Search Results (2,071)

In this study, emodin was used as the starting material to synthesize two novel ligands, L1 and L2, containing bipyridine or phenanthroline moieties. Seven metal complexes (1–7) were obtained through coordination with Co, Rh, Ru, and Pt ions. Their structures were confirmed via NMR, HRMS, UV–Vis, IR, HPLC and SC-XRD analyses. The MTT assay showed that L1 and complex 2 selectively inhibited HepG-2 cells, with IC₅₀ values of 8.77 μM and 6.10 μM, respectively. Both compounds exhibited stronger activity than cisplatin (9.05 μM) and low toxicity toward normal 293T cells. Mechanistic studies demonstrated that they induced G2/M phase arrest by regulating Cyclin B1 and P21 expression, which was accompanied by ROS and Ca²⁺ accumulation, mitochondrial membrane potential disruption, and activation of the Caspase-9/3 cascade. Complex 2 showed superior antitumor activity to L1, and this finding was further supported by molecular docking analysis. In sum, Rh(III) complex 2 was identified as a selective and mechanistically defined anti-hepatocellular carcinoma lead compound, providing a potential strategy for the development of natural product-based metal anticancer agents. Full article

Vanadium–titanium-bearing direct reduced iron (V-Ti DRI) is a promising feedstock for the full-value utilization of V-Ti magnetite. Selective partition of V and Cr into the metal phase, with Ti retained in the slag, requires quantitative thermodynamic guidance. We investigate this slag–metal distribution using the ion and molecule coexistence theory (IMCT). An eight-component slag model with 33 complex-molecule equilibria is coupled to reduction thermodynamics through an iterative mass-balance procedure; the metal-phaseWagner activity is temperature-scaled by Chipman’s rule, and the dissolved oxygen concentration is closed through the C-CO-O equilibrium. The equilibrium V and Cr recovery ceilings (metal side) rise from 89%/96% at 1400 °C to approximately 99.4% at 1500 °C and exceed 99.8% at 1550 °C. Ti-in-slag retention (slag side) drops steadily from 99.998% at 1400 °C to 99.4% at 1700 °C, giving a V/Ti separation factor above 104. Fe recovery to the metal phase exceeds 97% at 1600 °C and above, driven by the strong reduction of FeO, which constitutes approximately 32 wt.% of the initial slag. Carbon activity exerts a cubic power-law effect: at 1450 °C, the V recovery ceiling collapses from 97.4% at a_C = 1 to 6.5% at a_C = 0.05, identifying imperfect carbon saturation as a primary thermodynamic mechanism behind the ceiling-to-pilot gap. Once temperature and oxygen closure are enforced, the ceilings are only weakly sensitive to metallization, basicity, coke ratio, and TiO₂ content. Comparison with pilot data shows the ceilings exceed reported yields by 16–29 percentage points (pp), quantifying the kinetic/mass-transfer deficit and providing a benchmark for scale-up. Full article

The transport of metal ions from highly saline matrices remains challenging due to the elevated ionic strength and complex chemical speciation that characterize seawater and desalination brines. In this work, the influence of membrane composition on Cd(II) transport through polymer inclusion membranes (PIMs) was evaluated using cellulose triacetate (CTA), poly(vinyl chloride) (PVC), and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membranes containing Aliquat 336. Membranes were tested using model NaCl solutions, seawater, and desalination brine, and the effects of membrane mass, polymer matrix, carrier/plasticizer composition, and receiving phase were investigated. Reducing the CTA membrane mass by 50% did not significantly affect transport efficiency, indicating that membrane composition had a greater influence on Cd(II) transport than membrane mass under the conditions evaluated. Among the evaluated formulations, the optimum PVDF-HFP membrane contained 60 wt.% PVDF-HFP, 30 wt.% Aliquat 336, and 10 wt.% butyl stearate (BTS), achieving a transport efficiency of 95.5% and an initial flux of 2.7 × 10⁻⁶ mol m⁻² s⁻¹ in desalination brine. The use of 0.5 M HNO₃ as the receiving phase markedly improved Cd(II) transport in both synthetic saline solutions and real seawater and desalination brine compared with ultrapure water. These results highlight the importance of polymer–plasticizer interactions in controlling Cd(II) transport and demonstrate the potential of PVDF-HFP/Aliquat 336/BTS membranes for metal recovery from complex saline media. Full article

