created permanent colloidal nano-solutions, demonstrated excellent dispersion, and appeared at the nanoscale. The antimicrobial, antifungal, and antibiofilm characteristics of the ATE@Ag-ZnO nanocomposite were assessed. For every studied microbial strain, the ATE@Ag-ZnO nanocomposite's minimum inhibitory concentration (MIC) was determined. The encouraging findings showed that the MIC range of ATE@Ag-ZnO against all strains was 250-31.25µg/mL. It demonstrated promise against S. epidermidis and A. calcoaceticus, with a MIC of 31.25µg/mL. Furthermore, with inhibition zones of 22.0, 20.0, and 15.0mm, respectively, the ATE@Ag-ZnO nanocomposite demonstrated antibacterial efficacy against gram-positive bacteria A. calcoaceticus, S. epidermidis, and C. tropicalis at 250µg/mL. The highest percentage of inhibition (91.44%) was seen in S. aureus treated with 250µg/mL ATE@Ag-ZnO nanocomposite, followed by A. calcoaceticus (68.83%) and C. albicans (64.81%). In conclusion, we successfully created the green synthesized ATE@Ag-ZnO nanocomposite, which demonstrated promising antibacterial, antifungal, and antibiofilm agents against some pathogenic microbes.

Plant-symbiotic Trichoderma fungi attack microorganisms by secreting antibiotic membrane-permeabilising peptaibols such as alamethicin. These peptaibols also permeabilise plant root epidermis plasma membranes (PMs), but mild pretreatment with Trichoderma cellulase activates a unique cellulase-induced resistance to alamethicin (CIRA), via an unknown mechanism. We identify two Arabidopsis genes that are essential for the CIRA process: CIRA12 encodes a phosphatidylserine (PS) decarboxylase and CIRA13, a phospholipase Dζ, implying that specific changes in anionic membrane lipids mediate alamethicin resistance. Fluorescent sensors revealed that cellulase induced a laterally asymmetric decrease in PS and surface charge to outer periclinal root epidermal PMs. Consistently, the CIRA response was reversed by addition of lysoPS. CIRA13 is essential for vesicle trafficking, which in turn is crucial for CIRA induction. Overall, cellulase induces a cellular polarity with respect to phospholipids, not previously observed in plants, that is leading to increased lipid packing and preventing peptaibol permeabilization of the outer periclinal membrane.

Selective in situ growth of metal-organic frameworks (MOFs) within polymeric supports under mild, aqueous conditions remains a synthetic challenge due to interfacial instability, uncontrolled crystallization, and MOF leaching. Here, this study reports a binding-assisted strategy for the selective in-pore growth of MOF-808 within polyacrylonitrile (PAN)/polyvinyl pyrrolidone (PVP) hollow fibers at 30 °C. Alkaline hydrolysis of PAN introduces anchoring sites for zirconium clusters, while ethanol-assisted solvation promotes MOF crystallization under ambient conditions. The spatial distribution and surface charge of hydrolyzed PVP suppress MOF nucleation on the outer surface, enabling uniform in-pore growth with 34 wt.% loading and > 99% retention after ultrasonication. Post-synthetic functionalization with ethylenediaminetetraacetic acid (EDTA) imparts a strong affinity for Pb2+, Ni2+, and Co2+ ions. The EDTA-modified composite exhibits a 2.5-fold increase in Pb2+ adsorption kinetics compared to physically blended counterparts. A modularized 105 cm fiber unit effectively treats 1 L of a mixed-metal solution (10 ppm each), underscoring the scalability and process compatibility of this approach. This work demonstrates a mild, scalable, and leaching-resistant route for fabricating MOF-polymer hybrid sorbents through spatially controlled in-pore crystallization, offering a robust platform for water treatment and metal recovery applications.

