Hydrophobic Research Articles

Examining the inhibitory potency of metal polyphenolic network–coated silver nanoparticles against amyloid fibrillogenesis of lysozyme

There are currently over forty degenerative diseases that are correlated with abnormal accumulation of peptide/protein aggregates in the human body, such as Alzheimer’s disease. Due to their unique physiochemical properties (e.g., small size, large surface-to-volume ratio, and facile surface modification), silver nanoparticles (AgNPs) have been considered potential substrates for designing inhibitors against amyloid fibrillogenesis. Metal polyphenolic network (MPN) that combines the characteristics of organic and inorganic components has been used to suppress amyloid fibril formation. This study is aimed at investigating the effects of MPN–coated AgNPs (MPN–AgNPs) on the in vitro amyloid fibrillogenesis of hen lysozyme (HEWL). The two types of MPN–AgNPs (Zn/MPN–AgNPs and Co/MPN–AgNPs) were synthesized through chemical reduction and metal chelation, and their particle sizes were determined to be in the range of 40–60 nm. The characterization of MPN–AgNPs by ζ–potential and transmission electron microscopy showed that the MPN–AgNPs had negative surface charge and spherical-shaped morphology. Furthermore, the elemental analysis demonstrated that the MPN was uniformly coated on the surface of AgNPs. The thioflavin T fluorescence results revealed that the Co/MPN–AgNPs showed a better percent of inhibition compared to Zn/MPN–AgNPs and TA–AgNPs. The kinetics data of amyloid fibril formation in the presence of MPN–AgNPs were analyzed using the sigmoidal curve, showing that the MPN–AgNPs reduced fibril growth rate and prolonged lag time. Our findings also demonstrated that MPN–AgNPs could effectively suppress HEWL aggregation upon binding to aggregation-prone regions. The quenching of intrinsic fluorescence of HEWL by MPN–AgNPs was found to be a static type. Moreover, the fluorescence quenching data were analyzed using the modified Stern-Volmer equation to determine the number of binding sites. Notably, our findings indicated that the binding between HEWL and MPN–AgNPs was mainly governed by hydrophobic interaction. This work offers an excellent example of utilizing MPN–based materials as anti-aggregating/anti-fibrillogenic nano-drugs for the treatment of amyloidosis.

One-pot synthesis of tricyclic pyrano[3.2-c]chromene derivatives and their evaluation through in vitro immunomodulatory activity against T cells; Molecular docking investigations and ADME-Tox prediction studies

The aim of this work is the in vitro determination of the immunomodulation effect of pyrano[3,2-c]chromenes on the proliferation of T lymphocyts. These tricyclic heterocycles were prepared at room temperature via a one-pot, three-component condensation reaction involving 4-hydroxy-2H-chromen-2-one, aromatic aldehydes, and malononitrile, using morpholine as a catalyst in a 1:1 ethanol/water mixture. This multicomponent reaction affords the product in high yields, in accordance with the criteria of green chemistry. The structure elucidation was accomplished by spectral data, IR, NMR (1H, 13C, 2D). We determined the in vitro effects of 2-amino-4-(3-hydroxy-5-methoxyphenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile (AC09) the 2-amino-5-oxo-4-(thiophen-2-yl)-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile (AC11) derivatives, on the proliferative responses of human T lymphocyts cells, cytokine secretion and intracellular redox status. The study revealed that compounds AC09 and AC11 are efficient immunostimulants in a dose-dependent manner.Human lymphocytes were less sensitive to AC11 at high concentrations compared to the potency of AC09. Human lymphocyte IL-2, IFNγ and IL-4 secretions were significantly enhanced by those pyrano[3,2-c]chromenes derivatives in a dose-dependent manner. The levels of intracellular lymphocytes glutathione (GSH), were unaffected by AC09 and AC11 at any concentrations. AC09 and AC11 induce a significant increase in hydroperoxide and carbonyl protein contents at high concentrations. Conversely, a computational study using molecular modelling revealed that compounds AC09 and AC11 exhibit a strong affinity for the active site residues of Interferon-γ (IFN-γ; PDB ID: 6E3K) target. This is confirmed by the low score energy value and the formation of different types of interactions such as: hydrogen bonds, hydrophobic interactions, and van der Waals forces. Moreover, all Drug likeness's rules were validated, and no toxicity is presented by these compounds. Finally, in vitro studies, molecular docking techniques and ADME-T (Absorption, Distribution, Metabolism, Excretion and Toxicity) evaluations were successfully conducted, aiding in the identification of new IFN-γ target inhibitors. A comparative analysis /or studies was then carried out to highlight the complementary effects of the two approaches.