Lead (Pb²⁺) pollution poses a severe threat to the ecological environment and human health due to its high toxicity, bioaccumulation, and refractory nature. Traditional treatment technologies for lead-contaminated wastewater, such as chemical precipitation, ion exchange, and membrane separation, often face limitations, including secondary pollution, high costs, and high energy consumption. In contrast, adsorption has emerged as a promising alternative technology with advantages such as a simple process, high efficiency at low concentrations, and renewability. Biomass-based hydrogels and their composite systems, as novel green adsorbent materials, combine the abundant functional groups of natural biomass with the structural stability, high porosity, and recoverability of hydrogels through a three-dimensional cross-linked network, offering unique advantages for lead ion adsorption. Depending on their composition, these systems range from fully biodegradable pure biopolymer networks to partly biodegradable or biomass-containing composites incorporating inorganic, carbon-based, or metal–organic framework (MOF) materials. This paper systematically reviews the latest research progress on cellulose, lignin, sodium alginate, chitosan, starch-based hydrogels, and their composite systems for lead (Pb²⁺) adsorption. First, the structural characteristics, cross-linking mechanisms, and functional modification strategies of various biomass hydrogels are introduced. Then, the adsorption mechanisms of Pb²⁺, including multiple modes of action such as coordination complexation, ion exchange, electrostatic interaction, and physical adsorption, are systematically analyzed. The adsorption performance of different material systems is compared in detail. The regeneration and recycling performance, as well as the potential practical applications, of the materials are evaluated. On this basis, the main challenges in current research are summarised: balancing adsorption capacity and mechanical strength, achieving selective adsorption in actual wastewater, improving regeneration efficiency, and optimizing costs. In addition, future development directions for biomass hydrogel adsorbent materials are discussed, including the design of multi-functional composite materials, the development of intelligent, responsive hydrogels, engineering-scale-up, and life-cycle assessment. This review aims to provide a theoretical framework and technical roadmap for the rational design of high-performance, sustainable hydrogel adsorbents and to promote their engineering application for the treatment of lead-contaminated wastewater. Full article

The development of reusable nanomaterials for the extraction of trace-metals from complex matrices remains challenging because strong metal-chelating functionalities often hinder desorption and regeneration, whereas weaker binding sites compromise selectivity and enrichment efficiency. This limitation has been addressed by designing a ligand-engineered fibrous mesoporous silica nanomaterial (Van-KCC-1) via the integration of the unique structural features of KCC-1 with an o-vanillin-derived Schiff-base chelator. The material was synthesized throughout the chemical grafting of 3-aminopropyltriethoxysilane (APTES) onto fibrous mesoporous silica KCC-1, followed by condensation with 3-methoxy-2-hydroxybenzaldehyde (o-vanillin). The successfulness of functionalization and Schiff-base formation were confirmed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The radially oriented fibrous channels of KCC-1 provide a highly accessible surface that remains available for interaction with the targeted ions even after chemical modification. This architecture facilitates rapid mass transfer and efficient utilization of binding sites, while the incorporated Schiff-base ligand introduces imine, phenolic, and methoxy donor groups capable of selectively and reversibly coordinating Ni(II) and Cd(II). The resulting balance between adsorption strength and desorption efficiency enables both effective metal capture and sorbent reusability. More importantly, the study demonstrates how KCC-1 can serve as a versatile nanosilica scaffold for the incorporation of tailored chelating ligands without sacrificing structural accessibility. The functionalized nanomaterial was evaluated as a dispersive solid-phase extraction (DSPE) sorbent coupled with inductively coupled plasma optical emission spectrometry (ICP-OES). Under optimized conditions, linear ranges of 0.035–50 μg L⁻¹ for Ni(II) and 0.058–50 μg L⁻¹ for Cd(II) were obtained, with limits of detection of 0.011 and 0.019 μg L⁻¹, respectively. The method exhibited excellent precision (relative standard deviation ≤ 3.6%) and recoveries of 92.00–98.83% in certified reference materaisl (NIST CRM 1643d), mineral water, tap water and synthetic wastewater. In addition, the nanochelator has retained more than 87% of its initial sorption efficiency after six adsorption–desorption cycles and showed minimal interference from common coexisting ions. These findings establish Van-KCC-1 as an efficient, selective, and reusable DSPE sorbent in the determination of trace-metals while highlighting the broader potential of fibrous mesoporous silica KCC-1 as a platform for the rational design of next-generation chelated nanomaterials. Full article

