Search Results (1,361)

Background/Objectives. Efficient nucleic acid delivery into target cells remains a critical challenge in gene therapy. Due to its advantages in biocompatibility and safety, recent research has increasingly focused on non-viral gene delivery. Methods. A series of copolymers—synthesized by integrating thermally sensitive poly(N-isopropylacrylamide) (PNIPAm), hydrophilic poly(ethylene glycol) (PEG) grafts, and a polycationic poly(L-lysine) (PLL) block of varying lengths ((PNIPAm)₇₇-graft-(PEG)₉-block-(PLL)_z, z = 10–65)—were investigated. Plasmid DNA complexation with the copolymers was achieved through temperature-modulated methods. The resulting polyplexes were characterized by evaluating complex strength, particle size, zeta potential, plasmid DNA loading capacity, resistance to anionic stress, stability in serum, and lysosomal membrane destabilization assay. The copolymers’ potential for plasmid DNA delivery was assessed through cytotoxicity and transfection studies in cancer cell lines. Results. Across all complexation methods, the copolymers effectively condensed plasmid DNA into stable polyplexes. Particle sizes (60–90 nm) ranged with no apparent correlation to copolymer type, complexation method, or N/P ratio, whereas zeta potentials (+10–+20 mV) and resistance to polyanionic stress were dependent on the PLL length and N/P ratio. Cytotoxicity analysis revealed a direct correlation between PLL chain length and cell viability, with all copolymers demonstrating minimal cytotoxicity at concentrations required for efficient transfection. PNL-20 ((PNIPAm)₇₇-graft-(PEG)₉-block-(PLL)₂₀) exhibited the highest transfection efficiency among the tested formulations while maintaining low cytotoxicity. Conclusions. The study highlights the promising potential of (PNIPAm)₇₇-graft-(PEG)₉-block-(PLL)_z copolymers for effective plasmid DNA delivery to cancer cells. It reveals the importance of attaining the right balance between polyplex tightness and plasmid release to achieve improved biocompatibility and transfection efficiency. Full article

Recent research on the design and synthesis of new and upgraded materials for secondary batteries is growing to fulfill future energy demands around the globe. Herein, by using DFT calculations, the thermodynamic and electrochemical properties of Na/Na⁺@C₁₂ complexes and then halogens (X⁻ = Br⁻, Cl⁻, and F⁻) as counter anions are studied for the enhancement of Na-ion battery cell voltage and overall performance. Isolated C₁₂ nanorings showed a lower cell voltage (−1.32 V), which was significantly increased after adsorption with halide anions as counter anions. Adsorption of halides increased the Gibbs free energy, which in turn resulted in higher cell voltage. Cell voltage increased with the increasing electronegativity of the halide anion. The Gibbs free energy of Br⁻@C₁₂ was −52.36 kcal·mol⁻¹, corresponding to a desirable cell voltage of 2.27 V, making it suitable for use as an anode in sodium-ion batteries. The estimated cell voltage of these considered complexes ensures the effective use of these complexes in sodium-ion secondary batteries. Full article

