RSC Advances最新文献

Multifunctional organic-inorganic materials are promising candidates for next-generation optoelectronic devices. This study reports the design, characterization, and device application of a copper-based pyranoquinoline complex, Cu(HMDPQ), with enhanced optoelectronic performance. Structural analysis confirmed a square-planar geometry with bidentate oxygen coordination. Density functional theory (DFT) calculations using the 6-311G(d,p) basis set supported the experimental findings, revealing an energy gap of 2.86 eV and a pronounced nonlinear optical (NLO) response attributed to efficient intramolecular charge transfer. Thin films showed uniform morphology, an average grain size of 80.3 nm, and low surface roughness (∼8.5 nm), favoring charge transport. Optical studies revealed dual direct band gaps (1.81 and 1.93 eV), strong blue emission, and lower-energy transitions from metal-ligand interactions. A metal/organic/semiconductor heterojunction exhibited rectifying behavior, low dark current (∼1.6 × 10^-8 A cm^-2), a barrier height of ∼1.05 eV, responsivity of 3.7 × 10^-2 A W^-1, and detectivity of 5.2 × 10¹¹ Jones, demonstrating potential for photodetector and temperature-sensing applications.

Sensitive and reliable electrochemical detection of circulating microRNAs requires sensing interfaces that combine rapid electron transfer, stable probe immobilization, and high analytical performance in complex biological media. Herein, a label-free electrochemical biosensor based on an in situ engineered, surfactant-free Au@nitrogen-doped graphene quantum dot (Au@N-GQD) heterointerface was developed for the sensitive detection of microRNA-9 (miR-9), a clinically relevant biomarker associated with lung cancer progression. The sensing interface was constructed by sequential modification of a fluorine-doped tin oxide (FTO) electrode with nitrogen-doped graphene quantum dots, followed by electrodeposition of gold nanostructures and immobilization of a thiolated DNA capture probe. The synergistic integration of Au nanostructures and N-GQDs provided a highly conductive heterointerface, facilitating electron-transfer kinetics and probe immobilization through Au-S interactions without the need for external labels or enzymatic amplification. The successful fabrication of the sensing interface was confirmed by complementary spectroscopic, microscopic, and electrochemical characterization. Electrochemical measurements using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS), demonstrated a limit of detection of 0.018 aM over a broad investigated concentration range extending from zeptomolar to micromolar levels. The biosensor exhibited high selectivity toward miR-9 in the presence of interfering microRNAs, including miR-21 and miR-223, and enabled reliable detection in spiked human serum samples, demonstrating its potential applicability in complex biological matrices. Overall, the proposed sensing strategy provides a robust, and reproducible platform for sensitive microRNA analysis and shows promise for future applications in lung cancer biomarker detection and point-of-care diagnostics.

The traditional synthesis of nucleotide 5'-5' triphosphate linkages involves a "2 + 1" phosphate coupling mediated by a large excess of metal salts, where the salt removal is a labor and waste-intensive step. We have omitted the metal salts from this reaction by modulating the solubility and reactivity of the monophosphate coupling partner using a precise combination of the reaction solvent and the paired cation. This resulted in simplified downstream purification, where the amount of waste generated was reduced by over 60% throughout the whole process. We have demonstrated this synthetic approach on ARCA, an mRNA 5'-capping agent. Both the chemical purity of the product and its performance in mRNA was comparable to commercial samples.

The interplay between interfacial interactions and pore accessibility during binary adsorption of co-existing metal ions and anionic dyes on biomass-derived pyrochars remains insufficiently understood. Here, a pyrochar derived from black bean pods was investigated for Cu(ii) and Direct Red 79 (DR79) adsorption in single-solute and binary systems. Controlled pyrolysis (300-700 °C, 1-5 h) progressively altered the carbon structure and pore characteristics of the resulting pyrochars. BP7003, prepared at 700 °C for 3 h, exhibited a specific surface area of 517 m² g^-1, a substantial microporous contribution accompanied by mesopore-range features, and oxygen-containing surface functionalities. Cu(ii) showed rapid uptake, reaching a maximum experimentally determined equilibrium adsorption capacity of 117.13 ± 0.95 mg g^-1 at pH 5 under the investigated conditions. Its adsorption behaviour was consistent with contributions from surface electrostatics and oxygen-containing surface functionalities. DR79 exhibited a lower experimental equilibrium adsorption capacity of 66.05 ± 1.15 mg g^-1, with its adsorption behaviour suggesting a stronger influence of pore accessibility within the heterogeneous carbon structure. Kinetic and equilibrium analyses were consistent with heterogeneous adsorption environments for both solutes. Binary adsorption exhibited concentration-dependent behaviour under the investigated binary conditions, with small deviations from the corresponding single-solute reference systems across the tested concentration combinations. These observations are compatible with changes in the interfacial environment and competition for accessible adsorption domains, although a specific Cu-associated interaction mechanism remains unconfirmed. BP7003 retained most of its adsorption performance after four regeneration cycles, although a greater decline was observed for DR79. Overall, the results highlight the combined roles of surface chemistry, interfacial electrostatics, and pore accessibility in shaping Cu(ii)-DR79 co-adsorption across different loading regimes.

