Analyst最新文献

Fumonisin B1 (FB1), a highly toxic secondary metabolite produced by Fusarium fungi, poses a significant threat to global food safety; therefore, sensitive, selective, and reliable analytical methods are urgently needed. In this work, we report a novel molecularly imprinted electrochemiluminescence (ECL) sensor for the quantitative determination of FB1. A Co/Zn bimetallic metal-organic framework@polyoxometalate (Co/Zn-MOF@POMs) nanocomposite was synthesized via a one-pot strategy and used to modify a glassy carbon electrode. The incorporated polyoxometalates (POMs) markedly improved the interfacial electron-transfer kinetics of the Co/Zn-MOF scaffold, resulting in substantial amplification of the ECL signal generated by ZnAgInS quantum dots (QDs). Subsequently, a molecularly imprinted polymer (MIP) layer was electropolymerized on the modified electrode using o-phenylenediamine as the functional monomer and 1,2,3-propanetricarboxylic acid as a structural dummy template designed to mimic key topological and functional features of FB1. Upon FB1 rebinding, the exposed amine groups on the captured FB1 molecules underwent a condensation reaction with carboxyl-functionalized ZnAgInS QDs, enabling site-specific immobilization of the luminophores close to the recognition cavities. Under optimized conditions, the sensor exhibited a linear ECL response to FB1 over a concentration range of 6.0 × 10^-14 to 1.0 × 10^-10 mol L^-1 (R² = 0.9987), with a detection limit of 3.3 × 10^-15 mol L^-1 (S/N = 3). This approach offers a robust and reproducible platform for trace-level FB1 monitoring in real-world food and agricultural samples.

The application of tandem mass spectrometry (MS/MS) for detecting inborn errors of metabolism (IEM) is an important achievement in newborn screening (NBS). A single blood spot provides information on about 60 metabolites and related ratios that enable the screening of approximately 50 different diseases. A major limitation of newborn screening for IEM is the lack of matrix-matched dried blood spot (DBS) quality control (QC) materials in clinical laboratories. Herein, we developed DBS QC materials for IEM and investigated their recovery, homogeneity, and stability. Four concentration levels of DBS materials were prepared by spiking 9 amino acids, 6 acylcarnitines, and succinylacetone into a hemoglobin solution, which was dialyzed prior to preparing DBS. Hemoglobin solutions containing the predetermined quantities of metabolites were spotted, dried, and packaged. Isotope-dilution mass spectrometry was employed to estimate the endogenous contents and validate the final concentrations of alanine (Ala), proline (Pro), valine (Val), leucine (Leu), ornithine (Orn), methionine (Met), phenylalanine (Phe), arginine (Arg), citrulline (Cit), carnitine (C0), acetylcarnitine (C2), glutarylcarnitine (C5DC), octanoylcarnitine (C8), decanoylcarnitine (C10), dodecanoylcarnitine (C12), and succinylacetone (SA). The recovery, homogeneity, and post-preparation short-term stability of the DBS materials were also evaluated using an MS/MS assay. The recovery for amino acids was 81.4%-121.7%, with the exception of 68.2% for Arg. The recovery for acylcarnitines and succinylacetone was 60.0%-97.9%. The homogeneity, evaluated as between-spot coefficient of variation (CV) for the multilevel DBS materials, was 4.4%-16.6% for amino acids and 3.3%-19.8% for acylcarnitines and succinylacetone. Furthermore, DBS materials stored at 4 °C showed minimal deviation over the 28-day evaluation period for all metabolites. Multilevel DBS QC materials based on a hemoglobin matrix for newborn screening of IEM were developed for the first time. These QC materials can be used to monitor the daily analytical performance and improve the technical proficiency in clinical laboratories.

Bimetallic nanozymes leverage electronic and geometric synergy to overcome single-metal limitations, which may enhance the stability and catalytic efficiency for sensing. We herein synthesize a gold-palladium (Au-Pd) bimetallic nanozyme via a one-step co-reduction method. It exhibits excellent peroxidase-like activity with high substrate affinity and catalytic efficiency. We further construct a colorimetric system for nitrite assay. The AuPd₃ nanozyme catalyzes the oxidation of colorless TMB to blue oxidized TMB (oxTMB) in the presence of H₂O₂. The introduced nitrite could react with oxTMB via diazotization to form yellow products. The recorded absorbance ratio (A₆₅₂/A₄₅₀) thus enables quantitative nitrite detection. This method shows a good linear range from 5 to 500 μM with the limit of detection as low as 0.23 μM. It features simple operation, high sensitivity and favorable accuracy, offering reliable technical support for food safety and environmental monitoring.