Rapid socio-economic development and the impact of human activities have exerted tremendous pressure on the groundwater system of the Dawen River Basin (DRB), the largest tributary in the middle and lower reaches of the Yellow River. Hydrochemical studies on the DRB have largely centered on the upstream Muwen River catchment and downstream Dongping Lake, with some focusing solely on karst groundwater. Basin-wide evaluations suggest good overall groundwater quality, but moderate to severe contamination is confined to the lower Dongping Lake area. The hydrogeologically complex mid-reach, where the Muwen and Chaiwen rivers merge, warrants specific focus. This region, adjacent to populous areas and industrial/agricultural zones, features diverse aquifer systems, necessitating a thorough analysis of its hydrochemistry and origins. This study presents an integrated hydrochemical, isotopic investigation and EWQI evaluation of groundwater quality and formation mechanisms within the multiple groundwater types of the central DRB. Central DRB groundwater has a pH of 7.5–8.2 (avg. 7.8) and TDSs at 450–2420 mg/L (avg. 1075.4 mg/L) and is mainly brackish, with Ca²⁺ as the primary cation (68.3% of total cations) and SO₄²⁻ (33.6%) and NO₃⁻ (28.4%) as key anions. The Piper diagram reveals complex hydrochemical types, primarily HCO₃·SO₄-Ca and SO₄·Cl-Ca. Isotopic analysis (δ²H, δ¹⁸O) confirms atmospheric precipitation as the principal recharge source, with pore water showing evaporative enrichment due to shallow depths. The Gibbs diagram and ion ratios demonstrate that hydrochemistry is primarily controlled by silicate and carbonate weathering (especially calcite dissolution), active cation exchange, and anthropogenic influences. EWQI assessment (avg. 156.2) indicates generally “good” overall quality but significant spatial variability. Pore water exhibits the highest exceedance rates (50% > Class III), driven by nitrate pollution from intensive vegetable cultivation in eastern areas (Xiyangzhuang–Liangzhuang) and sulfate contamination from gypsum mining (Guojialou–Nanxiyao). Karst water (26.7% > Class III) shows localized pollution belts (Huafeng–Dongzhuang) linked to coal mining and industrial discharges. Compared to basin-wide studies suggesting good quality in mid-upper reaches, this intensive mid-reach sampling identifies critical localized pollution zones within an overall low-EWQI background. The findings highlight the necessity for aquifer-specific and land-use-targeted groundwater protection strategies in this hydrogeologically complex region. Full article

In this study, high-energy milled (HEM) samples of natural phosphorites from Estonian deposits were investigated. The activation was performed via planetary mill with Cr-Ni grinders with a diameter of 20 mm. This method is an ecological alternative, since it eliminates the disadvantages of conventional acid methods, namely the release of gaseous and solid technogenic products. The aim of the study is to determine the changes in the structure to follow the solid-state transitions and the isomorphic substitutions in the anionic sub-lattice in the structure of the main mineral apatite in the samples from Estonia, under the influence of HEM activation. It is also interesting to investigate the influence of HEM on structural-phase transformations on the structure of impurity minerals-free calcite/dolomite, pyrite, quartz, as well as to assess their influence on the thermal behavior of the main mineral apatite. The effect of HEM is monitored by using a complex of analytical methods, such as chemical analysis, powder X-ray diffraction (PXRD), wavelength-dispersive X-ray fluorescence (WD-XRF) analysis, and Fourier-transformed infrared (FTIR) analysis. The obtained results prove the correlation in the behavior of the studied samples with regard to their quartz content and bonded or non-bonded carbonate ions. After HEM activation of the raw samples, the following is established: (i) anionic isomorphism with formation of A and A-B type carbonate-apatites and hydroxyl-fluorapatite; (ii) solid-phase synthesis of calcium orthophosphate-CaHPO₄ (monetite) and dicalcium diphosphate-β-Ca₂P₂O₇; (iii) enhanced chemical reactivity by approximately three times by increasing the solubility via HEM activation. The dry milling method used is a suitable approach for solving technological projects to improve the composition and structure of soils, increasing soil fertility by introducing soluble forms of calcium phosphates. It provides a variety of application purposes depending on the composition, impurities, and processing as a soil improver, natural mineral fertilizer, or activator. Full article

Background: Transition metal complexes incorporating fluorinated counter anions represent a significant class of compounds with broad applications in industry, pharmaceuticals, and biomedicine. These fluorinated anions are known to enhance the solubility, stability, and reactivity of the complexes, thereby expanding their functional utility in various chemical and biological contexts. Methods: A set of metal(II) complexes of the general formula [MPy₆][B(C₆F₅)₄]₂ where (Py = pyridine, M = Mn (1), Fe (2), Co (3), Ni (4), Cu (5), Zn (6)) have been synthesized by direct reaction of metal halides and pyridine in the presence of Ag[B(C₆F₅)₄]. The complexes were characterized using different techniques to assure their purity, such as elemental analysis (EA), electron paramagnetic resonance (EPR) spectroscopy, thermogravimetric analysis (TGA), ultraviolet–visible (UV–Vis) spectroscopy, ¹¹B-NMR, ¹H-NMR, and FT-IR spectroscopy. The antimicrobial and antifungal properties against different types of bacteria and fungi were studied for all prepared complexes. Results: The synthesized complexes exhibited broad-spectrum antimicrobial activity, demonstrating variable efficacy compared to the reference antibiotic, oxytetracycline (positive control). Notably, complex 6 displayed exceptional antibacterial activity against Streptococcus pyogenes, with a minimum inhibitory concentration (MIC) of 4 µg/mL, outperforming the control (MIC = 8 µg/mL). Complexes 1, 2, and 4 showed promising activity against Shigella flexneri, Klebsiella pneumoniae, and Streptococcus pyogenes, each with MIC values of 8 µg/mL. Conversely, the lowest activity (MIC = 512 µg/mL) was observed for complexes 3, 5, and 6 against Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae, respectively. Regarding antifungal properties, complexes 5 and 6 demonstrated the highest activity against Candida albicans, with MIC values of 8 µg/mL, equivalent to that of the positive control, fluconazole. Density functional theory (DFT) calculations confirmed an overall octahedral coordination geometry for all complexes, with tetragonal distortions identified in complexes 3, 4, and 5. Full article

