Search Results (56)

Human serum albumin (HSA) binding critically influences drug distribution and pharmacokinetics. In this study, HSA affinity chromatography was integrated with machine-learning-based quantitative structure–retention relationship (QSRR) modeling to elucidate structural determinants of albumin binding in a library of 115 fluoroquinolone (FQs) derivatives. Experimentally determined logk_HSA values were obtained using biomimetic chromatography, and these were then used as modelling endpoints. Following descriptor reduction via Least Absolute Shrinkage and Selection Operator (LASSO) and systematic benchmarking of 42 regression algorithms, support vector regression (SVR) and nu-support vector regression (ν-SVR) with radial basis function kernels demonstrated superior predictive performance. A parsimonious 12-descriptor ν-SVR model achieved strong calibration and validation metrics (R² = 0.916, Q²_test = 0.823, concordance correlation coefficient (CCC) = 0.899) and satisfied Organisation for Economic Co-operation and Development (OECD) criteria, including applicability domain assessment. Shapley Additive exPlanations (SHAP)-based interpretation revealed that albumin binding is governed by a balance between hydrophobic surface area and distributed electronic properties, whereas excessive localized polarity and quaternary ammonium functionalities reduce affinity. This experimentally anchored and interpretable modeling framework provides mechanistic insight into HSA binding in fluoroquinolones and offers a robust tool for rational pharmacokinetic optimization. Furthermore, in order to make the model easily accessible to users, we have packaged it in the form of an online application. Full article

Perchlorate (ClO₄⁻) is difficult to remove efficiently using conventional treatment technologies, such as coagulation and reverse osmosis, due to its high water solubility and exceptional chemical stability. Quaternary ammonium resins have emerged as cost-effective and efficient materials for ClO₄⁻ removal; therefore, the development of high-performance quaternary ammonium resins is critical for improving ClO₄⁻ remediation. In this study, a novel resin (PS-QA) was synthesized by aminating poly (vinylbenzyl chloride) with N,N-dimethylethanolamine, and its adsorption performance was systematically compared with that of three internationally recognized commercial ClO₄⁻ removal resins. Although all four resins exhibited spherical morphologies, the polystyrene backbone exhibited strong hydrophobicity, and the functional group –[R-N⁺(CH₃)₂(C₂H₄OH)]Cl⁻ possesses good electrophilicity, thereby conferring excellent selectivity toward ClO₄⁻. PS-QA exhibited a specific surface area of 19.94 m²/g, an average pore diameter of 32 nm, and a pore volume of 0.157 cm³/g, indicating comparable adsorption performance relative to the commercial counterparts. Its high thermal stability was further demonstrated through thermogravimetric analysis. Adsorption equilibrium was reached within 60 min, and the kinetic performance of PS-QA was comparable to that of the commercial resins. Isotherm analysis showed that ClO₄⁻ adsorption conformed to the Freundlich model, suggesting a coupled physical–chemical adsorption mechanism. Moreover, PS-QA exhibited both strong resistance to interference in complex water matrices and excellent reusability. After three adsorption–desorption cycles, more than 80% of the adsorption sites remained active. Notably, PS-QA also demonstrated outstanding performance in pilot-scale applications. Full article

Tröger’s base (TB) polymers have received increasing attention as a novel class of polymers with intrinsic microporosity, particularly for applications in gas separation. In this study, TB was quaternized with hydrophobic long chains to create a microphase-separated structure to enhance gas separation performance. On one hand, the tertiary amine structure of TB enabled facile grafting modification through the Menshutkin reaction. On the other hand, microphase-separated channels were created in the quaternized Tröger’s base (QTB) membrane due to the polarity differences between the hydrophilicity of the quaternary ammonium groups and hydrophobicity of iodoalkanes, providing channels for gas transport within the membrane and thereby improving permeability selectivity. The successful synthesis of QTB membranes was confirmed by FTIR and ¹H NMR spectroscopy, while AFM and SAXS analyses validated the microphase-separated morphology. To investigate the impact of microphase separation on oxygen permeability and selectivity, different iodoalkanes and various concentrations of iodobutane were grafted onto the TB backbone. Among the prepared membranes, QTB-C₄-70% membrane exhibited the highest in O₂ permeability. Gas separation performance under different O₂ pressures and temperatures revealed that O₂ permeability decreased slightly with increasing pressure, indicating good pressure stability of the membrane. With increasing temperature, the permeability increased while the selectivity decreased. These findings demonstrated that microphase-separated QTB membranes offer a viable strategy for creating effective materials for gas separation. Full article

