RSC Advances最新文献

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder marked by persistent lung inflammation and airway constriction. It presents a formidable global health challenge owing to its high morbidity and mortality rates. It is often aggravated by infections from pathogens such as Pseudomonas aeruginosa, a predominant pathogen that accelerates lung function deterioration and triggers frequent exacerbations. Ensifentrine (ENF) exhibits strong anti-inflammatory effects and is a selective dual inhibitor of the enzymes PDE3 and PDE4, which have been reported to be beneficial in treating COPD exacerbation. This study examined the anti-pathogenic activity of ENF against P. aeruginosa by adopting an innovative synthetic route. A series of intermediates were synthesized via the novel route, optimizing the yield and integrity of ENF. Further investigations to determine the activity of the compound against P. aeruginosa involved antibacterial and antibiofilm testing and identification of the potential mechanisms of action. Preliminary results demonstrate that ENF and its intermediate ENF^A exhibit 50–60% robust biofilm-inhibition and biofilm-eradication effects at remarkably low concentrations of 3.9 μM and 7.9 μM, respectively. Furthermore, ENF disrupts quorum sensing, leading to a 35% reduction in the production of pyoverdine and exopolysaccharide, which are two key virulence factors of P. aeruginosa. Importantly, ENF exhibits synergistic activity with ciprofloxacin, further enhancing its antimicrobial efficacy at a concentration of 0.25 μg mL⁻¹. This study focuses on the innovative synthesis of ENF and its promising anti-pathogenic properties, which may make it an effective adjunctive treatment for COPD caused by P. aeruginosa.

With technological advancements driving the demand for innovative materials, triple tungstate compounds, like Li₂Mg₂(WO₄)₃ (LMWO), offer exceptional properties for optoelectronic technologies. To investigate these potential outcomes, the LMWO compound was prepared via the solid-state reaction approach. The X-ray diffraction analysis revealed a single-phase material crystallizing in the orthorhombic structure, belonging to the Pnma space group. The crystallite size of the material was determined to be 58.32 nm, which played a significant role in enhancing its electrical performance. Scanning electron microscopy (SEM) revealed prismatic or rod-shaped particles with an average grain size of approximately 2.83 μm. Additionally, EDX confirmed the elemental composition, verifying the presence of Mg, W, and O, and ensuring the material's purity. Nyquist plots indicated non-Debye type relaxation, and further analysis of the relaxation frequency confirmed long-range motion of charge carriers. The temperature dependence of dielectric relaxation followed the Arrhenius law, yielding an activation energy of 0.84 eV. The frequency dependent behavior of M′′ and Z′′ at various temperatures indicated a shift from short-range to long-range mobility of charge carriers. The conductivity of the material increased with both temperature and frequency, demonstrating its semiconducting behavior. The temperature dependence of Jonscher's exponent suggests that conduction follows the non-overlapping small polaron tunneling (NSPT) model. This compound exhibited a high dielectric constant (ε ∼ 10⁵) and low dielectric loss at high frequencies, making it promising for applications in laser host materials and energy storage.

Quantitative nuclear magnetic resonance (qNMR) spectroscopy could potentially be used for environmental microplastic analyses, provided the challenges posed by mixed polymer samples with varying concentrations and overlapping signals are understood. This study investigates the feasibility of qNMR as a reliable and cost-efficient method for quantifying synthetic polymers in mixtures of low and varying concentrations, addressing key challenges and limitations. Polymer mixtures were analysed using deuterated chloroform (CDCl₃) and deuterated tetrahydrofuran (THF-d₈) as solvents, with polystyrene (PS), polybutadiene-cis (PB), polyisoprene-cis (PI), polyvinyl chloride (PVC), polyurethane (PU), and polylactic acid (PLA) as selected polymers. Mixtures contained either low and high concentrations of each polymer or equal concentrations of all six polymers. Polymer concentrations were measured using the internal standard method. The method showed low relative errors for low concentrations of PS in CDCl₃ and PVC in THF-d₈, with values of −5% and 0%, respectively, while PB and PI in CDCl₃ show relative errors of +5% and −3%, respectively. We observe significant linearity between nominal and measured concentrations with R² values ranging from 0.9655 to 0.9981, except for PU, which had high relative errors and poor linearity (R² = 0.9548). Moreover, simultaneous quantification of six polymers in THF-d₈ proves effective at intermediate concentrations. However, overlapping proton signals are observed, causing high-concentration polymers to mask low-concentration ones. While this study demonstrates low limit of quantification (LOQ) and advances in simultaneous polymer quantification, further research is needed to improve qNMR accuracy for mixed polymer samples and environmentally relevant concentrations.