In recent years, a novel class of highly stable multiprotein complexes, with molecular masses ranging from 1 to 2 MDa, has been identified in human milk, placenta, sea urchin eggs, and sea cucumbers. These complexes exhibit extraordinary stability, dissociating only under stringent conditions involving 8 M urea, 3 M MgCl₂, EDTA, and DTT. Previous investigations have demonstrated that complexes derived from different organs of the sea cucumber Paracaudina chilensis differ in size, molecular mass, and protein/peptide composition; however, their enzymatic activities have remained unexplored. In the present work, we performed the first systematic analysis of phosphatase activity associated with highly stable complexes isolated from five organs of P. chilensis: the body wall, gonads, respiratory trees, intestine, and coelomic fluid. Complexes were purified via gel filtration chromatography on Sepharose 4B, followed by ultracentrifugation. Phosphatase activity was determined spectrophotometrically by monitoring the hydrolysis of p-nitrophenyl phosphate. Our results indicate that all five complexes harbor phosphatases with optimal pH values spanning 7.0 to 10.0. Alkaline phosphatases (pH 9.0–10.0) displayed pronounced organ specificity: maximal activity was observed in the intestinal complex, whereas minimal activity was detected in the gonadal complex. Phosphatase activity in complexes from the body wall and respiratory trees exhibited a bell-shaped dependence on Mg²⁺ concentration, with optima at 5 mM and 1 mM, respectively; in contrast, activity in the intestinal and coelomic fluid complexes increased to a plateau at 5–10 mM Mg²⁺. Ca²⁺ ions predominantly inhibited activity, with the notable exception of the intestinal complex, where they exerted no effect on hydrolysis. EDTA treatment resulted in complete inactivation of the enzymes in most complexes; however, intestinal activity was retained at 50% even at high chelator concentrations, suggesting the presence of a metal-independent phosphatase. Collectively, these data indicate that the stable multiprotein complexes of P. chilensis contain an organ-specific repertoire of phosphatases that differ in pH optimum, metal ion dependence, and inhibitor sensitivity. These findings open new avenues for understanding the roles of such complexes in organ-specific physiological functions and regenerative mechanisms in echinoderms. Full article

Cryo-electron tomography (Cryo-ET) has emerged as a transformative tool for visualizing viral components within their native cellular environment, enabling structural interrogation of viral life cycle events at nanometer resolution without chemical fixation or heavy metal staining. However, a persistent challenge in applying Cryo-ET to virus research is the unambiguous identification of specific viral components within densely crowded tomographic volumes. Electron density encodes mass and shape but not molecular identity, and as the cellular environment grows more complex, the assumption that a given density has no plausible alternative assignment becomes increasingly difficult to defend. This review surveys labeling and localization strategies for in situ Cryo-ET of viral components, encompassing label-free exploitation of native electron density, Cryo-immunogold labeling, genetically encoded and synthetic molecular tags, and correlative Cryo-light/electron microscopy (Cryo-CLEM) combined with Cryo-focused ion beam (Cryo-FIB) milling. We first summarize the landmark structural discoveries that in situ Cryo-ET has delivered across virus families, and then evaluate each labeling strategy against the structural and functional constraints that viral proteins impose, providing a practical framework for matching a labeling approach to a specific viral component and life-cycle stage. Full article