Lung cancer remains a major global health challenge, in part because the efficacy of current treatment modalities is reduced by drug resistance and substantial adverse effects. This study assessed the suitability of liposomes as a drug delivery system to enhance the therapeutic efficacy of docetaxel (DTX) and all-trans retinoic acid (ATRA) against lung cancer. DTX- and ATRA-encapsulated liposomes were synthesized and characterized, exhibiting desirable physicochemical properties such as an appropriate particle size, a negative surface charge, and high drug encapsulation efficiency. in vitro assays using A549 lung cancer cells demonstrated that these liposomes produced markedly greater cytotoxicity compared to free drugs; additionally, these two medications acted synergistically to enhance antitumor activity. Treatment with the liposomes resulted in upregulation of the pro-apoptotic gene Bax and downregulation of the anti-apoptotic gene Bcl-2, indicating activation of apoptotic pathways. Furthermore, the liposomes inhibited cancer cell migration and invasion in vitro, suggesting that they could suppress tumor metastasis. Collectively, these findings provide evidence that liposomes containing DTX and ATRA possess favorable properties for the treatment of lung cancer and may overcome existing challenges to improve patient treatment outcomes. However, comprehensive in vivo studies are required to validate the efficacy and clinical potential of these nanocarriers.

This study explores the novel application of a pyridine-thiazole hybrid adsorbent, MPHT 4, for the efficient removal of methylene blue (MB) from contaminated water. The adsorbent was synthesized via a high-yield route and characterized using 1H/13C NMR, IR spectroscopy, HRESI-MS, elemental analysis, SEM, and BET surface area measurements. SEM revealed a homogeneous morphology with low porosity, while BET analysis indicated a surface area of 68.83m2/g and a total pore volume of 0.113cm³/g, classifying the material as a Type IV isotherm with micropores. The adsorption efficiency of MPHT 4 was systematically evaluated, achieving 86.7% removal of 25 ppm MB at pH 7 with a dosage of 1.0g/L within 60min. Kinetic studies confirmed a pseudo-second-order mechanism, while equilibrium data best fit the Freundlich isotherm, indicating multilayer adsorption on a heterogeneous surface. Thermodynamic analysis revealed a spontaneous and exothermic process, supported by a negative ΔG° (- 18.39kJ/mol) and a positive ΔH° (29.92kJ/mol). The adsorbent exhibited excellent stability and reusability over six cycles, facilitated by electrostatic interactions between MB and the negatively charged surface (pHPZC = 7.8). These findings highlight MPHT 4 as a promising, high-capacity adsorbent for MB removal, combining structural robustness, optimal porosity, and efficient regeneration for practical wastewater treatment applications.

Nanoaperture optical tweezers (NOTs) can trap single proteins using local electromagnetic field enhancements at metal surfaces and therefore they are also subject to surface interactions. To probe these interactions, we consider the power dependence of the trapping stiffness at the limit of zero power, where an attractive or repulsive static force remains. We analyze various proteins with different charge and find that negatively charged proteins are attracted to the gold surface and positively charged proteins are repelled. We interpret this attraction as coming from local positive image charges on the gold adjacent to the negatively charged glass-water interface, as confirmed by finite-element Poisson equation simulations.This work shows a way to quantify the important impact of surface interactions in nanophotonic single molecule sensors of biomolecules and nanoparticles and to gauge their surface charge.

Per- and polyfluoroalkyl substances (PFASs) are a category of extremely persistent environmental pollutants. Metal-organic frameworks (MOFs) have appeared as promising adsorbents for PFAS removal due to their large surface area, tunable porosity, and versatile surface chemistry, which are among the numerous treatment technologies available. This review critically evaluates current developments in the design, fabrication, and application of MOF-based (nano)materials for the adsorption of PFAS in aqueous environments. The adsorption efficacies of MOFs (e.g., pore size, surface charge, and functional groups) and PFASs (e.g., chain length, head group functionality, and polarity) are significantly influenced by their physicochemical properties. The selective and efficient removal of PFASs is governed by the interaction mechanisms such as electrostatic attraction, hydrophobic interactions, H-bonding, and Lewis acid-base coordination. In addition, the adsorption efficacy is significantly influenced by water quality conditions, including pH, ionic strength, background ions, and natural organic matter. Functionalized MOFs (e.g., those with amine, fluorinated, or hydrophobic groups) exhibit resilience to interference, although these factors can sometimes hinder their removal. Both experimental and computational studies have provided valuable mechanistic insights into the rational design of MOFs with improved selectivity and capacity. In addition, this review identifies critical challenges and future perspectives, such as the necessity of standard performance testing under realistic water matrices; the development of scalable, stable, and regenerable MOFs; and their integration into life-cycle assessment and toxicity evaluation.

