RSC Advances最新文献

This work aims to develop an ultrasensitive electrochemical aptameric immunosensor for quantitative liquid-biopsy detection of colorectal cancer (CRC) exosomes. We engineered a glassy carbon electrode modified with a Ti₃C₂T _x MXene-AuPtPdCu nanoalloy nanocomposite, where uniformly dispersed alloy nanoparticles (8.5 ± 1.2 nm) provide a highly conductive and electrocatalytically active interface, and enable stable immobilization of a thiolated CD63 aptamer via Au-S bonding. Exosome capture forms an interfacial blocking layer that hinders [Fe(CN)₆]^3-/4- redox probe access, producing a concentration-dependent decrease in differential pulse voltammetry current. Under optimized conditions, the sensor exhibited a linear response from 50 to 5.0 × 10⁴ particles µL^-1 (R ² = 0.998) with a detection limit of 19 particles µL^-1, and delivered 1.8-2.0× signal amplification relative to monometallic MXene-based controls, consistent with the synergistic effects of multicomponent nanoalloys. The platform showed high selectivity against non-target exosomes and serum proteins, good fabrication reproducibility (inter-electrode RSD < 4.5%), and strong storage stability (94.6% signal retention after 28 days at 4 °C). In clinical serum analysis, CRC patients presented significantly elevated exosome levels compared with healthy controls (2.1 × 10⁴ vs. 0.8 × 10⁴ particles µL^-1, p < 0.001), and the results agreed well with a commercial ELISA (R ² = 0.995). These findings demonstrate that MXene-supported AuPtPdCu nanoalloy interfaces can substantially enhance aptamer-based electrochemical exosome quantification, offering a sensitive and reliable strategy for CRC-related liquid biopsy.

In this study, one-dimensional carbon nanotube (CNT) and zero-dimensional MoO₃ nanohybrids were synthesized using a simple arc-discharge method for ethanol gas sensor applications. MoO₃ nanoparticles were uniformly distributed on the surface of mesoporous CNTs, which increased the specific surface area and the availability of active sites for charge carriers within the nanohybrid. MoO₃ functions as the receptor, while the CNTs serve as the transducer, leading to the modification in the depletion region at the hybrid surface, followed by enhancement of the sensing performance. The CNT/MoO₃ sensor exhibited the highest response of 76.5% to 1 ppm ethanol even at room temperature operation (30 °C), significantly outperforming CNT (12.5%) and MoO₃ (2.5%). Additionally, the CNT/MoO₃ sensor revealed rapid response and recovery time, excellent selectivity, and minimal humidity dependence. SEM, TEM, XRD, XPS, and BET analyses confirmed that the improved gas sensitivity of the CNT/MoO₃ nanohybrid is attributed to the increased active sites for charge carriers, abundant surface vacancies, and modification in the depletion region.

Catalytic steam reforming of biomass-derived bio-oil offers a promising route for renewable hydrogen production, yet catalyst deactivation and coke formation limit its practical application, particularly for complex whole bio-oils. Herein, hydrogen production from corn stover-derived whole bio-oil was investigated via an integrated fast pyrolysis-steam reforming process using char-supported Ni-Cu bimetallic catalysts. The optimized Ni-Cu composition exhibited enhanced hydrogen yield (∼53%) and feedstock conversion (∼78%), with low carbon deposition compared to monometallic counterparts. Elevated reforming temperatures promoted hydrocarbon cracking and suppressed coke formation. Long-term stability tests demonstrated sustained catalytic performance under steam oxygen reforming conditions. Structural characterization confirmed uniform metal dispersion and preserved catalyst porosity after reaction. The improved performance is attributed to the synergistic interaction between Ni, facilitating C-C bond cleavage, and Cu, enhancing water-gas shift activity and mitigating carbon deposition. These findings highlight the potential of char-supported Ni-Cu catalysts as a robust and coke-resistant system for scalable hydrogen production from real biomass-derived bio-oil.

