Search Results (751)

Hydrogen peroxide (H₂O₂) plays a vital role as an eco-friendly oxidizer, extensively used in environmental cleanup, energy transformation, and organic production. Nonetheless, the conventional method of creating anthraquinones is intricate, resulting in significant energy and ecological costs, which calls for the development of more eco-friendly and efficient substitute technologies. The article methodically examines the reaction processes and methods for improving efficiency in photocatalytic H₂O₂ generation in the past few years. This review summarizes the design principles and key structural features of various novel catalytic materials, focusing on light absorption, charge separation and migration, surface redox reactions, and enhanced mass transfer. Approaches such as expanding the range of bandgap absorption, building conjugated structures, and incorporating metal nanoclusters can significantly enhance the efficiency of light absorption. In the charge separation process, constructing built-in electric fields at the interfaces of heterojunctions, homojunctions, and Schottky junctions is crucial for improving reaction efficiency. Additionally, defect engineering may encourage targeted carrier movement and minimize recombination. The review highlights the latest advancements in enhancing selectivity and reducing H₂O₂ breakdown in surface redox reactions, achieved by regulating active sites, introducing new functional groups, and developing dual-channel reaction pathways. Furthermore, constructing three-phase interfaces, regulating asymmetric wettability, and designing cyclic/flow reactors provide innovative engineering solutions to address the challenges of insufficient oxygen supply and large-scale continuous production. Ultimately, the potential for producing H₂O₂ in photocatalytic systems is detailed. Full article

Heavy metal mercury is one of the most significant and toxic environmental contaminants. Its inorganic form (Hg²⁺) and organic form (organic mercury, OrHg) can cause irreversible harm to human health and the ecological environment, and the latter is particularly prone to bioaccumulation and bioamplification in the food chain. Therefore, there is an urgent need for a rapid, reliable and specific detection of Hg²⁺ and OrHg to evaluate the potential risk for human health. Here, a novel label-free fluorescent sensing platform based on ssDNA aptamer (A_A-T7)-templated AuNCs was established for sensitive recognition and specific detection of Hg²⁺ and OrHg. In the presence of OrHg, the fluorescence of pure A_A-T7-templated AuNCs was visibly enhanced through forming Ag/AuNCs based on Ag⁰-doped AIEE effect. However, they were obviously quenched because of generating non-fluorescent Au/Ag/Hg ANPs via metallophilic interactions among Au³⁺, Ag⁺, and Hg²⁺ (5d¹⁰-4d¹⁰-5d¹⁰) when only Hg²⁺ existed. This fluorescent sensing platform could detect as low as 20.0 nM (4.0 ng Hg/g) and has a good linear detection range, with target concentrations ranging from 0.25 μM to 2.00 μM, recoveries of 98.0–108.0%, and RSD ≤ 5.0%. Low-toxic A_A-T7-templated AuNCs could be used for cytotoxicity analysis and intracellular fluorescent imaging. The method has been successfully applied to the determination of Hg²⁺ and OrHg in tap water, seawater and dried golden pomfret fish muscle samples, demonstrating promising prospects for the assay of mercury species in environmental samples and aquatic products to ensure human health and food safety. Full article

Converting carbon dioxide (CO₂) into value-added chemicals and/or capturing it before emission are complementary strategies to mitigate rising atmospheric CO₂ levels. Copper-based materials are widely investigated for CO₂ conversion because Cu can bind and electronically activate CO₂ and related intermediates. In this computational research, an evaluation of CO₂ activation in Cu_xSc_γ nanoclusters (Cu₃Sc, Cu₂Sc₂, and CuSc₃) anchored on a graphene bilayer doped with three nitrogen atoms (graphene-3N) was performed using conformational screening and thermochemical adsorption analysis at 298.15, 300, and 400 K. Initially, the Cu₃Sc, Cu₂Sc₂, and CuSc₃ nanoclusters were optimized and characterized (relative energy, multiplicity, and electronic characteristics), and the support model (graphene-3N bilayer) was validated by comparing free geometry with partially restricted geometry, corroborating minima through vibrational analysis. Subsequently, CO₂ adsorption/activation on Cu_xSc_γ @graphene-3N was evaluated, and ΔH and ΔG values were calculated. Ultimately, based on the ΔG(T) values, the Sabatier regimes were established, where it was observed that Cu₃Sc exhibits moderate exergonic adsorption (ΔG = −76.07, −67.31, and −58.92 kJ·mol⁻¹ at 298.15, 350, and 400 K). In contrast, Cu₂Sc₂ exhibits intense adsorption (−165.02, −156.36, and −148.04 kJ·mol⁻¹), and CuSc₃ results in practically irreversible fixation (−293.98, −287.32, and −279.09 kJ·mol⁻¹), giving priority to Cu₃Sc as the most optimal cluster in terms of activation-regeneration. Full article