Incorporation of lanthanide (Ln) and actinide (An) ions into the human body poses significant chemotoxic and radiotoxic risks, necessitating effective decorporation strategies. This study investigates the displacement of biologically relevant ligands from trivalent ions of europium, Eu(III), and curium, Cm(III), in artificial biofluids by various complexing agents, i.e., ethylenediaminetetraacetic acid (EDTA), ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA), diethylenetriaminepentaacetic acid (DTPA), and spermine-based hydroxypyridonate chelator 3,4,3-LI(1,2-HOPO) (HOPO). Utilizing a modified unified bioaccessibility method (UBM) to simulate gastrointestinal conditions, we conducted concentration-dependent displacement experiments at both room and body temperatures. Time-resolved laser-induced fluorescence spectroscopy (TRLFS) supported by ²H nuclear magnetic resonance (NMR) spectroscopy and thermodynamic modelling revealed the complexation efficacy of the agents under physiological conditions. Results demonstrate that high affinity, governed by complex stability constants and ligand pK_a values, is critical to overcome cation and anion competition and leads to effective decorporation. Additionally, there is evidence that cyclic ligands are inferior to linear ligands for this application. HOPO and DTPA exhibited superior displacement efficacy, particularly in the complete gastrointestinal tract simulation. This study highlights the utility of in vitro workflows for evaluating decorporation agents and emphasizes the need for ligands with optimal binding characteristics for enhanced chelation therapies. Full article

Four novel crystalline architectures based on benzo[c]cinnolininium trifluoromethanesulonate salts, [C₁₂H₉N₂]⁺[CF₃SO₃]⁻, have been isolated as single-crystals, and their structures have been determined by X-ray diffraction analysis. The formation of the new salts results from reactions involving the dimeric hydroxo di-n-butylstannane trifluoromethanesulfonato complex [n-Bu₂Sn(OH)(H₂O)(CF₃SO₃)]₂ (1) and benzo[c]cinnoline (C₁₂H₈N₂, BCC). Organic salts I, II, III, and IV were crystallized through slow evaporation at room temperature from a mixture of toluene/dichloromethane. The cystallographic structures of I, II, and IV exhibit the presence of monoprotonated benzo[c]cinnolinium cations in interactions with a free benzo[c]cinnoline molecule through N–H···N hydrogen bonding, while for salt III, the monoprotonated cation directly interacts with the CF₃SO₃⁻ anion via an N–H···O interaction. For all four salts, aromatic π-π interactions involving rings of various components (free benzo[c]cinnoline molecule, benzo[c]cinnolinium cation, toluene molecule), combined with weak C–H···O and C–H···F interactions implying the trifluoromethanesulfonate anion, promote the solid-state self-assembly of supramolecular stacks. In parallel to the formation of benzo[c]cinnolinium based-salts, organotin(IV) 1 was converted into a distannoxane compound, ²_∞{[n-Bu₂(μ-OH)SnOSn(μ-η²-O₃SCF₃)n-Bu₂]₂[n-Bu₂(η¹-O₃SCF₃)SnOSn(μ-OH)n-Bu₂]₂} (3), which was also isolated as a single crystal and whose crystallographic structure was previously established by us. Full article