Hydrothermal carbonization (HTC) research has mainly focused on primary char production, with limited attention to secondary char, which is formed through polymerization and condensation of dissolved organic compounds in the liquid phase. This research aims to address this gap via an experimental investigation of the impact of stirring on the mass and carbon balance of HTC reaction products, surface functional groups, and surface morphology of secondary char, using fructose as a model compound. A 3D hydrodynamic simulation model was developed for a two-liter HTC stirred reactor. The experimental results indicated that stirring did not significantly influence the pH, mass, carbon balance, and surface functional groups of secondary char produced under the range of experimental conditions (180 °C, 10% biomass to water (B/W) ratio, and a residence time of 0–120 min) studied. Nonetheless, it was observed that a stirring rate of 200 rpm influenced the morphology and shape of the secondary char microspheres, leading to a significant increase in their size i.e., from 1–2 μm in unstirred conditions compared with 70 μm at a stirring rate of 200 rpm. This increase in size was attributed to the aggregation of microspheres into irregular aggregates at stirring rates > 65 rpm and residence times > 1 h. The hydrodynamic model revealed that high turbulence of Re > 10⁴ and velocities > 0.17 m s⁻¹ correlated with regions of secondary char formation, emphasizing their role in particle aggregation. Particle aggregation is significant above a stirring rate of 65 rpm, which corresponds to the onset of turbulent flow in the reactor. Finally, a mechanism is proposed, based on reactor hydrodynamics under stirred conditions, that explains secondary char deposition on the reactor walls and stirrer.

The catalytic hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-dihydroxymethylfuran (DHMF) represents a promising pathway for the valorisation of lignocellulosic-derived biomass feedstock. This study investigates the use of Ru–PNP complexes as (pre)catalysts to achieve efficient and highly selective hydrogenation of HMF in ionic liquids (ILs) as green reaction media under mild reaction conditions. Our results indicate that ^iPrRu-MACHO leads to excellent conversion and yield (up to 99%) of HMF to DHMF using 1-butyl-3-methylimidazolium acetate (BMIM OAc). The analogous cationic Ru–PNP complex bearing acetonitrile as ancillary ligand and hexafluorophosphate (PF₆⁻) as counterion also shows high catalytic activity (up to 99% conversion) in BMIM OAc under mild reaction conditions. Interestingly, the IL seems to prevent HMF polymerization to humins. Furthermore, the recyclability and reusability of the ionic liquid are systematically investigated.

The 10–23 DNAzyme is a catalytic DNA molecule that efficiently cleaves RNA in the presence of divalent cations such as Mg²⁺ or Ca²⁺. Following their discovery, the 10–23 DNAzymes demonstrated numerous advantages that quickly led them to be considered powerful molecular tools for the development of gene-silencing tools. In this study, we evaluate the efficiency of the 10–23 DNAzyme and an LNA-modified analog in cleaving human MALAT1, an RNA overexpressed in cancer cells. First, we perform in vitro assays using a 20 nt RNA fragment from the MALAT1 sequence, with 2 mM and 10 mM Mg²⁺ and Ca²⁺ as cofactors, to evaluate how LNA modifications influence catalytic activity. We found that the activity is increased in the LNA-modified DNAzyme compared to the unmodified version with both cofactors, in a concentration-dependent manner. Finally, the RNA-cleaving activity of the LNA-modified, catalytically active 10–23 DNAzyme was tested in MCF7 human breast cancer cells. We found that the DNAzyme persists for up to 72 h in cells and effectively silences MALAT1 RNA in a concentration-dependent manner as early as 12 h post-transfection.

The rising threat of multidrug-resistant tuberculosis, caused by Mycobacterium tuberculosis, underscores the urgent need for new therapeutic solutions to tackle the challenge of antibiotic resistance. The current study utilized an innovative 3R infection model featuring the amoeba Dictyostelium discoideum infected with Mycobacterium marinum, serving as stand-ins for macrophages and M. tuberculosis, respectively. This high-throughput phenotypic assay allowed for the evaluation of more specific anti-infective activities that may be less prone to resistance mechanisms. To discover novel anti-infective compounds, a diverse collection of 1600 plant NEs from the Pierre Fabre Library was screened using the latter assay. Concurrently, these NEs underwent untargeted UHPLC-HRMS/MS analysis. The biological screening flagged the NE from Stauntonia brunoniana as one of the anti-infective hit NEs. High-resolution HPLC micro-fractionation coupled with bioactivity profiling was employed to highlight the natural products driving this bioactivity. Stilbenes were eventually identified as the primary active compounds in the bioactive fractions. A knowledge graph was then used to leverage the heterogeneous data integrated into it to make a rational selection of stilbene-rich NEs. Using both CANOPUS chemical classes and Jaccard similarity indices to compare features within the metabolome of the 1600 plant NEs collection, 14 NEs rich in stilbenes were retrieved. Among those, the roots of Gnetum edule were flagged as possessing broader chemo-diversity in their stilbene content, along with the corresponding NE also being a strict anti-infective. Eventually, a total of 11 stilbene oligomers were isolated from G. edule and fully characterized by NMR with their absolute stereochemistry established through electronic circular dichroism. Six of these compounds are new since they possess a stereochemistry which was never described in the literature to the best of our knowledge. All of them were assessed for their anti-infective activity and (−)-gnetuhainin M was reported as having the highest anti-infective activity with an IC₅₀ of 22.22 μM.