Background: Cancer is a major health concern that significantly impacts the global population. Selective chemotherapeutic delivery is needed to improve the efficacy of cancer therapy while minimizing side effects in healthy cells. This study investigated the potential of gold nanoclusters (AuNCs) functionalized with poly(amidoamine) dendrimers (PAMAM) and folic acid (FA) to selectively deliver doxorubicin (DOX) to cancer cells that express the folate receptor (FR). Methods: AuNC synthesis was confirmed via UV–visible and Fourier transform infrared spectroscopy, nanoparticle tracking analysis, and transmission electron microscopy. Folic acid (FA) was incorporated for cell surface receptor targeting, while the triphenylphosphonium cation (TPP⁺) was added to improve mitochondrial localization. Cytotoxicity (MTT), apoptosis, caspase 3/7, mitopotential, and oxidative stress assays were assessed using human MCF-7 (breast adenocarcinoma), HeLa (cervical carcinoma), Caco-2 (colon adenocarcinoma), MDA-MB-231 (epithelial breast cancer), and the embryonic kidney (HEK293) cells. Results: Favorable DOX loading (>78%), with more than 90% of the drug released at pH 4.5, was achieved. A dose-dependent increase in cytotoxicity was observed, with IC50 values lower in cancer cells than HEK293 cells, indicating selective toxicity and minimal off-target effects. Targeting nanocomplexes produced the best responses in the mitopotential, caspase, and oxidative stress assays in HeLa and MCF-7 cells. Conclusions: The improved cytotoxicity in cancer cells may be due to folate-receptor-mediated cellular uptake, as well as the mitochondrial uptake of TPP⁺ nanocomplexes. This highlighted the potential of the drug–AuNC nanocomplexes to limit systemic side effects, proposing a potential novel strategy for drug delivery to cancer cells. Full article

Magnetic drug targeting (MDT) is commonly evaluated by peak accumulation at the target site. Under pulsatile flow, however, initial deposition does not predict sustained localisation. We introduce the Magnetic Targeting Optimisation Concept (M-TOC), a safety-constrained framework that restructures MDT evaluation by separating geometric deposition from retention stability and embedding both within a defined hemodynamic safety window. Deposition (D) was quantified by using obstruction degree at the injection end, OD(T0), and restricted by a structural admissibility limit (OD_max = 40%). Retention stability (R) was quantified using early washout at T0 + 30 s and an apparent half-life (τ_1/2) derived from coverage decay under controlled pulsatile washout. These descriptors were integrated into a Unified Targeting Score (UTS), applied only within the admissible domain, thereby enforcing feasibility before optimisation. Three PEG-functionalised magnetoresponsive nanocluster formulations were evaluated under identical magnetic and flow conditions. D–R mapping identified distinct operating regimes and showed that no tested configuration simultaneously achieved admissible deposition and robust pulsatile stability. By formalising MDT as a constrained multi-objective problem, M-TOC provides an objective method for regime discrimination and a transferable design principle for stability-guided targeting under physiological flow. Full article

