化学最新文献

Glyphosate (Gly), a widely used potent herbicide worldwide, possess potential harm to human health and environment due to accumulation in water and soil. Hence, there is a pressing need to realize the simple and precise detection of Gly to ensure human health and environmental safety. Although various nanozyme-based detection methods have been developed for Gly, they frequently require additional enzymes and hydrogen peroxide (H₂O₂). H₂O₂ not only exhibits certain toxicity but is also prone to decomposition, resulting in poor accuracy and reproducibility. In this study, we report the synthesis of nanoscale copper-based metal-organic framework (Cu-MOF) through a facile ultrasound method, and the resulting Cu-MOF demonstrate excellent laccase-mimicking activity. Our Cu-MOF nanozyme can catalyze the conversion of substrates into chromogenic products without the need for H₂O₂, offering a simple and mild operational approach. The presence of Gly significantly inhibits the catalytic activity of the Cu-MOF, hindering the chromogenic reaction between 2,4-dichlorophenol (2,4-DP) and 4-aminoantipyrine (4-AP). We propose a detection method for Gly that is repeatable, reliable, highly selective, and cost-effective, eliminating the need for additional H₂O₂, or bioenzymes. This facile strategy paves a new path for the applications of laccase-mimicking nanozyme in environmental monitoring.

Formaldehyde (HCHO), as a representative biomarker associated with lung cancer screening, plays a key role in distinguishing healthy individuals from those with diseases through its ppb-level concentration differences. Therefore, achieving high sensitivity and low limit of detection (LOD) for specific detection of HCHO is critically important. In this work, a HCHO electrochemical sensor was prepared using a two-step drop-coating method on a flexible planar screen-printed electrode, with 60 % Pt/C-Nafion catalyst as the sensing layer and Nafion as the solid-state electrolyte. At a working potential of 0.5 V, high sensitivity (0.197 μA/ppm), a wide linear response range (HCHO concentration from 500 ppb to 100 ppm) and a low LOD (2.5 ppb) have been achieved for HCHO detection at room temperature. The sensor also exhibits excellent selectivity, consistency and long-term stability (>15 days). Through ultra-low concentration sensing tests of 50-400 ppb HCHO using a fluorine membrane gas bag, the sensor demonstrates good linearity with a sensitivity of 0.8 nA/ppb, which can effectively distinguish between exhaled breath from healthy individuals and simulated lung cancer patients. The appropriate selection of working potential, efficient construction of three-phase boundary (TPB) and excellent electrocatalytic performance of the Pt/C catalyst enable the realization of high-performance HCHO detection. Additionally, the sensor preparation method is simple and cost-effective. Therefore, the proposed Nafion-based HCHO electrochemical sensor is expected to provide a promising sensing platform for lung cancer screening in clinical diagnosis and indoor HCHO concentration monitoring.

A ready-made electrochemical sensor has been developed as an innovative platform for detecting nonaqueous chlorpyrifos (CPF), a water-insoluble organophosphate pesticide. Despite its effectiveness, CPF is among the most frequently detected pesticides in food and water and poses severe health risks, including neurological disorders and acute poisoning. As a tool for potentially limiting the harm caused by CPF, this study introduces a CPF sensor designed for simplified sample preparation, enhanced safety, and rapid monitoring in environmental and agricultural samples. The sensor integrates an agarose-based gel electrolyte with a cellulose acetate/reduced graphene oxide-modified screen-printed carbon electrode. The gel electrolyte was prepared by dissolving agarose in a methanol-tetraethylammonium iodide solution and casting it onto the electrode. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) confirmed excellent linearity (R² > 0.999) over 0.05-8.00 mM and 0.10-2.00 mM, respectively, with LoDs of 0.166 mM (CV) and 34.3 μM (0.012 mg/kg, DPV). This allows reliable quantitative analysis and detection below CPF residue limits set by the U.S. EPA and Thai Agricultural Standards. The recoveries for the application of ready-made sensor in environmental and agricultural samples achieved recoveries of 89.8-106.6 % with %RSD below 5 %, demonstrating high feasibility for CPF detection. This sensor enables direct CPF detection in organic solvents without complex preparation or electrochemical expertise. Its agarose gel matrix enhances safety by immobilizing the electrolyte, minimizing leakage, and improving stability, making it suitable for portable use. This ready-made sensor provides a reliable, user-friendly solution for CPF monitoring in agriculture and food safety.