Inhibitory Mechanism of Apigenin, Quercetin, and Phloretin on α-Glucosidase

Flavonoids present promising potential as α-glucosidase inhibitors, with potential benefits in lowering blood glucose levels. In our previous study, apigenin, quercetin, and phloretin obtained from whole-grain highland barley demonstrated notable efficacy as α-glucosidase inhibitors. Therefore, in this study, we used enzyme kinetics, fluorescence spectroscopy, circular dichroism, and molecular docking to explore the interactions between apigenin, quercetin, and phloretin, and α-glucosidase. With the addition of three flavonoids, the inhibitory effect of all the flavonoids on α-glucosidase activity was reversible and exhibited a mixed-type pattern. Molecular docking analysis revealed that the three flavonoids predominantly bind to yeast-derived α-glucosidase mainly through hydrophobic interactions and van der Waals forces, whereas the interaction with human-derived α-glucosidase involved hydrophobic interactions. Further experiments revealed that the flavonoids quenched the fluorescence of α-glucosidase due to the complex formation between the flavonoids and α-glucosidase, leading to changes in the protein secondary structure and conformational changes, which was further supported by molecular dynamics simulations. These results provided insights into the mechanism of the flavonoid inhibition of α-glucosidase. These findings could promote the consumption of whole-grain highland barley and the development of hypoglycemic foods rich in flavonoids.

Study on the effects of endogenous polyphenols on the structure, physicochemical properties and in vitro digestive characteristics of Euryales Semen starch based on multi-spectroscopies, enzyme kinetics, molecular docking and molecular dynamics simulation

Euryales Semen (ES) is a highly nutritious food with low digestibility, which is closely associated with its endogenous phenolic compounds. In this study, five phenolic compounds (naringenin, isoquercitrin, gallic acid, epicatechin and quercetin) with high concentrations in ES were selected to prepare starch-polyphenol complexes. Subsequently, the effects of endogenous polyphenols on the structure, physicochemical properties and digestion characteristics of ES starch were studied using multiple techniques. The addition of phenolic compounds markedly reduced the in vitro digestibility, swelling power, gelatinization enthalpy, while increased the solubility of ES starch. Fourier-transform infrared spectroscopy and X-ray diffraction analysis showed that phenolic compounds interacted with the starch through non-covalent bonds. Five phenolic compounds inhibited α-amylase activity through a mixed competitive inhibition mechanism, with the inhibition potency ranked as follows: quercetin > epicatechin > gallic acid > isoquercitrin > naringenin. The spectroscopic analysis and molecular dynamics simulations confirmed that five phenolic compounds interacted with the amino acid residues of α-amylase through hydrogen bonding and hydrophobic interactions, caused α-amylase static fluorescence quenching, and altered its conformation and microenvironment. This study provides a better understanding of the interaction mechanisms between ES starch and polyphenols, and supports the development of ES as a food that lowers sugar levels.

Unraveling the molecular interactions and antioxidant mechanism of β-lactoglobulin with aloe’s hydroxyanthracene derivatives: A focus on aloin and aloe-emodin

Aloe dairy products have occupied a certain market share, and the interaction between the small bioactive molecules contained in aloe and milk proteins during product processing profoundly affects the performance of dairy products. In this study, two typical and potentially dangerous bioactive small molecules of aloe, aloin (AA) and aloe-emodin (AE), were selected to investigate their interaction mechanism with β-lactoglobulin (β-La). Computer simulations showed that AA/AE had the potential to form complexes with β-La, and the β-La-AA system exhibited a stronger binding affinity than the β-La-AE system. Fluorescence analysis showed that the binding affinity values of AA to β-La at 298 K were deduced to be (4.184 ± 1.06) × 104 M−1, meaning medium-strength interactions, comparatively, AE to β-La was weaker, were deduced to be (3.15 ± 1.25) × 103 M−1. In addition, the thermodynamic analysis found that ΔH0 and ΔS0 were positive in both the β-La-AA system and the β-La-AE system, which implies that the main driving force for the combination of AA/AE and β-La to form the ground state complex is the hydrophobic force. The conformation changes in β-La brought about by binding to AA/AE may alter the properties and functions of the protein, such as surface hydrophobicity and oxidation resistance. Analysis shows that β-La is potentially present in whey as an AA/AE carrier during the production of aloe milk.