Low-temperature methanation technology offers a promising pathway for carbon recycling and sustainable energy storage by enabling near-equilibrium CO₂ conversion under atmospheric pressure. However, efficiently activating CO₂ at low temperatures remains a significant challenge due to the kinetic limitations of hydrogenation intermediates. We construct a composite oxide–metal interface structure by anchoring highly dispersed CeCrO_x nanoclusters onto metallic nickel via an ion-exchange method. This catalyst exhibits superior activity compared to conventional Ni/oxide catalysts with identical composition. Under atmospheric pressure at 220 °C, it achieves nearly 80% CO₂ conversion with over 99% methane selectivity and maintains excellent catalytic performance and structural stability during a 240-h continuous test. Systematic characterizations, including high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, CO₂ temperature-programmed desorption, and in situ DRIFTS reflectance infrared Fourier-transform spectroscopy, reveal that the synergistic modification by CeO₂ and Cr₂O₃ not only optimizes the electronic structure of Ni to promote CO₂ adsorption and activation, but also enhances H₂ dissociation and intermediate conversion by regulating oxygen vacancy concentration and alkaline site distribution. Mechanistic studies indicate that the reaction follows a synergistic mechanism dominated by the formate pathway and assisted by the CO pathway. Moreover, the interfacial structure effectively stabilizes active sites and inhibits carbon deposition from CH₄ decomposition. This study provides a universal and effective strategy for designing Ni-based CO₂ conversion catalysts suited for mild reaction conditions and characterized by high energy efficiency. Full article

Current efforts to improve photodynamic therapy focus on nanomaterials that integrate deep tissue imaging with efficient reactive oxygen species generation. Gold nanoclusters (Au NCs) are promising alternatives to conventional photosensitizers due to their effective ROS production and enhanced biocompatibility when stabilized by a protein corona. However, both photosensitizers and Au NCs are typically activated by ultraviolet or visible light, which cannot penetrate deeper into tissues and is limited to superficial applications. Here, we report a near-infrared (NIR)-activated photodynamic nanoplatform based on core–shell upconverting nanoparticles (UCNPs; NaGdF₄:Yb³⁺,Er³⁺@NaGdF₄:Yb³⁺,Nd³⁺), functionalized with a protein corona containing bovine serum albumin-stabilized Au NCs (BSA–Au NCs) and photosensitizer chlorin e6 (Ce6). Spectroscopic data confirmed the formation of the UCNP-BSA–Au-Ce6 nanoplatform and demonstrated 32% energy transfer efficiency from UCNPs to Ce6, resulting in efficient reactive oxygen species generation under 808 nm irradiation. Cellular experiments confirmed the effective internalization and optimal biocompatibility of the nanoplatform in human breast cancer and healthy cells. Upon irradiation at 808 nm, the nanoplatform significantly reduced the viability of MDA-MB-231 cancer cells. These findings indicate that the UCNP-BSA–Au-Ce6 nanoplatform couples NIR activation with enhanced singlet oxygen production, providing a multifunctional platform for deep tissue imaging and NIR-activated photodynamic therapy. Full article

This study investigates the properties of ZnO nanorod-based sensors and ZnO nanorods modified with tin dioxide (ZnO/SnO₂) and gold (ZnO/Au) nanoclusters and their response to low concentrations of carbon monoxide (CO). It was demonstrated that the ZnO/SnO₂(3) nanorod-based sensor exhibited the highest sensitivity (S = 1.64) to 10 ppm CO, while the ZnO/Au(3) sensor displayed the shortest response (69–207 s) and recovery (203–233 s) times. This behavior can be explained by ZnO/Au and ZnO/SnO₂ nanostructures having low activation energies (0.23–0.25 eV) and high potential barrier values (0.37–0.43 eV). Sensors based on ZnO/Au and ZnO/SnO₂ nanorods demonstrate sensitivity to 10 ppm CO at 250 °C and at 200 °C. In contrast, ZnO nanorod-based sensors are sensitive to 2 ppm CO at 250 °C. Full article

The adsorption and activation of CO₂ on Cu_xSc_y nanoclusters with x + y equal to 4 were analyzed using DFT and PDOS and TDOS signatures. The geometries of Cu₃Sc, Cu₂Sc₂, and CuSc₃ were optimized in the gas phase, and the minima were verified by frequencies in ORCA using M06-2X/def2-TZVP. Multiplicities 1, 3, and 5, temperatures between 298 and 400 K, and four CO₂ coordination modes R1 to R4 were evaluated. Naked and complex cluster comparison panels were constructed, and two energy windows, −18 to −10 eV and −8 to 6 eV around the Fermi level, were analyzed, complemented by frontier orbitals and charge maps. Thermodynamics indicated that mode and multiplicity control the adsorption energy, with ANOVA p-values of 0.002 and 0.008, while temperature was not significant (p = 0.682). In Cu₃Sc–C₂v(1), the R1 singlet at 298 K showed E_ads −33.43 kcal·mol⁻¹ with spin contamination, while alternative modes in the singlet were unfavorable. In PDOS and TDOS, the bare cluster exhibits a Cu d band at −11 to −10 eV and a valley around −5 eV. The exergonic complexes show CO₂ signals near the Fermi level, superimposed on Cu and Sc states, with state filling and broadening. Transferable indicators based on CO₂ intensity in the −8 to 6 eV range and metal–adsorbate overlap are proposed as predictors of exergonic adsorption. Full article