Bentonite is the most widely used raw material for producing organoclays, which have numerous industrial and environmental applications. Due to their hydrophobicity, high swelling, and strong affinity for organic compounds, organoclays are effective in removing organic solvents from contaminated water originating from pipeline leaks, oil spills, traffic accidents, and industrial discharges. Such contamination not only degrades water quality but also forms surface films that hinder oxygen transfer, threatening aquatic ecosystems. In this study, two sodium bentonites with different specific surface areas (30 and 50 m²/g) were modified with three quaternary ammonium salts of varying molar masses and alkyl chain lengths (Sun, Arq, and Arm) to evaluate their performance in organic solvent sorption (gasoline, diesel, and kerosene). The materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM), and swelling capacity and sorption efficiency. The swelling capacity was determined according to ASTM D5890-19 (Foster method) using gasoline, diesel, kerosene, toluene, and xylene, while the sorption efficiency was assessed following ASTM F726-17 in gasoline, diesel, and kerosene, chosen due to their high potential for water contamination and frequent occurrence in oil spill and leakage scenarios. These solvents also differ in polarity and aromatic content, providing a relevant model for hydrocarbon mixtures commonly found in the environment. Results showed that the interaction between the clay and the surfactant depended strongly on the modifier’s chemical structure. The sorption capacity increased with greater interlayer expansion, surfactant molar mass, and specific surface area of the clay. Among all samples, the Arm-modified natural bentonite (VLArm) exhibited the best performance, with adsorption capacities of up to 6 g/g for diesel, 5 g/g for gasoline, and 5 g/g for kerosene. These values exceeded most previously reported organoclays. These findings demonstrate that optimizing the combination of clay properties and surfactant chemistry can yield highly efficient, low-cost organoclays for environmental remediation of organic contaminants. Full article

Sodium alginate (SA) is widely used as an edible coating for fruit preservation, but its weak water barrier and antibacterial properties limit broader application. In this study, quaternary ammonium lignin–cinnamaldehyde (QKC) composite particles were incorporated into SA as multifunctional fillers to construct antibacterial coatings. Electrostatic and hydrogen-bonding interactions between cationic QKC and anionic SA yielded a uniform, stable network with improved hydrophobicity and UV-shielding capacity. At 5 wt% QKC loading (SA5), the tensile strength increased from 11.53 to 24.42 MPa (111.8% higher than SA0), while water vapor permeability decreased by 35.4%. SA coatings also exhibited strong antioxidant activity, and the ABTS radical scavenging rate increased to 70.22% at 7 wt% QKC, with SA5 offering a favorable balance between antioxidant, barrier, and mechanical properties. SA5 showed pronounced antibacterial efficacy, giving inhibition rates of 96% against Staphylococcus aureus and 65% against Escherichia coli. Coating trials on persimmons and tangerines demonstrated that SA5 reduced weight loss, delayed firmness decline, and mitigated decay during storage. In addition, calcium-crosslinked SA/QKC hydrogel beads markedly delayed visible mold growth on blueberries. These results indicate that QKC-reinforced SA coatings provide a promising strategy for enhancing the postharvest quality and shelf life of fresh fruit. Full article

A quaternized and phenyl-functionalized hyperbranched PEI-based sponge (S_HPEI-QP) was successfully prepared, and its adsorption performance was investigated to evaluate its potential for removing the anionic non-steroidal anti-inflammatory drug (ibuprofen (IBU)). We reported that the synthesis of polyethyleneimine-based sponges was achieved through cryo-polymerization using 1,4-butanediol diglycidyl ether (BDDE) as the crosslinking agent. Subsequent functionalization with resorcinol diglycidyl ether (RDGE) and trimethylamine introduced quaternary ammonium cations, imparting strong basicity and hydrophilicity, as well as phenyl groups, conferring hydrophobic characteristics, respectively. The aforementioned sponge material, S_HPE-QPI, primarily facilitates the efficient adsorption of IBU in aqueous solutions through the anion exchange properties of quaternary ammonium groups and the π-π interactions associated with oxygen-activated benzene rings. Various characterizations, such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and specific surface area determination method (BET), confirmed the successful synthesis of the bifunctionalized S_HPEI-QP adsorbent. This adsorbent features a porous structure (specific surface area of 77.2 m² g⁻¹ and pore size distribution of 25–100 nm) and an isoelectric point (pH_pzc) of 9.38. The adsorption kinetics of the adsorbent for IBU were extremely rapid and conformed to a pseudo-second-order kinetic model, and the adsorption isotherm aligned with the Langmuir isotherm model. Noteworthily, S_HPEI-QP demonstrated an exceptionally high adsorption capacity for IBU, achieving a maximum uptake of 905.73 mg g⁻¹ at pH 7.0, which surpassed that of most of the previous reported adsorbents. Moreover, the sponge material can be chemically regenerated. After eight cycles of use, the adsorption efficiency decreased by only 4%. These findings suggest that the synthesized dendritic anion exchange adsorbent represents a promising candidate for the removal of IBU from contaminated water sources. Full article