Utilization of soybean protein isolate hydrolysates as carriers: Improved encapsulation efficiency and stability of curcumin

This study aimed to explore the potential of soybean protein isolate hydrolysates (SPIH) prepared via Alcalase as delivery carriers and develop novel SPIH-Cur nanoparticles. Hydrolysis caused the varying degrees degradation in the 7S and 11S subunits, significantly enhancing SPI's antioxidant activity. The reduction in particle size and the exposure of hydrophobic groups in SPIH contributed to the formation of stable SPIH-Cur nanoparticles, due to their well binding capacity to curcumin (Cur). The 30 min SPIH-Cur sample exhibited the highest encapsulation efficiency (83.09 %), owing to its high binding affinity (Ka = 9.56 × 103 M−1). Encapsulation by SPIH also significantly improved Cur's thermal and light stability. Moreover, FTIR, fluorescence spectra, and molecular docking analyses revealed that the formation of SPIH-Cur were primarily driven by hydrophobic forces and hydrogen bonds. Above results provide a foundation for fabricating nanoparticles that deliver lipophilic bioactive compounds with high encapsulation efficiency and stability derived from SPIH.

Investigation on the interaction mechanism of trilobatin with pepsin and trypsin by multi-spectroscopic and molecular docking methods

Pepsin and trypsin are noteworthy for the digestion of proteins in the human body. Trilobatin is a dihydrochalone that has anti-obesity, antioxidant, and anti-diabetes functions. The interaction of trilobatin and pepsin or trypsin is not currently being explored. Therefore, in this research multiple methods involving fluorescence spectroscopy, synchronous fluorescence spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) and molecular docking were employed for studying the interaction between trilobatin and pepsin or trypsin. During the interaction between trilobatin and pepsin or trypsin, the quenching type was static quenching and a single binding site existed. The binding constants (Ka) values were 2.177 and 3.028 × 104 L/mol in trilobatin-pepsin and trilobatin-trypsin system at 298 K, respectively. However, the presense of metal ions (Zn2+, Ca2+ and K+) decreased the binding of trilobatin to pepsin and trypsin. The complex between trilobatin and pepsin was generated typically through hydrogen bonding and van der Waals force (ΔH° < 0 and ΔS° < 0), in comparison the complex between trilobatin and trypsin was established chiefly through hydrogen bond and hydrophobic force (ΔH° > 0 and ΔS° > 0). The data from UV–Vis, synchronous fluorescence, FT-IR and CD spectra indicated that trilobatin reduced the hydrophobicity of Tyrosine (Tyr) residues of pepsin and trypsin. Furthermore, trilobatin altered the secondary structures of pepsin and trypsin. Meanwhile, trilobatin changed the conformation of pepsin and trypsin so that the viscosity of the interaction systems decreased with increased of trilobatin concentration. The molecular docking modeling identified that the trilobatin interacted with amino acid residues around pepsin and trypsin. This work consistently showed the interaction between trilobatin and pepsin or trypsin, in addition to offering valuable information for the application of trilobatin.

Microplastic and antibiotics in waters: Interactions and environmental risks.

Antibiotics (ATs) are ubiquitously detected in natural waters worldwide, and their tendency to co-migrate with microplastics (MPs) post-adsorption leads to heightened environmental risk. Research on the adsorption of ATs on MPs and their subsequent effects on the environmental risks is gaining significant attention globally. This adsorption process predominantly occurs through hydrophobic forces, hydrogen bonds, and electrostatic interactions and is influenced by various environmental factors. The interaction between MPs and ATs exhibited varying degrees of efficiency across different pH levels and ionic strengths. Furthermore, this paper outlines the environmental risks associated with the co-presence of MPs and ATs in aquatic environments, emphasizing the potential effect of MPs on the distribution of antibiotic resistance genes (ARGs) and related environmental risks. The potential hazards posed by MPs and ATs in aquatic systems warrant serious consideration. Future research should concentrate on the adsorption of ATs/ARGs on MPs under real environmental conditions, horizontal gene transfer on MPs, as well as biofilm formation and agglomeration behavior on MPs that needs to be emphasized.