Fluorescent metal nanoclusters show great promise in heavy metal ion sensing. Herein, a bimetallic nanocluster (GSH-Au/Ag NCs) with orange fluorescence was synthesized through a facile one-pot method. The synthesized GSH-Au/Ag NCs displayed optimal excitation and emission peaks at 275 and 610 nm, respectively. The incorporation of silver can enhance the fluorescence of metal nanoclusters. The fluorescence of as-synthesized GSH-Au/Ag NCs can be significantly quenched by Hg²⁺ and Cu²⁺, and a “on–off” fluorescent probe was designed. The detection conditions, including pH and the concentration of the probe, were optimized. The respective detection limits for Hg²⁺ and Cu²⁺ ions under optimal detection conditions are estimated to be 40 nM and 33 nM, over the linear range of 100–1200 nM. Furthermore, a ratiometric fluorescent probe was prepared by mixing quinine sulfate and as-synthesized GSH-Au/Ag NCs. Hg²⁺ and Cu²⁺ can effectively quench the red fluorescence of GSH-Au/Ag NCs, whereas the blue fluorescence of quinine sulfate remains invariant. This leads to measurable changes in the RGB values of the resulting fluorescence images. The ratio (R/B) exhibits a linear relationship with the concentration of Hg²⁺ and Cu²⁺, enabling the determination of its concentration by analyzing RGB values in fluorescence images. This visual detection method significantly reduces both assay time and cost, making it suitable for on-site detection of heavy metal ions in water samples. Full article

In this work, we demonstrate a functional and previously insufficiently explored route for converting cyclic olefin copolymer (COC) TOPAS^® thin films into antibacterial hybrid materials through a combination of solvent casting, plasma activation, noble-metal sputtering, and subsequent thermal or laser treatment. While COC is already well-known as a transparent, chemically resistant material for pharmaceutical and optical applications, its coupling with post-treated noble-metal nanostructures for antibacterial functionality has not been systematically described. The main contribution of this study lies in showing that COC can serve not only as a passive packaging substrate, but also as an active platform for the formation of biologically relevant surface nanostructures. Compared with previously reported metal/polymer systems, the present work provides clear evidence that noble-metal layers on COC undergo substantial structural evolution after thermal and excimer-laser treatment, resulting in regular nanoclustered morphologies. A particularly important finding is the detection of Au particle implantation below the COC surface during sputtering, as revealed by Rutherford backscattering spectrometry, which distinguishes this system from conventional surface-only metal coatings. Furthermore, we show that laser and thermal processing do not merely reshape the deposited layer, but significantly influence the final biological response of the material. Ag-based structures showed strong bactericidal behavior against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. The prepared samples were comprehensively characterized by AFM, DSC, RBS, SEM, and TGA, and their roughness and wettability were also evaluated, enabling direct correlation between physicochemical changes and antibacterial performance. These results introduce a new strategy for upgrading conventionally used pharmaceutical COC materials into multifunctional surfaces with added antibacterial value. Full article

In this work, a ratiometric fluorescent method for carbaryl detection is reported. We found that the combination of rapid hydrolysis of carbaryl and cetyltrimethylammonium bromide (CTAB) emulsification could significantly enhance the intrinsic weak blue fluorescence of carbaryl. By using red fluorescent glutathione-gold nanoculsters (GSH-Au NCs) as a reference signal, ratiometric detection of carbaryl within 3 min was successfully achieved. The method exhibited high sensitivity, with a linear response to carbaryl in the range from 1.0 to 70 ng/mL and an LOD of 0.05 ng/mL. The method was applied for detection of carbaryl in apple and cabbage samples, and recovery rates of 90~101% and 93~110%, respectively, were obtained. These results show that the proposed method for carbaryl detection has great potential for application in food sample monitoring. Full article