Abstract Leveraging ferroelectric polarization is a viable method for boosting catalytic efficiency. The ferroelectric effect has shown enormous promise in enhancing the efficiency rate of catalysis, such as water splitting, CO2 reduction, and hydrogen production, in conventional catalytic systems like oxides and perovskites. By offering improved control over surface polarization, charge separation, and defect engineering, emerging materials; such as heterostructures and 2D materials are significantly expanding the possibilities of catalysis. The significance of ferroelectric materials in catalysis is examined in this review, with particular attention paid to how their switchable polarization can improve catalytic performance in various applications.

Ultra-high-voltage direct current (UHVDC) wall bushings are critical components in DC transmission systems, ensuring insulation integrity and operational reliability. In recent years, surface discharge incidents induced by charge accumulation at the gas–solid interface have become increasingly prominent. A comprehensive understanding of the electric field distribution and charge accumulation behavior of wall bushings under UHVDC is therefore essential for improving their safety and stability. In this work, an electrostatic field model of a ±800 kV UHVDC wall bushing core was developed using COMSOL Multiphysics 6.3. Based on this, a geometrically scaled model of the bushing core was further established to investigate charge distribution characteristics along the gas–solid interface under varying voltage amplitudes, application durations, and practical operating conditions. The results reveal that the maximum surface charge density occurs near the geometric corner of the core, with charge accumulation increasing as the applied voltage amplitude rises. Over time, the accumulation exhibits a saturation trend, approaching a steady state after approximately 480 min. Moreover, under actual operating conditions, the charge accumulation at the gas–solid interface increases by approximately 40%. These findings provide valuable insights for the design optimization of UHVDC wall bushings, thereby contributing to improved insulation performance and enhanced long-term operational reliability of DC transmission systems.

Mesenchymal Stem Cells Conditioned Media-Chitosan Nanoparticles against Clinical Carbapenem-Resistant Acinetobacter Baumannii: In-Vitro Study.

Extracellular Vesicles from Streptococcus parauberis Facilitate the Efficient Delivery of LL37 with Enhanced Antibacterial Activity.

The bioleaching efficiency of various solids, including mining waste, is influenced by the physicochemical changes occurring on the particle surface in the presence of microorganisms. Mineral modification is widely used in mineral processing and can also be applied in bioextraction and bioremediation. Surfactant adsorption can serve as a tool to control bacterial attachment, a critical factor in such processes. Bacterial adhesion promotes the intensification of leaching, while increased mobility reduces the metal removal. Therefore, the impact of such modification and its further effect on the release of toxic metals from mining waste was investigated, focusing on physicochemical aspects. Bioleaching experiments were conducted in shaken flasks for four weeks, with solid to liquid ratio of 1:10. Two types of surfactants were used: cationic (cetyltrimethylammonium bromide) and anionic (sodium dodecyl sulfate). Zeta potential was measured using the classic streaming potential and streaming current method. The surface morphology of the leaching residue was analysed using scanning electron microscopy. Secondary precipitates formed were identified by X-ray diffraction, revealing jarosite formation. The presence of surfactants caused a change in the surface charge of particles, which could affect the behaviour of bacteria during leaching and, thus, its efficiency. Arsenic was identified as the primary toxic element. When no modifications were applied, its recovery from the solid reached 1631 g/L after four weeks of leaching. Conditioning of the mineral waste with surfactants before the process resulted in lower metal content: 1264 mg/L for a cationic surfactant and 937 mg/L for an anionic surfactant. Moreover, a correlation was observed between the efficiency and the measured surface area — higher recovery rates were associated with larger specific surface area values. The adsorption of surface-active agents altered the surface properties of the waste material. Treatment with the anionic surfactant increased the negative zeta potential, whereas exposure to the cationic surfactant resulted in a positive surface charge. At the end of the bioleaching, all leaching residues exhibited a positive zeta potential. This effect was primarily caused by the formation of positively charged iron(III) precipitates under acidic conditions. It has been demonstrated that in the presence of microorganisms, arsenic can be released from mining waste and that surface modification with surfactants inhibits this process, which may have potential applications in preventing unwanted effects of bioweathering.