The issue of antibiotic resistance is becoming increasingly severe, urgently requiring the development of new antibacterial strategies. Photodynamic therapy (PDT) has gradually emerged as a promising alternative due to its spatiotemporal controllability, low risk of drug resistance, and broad-spectrum antibacterial properties. However, most existing photosensitizers (PSs) are hydrophobic, which limits their application efficiency in PDT. To address this problem, we designed and synthesized a water-soluble perylene diimide derivative (PDICN-CBn) as a photosensitizer. By introducing quaternary ammonium salt groups, its water solubility was improved, and antibacterial activity was enhanced. Subsequently, PDICN-CBn was assembled into silk fibroin/polylactic acid (SF/PLA) nanofibrous membranes via electrospinning technology, successfully constructing a visible-light-responsive ternary composite nanofibrous membrane (SF/PLA@PDICN-CBn). Using various characterization methods such as nuclear magnetic resonance (¹H-NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), the microstructure, chemical composition, and structural characteristics of the nanofibrous membranes were systematically analyzed, verifying the successful synthesis of the photosensitizer and its assembly into the nanofibrous membranes. In the reactive oxygen species (ROS) experiment, electron spin resonance (ESR) spectra showed that PDICN-CBn efficiently generated singlet oxygen (¹O₂), superoxide anion (·O₂⁻), and hydroxyl radical (·OH) under visible light irradiation, confirming its ability to produce different types of ROS through both type I and type II photodynamic reactions. In the antibacterial experiments, Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and methicillin-resistant Staphylococcus aureus (MRSA) were selected for a series of tests, including plate-counting antibacterial assays, bacterial live/dead staining, and SEM observation of morphology. The results showed that 8 μg/mL of PDICN-CBn effectively destroyed the bacterial cell membrane structure and killed bacteria (bactericidal rate > 95%) after 2 h of visible light irradiation. This work successfully developed a novel visible-light-responsive SF/PLA@PDICN-CBn nanofibrous membrane with a dual antibacterial system combining photodynamic and electrostatic adsorption antibacterial properties, providing new ideas and methods for the design and development of photodynamic antibacterial materials. The prepared nanofibrous membrane has potential application values in fields such as wound dressings and medical protective materials and is expected to provide strong support for solving clinical infection problems. Full article

Palm-leaf manuscripts (PLMs) represent a significant component of cultural heritage as a medium for information recording. However, the inherent fragility of these organic materials presents a major challenge for their long-term preservation. Therefore, enhancing the durability of PLMs to ensure longevity has become a critical issue in conservation research. This study includes an examination of the potential of two polymers, cationic polyacrylamide (CPAM) and chitosan quaternary ammonium salt (CQAS), for PLM encapsulation. The encapsulation effects of these materials were assessed through artificial moist heat-accelerated aging tests, enabling a comprehensive evaluation of structural and mechanical properties at both the macroscopic and microscopic levels. The results indicated that CPAM provided superior performance in terms of gloss, color stability, hydrophobicity, pH value, and tensile properties, whereas CQAS demonstrated notable antifungal efficacy. Both CPAM and CQAS possess distinct advantages and can significantly contribute to the preservation of PLMs. This work offers valuable insights for developing effective conservation strategies, emphasizing the potential of CPAM and CQAS as viable encapsulation materials in the face of conservation requirements. Full article