The persistence of antibiotics in aquatic environments has emerged as a critical environmental challenge due to their extensive use, incomplete metabolism, and continuous release from municipal, hospital, and industrial sources. Their accumulation in water and wastewater systems fosters antimicrobial resistance, disrupts ecosystems, and poses severe risks to public health. Conventional adsorbents such as activated carbon and zeolites often fall short in terms of selectivity, regeneration, and adsorption capacity, necessitating innovative alternatives. Metal-organic frameworks (MOFs), with their tunable porosity, high surface areas, adjustable chemical functionalities, and structural diversity, have attracted significant attention as next-generation adsorbents for antibiotic removal. This review provides a comprehensive discussion of the occurrence and impacts of antibiotics in aquatic systems, followed by a critical evaluation of the adsorption performance of pristine MOFs, MOF derivatives, and MOF-based composites. Emphasis is placed on synthetic methodologies, purification/activation strategies, and mechanistic insights underlying antibiotic-MOF interactions. Furthermore, the study highlights the regeneration potential of MOFs for sustainable applications, compares their performance with conventional adsorbents, and identifies the persisting challenges in stability, scalability, and selectivity. Finally, knowledge gaps and future directions are outlined, focusing on defect engineering, hybrid frameworks, and other critical factors governing efficient application in real wastewater treatment to accelerate the translation of laboratory studies into practical deployment. By consolidating advances and challenges, this work positions MOFs as promising candidates for addressing the global threat of antibiotic pollution in water and wastewater.

8-Chloro-5H-dibenzo[b,e][1,4]diazepin-11(10H)-one (lactam) is a key intermediate in clozapine synthesis. Its formation by cyclization is limited by a long reaction time, and the acid-catalyzed mechanism has not been fully elucidated. This study develops and optimizes the intramolecular cyclization to form the lactam in a continuous-flow system and uses DFT calculations to establish the reaction pathway and examine the cyclization mechanism in the presence of H₂SO₄ at the molecular level. Batch screening identified DMF/H₂SO₄ as a suitable reaction system, giving an 80% yield after 16 h. After transfer to a Vapourtec E-Series system and optimization using a Box-Behnken design, the reaction time was reduced 16-fold to a residence time of 60 min, while the HPLC yield increased to 90.87 ± 1.22% (n = 3) at 130 °C with 3% H₂SO₄. DFT analysis identified a reaction pathway comprising three main stages: proton transfer and carbonyl activation, intramolecular C-N bond formation, and concerted proton transfer-water elimination, and confirmed two reaction pathways originating from intermediate INT3: one via TS3 and an alternative via TS3' and TS3″. Thus, continuous-flow optimization substantially improved the efficiency of the cyclization, while the DFT study elucidated the acid-catalyzed mechanism involving H₂SO₄ at the molecular level.

Multifunctional wound dressings require polysaccharide-based biomaterials combining structural integrity, antimicrobial activity, and cytocompatibility. In this study, graphene oxide (GO)-functionalized chitosan-carboxymethylcellulose-alginate (ChitCMCAlgGO) sponge scaffolds were developed to investigate the role of GO in modulating the molecular organization and functional properties of a multicomponent polysaccharide network. The composites were characterized using SEM, FT-IR spectroscopy, solid-state ¹³C CP/MAS NMR with T₁ρH and T₁ρC relaxation analyses, mechanical testing, fluid-handling evaluation, antimicrobial and antibiofilm assays, and cytocompatibility assessment according to ISO 10993. GO incorporation enhanced the mechanical performance of the scaffolds, increasing tensile strength from 0.032 to 0.122 MPa and maximum tensile force from 0.93 to 3.48 N, while improving elongation at maximum stress from 37.6% to 110%. Spectroscopic and NMR analyses revealed that GO did not modify the chemical structure of the polysaccharide components but likely promoted non-covalent interactions and altered polymer-chain dynamics, resulting in increased scaffold density and reduced porosity. Despite a moderate decrease in fluid uptake, GO-functionalized scaffolds maintained high absorption capacity (34.2 g g^-1 after 24 h). Moreover, GO improved antimicrobial activity against wound-associated pathogens and preserved cytocompatibility. These findings demonstrate that GO functions as a structural nanofiller regulating polysaccharide network organization, providing a rational strategy for designing advanced carbohydrate-based wound dressing materials.