A Study on a New Method for Simultaneous Internal Curing and hydrophobic in Concrete

The high hydrophilicity and permeability of concrete caused by many pores and hydroxyl groups produced by cement hydration are the main factors leading to dry shrinkage, cracking, and poor corrosion resistance of concrete. Giving concrete internal curing and hydrophobicity is an effective measure to solve the above problems. In this paper, a new idea and preparation method for an organic combination of hydrophilic and hydrophobic materials are proposed to improve the service life of concrete structures. Furthermore, the combined effects of hydrophilic and hydrophobic amphoteric materials (HAM) on the mechanical properties, internal curing properties, and hydrophobic properties of concrete were comprehensively investigated. In addition, the physical and chemical action mechanisms were analyzed in conjunction with microscopic tests. The results indicated that HAM rapidly released water within 3-7 days before concrete curing, and then slowly released water accompanied by the release of hydrophobic materials, gradually from hydrophilic to hydrophobic properties; The addition of HAM did not reduce the mechanical properties of concrete, which solved the problem of low compressive strength of integral hydrophobic concrete; The addition of HAM reduced the drying shrinkage of concrete by 154.12%, increased the contact angle to 96°, and decreased the water absorption rate by 36%, allowing the concrete to achieve better internal curing and a hydrophobic effect. The preparation of this material can open up a new way to solve the hydrophilic and hydrophobic properties required by concrete at the same time, and fill the gap that concrete can not balance hydrophilic and hydrophobic properties.

In-depth recognition of mixed surfactants maintaining the enzymatic activity of cellulases through stabilization of their spatial structures

Mixed surfactants improve the enzymatic hydrolysis of lignocellulosic substrates by enhancing cellulase stability against heat, pH, shear, and air–liquid interface stress. Under conditions of multiple factorial stresses (50 °C, pH 4.8, 180 rpm, and 15.5 cm2 air–liquid interface), cellulase with ternary surfactants (Tween 60/Triton X-114/CTAB, the molar ratio 14:5.5:1) retained 84 % of its activity after 48 h of incubation, representing 1.15 and 1.29 folds that of the cellulase activity with the single Tween 60 and with no surfactants, respectively. This is attributed to the fact that ternary surfactants possess better rheology modulation and air–liquid interface competitiveness. In addition, the computational approach demonstrated that the ternary surfactants were capable of forming stronger hydrophobic and hydrogen-bond interactions with cellulase enzymes, thus maintaining its secondary structure and preventing the detrimental α-helix to β-sheet transformation known to compromise cellulase activity. This synergy offers valuable insights into surfactant-cellulase interactions and supports efficient enzymatic hydrolysis in biorefineries.

Effects of freeze-thaw cycles and heat treatment on the odor-binding properties of myofibrillar protein to key fishy compounds

This study investigated the effects of different freeze-thaw (F-T) cycles and subsequent heat treatment on the odor-binding properties of myofibrillar protein (MP) in grass carp to four key fishy substances. The odor-binding ability of MP significantly decreased as freeze-thaw (F-T) cycles increased (p < 0.05). After heating, the odor-binding ability of MP further decreased. Freeze-thaw treatment induced the oxidative denaturation, decreased total sulfhydryl content and unfolded the α-helix in MP, which modified and re-buried the exposed odor-binding sites, reducing odor-binding ability. After heating, the oxidative damage and aggregation of MP induced by freeze-thaw cycles, along with thermal effects, synergistically accelerated the oxidative denaturation and formation of disordered structures of heated MP. Enhanced hydrophobic interactions led to a dominant aggregation effect, which reduced the binding sites and further decreased the odor-binding ability of heated MP, resulting in more release of odors.

Entropy Changes in Water Networks Promote Protein Denaturation.