Using renewable D-gluconic acid δ-lactone as the starting material, two novel glucosamide-based organosilicon quaternary ammonium surfactants (2/3SiDDGPBH) were synthesized through an environmentally friendly three-step process involving amidation, hydrophobic modification, and quaternization. Comprehensive characterization demonstrated their exceptional performance: surface tension reduction to 33.4 mN/m (2SiDDGPBH) and 33.64 mN/m (3SiDDGPBH), uniform spherical micelles (1–10 nm and 30–100 nm) were formed, and outstanding foam properties with 3SiDDGPBH developed, showing superior foamability and stability. Material modification tests on polymethyl methacrylate (PMMA) plates, mature acacia leaves, oilpaper, vegetable-tanned top-grain leather, and melamine-formaldehyde resin (MFR) faced with plywood revealed excellent spreading performance and durability, particularly for 3SiDDGPBH-treated MFR plywood, which maintained excellent spreading performance even after 80 washing cycles. Scanning electron microscopy (SEM) analysis confirmed that the Si wt% of MFR plywood treated with 2/3SiDDGPBH and scrubbed MFR plywood both exhibited a significant increase, and the 3SiDDGPBH-treated MFR plywood demonstrated superior bonding properties. These surfactants combine low surface tension, excellent foaming properties, and outstanding spreading performance, demonstrating broad application prospects in fields such as pesticide adjuvants, industrial and household cleaning agents, cosmetics, oilfield extraction, textile printing and dyeing, and functional coatings. Full article

Due to the growing emergence of bacterial and fungal resistance, there is an urgent need for novel antimicrobial compounds. Cationic surfactants are effective antimicrobial agents; however, traditional quaternary ammonium compounds (QACs) are increasingly scrutinized due to their cytotoxicity, poor biodegradability, and harmful effects on aquatic ecosystems. While the antimicrobial efficacy of many new biocides, including QACs, has been extensively studied, comprehensive experimental strategies that simultaneously assess antimicrobial activity, mammalian cell toxicity, and ecotoxicity remain limited. Recent studies have reported that amino-acid-based surfactants containing arginine-phenylalanine and arginine-tryptophan exhibit excellent antibacterial activity and are biodegradable. This work extends their biological characterization to evaluate their potential applications. Specifically, we examined how variations in the head group architecture and hydrophobic moiety influence antifungal and antibiofilm activity. We also assessed how these structural parameters impact cytotoxicity and ecotoxicity. These compounds demonstrated strong activity against a wide range of Candida strains. Their hydrophobic character primarily influenced both antifungal efficacy and cytotoxicity. Importantly, these surfactants exhibited potent antimicrobial and antibiofilm effects at non-cytotoxic concentrations. Notably, their aquatic toxicity was significantly lower than that of conventional QACs. Full article

Urushiol, the principal bioactive component of natural lacquer, has emerged as a promising candidate for developing eco-friendly antimicrobial coatings due to its unique catechol structure and long alkyl chains. This review systematically elucidates the molecular mechanisms underpinning urushiol’s broad-spectrum antimicrobial activity, including membrane disruption via hydrophobic interactions, oxidative stress induction through redox-active phenolic groups, and enzyme inhibition via hydrogen bonding. Recent advances in urushiol-based composite systems—such as metal coordination networks, organic–inorganic hybrids, and stimuli-responsive platforms—are critically analyzed, highlighting their enhanced antibacterial performance, environmental durability, and self-healing capabilities. Case studies demonstrate that urushiol derivatives achieve >99% inhibition against both Gram-positive and Gram-negative pathogens, outperforming conventional agents like silver ions and quaternary ammonium salts. Despite progress, challenges persist in balancing antimicrobial efficacy, mechanical stability, and biosafety for real-world applications. Future research directions emphasize precision molecular engineering, synergistic multi-target strategies, and lifecycle toxicity assessments to advance urushiol coatings in medical devices, marine antifouling, and antiviral surfaces. This work provides a comprehensive framework for harnessing natural phenolic compounds in next-generation sustainable antimicrobial materials. Full article

Obtaining the dielectric constant and refractive index of the siloxane surface of montmorillonite (Mnt) and organic groups is difficult, limiting the study of Van der Waals (VDW) interactions between the hydrophilic end of quaternary ammonium surfactants (QASs) and Mnt. In this study, the average adsorption distance, VDW adsorption energy, and VDW constant of QASs and their groups adsorbed on the montmorillonite surface are obtained by microcalorimeter. Herein, the VDW interactions between five QASs and a Mnt surface are compared. Interactions between QASs with different hydrophilic ends and Mnt in aqueous solution were positively correlated with the dipole moment of the hydrophilic end groups, and the VDW interaction energies differed depending on the superposition of CH₂ adsorption at the hydrophobic ends. The electrostatic and VDW adsorption capacities were studied through zeta potential and adsorption capacity experiments. Physical adsorption was determined using Fourier-transform infrared spectroscopy, and the hydrophobic floc morphology was characterized using environmental scanning electron microscopy. Focused beam reflectance measurements, thermogravimetric-differential scanning calorimetry, and light transmittance were used to quantitatively analyze the hydrophobic effect of the QASs. Full article

