化学最新文献

Solid phase microextraction (SPME), as a sampling/sample preparation technique, offers unique solutions for the most challenging applications, including metabolomics studies of living systems. However, for global metabolomics it is critical to use an SPME sampler facilitating the extraction of both volatiles and nonvolatiles, which at the same time is compatible with thermal and solvent-assisted desorption. As a promising universal coating, recently hydrophilic-lipophilic balanced (HLB) particles immobilized in PTFE have been introduced as a new SPME sampler to provide a wide-range of analyte coverage and compatibility with solvent and thermal desorption. Thus, making it suitable for both gas and liquid chromatography (GC/LC) based applications. However, its potential in metabolomics has not been investigated to date. In this study, HLB/PTFE SPME fibers were prepared, evaluated with selected polar and non-polar metabolites relevant to biological systems, and validated for cell-line studies. The validation proved that these fibers can extract a wide-range of molecules (LogP: 4.2 to 15.6) with acceptable accuracy (≤19% RE%) and repeatability (intra-day ≤17% and inter-day 12% RSD%). The LOQ was determined to vary between 150.0 and 500.0 ng/mL. Upon validation, the fibers were used in a proof-of-concept study for extraction of endometabolome and exometabolome of melanoma B16F10 and lung cancer LL2 cell lines. The metabolome studies showed that HLB/PTFE fibers provide lower coverage, but for some compounds higher extraction efficiency compared to HLB/PAN fibers used in LC-based metabolomics. Fibers also proved suitable for GC-MS analysis, allowing for the detection of 36 volatile organic compounds in the headspace of the cell lines and RPMI medium.

Transition metal sulfides have attracted much attention due to their low cost, high stability, adjustable performance, diverse morphology and good catalytic activity. In this work, nitrogen-doped carbon dots (N-CDs) were loaded onto bimetallic sulfides (FeCuS) and FeCuS/N-CDs could act as catalyst and fluorescent probe, which applied to the detection of uric acid (UA) in human blood and urine using dual-model assay (colorimetry and ratiometric fluorescence). The nanozyme has excellent peroxidase-like activity and steady-state kinetic results showed that the material prepared under optimized conditions had better affinity (K_m = 0.42 mM) for the substrate and faster reaction rate (V_max = 14.1 × 10^-8 M s^-1). •OH and O₂^•- were involved in the catalytic process of o-phenylenediamine (OPD) by FeCuS/N-CDs nanozymes. A profound discussion and quantitative analysis about the sensing mechanism of UA and fluorescence quenching mechanism between FeCuS/N-CDs and diaminophenazine (DAP) was performed. According to Parker equation, the inhibition efficiency of DAP in FeCuS/N-CDs was as high as 83 % of the total inhibition efficiency, confirming that the inhibition efficiency mainly came from internal filtering effect (IFE). The detection limits of ratiometric fluorescence method and colorimetric method were as low as 0.13 μM and 0.27 μM, respectively. Finally, principal component analysis was used to successfully distinguish three groups of people (healthy people, potential people and gout patients) and the model has potential value in clinical applications.

The development of advanced bifunctional oxygen electrocatalysts for the oxygen reduction reactions (ORR) and oxygen evolution reactions (OER) is crucial for the practical application of zinc-air batteries (ZABs). Herein, porous carbon nanosheets integrated with abundant graphene-wrapped CoO and CoNx (CoO/CoNx-C) were successfully fabricated through a simple one-step pyrolysis. With convenient porous channel and large accessible surface, abundant CoO/CoNx species and graphene wrapping structure, CoO/CoNx-C exhibited a half-wave potential of 0.844 V in ORR and an overpotential of 384 mV (@10 mA cm^-2) in OER in the alkaline environment and presented a negative shift of 9 mV in ORR after 8000 cycles and positive shift of 19 mV in OER after 2000 cycles. Electrochemical acid-washing and comparison analysis revealed that the ORR activity mainly originated from CoO nanoparticles, while CoNx species were greatly responsible for OER catalysis. Furthermore, the as-prepared CoO/CoNx-C endowed the rechargeable liquid and solid ZABs with superior power density (161 mW cm^-2 for liquid ZABs and 137 mW cm^-2 for solid ZABs) and long-term stability (stable in 1000 h charge/discharge tests) compared to commercial catalysts. This work provides a feasible strategy for cobalt/carbon hybrid materials as advanced bifunctional electrocatalysts for ZABs.

Cancer biomarkers have been facing some issues such as poor accuracy and low sensitivity in the early diagnosis of tumors. Utilizing biotin-labelled peptide as a mass tag (MT), this work proposes a high-throughput biosensing strategy for matrix-assisted laser desorption/ionization-time of flight mass spectrometric (MALDI-TOF-MS) immunoassay of multiple lung cancer biomarkers. Due to little required dosage, satisfied stability, high sensitivity and accuracy, this method can achieve off-site centralized signal detection after on-site sample incubation. The proposed approach has been successfully applied for the detection of carcinoembryonic antigen (CEA), carbohydrate antigen199 (CA199), carbohydrate antigen 125 (CA125) and cytokeratin-19-fragment (CY211) in serum samples from various stages of non-small cell lung cancer. Based on the analysis of multiple parameters and pathological results, significant differences in biomarkers are found in serum samples of lung cancer patients at different stages. More importantly, the analysis of multiple tumor biomarkers can improve the accuracy and sensitivity of early diagnosis. Therefore, the multiple immunoassay based on MALDI-TOF MS exhibits exceptional performance in terms of high throughput, little sample dosage, stability and sensitivity.