This study discloses the noncovalent immobilization of a bienzyme cascade composed of glucose oxidase (GOx) and horseradish peroxidase (HRP) onto magnetically responsive polyamide microparticles (PA MPs). Porous PA6, PA4, and PA12 MPs containing iron fillers were synthesized via activated anionic ring-opening polymerization in suspension, alongside neat PA6 MPs used as a reference. Four hybrid catalytic systems (GOx/HRP@PA) were prepared through sequential adsorption of HRP and GOx onto the various PA MP supports. The initial morphologies of the supports and the hybrid biocatalysts were characterized by SEM, followed by evaluation of the catalytic performance using a two-step glucose oxidation cascade process. Among all systems, the GOx/HRP@PA4-Fe complex exhibited the highest activity, being approximately 1.5 times greater than the native enzyme dyad, followed by the PA6-supported system with slightly inferior performance. All systems obeyed Michaelis–Menten kinetics, with the immobilized cascades displaying higher Kₘ and Vₘₐₓ values than the non-immobilized enzyme pair while maintaining comparable catalytic efficiencies, CE (CE = k_cat/Kₘ). Subsequently, the immobilized and native enzyme systems were employed for the polymerization of aniline. According to UV–VIS, complete monomer conversion was achieved within 24 h for selected catalysts, and FTIR analysis confirmed the formation of polyaniline in the emeraldine base form without the use of template molecules. These findings highlight the potential of Fe-containing polyamide microparticles as efficient supports for the sustainable, enzyme-mediated synthesis of intrinsically conductive aromatic polymers. Full article

In this study, 3-chlorothiophene-2-carboxylic acid (HL) was used as a main ligand to successfully synthesize four novel complexes: [Cu(L)₂(Py)₂(OH₂)₂] (1), [Co(L)₂(Py)₂(OH₂)₂] (2) (Py = pyridine), [{Ni(L)₂(OH₂)₄}₂{Ni(L)(OH₂)₅}]L•5H₂O (3), and [{Co(L)₂(OH₂)₄}₂{Co(L)(OH₂)₅}]L•5H₂O (4). All four compounds were identified by elemental analysis and ESI mass spectrometry, and subsequently characterized by IR spectroscopy, UV-visible diffuse reflectance spectroscopy, electron paramagnetic resonance spectroscopy, thermogravimetric analysis, single-crystal X-ray crystallography, and cyclic voltammetry. X-ray analyses revealed that complexes 1 and 2 exhibit a centrosymmetric pseudo-octahedral coordination geometry; the copper (II) and cobalt (II) metal ions, respectively, are located at the crystallographic center of inversion. The coordination sphere of the copper (II) complex is axially elongated in accordance with the Jahn–Teller effect. Intriguingly, for charge neutrality, compounds 3 and 4 crystallized as three independent mononuclear octahedrally coordinated metal centers, which are two $\left[\mathrm{M}{\mathrm{L}}_2{\left({\mathrm{O}\mathrm{H}}_2\right)}_4\right]$ complex molecules and one ${\left[\mathrm{M}\mathrm{L}{\left({\mathrm{O}\mathrm{H}}_2\right)}_5\right]}^{+}$ complex cation (M = ${\mathrm{N}\mathrm{i}}^{\mathrm{I}\mathrm{I}}$ and ${\mathrm{C}\mathrm{o}}^{\mathrm{I}\mathrm{I}}$, respectively), with the ligand anion ${\mathrm{L}}^{-}$ serving as the counter ion. The anticancer activities of these complexes were systematically assessed on human leukemia K562 cells, lung cancer A549 cells, liver cancer HepG2 cells, breast cancer MDA-MB-231 cells, and colon cancer SW480 cells. Among them, complex 4 shows significant inhibitory effects on leukemia K562 cells and colon cancer SW480 cells. Full article