Silica gel polymer material with imprinted phosphate cavities was successfully obtained using one-pot sol–gel reaction. Differences in the textural properties concerning the reduction in specific area and pore size between functionalized and pristine silica gel demonstrated the presence of the phosphate moieties in the cavities. The chemical and structural characterization of the functionalized material before and after copper adsorption was performed by Fourier-transform infrared spectroscopy (FTIR) and solid-state ²⁹Si and ³¹P nuclear magnetic resonance (NMR) spectroscopy. All these measures proposed a phosphate non-covalently bound in the cavities of the silica gel and stabilized by silanol groups on the surface of the matrix. The phosphate–copper complex is removed after the metal desorption process, and the free cavities in the silica matrix can be replenished with phosphoric acid without affecting its adsorption capacity. The entire process of phosphate incorporation, copper adsorption, and metal-ligand desorption was repeated in three cycles, showing a similar metal adsorption capacity. Energy-dispersive X-ray spectroscopy (SEM-EDX) experiments were performed to monitor the presence and proportion of phosphorus and copper at each step of the phosphate loading and copper adsorption processes. These results demonstrate the feasibility of synthesizing a rechargeable polymer material with functional molded cavities with phosphate groups capable of adsorbing copper ions. Finally, this investigation represents the first approach to new materials with a rechargeable ligand system for the adsorption of heavy metals. Full article

Integrated circuits (ICs), a major fraction of waste electrical and electronic equipment (WEEE), represent an important secondary source of gold (Au). However, recovering high-purity Au from ICs remains challenging due to the high silicon dioxide content that encapsulates Au within the IC core and the presence of complex base-metal mixtures that hinder selective purification. This study proposes a simplified end-to-end process that integrates mechanical liberation, magnetic separation, oxidative chlorination, ion-exchange purification and Au recovery from isolated ICs. Unlike conventional multi-stage comminution routes, the proposed pretreatment combines hydraulic pressing, milling/sieving and magnetic separation to maximize Au exposure while minimizing dust generation, metal losses and base-metal interference, which is subsequently subjected to oxidative leaching and purification. Optimal extraction conditions, determined through a Taguchi design (2.5 M HCl, 0.34 M NaClO, 40 °C, solid–liquid ratio 1 g/40 mL, 3 h), achieved a Au leaching efficiency of 89%. The resulting multi-metal leachate was treated with a strong anionic ion-exchange resin, increasing Au purity from 8% to 86% after thiourea elution in a sulfuric-acid medium. Final Au recovery was completed by reductive precipitation with sodium borohydride, yielding complete solidification (~100% efficiency). A comparative life-cycle assessment showed that this recycling route offers favourable environmental performance relative to primary mining. Beyond achieving efficient Au recovery, this work establishes an integrated recovery route for isolated ICs that combines process simplification with environmental positive impact, addressing an important gap in WEEE recycling. Full article

This review examines recent quantum chemical methodologies applied to investigating antibiotic structure and mechanisms of action. The discussion is organised into three sections: (1) enzymatic hydrolysis of the β-lactam ring, (2) interactions of antibiotics with ribosomal subunits and enzyme active sites, and (3) complex formation with metal ions. Each section evaluates how quantum chemical approaches, particularly density functional theory (DFT) and hybrid QM/MM techniques, model molecular processes relevant to antibiotic function, including transition states, electron density analyses, and metal coordination effects on antibacterial activity. Selected studies demonstrate the utility of these methodologies in interpreting experimental data and predicting physicochemical and biological properties of novel compounds. Distinct from previous literature, this review provides a comparative and up-to-date synthesis of quantum chemical methods related to enzymatic mechanisms and metal-based antibiotic systems, emphasising experimental validation strategies and practical guidelines for method selection in antibiotic research. It also identifies areas where quantum chemical modelling can integrate with experimental pharmacology and structural biology to support the rational design of next-generation antimicrobial agents. The review concludes by advocating an interdisciplinary framework combining quantum chemistry, biochemistry, and pharmacology to address antibiotic resistance. The review focuses primarily on antibiotics targeting bacterial cell wall and protein synthesis, particularly β-lactam antibiotics, ribosome-targeting agents, and their interactions with metal ions. Computational methods discussed are mainly limited to DFT, ab initio, and hybrid QM/MM approaches. It does not cover membrane-disrupting antibiotics, antiviral or antifungal agents, machine learning-based prediction methods, or purely molecular dynamics approaches outside a quantum mechanical context. Full article