Oak (Quercus spp.) acorns are used in animal feed and in the treatment of specific diseases due to their nutritional value and high content of bioactive compounds. The aim of the present work is to investigate and compare polyphenolic compounds and the antioxidant activity of Quercus ilex and Quercus robur acorn extracts. This is performed using the matrix solid-phase dispersion (MSPD) extraction process, in an environmentally friendly way with different generally recognised as safe (GRAS) solvents. The GRAS solvents considered were an alcohol, a ketone, an ester and a glycol. Total polyphenolic content (TPC) and antioxidant activity (DPPH and ABTS scavenging test) were determined spectrophotometrically. The different antioxidant data obtained by two approaches are discussed. All Quercus robur extracts show better results than Quercus ilex in both total polyphenolic content and antioxidant activity, the highest results being obtained with ethyl lactate, 76 mgGAE g⁻¹ DW and 2636 μmolTE g⁻¹ DW, respectively. These results demonstrate the correlation between total polyphenolic content and antioxidant activity, and that free radical scavenging is concentration dependent. Individual quantification of the polyphenols was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), with the major compounds being gallic acid, ellagic acid, catechin, quercetin and gallotannins in all extracts. MSPD, for the first time applied to acorns, has proven to be a good alternative to conventional processes for obtaining antioxidant extracts rich in bioactive compounds.

In the context of sustainable development, the utilization of semiconductor materials for the degradation of dyes, antibiotics, heavy metals, and pesticides in wastewater under visible light has emerged as a focal point of contemporary research. In this investigation, a WO₃@TiO₂ composite was synthesized via a solvothermal method, with the composite exhibiting a molar ratio of 5% WO₃ to TiO₂ precursors demonstrating optimal photocatalytic degradation performance. This material achieved complete degradation of 20 mg per L Rhodamine B (RhB) dye and tetracycline (TC) antibiotic within 30 min. Furthermore, the effects of initial pollutant concentration and solution pH on catalytic efficacy were systematically explored. The findings revealed that at RhB concentrations below 40 mg L⁻¹, the degradation proceeded at an accelerated rate, with a rate constant exceeding 0.128 min⁻¹. The catalyst exhibited robust performance across a broad pH range, attaining peak degradation efficiency at pH ≈ 3. The exceptional photocatalytic prowess of the WO₃@TiO₂ composite is predominantly attributable to its distinctive hollow microstructure, the intimate interfacial synergy between WO₃ and TiO₂, and the efficient separation of photogenerated electrons and holes facilitated by the type-II heterojunction architecture.

In this study, we developed a biosensor using a gold screen-printed electrode (Au-SPE) functionalized with mercaptoundecanoic acid (MUA) and an antibody for detecting the vascular-endothelial cadherin (CD144) as a endothelial biomarker protein on extracellular vesicles (EVs) isolated from saliva. The MUA functionalization provides a stable platform for immobilizing the CD144 antibody, ensuring the detection of the target protein. This biosensor combines Au-SPE technology with an immunoassay, offering a rapid, sensitive, and non-invasive method for detection of CD144 carried by EVs. Characterization of saliva-derived EVs using transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) confirmed their morphology and size, which fell within the expected range of 80–180 nm. NTA indicated a lower concentration of particles in saliva-EVs than in serum-EVs (controls), highlighting the need for sensitive detection of EV cargos in this type of EV. Immunodetection confirmed the presence of CD144 in both saliva and serum-derived EVs, with higher concentrations in serum. Functionalization of Au-SPEs with MUA and CD144 antibodies was confirmed by significant resistance changes, and atomic force microscopy (AFM) was used to verify the preservation of EV morphology and their capturing post-immune adsorption. A calibration curve demonstrated the high sensitivity of the biosensor prototype for detecting CD144-positive EVs, with a limit of detection (LOD) of 0.111 ng mL⁻¹ and a limit of quantification (LOQ) of 0.37 ng mL⁻¹, requiring only 3 μL of EV-sample. This biosensor shows potential as a novel method for detecting and studying endothelial biomarkers associated with cardiovascular disease in EVs isolated from saliva, a capability not currently available with existing tools. Furthermore, it provides a key platform for expanding research to other biomarkers and diseases by monitoring protein cargos in the EVs, enhancing its utility across diverse clinical applications.