Rare earth metals (REMs) are vital for high-tech industries, but their extraction from secondary sources is challenging due to environmental and technical constraints. This study investigates the ion-exchange extraction of light REMs (neodymium, praseodymium, and samarium) from sulfuric and phosphoric acid solutions, modeling industrial leachates from apatite concentrates and phosphogypsum. The study considers the use of anion- and cation-exchange resins with different functional groups for efficient and environmentally safe REM separation. Experimental sorption isotherms were obtained under static conditions at 298 K and analyzed using a thermodynamic model based on the linearization of the mass action equation. Equilibrium constants and Gibbs energy were calculated, which reveals the spontaneity of the processes. Cation-exchange resins demonstrated high selectivity towards individual REMs, while anion-exchange resins were suitable for group extraction. Infrared spectral analysis confirmed the presence of sulfate and phosphate complexes in the resin matrix, clarifying the ion-exchange mechanisms. Thermal effect measurements indicated exothermic sorption on anion-exchange resins with negative entropy and endothermic sorption on cation-exchange resins with positive entropy. The findings highlight the potential of ion-exchange resins for selective and sustainable REM recovery, offering a safer alternative to liquid extraction and enabling the valorization of industrial wastes like phosphogypsum for resource recovery. Full article

Presently, extensive research has been conducted on the electrochemical behavior of titanium ions in molten salt, especially in relation to titanium fluoride coordination. However, there is limited research on the coordination between titanium and oxygen. Consequently, this research delved into the influence of oxygen ions on the electrochemical behavior and coordination properties of titanium ions through the utilization of both electrochemical and spectroscopy techniques. The study involved the use of cyclic voltammetry (CV), square wave voltammetry (SWV), and the open-circuit potential (OCP) method to explore the electrochemical properties of titanium ions at different titanium-oxygen ratios. Furthermore, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were applied to assess the presence of titanium ions in molten salt and the coordination structure of titanium ions and anions in molten salts, respectively. The results demonstrate that with an increase in oxygen ion content, chloride ions are gradually replaced by oxygen ions, forming TiO_xCl_y^m− complexes. Full article

The efficacy of water resource management and protection hinges on a profound understanding of the controlling factors and regulatory mechanisms that shape groundwater chemistry within aquifers. Despite this, our comprehension of how groundwater chemistry and ion sources vary across diverse aquifer types remained limited. To bridge this gap, our study conducted a detailed hydrochemical and statistical investigation of porous, fissured, and karst aquifers. By applying multivariate statistical techniques, including principal component analysis (PCA) and hierarchical cluster analysis (HCA), the hydrochemical characteristics and main ion sources of each aquifer type, as well as distinct controlling factors and regulation patterns, were determined. Notably, evaporation predominantly affected the hydrochemistry of porous aquifers, whereas mineral dissolution and rock weathering processes played a pivotal role in shaping the groundwater evolution of fissured and karst aquifers. HCO₃⁻ and SO₄²⁻ are the most common anions of all types, while Na⁺ is dominant in porous and fissured aquifers and Ca²⁺ is dominant in karst aquifers. The most common hydrochemical types identified were HCO₃-Ca·Mg (accounting for approximately 56.84%) and SO₄·Cl-Na (constituting approximately 21.75%). PCA results revealed that lateral recharge from fissured aquifers in hilly regions into the groundwater of porous aquifer, and wastewater discharge and agricultural fertilizer application, significantly impact the groundwater chemistry across all three aquifer types. It is worth noting that the dissolution of carbonate minerals, often influenced by human activities, had a profound effect on the hydrochemistry of each aquifer. Conversely, the dissolution of evaporitic minerals affected groundwater chemistry primarily through cation exchange processes. In summary, the hydrochemical characteristics of these aquifer types were predominantly shaped by a complex interplay of mineral dissolution, cation exchange, evaporation, and anthropogenic activities, with notable contributions from fissured aquifer recharge and pollution. These insights were critical for informing national-level strategies for groundwater resource protection and management. Full article