This study synthesizes ZnFe₂O₄ spinel via a co-precipitation method using ZnCl₂ and Fe(NO₃)₃·9H₂O as precursors, and the reaction pH is adjusted to 10, 11, and 12 to regulate the particle-size evolution. Based on the thermal analysis of the precursors, the resulting products inform the selection of the optimal calcination temperature for spinel formation (750 °C); the resulting samples are denoted as ZFO_pH 10, ZFO_pH 11, and ZFO_pH 12. Comparative analysis of the pH-regulated samples reveals that pH strongly influences the particle size and key electrochemical properties, including Li⁺-storage performance, cycling stability, and electrical conductivity. X-ray diffraction (XRD) analyses confirm that all samples predominantly comprise well-crystallized ZnFe₂O₄ without detectable secondary phases within the XRD detection limit. Notably, ZFO_pH 11 exhibits an average particle size of approximately 37 nm, which is considerably smaller than the approximately 42 nm particles observed in ZFO_pH 10. Consequently, the ZFO_pH 11 electrode delivers a high initial charge capacity of 992.78 mAh g^-1 and maintains a capacity of approximately 910.84 mAh g^-1 after 60 cycles at 0.1 A g^-1. These results demonstrate that pH adjustment is an effective strategy for tuning particle size and crystallinity, thereby enhancing electrochemical performance. Among the synthesized materials, ZFO_pH 11 demonstrates strong potential as an anode material for lithium-ion batteries owing to its favorable combination of particle size, crystallinity, and phase purity.

Expression of concern for 'd-Penicillamine functionalized dendritic fibrous nanosilica (DFNS-DPA): synthesise and its application as an innovative advanced nanomaterial towards sensitive quantification of ractopamine' by Milad Baghal Behyar and Nasrin Shadjou, RSC Adv., 2021, 11, 30206-30214, https://doi.org/10.1039/D1RA05655G.

We report an FeCl₃-catalyzed transformation of 4-methyl-1-siloxy-1,4-epoxy-1,4-dihydrobenzene. Reaction in toluene gave the phenol product, whereas the addition of i-PrOH in 1,2-dichloroethane induced desilylative ring opening to produce 4-hydroxy-4-methyl-2,5-cyclohexadienone, which subsequently underwent a CO₂Me-induced regioselective 1,2-methyl shift (C4 to C3) to afford 6-methyl-2,4-cyclohexadienone. This product bears a methyl-substituted quaternary carbon center that is difficult to access by existing methods and serves as a versatile intermediate for further structural elaboration. These results highlight a new mode of skeletal rearrangement and demonstrate regioselective control over competing reaction pathways.

This work presents the inaugural synthesis and detailed characterization of a novel BaO₂/Mn₂O₃/ZnO/BaMnO₃ nanocomposite fabricated via a straightforward co-precipitation technique, utilizing solely distilled water as the solvent, followed by calcination at 500 °C for two hours. This eco-friendly approach marks a notable improvement over conventional methods by eliminating the use of harmful organic solvents. Comprehensive analyses, including XRD, SEM, EDX, TEM, TGA, and UV-Vis spectroscopy were employed to elucidate the structural, morphological, optical, and thermal features of the synthesized material. XRD results confirmed the successful formation of the composite phase with an average crystallite size below 85 nm. EDX spectra verified the presence of constituent elements (Ba, Mn, Zn, O) with no detectable contaminants. Fourier-transform infrared (FTIR) measurements further supported the synthesis of the corresponding oxide phases. Optical investigations indicated a band gap value of approximately 2.74 eV. Thermal analysis demonstrated remarkable stability, signifying suitability for applications involving elevated temperatures. Antibacterial efficacy was assessed against Gram-negative E. coli and Gram-positive S. aureus through the disc diffusion assay. The nanocomposite displayed pronounced antibacterial activity, yielding a zone of inhibition measuring 13 mm against S. aureus. These findings underscore the potential of the material in thermal sterilization applications and as antimicrobial coatings within healthcare and industrial settings. Future work will delve into the antibacterial mechanism and expand application-oriented studies.