This work presents recent developments in the COSMO solvation model implementation in NWChem. A new cavity construction approach, based on the solvent-excluding surface (SES) and utilizing the well-established GEPOL algorithm, has been introduced. Additionally, a straightforward procedure to merge surface segments that are too close─often a source of numerical artifacts─has been implemented. The available methods for correcting outlying surface charges have also been reviewed and improved. To validate the new implementation, we computed dielectric solvation energies for a chemically diverse set of approximately 100 molecules, including neutral species, small ions, and common ionic liquid components. Results were compared to those from GAMESS using the double-cavity method as a reference. Although the double-cavity approach can be regarded as more accurate, the simpler correction schemes available in NWChem─based on scaling factors or Lagrange multipliers─can achieve excellent agreement if the potential is also properly corrected, with mean unsigned deviations of around 0.15 kcal/mol. Predictions of typical vapor-liquid and liquid-liquid equilibria using a COSMO-SAC variant based on NWChem also showed very promising results.

The objective of this research was to explore the application of controlled ice nucleation (CN) technology to enhance the critical quality attributes (CQAs) and manufacturing efficiency of freeze-dried monoclonal antibody (mAb) drug products. The study aimed to address challenges associated with conventional freeze-drying process, such as low supercooling temperatures and inhomogeneous ice nucleation temperatures, and to evaluate whether CN could improve product quality, and the overall efficiency of the lyophilization process. Various mAb drug products were manufactured using three different lyophilization methods during the freezing step, including conventional, annealing, and CN. The CQAs of the drug products were assessed, including residual moisture content, reconstitution time, product appearance, microscopic morphology, specific surface area, protein purity, charge variance, and sub-visible particulates. Comparative analyses were conducted to evaluate the impact of the CN on product quality and process efficiency. CN demonstrated significant improvements in product appearance, uniformity, reconstitution properties, and stability. It notably reduced the primary drying time, enhancing the overall efficiency of the freeze-drying process. Furthermore, the CN method produced lyophilized drug products with consistent cake appearance, improved quality, and enhanced stability, ensuring therapeutic efficacy and patient safety. CN technology represents a major advancement in pharmaceutical manufacturing. The implementation of CN has the potential to improve the CQAs of drug products, optimize the lyophilization process, reduce operational costs, and increase production throughput. These findings underscore the importance of adopting innovative technologies like CN to meet the growing demand for high-quality and efficient biopharmaceutical production.

Traditional photoelectrochemical (PEC) systems struggle to simultaneously achieve high efficiency, high stability, and low cost. Replacing water oxidation with oxidation of organic molecules emerges as an attractive strategy to enhance the hydrogen production efficiency of PEC systems while generating value-added anodic products. Here, a PEC system utilizing a Mo, N co-doped BiVO4 photoanode and NaClO4 electrolyte for the glycerol oxidation reaction to approaching the theoretical limit of current doubling that enables a two-electron reaction to be driven by a single photon, is reported. While nitrogen doping optimizes the bulk charge separation/transport performance of Mo-doped BiVO4 photoanodes, NaClO4 as the supporting electrolyte further enhances the reaction kinetics and surface charge extraction efficiency. The optimized system reaches a record photocurrent density of 9.73mAcm-2 at 1.23V versus RHE and a maximum internal quantum efficiency of 182%. It predominantly produces C-C cleavage products, including glycolaldehyde and formaldehyde, and can maintain stable performance for over 500h. DFT calculations reveal that glycerol can undergo adjacent hydroxyl bidentate chelation adsorption on the BiVO4 surface. This system is applicable for the current doubling reaction of various polyhydroxy alcohols, providing a potential pathway for efficient valorization of platform molecules and effective recycling of waste plastics.

On‐water surface synthesis has emerged as a powerful approach for constructing thin‐layer, crystalline 2D polyimines and their layer‐stacked covalent organic frameworks. This is achieved by directing monomer preorganization and subsequent 2D polymerization on the water surface. However, the poor compatibility of water with many organic monomers has limited the range of accessible 2D polyimine structures. Herein, the on‐liquid surface synthesis of crystalline 2D polyimine films from a water‐insoluble, C 3 ‐symmetric monomer previously deemed incompatible with aqueous systems is reported. In situ grazing incidence X‐ray scattering reveals a stepwise evolution of monomer adsorption, preorganization, and 2D polymerization assisted by the fluorinated surfactant monolayer, leading to the formation of large‐area, face‐on‐oriented 2D polyimine films. Notably, a pronounced lattice expansion from 3.4 nm in the monomer assembly to 5.3 nm in the 2D polyimine framework is observed, highlighting the templating effect of the preorganized monomers in defining the final crystallinity. The representative 2DPI‐TCQ‐DHB is obtained as free‐standing thin film with well‐defined hexagonal pores, mechanical robustness, and a negatively charged surface (zeta potential: −58.8 mV). Leveraging these structural characteristics, it is integrated 2DPI‐TCQ‐DHB films into osmotic power generators, achieving a power density of 16.0 W m −2 by mixing artificial seawater and river water, surpassing most nanoporous 2D membranes.