Flavonoid glycosides are formed by dehydration condensation of aglycones and sugar molecules. Therefore, discrimination of flavonoid glycosides from their corresponding aglycones is a challenging task because they contain the same aglycone part in their molecular structures. Herein, boric acid-functional Eu(III)-organic framework (BA-Eu-MOF) was applied to discriminate flavonoid glycosides including baicalin (Bai), wogonoside (Wog), rutin (Rut), puerarin (Pue), quercitrin (Que) and astragalin (Ast) from their corresponding aglycones for the first time. Besides as organic ligand to sensitize the luminescence of Eu³⁺ through "antenna" effect, 5-boronobenzene-1,3 dicarboxylic acid provided recognition site for flavonoid glycosides. Infrared, fluorescence, UV-vis, and mass spectra were used to investigate the recognition reaction between BA-Eu-MOF and flavonoid glycosides. The data indicated that the cis-diols of flavonoid glycosides from sugars covalently bonded to boric acid group to form cyclic boronic esters, which quenched the fluorescence of BA-Eu-MOF at 620 nm through decreasing the intersystem efficiency, inner filter effect and photoelectron transfer. In contrast, aglycones could not alter the fluorescence of BA-Eu-MOF because of no covalent bond between them. This probe exhibited high sensitivity towards flavonoid glycosides with the low detection limits of 3.3 nM, 3.5 nM, 33 nM, 56 nM, 5.1 nM and 5.5 nM for Bai, Que, Wog, Ast, Pue and Rut, respectively. The unique recognition ability of boric acid group enables selective and sensitive detection of flavonoid glycosides without the interference of their corresponding aglycones.

CYFRA21-1 is a tumor marker for lung cancer, and its rapid and accurate detection can provide evidence for the early diagnosis of lung cancer. In this work, Bi-Fe turnbull blue analogues (Bi-Fe-TBA) were synthesized by the self-templating method. Bi₂O₃-SFNs was prepared by simple oxidation in air using Bi-Fe-TBA as a template. Bi₂O₃ Star-like Flower Nanoclusters (Bi₂O₃-SFNs) and CdS Hollow Nanorods (CdS-HNRs) were used to form a unique type II heterojunction for the first time. The arrangement of energy levels between CdS-HNRs and Bi₂O₃-SFNs, along with their hollow structure and star shape, effectively suppressed the recombination of photogenerated electrons and holes while shortening carrier transport distance. An ultra-sensitive PEC biosensor was developed to detect the lung cancer marker CYFRA21-1, leveraging the superior photoelectric conversion capabilities of Bi₂O₃-SFNs/CdS-HNRs. The sensor demonstrates outstanding stability, specificity, reproducibility as well as a wide linear range (10^-4 - 10 ng mL^-1) and low detection limit (4.23 × 10^-5 ng mL^-1). This study is valuable for the preparation of other functional materials using TBA as a template.

The growing demand for glycolate, fueled by economic development, requires the advancement of production methods. Escherichia coli (E. coli), a preferred host for glycolate production, has undergone extensive metabolic engineering to improve yield. Developing rapid and precise methods for quantifying glycolate concentration is essential for screening high-yielding strains. Here, we present the engineering of a novel circularly permuted green fluorescent protein (cpGFP)-based glycolate sensor, termed GLYCO. GLYCO exhibits high specificity (minimal interference from other metabolites), stability (no decrease in performance after 15 days at -80 °C), and ease of detection via fluorescence measurement, enabling effective in vitro glycolate quantification. GLYCO spans a quantification range from 10 μM to 1 mM, facilitating effective monitoring of glycolate production in metabolically engineered E. coli strains. This biosensor represents a significant advancement in the metabolic engineering toolkit, facilitating efficient detection and optimization of glycolate production in E. coli, with potential applications in industrial biotechnology.

Directly detecting biomarkers in liquid biopsy for diagnosis and personalized treatment plays a crucial role in managing cancer relapse and increasing survival rates. Typically, the standard analysis of circulating tumour DNA requires lengthy isolation, extraction, and amplification steps, leading to sample contamination, longer turnaround time and higher assay costs. Surface plasmon resonance is an emerging and promising technology for rapid and real-time dynamic biomarker monitoring in liquid biopsy. Here, we propose a new SPR imaging biosensing approach to detect tumour DNA circulating in the blood of colorectal cancer patients by exploiting the unique properties of superparamagnetic particles. Micrometer beads functionalized with a biotinylated oligonucleotide can directly capture DNA target sequences bearing single-nucleotide variations of KRAS oncogene in human blood plasma. Mutated and wild-type peptide nucleic acid probes immobilized on an SPR gold surface recognize complementary and non-complementary DNA targets by discriminating a single nucleotide mismatch. The new assay allows for detecting p.G13D mutated DNA in buffer and spiked human plasma at attomolar level (down to 300 copies mL^-1) with minimal sample manipulation and in just a few microliters. The assay was validated using plasma samples from colorectal cancer patients and healthy donors, by discriminating mutated DNA circulating in patients and wild-type DNA found in healthy blood donors. This feature underscores the potential of the liquid biopsy assay as a valuable tool for the diagnosis and monitoring of cancer.