In this work, a complementary dual-modal immunosensing strategy was fabricated for the sensitive and selective detection of zearalenone (ZEN) by integrating immunochromatographic and electrochemical biosensing methods. For this, bimetallic NiFe Prussian blue analogue (NiFe-PBA) was simultaneously employed as a matrix for labelling ZEN-targeted antibody and the sensitive layer for anchoring antibody to construct an efficient immunochromatographic immunosensor (ICI) and electrochemical immunosensor (ECI), respectively. Due to porous network, good functionality, high bioaffinity, and rich metal redox, NiFe-PBA-based complementary dual-modal immunosensor exhibited low limit of detection, high selectivity and stability, and accepted practicality. Particularly, the developed ECI illustrated fast response, portability, and potentially commercial application. Coupling the ICI and ECI sensing strategy can markedly enhance the accuracy and sensitive detection of ZEN in complicated environments. This dual-modal ICI-ECI immunosensing strategy exhibits significant potential for the precise detection of mycotoxin in various agricultural products and improve the quality control for foods.

To address the increasing demand for wearable sensors, the development of gas sensors with high sensitivity and environmentally friendly power consumption for monitoring NO₂ at room temperature (RT) is particularly promising. In this paper, porous In₂O₃ microspheres are prepared via a hydrothermal method, followed by the incorporation of 2D MXene solution to synthesize In₂O₃@MXene composites. After characterizing the microstructures and morphology of the In₂O₃@MXene composites, the influence of MXene on the microstructures and NO₂ gas-sensing performance at RT is discussed in detail. The results indicate that a moderate amount of MXene greatly affects the energy band structure, chemisorbed and vacancy oxygen content, and the availability of reactive sites for oxygen and NO₂, thereby affecting the gas-sensing performance of the In₂O₃@MXene sensors. Notably, the In₂O₃@10MXene sensor exhibits the highest response value of 24.98 to 4 ppm NO₂ at RT, which is 5.90 times higher than that of In₂O₃ sensor (4.23). Furthermore, the In₂O₃@10MXene sensor still presents a response value of 2.83-500 ppb NO₂ under RT, confirming an ultra-low ppb level detection limit to NO₂ gas at RT. Additionally, the In₂O₃@10MXene sensor demonstrates favorable gas selectivity and long-term stability. The incorporation of an appropriate amount of MXene effectively enhances the gas-sensing performance of the In₂O₃@MXene sensors, attributed to the formation of a Schottky heterojunction, increased surface oxygen, and more reactive sites for oxygen and NO₂ from MXene.

The identification of new natural products is a critical step in the discovery of lead compounds, and is a prerequisite for the development of novel pharmaceuticals. Traditional Chinese medicines (TCMs) are renowned for their diverse pharmacological activities, and represent a valuable source of novel chemicals. The quinolizidine alkaloids are abundant in plants of the Fabaceae family and exhibit significant bioactivities, including anticancer and anti-inflammatory effects. However, the structural diversity of quinolizidine alkaloids and the chemical complexity associated with TCMs pose great challenges in the discovery of novel quinolizidine alkaloids. In the present study, Sophora flavescens Ait. was used as a model to establish a comprehensive strategy for characterizing quinolizidine alkaloids. A simple and selective method was developed using an FC8HL column for the efficient enrichment of polar quinolizidine alkaloids. Through the integration of high-resolution multi-stage mass spectrometry and feature-based molecular networking, the enriched alkaloids were thoroughly characterized, including matrine-type, cystine-type, aloperine-type, anagyrine-type, lupinine-type, and dimeric species. A total of 186 quinolizidine alkaloids were identified, including 131 newly discovered compounds. A series of novel substituents was also identified for the first time. The findings of this study not only deepen our understanding of the structural diversity of quinolizidine alkaloids, but they also offer a novel research strategy for the comprehensive characterization of quinolizidine alkaloids in other plants, potentially facilitating the discovery of new drug candidates.