A new series of brominated 1,4-dihydropyridine derivatives bearing various aryl and heteroaryl substituents was successfully synthesized through a microwave-assisted multicomponent Hantzsch reaction followed by bromination under solar irradiation. The synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR spectroscopy and elemental analyses. Their insecticidal activities were evaluated against adult and nymphal stages of the cotton aphid, Aphis gossypii, using the leaf-dipping bioassay technique. Biological evaluation demonstrated that all synthesized derivatives exhibited significant insecticidal activity, with nymphs showing greater susceptibility than adults. Among the tested compounds, derivative 5e displayed the highest activity, with LC₅₀ values of 0.18 and 3.03 mg L^-1 against nymphs and adults, respectively. To investigate the potential mode of action, molecular docking studies were performed against acetylcholinesterase (AChE). All compounds showed favorable binding affinities toward the enzyme, ranging from -8.3 to -9.0 kcal mol^-1. Compound 5d exhibited the strongest predicted binding affinity (-9.0 kcal mol^-1), while the biologically most active derivative, 5e, showed a docking score of -8.7 kcal mol^-1. The combined biological and computational results indicate that brominated 1,4-dihydropyridine derivatives represent promising lead structures for the development of new insecticidal agents against A. gossypii.

Starting from the serious environmental problems associated with the growing increase of pollution, the present study investigates a sustainable and eco-friendly approach to water treatment by synthesizing green gold nanoparticles (AuNPs) starting from Aloe barbadensis Miller (Aloe vera) waste (AVW). Bioactive compounds naturally present in AVW were extracted in water at different temperatures (25-90 °C). The extract prepared at 90 °C was identified as the most suitable for stable AuNPs formation, containing higher amounts of reducing and stabilizing agents such as α- and β-glucose, sucrose and malic acid, as confirmed by ¹H-NMR studies. The appearance of a typical plasmonic band at 560 nm confirmed the success of AuNPs synthesis. Selected-area electron diffraction and transmission electron microscopy analyses demonstrated the crystalline nature of the synthesized AuNPs with an average diameter of 10 nm and with a zeta potential of -32.3 mV. Moreover, FTIR analysis revealed the presence of an organic layer around the AuNPs, also confirmed from UV-vis analysis. Methylene blue (MB), rhodamine b (ROb), methyl orange (MO) and 4-nitrophenol (4NP) were selected as water pollutant models to test their catalytic activity. The results obtained showed the high capacity of green AuNPs to speed up the reduction rate following a pseudo first order kinetic with k values observed for MB, ROb, MO and 4NP of 0.32, 0.15, 0.09 and 0.04 min^-1 respectively. This behavior remains highly efficient even when all pollutants are present simultaneously in a mixture, demonstrating their potential use also in complex matrices.

The escalating global demand for sustainable and clean energy urges the development of efficient electrocatalysts to overcome sluggish oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) kinetics in overall water splitting. This study investigates the key role of interfacial engineering by integrating orthorhombic α-MoO₃ nanoparticles with conductive carbon nanotubes (CNTs) to form a MoO₃@CNTs nanocomposite and systematically compares it with pristine MoO₃ to address conductivity-limited electrochemical performance. The underlying poorly conductive MoO₃ is employed as a reference system to evaluate the impact of CNT incorporation on charge-transfer resistance, active-site accessibility, and overall bifunctional catalytic efficiency. The electrochemical evaluation trends in relation to overpotential, Tafel slopes, double-layer capacitance (C _dl), electrochemically active surface area (ECSA), and charge-transfer resistance (R _ct) are revealed with significantly improved outputs. Among the investigated materials, MoO₃@CNTs performs remarkably better than pristine MoO₃, achieving low overpotentials of 0.35 V for the OER (50 mA cm^-2) and 0.33 V for the HER (-10 mA cm^-2) in 1 M KOH, compared to 0.42 V and 0.40 V for MoO₃, respectively. This study also reveals the enhanced electrocatalytic behavior of MoO₃@CNTs, mainly due to improved electronic conductivity and increased active-site exposure induced by CNT integration, leading to reduced Tafel slopes (217 mV dec^-1 for OER and 170 mV dec^-1 for HER), lower R _ct (5.1 Ω vs. 10.3 Ω), and higher C _dl (26.07 mF cm^-2 vs. 19.85 mF cm^-2) and ECSA (43.71 cm² vs. 30.43 cm²). These findings deepen the understanding of CNT-based interfacial engineering and its effect on MoO₃ electrochemical activity and position MoO₃@CNTs as a promising bifunctional catalyst for efficient and sustainable hydrogen production.