Nickel’s durability and catalytic properties make it essential in the aerospace, automotive, electronics, and fuel cell technology industries. Wastewater analysis typically relies on sensitive but costly techniques such as ICP-MS, AAS, and ICP-AES, which require complex equipment and are unsuitable for on-site testing. This study introduces a novel screen-printed electrode array with 16 chemically and, optionally, electrochemically coated Au electrodes. Its electrochemical response to Ni²⁺ was tested using Na₂SO₃ and ChCl-EG deep eutectic solvents as electrolytes. Ni²⁺ solutions were prepared from NiCl₂·6H₂O, NiSO₄·6H₂O, and dry NiCl₂. In Na₂SO₃, the linear detection ranges were 20–196 mM for NiCl₂·6H₂O and 89–329 mM for NiSO₄·6H₂O. High Ni²⁺ concentrations (10–500 mM) were used to simulate industrial conditions. Two linear ranges were observed, likely due to differences in electrochemical behaviour between NiCl₂·6H₂O and NiSO₄·6H₂O, despite the identical Na₂SO₃ electrolyte. Anion effects (Cl⁻ vs. SO₄²⁻) may influence response via complexation or ion pairing. In ChCl-EG, a linear range of 0.5–10 mM (R² = 0.9995) and a detection limit of 1.6 µM were achieved. With a small electrolyte volume (100–200 µL), nickel detection in the nanomole range is possible. A key advantage is the array’s ability to analyze multiple analytes simultaneously via customizable electrode configurations. Future research will focus on nickel detection in industrial wastewater and its potential in the multiplexed analysis of toxic metals. The array also holds promise for medical diagnostics and food safety applications using thiol/Au-based capture molecules. Full article

Neurodegenerative diseases (NDDs), including Alzheimer’s disease (AD) and Parkinson’s disease (PD), are characterized by progressive neuronal dysfunction and loss and represent a significant global health challenge. Oxidative stress, neuroinflammation, and neurotransmitter dysregulation, particularly affecting acetylcholine (ACh) and monoamines, are key hallmarks of these conditions. The current therapeutic strategies targeting cholinergic and monoaminergic systems have some limitations, highlighting the need for novel approaches. Metallodrugs, especially ruthenium and platinum complexes, are gaining attention for their therapeutic use. Among metal complexes, gold(I) and silver(I) N-heterocyclic carbene (NHC) complexes exhibit several biological activities, but their application in NDDs, particularly as monoamine oxidase (MAO) inhibitors, remains largely unexplored. To advance the understanding of this field, we designed, synthesized, and evaluated the biological activity of a new series of Au(I) and Ag(I) complexes stabilized by NHC ligands and bearing a carboxylate salt of tert-butyloxycarbonyl (Boc)-N-protected proline as an anionic ligand. Through in silico and in vitro studies, we assessed their potential as acetylcholinesterase (AChE) and MAO inhibitors, as well as their antioxidant and anti-inflammatory properties, aiming to contribute to the development of potential novel therapeutic agents for NDD management. Full article

Phenylene-based bis-oxamate polydentate ligands offer a unique opportunity for creating a large variety of coordination compounds, in which paramagnetic metal ions are strongly magnetically coupled. The employment of imino nitroxyl (IN) radicals as supplementary ligands confers numerous benefits, including the strong ferromagnetic interaction between Ni and IN. Furthermore, the chelating IN can act as a capping ligand, thereby impeding the formation of coordination polymers. In this study, we present the molecular and crystal structure and experimental and theoretical magnetic behavior of an exceptional neutral trinuclear complex [Ni(L³⁻)₂(IN)₃]∙5CH₃OH (1) (L is N,N′-1,3-phenylenebis-oxamic acid; IN is [4,4,5,5-tetramethyl-2-(6-methylpyridin-2-yl)-4,5-dihydro-1H-imidazol-1-yl]oxidanyl radical) with a cyclic triangular arrangement. Moreover, in this compound three Ni²⁺ ions are linked by the two bis-oxamate ligands playing a rare tritopic function due to an unprecedented triple deprotonation of the related meta-phenylene-bis(oxamic acid). The main evidence of such a deprotonation of the ligand is the neutrality of the cluster, since there are no anions or cations compensating for its charge in the crystals of the compound. Despite the presence of six possible magnetic couplings in the trinuclear cluster 1, its behavior was reproduced with a high degree of accuracy using a three-J model and ZFS, under the assumption that the three different Ni-IN interactions are equal to each other, whereas only two equivalent-in-value Ni-Ni interactions were taken into account, with the third one being equated to zero. Our study indicates the presence of two opposite-in-nature types of magnetic interactions within the triangular core. DFT and CASSCF/NEVPT2 calculations were completed to support the experimental magnetic data simulation. Full article