Visualizing and monitoring of integrin expression on or within living cells is essential for cancer diagnosis and treatment as they correlate well with tumor invasion and metastasis. Here, a phosphorescence probe, named as Ir-[HRGDH], was designed and chemically synthesized for selectively monitoring integrin expression in living cells by simply functionalizing histidine-arginine-glycine-aspartate-histidine (HRGDH) motifs with an iridium(III) solvent complex ([(pbz)₂Ir(DMSO)Cl], pbz = 3-(2-pyridyl)benzoic acid, Ir-DMSO) via coordination reaction. The synthesized Ir-[HRGDH] shows strong photoluminescence (PL) emission with maximum wavelength at 483 nm and 506 nm. Absolute fluorescence quantum yield was determined to be 6.5 % and lifetime was determined to be 453 ns (67 ns, 1 %; 569 ns, 12 %; 442 ns, 87 %) for Ir-[HRGDH]. The synthesized Ir-[HRGDH], confirmed by mass spectrometry and optical technique, displayed high specificity to RGD-binding integrins and excellent biocompatibility. Good cell permeability enabled Ir-[HRGDH] to be distributed throughout the entire cell region. Cellular uptake pathways of Ir-[HRGDH] were further investigated for A549 cells and an energy-dependent endocytosis was revealed, in which the PL intensity of Ir-[HRGDH] within the cells decreased significantly by incubation at 4 °C, or uptake pathway inhibitor pretreatments. Importantly, time-dependent integrin expression within living cells stimulated by phorbol myristate acetate was successfully monitored by Ir-[HRGDH]. Particularly, Ir-[HRGDH] staining allowed for distinguishing cancer cells from normal cells based on their different intracellular levels of RGD-binding integrins. This work demonstrates that the synthesized Ir-[HRGDH] is a promising PL probe for targeting RGD-binding integrins within living cells, which can be further used for cancer diagnosis and treatment.

Anionic boron cluster compounds have recently made their way into many areas including medicinal chemistry and sensors due to favorable physical-chemical properties and their various biological activity. Notwithstanding the inherent chirality of these compounds, the exploration of the properties and activity of individual enantiomers remains uncharted territory. The permanent delocalized negative charge enables the electrophoretic mobility of these compounds. Thus, chiral electrophoresis, characterized by minimal consumption of chemicals and a sample, emerges as a promising candidate for a reliable quality control tool. The primary attempts in aqueous electrolytes showed some difficulties related to the limited solubility of these analytes. This study meticulously investigates the electrophoretic behavior and chiral separation of anionic [7,8-nido-C₂B₉H₁₁]^- and cobalt bis(dicarbollide)(1-) derivatives using a methanolic non-aqueous electrolyte with numerous derivatives of cyclodextrins. Randomly substituted hydroxypropyl-β-, methyl-β-, and hydroxypropyl-γ-cyclodextrins were identified as the most effective chiral selectors. The chiral separations delineated herein surpass previously published results in capillary electrophoresis in terms of resolution, peak shape, and the number of theoretical plates. Furthermore, the application of (2-hydroxy-3-N,N,N-trimethylamino)propylated β-cyclodextrin in non-aqueous environment resulted in the chiral separation of seven recently synthesized amino cobalt bis(dicarbollide)(1-) derivatives; thereby, reinforcing the extensive applicability of the developed methodology for different structural types of anionic cobalt bis(dicarbollides)(1-). These results qualify non-aqueous electrophoresis as a valuable tool for the enantiomeric purity control of anionic boron cluster compounds with respect to their further use in various areas.

The abnormal level of neurotransmitter serotonin often leads to the blood-brain barrier. Thus, it is urgent to develop a sensitive and efficient method for serotonin detection. Here, we constructed a resonance energy transfer-based electrochemiluminescence (ECL-RET) biosensor sensitized with bipedal DNA walker for the sensitive determination of serotonin. Benefitting from the specific recognition of aptamer to target and enrichment ability of magnetic bead separation, this system achieved the signal transduction of serotonin to nucleic acid and excellent selectivity for serotonin analysis among various analogues. The spectral overlap between the emission spectrum of CdS QDs (energy donor) and the absorption of Ag nanoclusters (Ag NCs, energy acceptor) enabled effective ECL-RET. Through proximity ligation, bipedal DNA walker driven by catalytic hairpin assembly (CHA) significantly accelerated the reaction kinetics and resulted in the amplified responses. Relying on the ECL quenching, serotonin was quantified with a linear detection range of 1 pM-1 μM and a low detection limit of 0.28 pM. More notably, the practical application of the sensor was tested in human serum with recovery rates ranging from 95.0 % to 105.7 %. The combination of ECL-RET, proximity ligation and CHA-driven bipedal DNA walker enabled the biosensor to represent a step forward in neurological-related disease diagnosis.