For over a century, an explanation for how concentrated ions denature proteins has proven elusive. Here, we report a novel mechanism of protein denaturation driven by entropy changes in water networks. Experiments and simulations show that ion pairs like LiBr and LiCl localize water molecules and disrupt the water network's structure, while others exert a more global effect without compromising network integrity. This disruption reduces the entropy penalty when proteins sequester water molecules during unfolding, resulting in a peculiar yet universal "inverse hydrophobic effect" that potentiates protein denaturation. Through successful isolation and systematic study of indirect solute effects, our findings offer a universal approach to salt induced protein denaturation and provide a unified framework for the decoding of the protein-water-solute nexus.

Investigation into the Quantitative Structure-Biotoxicity Relationship of Antibiotics and their Estrogenic Receptor Disruption Effects.

In light of antibiotics being classified as environmental hormone-like compounds, their interference with the endocrine system has significantly impacted human health and ecological environments. This study employed Gaussian09 software's Density Functional Theory (DFT) to structurally optimize and perform frequency calculations on 23 representative antibiotic molecules, aiming to obtain microscopic quantum mechanical structural parameters.Physicochemical property parameters were acquired through the RDKit database in the ChemDes platform. Through multiple linear regression analysis, the primary factors affecting antibiotic biotoxicity (pLD50) were identified, leading to the establishment of a QSAR model. The predictive capability of the model was analyzed using leave-one-out cross-validation, and molecular docking was used to investigate the binding mode and mechanism of action between estrogen receptors (ER) and antibiotics. Research outcomes indicate that the established QSAR model C has regression coefficients R2and leave-one-out cross-validation coefficients Q2of 0.92474 and 0.74913, respectively, demonstrating good stability and predictive power. Analysis through molecular surface electrostatic potential, frontier molecular orbitals,molecular docking, and molecular dynamicsrevealed that the potential estrogenic disrupting effects are primarily due to hydrogen bonds and hydrophobic interactions between antibiotics and estrogen receptors. This provides a valuable exploration for identifying and screening PPCPs with potential estrogenic disrupting effects.

Adsorption characteristics and mechanism of novel ink melanin composite modified chitosan for Cd(II) in water

In this study, chitosan (CS), carboxymethyl chitosan (CMCS), and chitosan quaternary ammonium salt (HACC) were successfully loaded with ink melanin (ME) as efficient adsorbents for Cd(II) removal. The results of batch adsorption experiments and structural characterization showed that the modified CS loaded with ME improved the adsorption capacity of the composites for Cd(II). The pseudo-second-order kinetic and Langmuir equations were better suited to describe the batch adsorption experiments. The adsorption of Cd(II) was chemisorption with desirable adsorption effect when the concentration of the three composites was 0.5 mg/mL and the pH value was neutral. Among them, HACC-ME demonstrated remarkable Cd(II) adsorption performance (107.18 mg/g) and sustained an 85 % efficiency in Cd(II) removal over five adsorption-desorption cycles. Ion exchange, complexation, electrostatic attraction, and hydrophobic interaction were the primary mechanisms for Cd(II) removal. Overall, HACC-ME could be employed as a low-cost and highly efficient new natural adsorbent material for the removal of Cd(II) ions from wastewater. These findings illuminate pathways for the development of efficient and novel natural adsorbent materials for environmental cleanup purposes.

Effects of BET Surface Area and Silica Hydrophobicity on Natural Rubber Latex Foam Using the Dunlop Process

To reinforce natural rubber latex foam, fumed silica and precipitated silica are introduced into latex foam prepared using the Dunlop process as fillers. Four types of silica, including Aerosil 200 (hydrophilic fumed silica), Reolosil DM30, Aerosil R972 (hydrophobic fumed silica), and Sipernat 22S (precipitated silica), are investigated. The latex foam with added silica presents better mechanical and physical properties compared with the non-silica foam. The hydrophobic nature of the fumed silica has better dispersion in natural rubber compared to hydrophilic silica. The specific surface area of silica particles (BET) also significantly influences the properties of the latex foam, with larger specific surface areas resulting in better dispersity in the rubber matrix. It was observed that exceeding 2 phr led to difficulties in the foaming process (bulking). Furthermore, higher loading of silica also affected the rubber foam, resulting in an increased shrinkage percentage, hardness, compression set, and crosslink density. The crosslink density increased from 11.0 ± 0.2 mol/cm3 for non-silica rubber to 11.6 ± 0.6 mol/cm3 for Reolosil DM30. Reolosil DM30 also had the highest hardness, with a hardness value of 52.0 ± 2.1 IRHD, compared to 45.0 ± 1.3 IRHD for non-silica foam rubber and 48 ± 2.4 IRHD for hydrophilic fumed silica Aerosil 200. Hydrophobic fumed silica also had the highest ability to return to its original shape, with a recovery percentage of 88.0% ± 3.5% compared to the other fumed silica. Overall, hydrophobic fumed silica had better results than hydrophilic silica in both fumed and precipitated silica.