To solve the copper brittleness problem of copper-bearing steel, support the ferritic rolling process, and ensure the continuity of rolling across different phase regions, this study focused on copper-bearing steel with w(Cu) = 1.56%. Gleeble thermal simulation tests were conducted to investigate the deformation behavior of Cu-bearing steel, and a corresponding deformation resistance model was established; meanwhile, the precipitation characteristics of the second phase were characterized by high-resolution transmission electron microscopy (HRTEM). The results show that the deformation resistance of copper-bearing steel increases with decreasing temperature and increasing strain rate, and its deformation resistance–temperature curve shows a unique bimodal trend, where the inflection point at 840 °C is attributed to the austenite–ferrite phase transformation, and the inflection point at 920 °C is caused by the precipitation of B2-FeCu ordered nanoclusters. HRTEM observations confirm that these nanoclusters are metastable phases with a size of less than 5 nm, and their orientation relationship with the matrix is (011)_B2//(011)_α-Fe and [001]_B2//[001]_α-Fe. The area fraction of B2-FeCu ordered nano-precipitates is in the range of 4.27% to 5.32%, which can reduce the lattice distortion of the matrix and thus decrease dislocation slip resistance. The segmented modified Zhou-Guan model has a coefficient of determination (R²) greater than 0.96 between the predicted and experimental values, which can accurately guide the optimization of low-temperature rolling process parameters for copper-bearing steel. Full article

Biocompatible nanocomposite hydrogels are emerging as versatile platforms in nanomedicine, particularly when natural proteins are used as both structural and chemical components. In this work, we report a green, simple, and rapid in situ synthesis of ultrasmall silver nanoparticles (uAgNPs) within a bovine serum albumin (BSA) hydrogel, in which albumin simultaneously acts as the reducing agent and three-dimensional scaffold. The confined reaction environment generated uniformly dispersed Ag nanostructures with diameters in the 4–40 nm range, as confirmed by DLS and TEM. High-resolution TEM revealed clear Face-Centered Cubic (FCC, 111) lattice fringes, demonstrating the crystalline nature of the embedded uAgNPs. Quantitative image analysis showed narrow size distributions and high circularities, consistent with cluster stabilization through protein–metal interactions. Rheological measurements further indicated that the incorporation of uAgNPs enhanced hydrogel stiffness and delayed yielding, reflecting a reinforcement effect mediated by the nanoparticles acting as additional cross-linking points. Moreover, when very small embedded uAgNPs are formed, the presence of emissive silver nanoclusters was found using fluorescence emission spectroscopy. Overall, our results show that BSA hydrogels provide an effective matrix for directing green uAgNP nucleation, ensuring high stability, controlled growth in less than 2 min, and improved mechanical properties. The resulting protein–nanoparticle composite constitutes a promising soft material for imaging, sensing, and other biomedical applications requiring stable, biocompatible nanoscale architectures. Full article

Monitoring the concentration of doxorubicin (DOX) was critical for tumor treatment, but existing methods failed to cross cell membrane. Here, an electrochemical platform for intracellular DOX detection in MCF-7 cells based on membrane-permeation strategy was developed. A modified gold electrode was prepared via electrodepositing AuNPs and assembling SH-DNA. Concurrently, the silica nanosphere/gold nanocluster-circular transmembrane peptide (SiO₂/AuNCs-iRGD) composite nanoparticles with membrane permeability, tumor targeting, and imaging capability were synthesized. After co-incubation of SiO₂/AuNCs-iRGD with MCF-7 cells and DOX, followed by co-incubation with the DNA-modified electrode, intracellular DOX intercalated into the DNA backbone, and redox-generated electrons were transferred to the electrode to produce a concentration-correlated electrochemical signal. The modification of the electrode, the morphology of the composite nanoparticles and the detection process were characterized by means of SEM, TEM, CV, EIS, DPV, fluorescence spectroscopy and laser confocal imaging. Under the optimized conditions, the proposed method exhibited a wide detection range of 0.05–300 μmol/L, with a detection limit of 0.01 μmol/L. Moreover, the modified electrode demonstrated satisfactory regenerability, and the proposed method showed excellent reproducibility and stability. The development platform could offer a new strategy for real-time assessment of drug concentration within cultured breast cancer cells in vitro. Full article