Extracellular vesicles (EVs) have emerged as critical mediators of intercellular communication, transporting diverse molecular cargoes such as proteins, lipids and nucleic acids. Despite their growing importance in both basic biology and clinical applications, the remarkable heterogeneity of EVs remains a major obstacle to their functional characterization. In a recent study, Maeda and colleagues developed a highly sensitive and quantitative method for monitoring EV release using high-affinity binary technology (HiBiT)-tagged marker proteins, combined with a novel chromatographic approach that fractionates EVs based on surface charge properties. This strategy enabled the identification of distinct EV subpopulations harbouring specific protein markers and differing in their biogenesis and intracellular origin. By integrating CRISPR-mediated tagging, live-cell luminescence assays and ion-exchange chromatography, the study establishes surface charge as a new physicochemical parameter for EV classification. These findings offer a powerful framework for dissecting EV heterogeneity and lay the foundation for the development of more precise EV-based diagnostic strategies.

Background: Zinc is an essential micronutrient as well as an effective antimicrobial agent, widely used in fish health management. Due to its relatively non-toxic nature, zinc is also employed in the green synthesis of nanoparticles. However, concerns remain regarding its potential toxicity, particularly in aquaculture and fish health applications. Methods: Pomegranate peel-mediated ZnO nanoparticles (PP-ZnO NPs) were synthesized via a green route. The nanoparticles were characterized using transmission electron microscopy (TEM) to determine particle morphology and size, dynamic light scattering (DLS) to assess hydrodynamic size distribution and polydispersity index (PDI) and zeta potential analysis to evaluate surface charge and colloidal stability. In vitro toxicity was assessed using the brine shrimp lethality assay (BSLA) to determine the effect of PP-ZnO NPs on shrimp survival. Result: TEM analysis revealed that the PP-ZnO NPs possessed a hexagonal wurtzite structure with an average size of 54±8 nm. DLS analysis showed that the nanoparticles were moderately monodispersed, with a PDI of 0.345, indicating slight agglomeration. Zeta potential measurements confirmed a negative surface charge (-41.5 mV), suggesting good colloidal stability. BSLA demonstrated that the PP-ZnO NPs were non-toxic to brine shrimp, indicating their biocompatibility and safety for potential applications.

High ionic conductivity electrolytes are vital for ensuring robust lithium-ion battery performance, especially in low-temperature environments. In this study, we systematically investigated a novel chemical space comprising 2604 electrolyte formulations using high-throughput molecular dynamics (MD) simulations, integrating the OPLS-AA force field with the RESP2 charge model. This methodology accurately replicated Li+ solvation shell structures and identified numerous innovative electrolytes exhibiting high room-temperature ionic conductivities more than 10 mS/cm, and many of which were experimentally validated for the first time. By leveraging MD data sets and the machine learning method, the composition-property relationships governing Li+ solvation shell structure and ion transport in electrolytes were elucidated. Li+ solvation shell structures are primarily influenced by solvent concentration, molecular topology, and surface charge distribution, with the higher solvent concentrations enhancing Li+-molecule coordination numbers. Ionic conductivity of electrolyte is predominantly determined by viscosity, and the low-viscosity components such as PF6-, DOL, DME, EA, and DMC boost ionic conductivity, while TFSI-, DEC, and EMC tend to reduce it. Additionally, the high coordination numbers with weakly coordinating solvents leading to the larger localized Li+ interactions further enhance ion transport in electrolyte. Molecular descriptors, including HallKierAlpha and MaxPartialCharge, exhibit strong correlations with ionic conductivity, serving as the effective metrics for the large-scale screening tasks. Consequently, the optimal high-conductivity electrolytes should incorporate low-viscosity solvents with high coordination numbers, strong Li+ binding energies, elevated HallKierAlpha values, and reduced MaxPartialCharges. This synergistic integration of high-throughput simulations and machine learning offers a powerful approach for the discovery of advanced electrolytes.