Synthesis, Biological Evaluation, Molecular Docking Studies and ADMET Prediction of Oxindole-Based Hybrids for the Treatment of Tuberculosis.

With a projected mortality toll of 1.4 million in 2019, tuberculosis (TB) continues to be a significant public health concern around the world. Studies of novel treatments are required due to decreased bioavailability, increased toxicity, increased side effects, and resistance of several first- and second-line TB therapies, including isoniazid and ethionamide. This study reports the synthesis of oxindole-based hybrids as potent InhA inhibitors targeting Mycobacterium tuberculosis. The synthesized compounds (5a-5e and 8a-8c) were evaluated for their anti-mycobacterial activity against Mycobacterium tuberculosis and nontuberculous mycobacteria (NTMs), viz. M. abscessus (ATCC 19977), M. fortuitum (ATCC 6841), and M. chelonae (ATCC 35752) using the Microplate Alamar Blue Assay (MABA). Molecular docking studies were performed using AutoDock Vina to explore the binding interactions of these compounds with the InhA enzyme (PDB: 2NSD). Additionally, biochemical and histopathological studies were conducted to assess the hepatotoxicity of the lead compounds. Insilico molecular properties and ADMET properties of the synthesized compounds were predicted using SwissADME and Deep-PK online tools to assess their drug-likeness. Among the tested compounds, 8b exhibited significant anti-mycobacterial activity with a minimum inhibitory concentration (MIC = 1 μg/mL) comparable to the reference drug ethambutol. Further, the compound demonstrated a binding affinity and orientation similar to the reference inhibitor 4PI, indicating its potential as a potent InhA inhibitor, and was found to be stabilized within the binding pocket of InhA through H-bonding, hydrophobic and van der Waal's interactions. Besides, the compounds hepatotoxicity assessment studies depicted that 8b showed no significant liver dysfunction or damage to liver tissues. Additionally, 8b adhered to Lipinski's rule of five and Veber's rule, displaying favourable pharmacokinetic and drug-like properties, including high human intestinal absorption, distribution, and acceptable metabolic stability and excretion. Compound 8b emerged as a promising candidate for further optimization and development as a therapeutic agent for tuberculosis, offering a new avenue for tackling tuberculosis.

Probing Electrostatic and Hydrophobic Associative Interactions in Cells.

Weak nonspecific interactions between biomacromolecules determine the cytoplasmic organization. Despite their importance, it is challenging to determine these interactions in the intracellular dense and heterogeneous mixture of biomacromolecules. Here, we develop a method to indicate electrostatic and hydrophobic associative interactions and map these interactions. The method relies on a genetically encoded probe containing a sensing peptide and a circularly permuted green fluorescent protein that provides a ratiometric readout. Inside bacterial and mammalian cells, we see that the cytoplasmic components interact strongly with cationic and hydrophobic probes but not with neutral hydrophilic probes, which remain inert. The Escherichia coli cytoplasm interacts strongly with highly negatively charged hydrophilic probes, but the HEK293T cytoplasm does not. These associative interactions are modulated by ATP depletion. Hence, the nonspecific associative interaction profile in cells is condition- and species-dependent.