Ionomers containing a small number of ionic side groups are a unique class of polymers with some valuable properties and distinct applications. To date, commercially important ionomers are exclusively anionomers that contain covalently bonded anions and are synthesized commonly by radical polymerization. The catalytic synthesis of polyethylene-based cationomers is challenging, while it is attractive due to the low cost of ethylene stocks and less stringent polymerization conditions, along with their desirable properties and broadened scope of commercial applications. Advances in catalyst technology—specifically, Pd-diimine catalysts—have recently enabled the synthesis of a class of hyperbranched polyethylene cationomers that are designed to contain quaternary ammonium cations. With their unique hydrophobic hyperbranched polyethylene backbone, this class of ionomers enables the successful functionalization of negatively surface-charged nanomaterials, thus improving the processing and application of the latter. This review summarizes the developments of this class of ionomers, including their synthesis, properties, and functionalization of various nanomaterials. Full article

Deep eutectic solvents (DESs), a novel class of eco-friendly solvents, are attracting considerable attention in extraction techniques. In this study, a hydrophobic DES, created by combining a quaternary ammonium salt and hexanoic acid, was coated onto a commercial cellulose membrane for polycyclic musks (cashmeran, celestolide, galaxolide, and tonalid) microextraction from surface waters followed by gas-chromatography–mass spectrometry (GC MS) analysis. A series of DESs were synthesized and characterized to identify suitable candidates for use as a coating on cellulose membranes. A factorial design approach was employed to investigate key factors, including DES volume, membrane type, dissolving solvent volume, DES incorporation time, and extraction duration, following a preliminary selection of the DES type, membrane, and dissolving solvent. Under optimized conditions, a cellulose acetate membrane impregnated with DES (TBAB:C6, 1:3 molar ratio) was used for 1 h to extract polycyclic musks from surface water; the extract was then dissolved in methanol prior to the GC-MS analysis. The DES-coated membrane demonstrated a linear detection range from 2.5 to 100 μg/L, with limits of detection (LODs) ranging from 0.06 to 0.15 µg/L, while the LOQ values varied from 0.2 to 0.5 µg/L. The validated method was successfully applied to real samples, allowing us to find the presence of galaxolide and tonalide. Full article

Polybenzoxazines (PBzs), a class of high-performance thermosetting polymers, have gained significant attention for their exceptional thermal stability, mechanical properties, and chemical resistance, making them ideal for aerospace, electronics, and biomedical applications. Recent advancements emphasize their antimicrobial potential, attributed to unique structural properties and the ability to incorporate bio-active functional groups. This review highlights the synthesis, antimicrobial mechanisms, and applications of PBzs and their bio-based derivatives, focusing on sustainable materials science. PBzs demonstrate antimicrobial efficacy through mechanisms such as hydrophobic surface interactions and reactive functional group formation, preventing microbial adhesion and biofilm development. The incorporation of functional groups like amines, quaternary ammonium salts, and phenolic moieties disrupts microbial processes, enhancing antimicrobial action. Modifications with metal nanoparticles, organic agents, or natural bio-actives further augment these properties. Notable bio-based benzoxazines include derivatives synthesized from renewable resources like curcumin, vanillin, and eugenol, which exhibit substantial antimicrobial activity and environmental friendliness. Hybrid PBzs, combining natural polymers like chitosan or cellulose, have shown improved antimicrobial properties and mechanical performance. For instance, chitosan-PBz composites significantly inhibit microbial growth, while cellulose blends enhance film-forming capabilities and thermal stability. PBz nanocomposites, incorporating materials like silver nanoparticles, present advanced applications in biomedical and marine industries. Examples include zirconia-reinforced composites for dental restoration and urushiol-based PBzs for eco-friendly antifouling solutions. The ability to customize PBz properties through molecular design, combined with their inherent advantages such as flame retardancy, low water absorption, and excellent mechanical strength, positions them as versatile materials for diverse industrial and medical applications. This comprehensive review underscores the transformative potential of PBzs in addressing global challenges in antimicrobial material science, offering sustainable and multifunctional solutions for advanced applications. Full article