Acinetobacter baumannii is a major global concern due to its multidrug resistance and persistence multidrug-resistant (MDR) pathogens pose a serious threat in hospital environments, particularly among immunocompromised patients. In this study, selenium nanoparticles (SeNPs) were biosynthesized using Ralstonia insidiosa isolated from petroleum-contaminated soils in Iraq. SeNP formation was confirmed by UV-visible spectroscopy, AFM, TEM, FE-SEM, and EDX analyses, which revealed predominantly spherical, well-dispersed nanoparticles in the nanoscale range. The antimicrobial activity of SeNPs was evaluated against Gram-positive and Gram-negative bacteria, Candida spp., and ten MDR Acinetobacter baumannii clinical isolates. SeNPs exhibited strong antimicrobial activity, with a uniform minimum inhibitory concentration (MIC) of 16 µg mL^-1 against all MDR A. baumannii isolates and concentration-dependent inhibition against other bacterial and fungal pathogens, showing notable activity against Candida guilliermondii. To explore potential resistance-related interactions, MexB efflux pump gene expression was analyzed in two representative MDR A. baumannii isolates. SeNP treatment resulted in strain-dependent modulation of MexB expression, indicating variable bacterial responses rather than consistent efflux inhibition. In addition, cytotoxicity assays demonstrated dose-dependent antiproliferative effects of SeNPs against PC3 prostate cancer cells, with lower toxicity toward normal WRL68 liver cells.

The selective oxidation of benzylic alcohols to carbonyl compounds under mild conditions remains a significant challenge in synthetic chemistry. Here, we report four cost-effective and efficient strategies for the selective aerobic oxidation of benzylic alcohols to carbonyl compounds in the presence of Cu(ii) nitrate, DDQ, and their combination under thermochemical and photochemical conditions in CH₃CN as a solvent: (1) thermally-assisted DDQ organocatalysis at 60 °C, (2) DDQ photochemical catalysis under light irradiation, (3) Cu(NO₃)₂·3H₂O/DDQ catalyst system, and (4) light-driven (blue LEDs 9 W) Cu(NO₃)₂·3H₂O/DDQ photocatalytic system. Among these methods, the photoactive DDQ/Cu(NO₃)₂·3H₂O catalytic system demonstrated the highest performance. These methods offer several notable advantages, including the use of oxygen as the terminal oxidant and the utilization of commercially available, inexpensive catalysts, making the process both economical and environmentally friendly. Furthermore, they produce environmentally benign water as the sole byproduct, offer 60-98% product yields, and allow for straightforward isolation and purification. The combination of these features makes these protocols both practical and sustainable for the selective oxidation of benzylic alcohols to carbonyl compounds under ambient aerobic conditions.

In this study, we explore the structural, electronic, optical, and elastic features of environmentally friendly lead-free mixed-halide double perovskites with the general composition A₃AsI₆ (A = K, Rb, and Cs), which are comprehensively analyzed using density functional theory (DFT). Our calculations reveal that the optimized lattice constants increase from 12.42 Å for K₃AsI₆ to 12.99 Å for Cs₃AsI₆, which is consistent with the progressive enlargement of the alkali metal ionic radii. To evaluate the electronic band structures, the Tran-Blaha-modified Becke-Johnson (TB-mBJ) potential was applied, with and without incorporating spin-orbit coupling (SOC), to achieve reliable estimations of the band gaps. The results reveal a consistent trend of decreasing band gap energies: 2.763 eV (mBJ) and 2.566 eV (mBJ + SOC) for K₃AsI₆ (indirect), 2.821 eV (mBJ) and 2.607 eV (mBJ + SOC) for Rb₃AsI₆, and 2.829 eV (mBJ) and 2.621 eV (mBJ + SOC) for Cs₃AsI₆. The density of states analyses further clarify the orbital contributions to the occupied and unoccupied bands. Elastic constants (C _ij) confirm the mechanical stability of the materials, while Poisson's and Pugh's ratios indicate brittle behavior. Moreover, the calculated Debye temperatures suggest that K₃AsI₆ could better withstand thermal stresses induced by lattice vibrations than its Rb and Cs analogues. The optical characteristics, such as the dielectric function ε(ω), absorption coefficient α(ω), reflectivity R(ω), and refractive index n(ω), were comprehensively examined, revealing robust interactions with incident electromagnetic radiation. These comprehensive results underscore the potential of A₃AsI₆ (A = K, Rb, and Cs) double perovskites as viable candidates for next-generation optoelectronic applications, particularly in environmentally benign, lead-free technologies.