TPEN (N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine) is a ligand containing six nitrogen donors. It is characterized by high structural flexibility, enabling the coordination of metals with various ionic radii and coordination numbers. It is an advanced metal chelator that demonstrates high selectivity, particularly towards “soft” and “medium” metal ions, and has a wide range of applications, from coordination chemistry, materials engineering, and nuclear energy to innovations in medicine. TPEN can cross cell membranes freely, which is important in cell biology. However, its presence is not neutral for healthy cells and can lead to apoptosis by depleting essential metals such as zinc, iron, and copper. Targeted delivery systems are therefore essential. This can be achieved, for example, by using nanoparticles that release TPEN upon ultrasound. This review systematizes the understanding of TPEN complexes. Methods for the coordination of various d-, p-, and f-block metals are presented, as well as the properties of these complexes, which are crucial to understanding the mechanisms of reaction with TPEN. This ligand may find applications both as a diagnostic tool (in sensors) and as a therapeutic tool (by inducing cancer cell death). This work also demonstrates the need to design new and more effective TPEN analogs that overcome problems with solubility and stability in acids. Full article

The proposed work assesses the potential of Paulownia leaf-derived materials as sustainable adsorbents for the efficient removal of Pb(II) from aqueous solutions. Raw Paulownia leaf biomass (PL), biochar obtained by pyrolysis at 400 °C (BC), and (3-aminopropyltriethoxysilane)-functionalized oxidized biochar (APTES-OBC) were prepared. Their physicochemical properties were characterized using SEM/EDS and FTIR, and their Pb(II) adsorption performances were comprehensively investigated through pH-dependent, adsorbent dosage, kinetic, isotherm, thermodynamic, and ion-exchange studies and compared. The obtained results showed that APTES functionalization significantly improved Pb(II) adsorption performance, with adsorption capacities following the order APTES-OBC (291.86 mg/g) > BC (121.82 mg/g) > PL (104.29 mg/g). The Sips isotherm best described Pb(II) adsorption on the carbonized adsorbents, indicating heterogeneous adsorption, whereas the Redlich-Peterson isotherm model showed the best agreement with Pb(II) adsorption on the PL. The adsorption kinetics were most accurately represented by the pseudo-second-order model, indicating that chemisorption-related interactions played a dominant role during Pb(II) uptake. Diffusion studies revealed a three-stage adsorption mechanism. Ion-exchange experiments confirmed the release of Ca²⁺, K⁺, Mg²⁺, and Na⁺ ions, indicating that ion exchange contributes to the Pb(II) adsorption mechanism. However, the lower release of these ions from APTES-OBC, despite its superior adsorption capacity, indicates that Pb(II) removal is predominantly governed by surface complexation and coordination with amino-functionalized silane groups following APTES functionalization. Overall, the findings highlight a sustainable approach for the valorization of Paulownia leaf waste into efficient and environmentally safe adsorbents for heavy metal elimination from water systems. Full article