Kinetic and thermodynamic analysis of alizarin Red S biosorption by Alhagi maurorum: a sustainable approach for water treatment

Synthetic dyes, such as Alizarin Red S, contribute significantly to environmental pollution. This study investigates the biosorption potential of Alhagi maurorum biosorbent for the removal of Alizarin Red S (ARS) from aqueous solutions. Fourier transform infrared spectroscopy (FTIR) was used to analyze the biosorbent’s adsorption sites. Various parameters were optimized to maximize dye adsorption. An optimal removal efficiency of 82.26% was attained by employing 0.9 g of biosorbent with a 25 ppm dye concentration at pH 6 and 60 °C over 30 min. The data were modeled using various isothermal and kinetic models to understand the adsorption behavior. Thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic. The pseudo-second-order kinetic model best described the data, indicating chemisorption as the rate-limiting step. The data matched best to the Langmuir model, indicating that the adsorption occurs as a monolayer on uniform surfaces with a finite number of binding sites. The model showed a strong correlation (R² = 0.991) and a maximum adsorption capacity (qmax) of 8.203 mg/g. Principal component analysis (PCA) identified temperature as the dominant factor, with the primary component, PC1 capturing 100% of its effect. The mechanisms involved in ARS biosorption on A. maurorum include electrostatic interactions, hydrogen bonding, hydrophobic interactions, dipole-dipole interactions, and π-π stacking. Alhagi maurorum showed promising potential for biosorbing toxic dyes from contaminated water, suggesting further investigation for practical applications.

Plasma-induced aging of microplastics and its effect on mercury transport and transformation

Microplastics are known to adsorb heavy metals, with aged microplastics exhibiting greater adsorption capacity. This study investigates the impact of microplastic aging on the transport and transformation of mercury (Hg), a highly toxic heavy metal. Polystyrene (PS) and polyvinyl chloride (PVC) were aged using plasma treatment to simulate environmental conditions. Characterization of virgin and plasma-treated microplastics revealed aging mechanisms induced by plasma treatment. Notably, aged PS, unlike PVC, did not show a decrease in particle size but exhibited a decrease in specific surface area, likely due to chain cleavage and re-polymerization of polystyrene fragments, and thermal effects during plasma treatment. Both aged PS and PVC demonstrated increased hydrophilicity, enhanced negative charge, and a higher presence of nitrogen- and oxygen-containing functional groups. These changes were correlated with a significant increase in Hg adsorption capacity. Density functional theory (DFT) calculations further indicated that the adsorption of Hg2+ by microplastics is promoted by the presence of oxygen- and nitrogen-containing functional groups. The particularly strong influence of nitrogen-containing functional groups on Hg2+ adsorption was confirmed through both experimental and theoretical approaches. Adsorption kinetics and isothermal experiments, along with X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) analyses, were conducted to elucidate the Hg adsorption mechanism of on microplastics before and after aging. The mechanisms involved include pore filling, van der Waals’ forces, electrostatic interactions, hydrophobic interactions, and functional group complexation. The intraparticle diffusion model indicated that adsorption is controlled by multiple steps. Importantly, the surface functional groups of aged microplastics can reduce Hg2+ to Hg+ and adsorb it, suggesting a more complex adsorption process for Hg on aged microplastics. This study provides a scientific basis for understanding microplastic aging and the Hg adsorption mechanism on microplastics, highlighting the complex dynamics of combined microplastic and heavy metal contamination.

Synergistic Effect of Surface Hydrophobicity and &lt;i&gt;In-Vitro&lt;/i&gt; Antimicrobial Activity of Polymeric Nano-Formulation in Textile Finishing

Fouling and damage of variety of surfaces including textile material is a global challenge. As textile wears next to the skin and health issues are more significant. Thus in an effort to address the issues related to textile surfaces damage, antimicrobial polymeric textile finishing was developed to impart antimicrobial functionalities to the textile fabric. The nanoprecipitation technique was done to synthesize antimicrobial polymeric nanoparticles and applied on to the cotton textile fabric via layer-by-layer self-assembled multilayers dip coating technique. The particle size and zeta potential of the nanoparticles was evaluated form dynamic light scattering analysis (DLS) as 216 nm and-11.2 mV. The antimicrobial polymeric finishing of cotton textile was done by alternate dip coating in polyelectrolytes and nanoformulation. The structural morphology and roughness of the resultant textile was studied by SEM and optical profilometery. While the surface hydrophobicity was found to increase with the number of bilayers coating of hydrophobic polymeric formulation as measured in term of contact angle θ. In-vitro antimicrobial activity was studied against gram negative E. coli and gram positive S. aureus with significant zone of inhibition against both strains. Thus surface hydrophobicity and antimicrobial activity of the textile fabric was synergistically achieved and have potential for biomedical and industrial application.