The escalating prevalence of bacterial infections has intensified the search for innovative antimicrobial strategies, particularly for infected wound management. Chondroitin sulfate (CS), a naturally occurring glycosaminoglycan with established biocompatibility, presents an attractive scaffold for developing metal ion-functionalized biomaterials. This study reports the fabrication of chondroitin sulfate–copper complex (CSCu) and chondroitin sulfate–zinc complex (CSZn) through an ion exchange method, wherein Cu²⁺ and Zn²⁺ ions bind to the groups of carboxylate, sulfate, or N-acetyl from the CS backbone. The resulting complexes exhibited copper or zinc loading capacities of about 6.6% and demonstrated potent antibacterial activity against E. coli and S. aureus. The integration of CSCu or CSZn with sodium alginate yielded a hydrogel system with a higher apparent viscosity, possessing injectability and spreadability on the skin surface and a porous three-dimensional internal structure conducive to wound healing applications. In a murine model of S. aureus-infected full-thickness wounds, topical application of CSCu and CSZn hydrogels substantially accelerated wound closure, achieving 97.46% and 98.11% healing, respectively, by day 10. Additionally, treatment with CSCu or CSZn hydrogels significantly attenuated systemic inflammatory responses, as reflected in lowered serum TNF-α, IL-1β, and IL-6 alongside increased IL-10. Histological evaluation confirmed enhanced re-epithelialization and stratum spinosum formation in treated wounds. These findings establish CSCu and CSZn as a promising bioactive agent for addressing bacterial wound infections through a dual mechanism of direct antibacterial action and immunomodulatory effects, offering a valuable alternative to conventional antibiotic therapies. Full article

A novel carbohydrazide-based ligand (L) and its binuclear Cu(II) complex were successfully synthesized and characterized. Structural analysis confirmed that the Cu(II) complex adopted a monoclinic crystal system with a distorted coordination configuration, in which the multidentate Schiff base ligand chelated and bridged two Cu(II) centers. The in vitro anti-tumor results revealed that the Cu(II) complex exhibited prominent cytotoxicity against five human cancer cell lines with much lower IC₅₀ values than the free ligand, copper chloride and cisplatin. Mechanistic studies demonstrated that the Cu(II) complex significantly increased intracellular ROS and MDA levels, decreased the GSH/GSSG ratio, and reduced ATP content, thereby disrupting cellular redox balance and bioenergetic metabolism. In addition, flow cytometry analysis verified that the complex effectively triggered tumor cell apoptosis. In contrast, free CuCl₂ showed almost no anticancer activity, indicating that the synergistic effect between the Schiff base ligand and copper ions contributed to the excellent anti-tumor performance. This work suggests that the prepared binuclear Cu(II) complex can serve as a promising candidate for developing metal-based anticancer agents. Full article

This study provides a detailed assessment of the corrosion-inhibiting performance of a previously synthesized pyrazole derivative (R9) for mild steel, using both experimental and theoretical methods. Electrochemical measurements, including potentiodynamic polarization and electrochemical impedance spectroscopy, showed that R9 achieved a maximum inhibition efficiency of 81% at a concentration of 10⁻³ M in 1 M hydrochloric acid. This improvement was reflected in the marked decrease in corrosion current density from 604 to 94 µA·cm⁻². The inhibitor displayed mixed-type behavior, influencing both anodic and cathodic corrosion reactions. This was confirmed by the small shift in corrosion potential recorded with and without R9, along with the increase in polarization resistance and the enhanced protection of the steel surface. Inductively coupled plasma spectrometry was used to measure dissolved metal ions, while scanning electron microscopy combined with energy-dispersive X-ray spectroscopy confirmed the formation of an adsorbed protective film on the steel surface. These findings further supported the effectiveness of R9 and agreed well with the electrochemical results. In the theoretical part, quantum chemical calculations on the isolated inhibitor R9 and the Fe-R9 complex (density functional theory, molecular electrostatic potential, Fukui indices, and atomic charges) were coupled with molecular simulations based on both molecular dynamics and Monte Carlo methods to provide a comprehensive understanding of the corrosion inhibition mechanism. The findings from the electronic structure studies, active site predictions, and adsorption analyses demonstrated effective and stable complexation of the R9 molecule with the steel. The results revealed an excellent correlation between the experimental and theoretical methods employed, highlighting the significance and robustness of the present study. Full article