Exosomal piR-823 is a promising specific biomarker for colorectal cancer, yet its ultrasensitive detection remains challenging due to its extremely low abundance and high sequence complexity. Herein, we developed a cascaded CHA-CRISPR/Cas12a photoelectrochemical (PEC) sensing platform enabled by an S-scheme Bi₂WO₆/BiOBr heterojunction for the reliable detection of piR-823. The flower-like spherical Bi₂WO₆/BiOBr heterojunction exhibits enhanced visible-light absorption and efficient charge transfer arising from the S-scheme structure, which establishes a strong photoactive basis for the PEC platform. By integrating catalytic hairpin assembly with CRISPR/Cas12a trans-cleavage activity, a cascaded signal amplification strategy is established, which significantly improves the detection sensitivity. Under optimized conditions, the platform shows a distinct negative correlation between transient photocurrent and the logarithm of piR-823 concentration (1.0-1.0 × 10⁶ fM), with an ultralow detection limit of 0.34 fM (S/N = 3). It also demonstrates high specificity, good reproducibility, and satisfactory recovery (96.87%-103.41%) in exosome lysate. This work not only presents an efficient PEC biosensing platform for piRNA analysis but also offers guidance for the rational construction of S-scheme heterojunctions in high-performance PEC biosensors, holding great promise for early colorectal cancer diagnosis and prognostic monitoring.

Jerantinines are natural indole alkaloids with promising anticancer activity in breast cancer cells via mechanisms of action involving tubulin binding and disruption of microtubule dynamics, with growth inhibition values, GI₅₀ < 0.4 µM. However, metabolic responses of different breast cancer phenotypes are not yet understood. In this work, LC-MS-based untargeted metabolomics was used to investigate the response of four selected breast cancer cell lines representing different subtypes (MCF-7, BT-474, MDA-MB-231, and SKBR-3) to treatment with Jerantinine A acetate (JAa). Based on univariate, multivariate and pathway analyses, the results showed metabolic perturbations in amino-acid metabolism, fatty acid oxidation, and redox homeostasis. In breast cancer cells treated with 0.4 µM of JAa for 72 h, the elevated levels of oxidation-related metabolites, including 2-oxoglutarate, butyryl carnitine, propionyl carnitine, and 5-oxo-L-proline, indicated increased oxidative stress. Interestingly, only MCF-7 cells accumulated the antioxidants glutathione and taurine relative to untreated controls, and this response was accompanied by upregulation of wild-type p53 in this cell line. This p53-associated antioxidant capacity offers a mechanistic explanation for the difference in observed GI₅₀ values: GI₅₀ of 0.37 µM in MCF-7 compared to 0.19 µM and 0.14 µM in SKBR-3 and BT-474 cells, respectively, both of which harbour mutant p53 and did not mount an equivalent antioxidant response. These findings provide new insights into the metabolic effects of JAa on breast cancer cells and further support its potential as an anticancer agent. The observed metabolic differences between cell lines may inform future strategies for personalized therapy.

This work designs and synthesizes three core-modified naphthalimide derivatives (NCD-B, NDI-I, and NDI-H). Benefiting from efficient intramolecular charge transfer and suppressed intermolecular π-π stacking, all three compounds exhibit remarkable electrochemiluminescence (ECL) performance. In particular, NDI-H functionalized with imidazole substituents delivers a strong ECL signal up to 17 000 a.u. and excellent long-term stability with an RSD of 0.32%. An ECL sensor for Cu²⁺ was further constructed based on NDI-H, which displays a favorable linear response in the range of 0-5000 μM and a low detection limit of 3.56 μM. With advantages of low background interference, simple operation, low probe and instrument costs, and excellent selectivity, this method has been successfully applied to the determination of Cu²⁺ in Astragalus membranaceus, providing a reliable ECL analytical strategy for heavy metal monitoring in traditional Chinese medicines.

The toxicity of organophosphate (OP) insecticides and pesticides is increasing in the human population owing to their indiscriminate use globally. The need to achieve food security for the rising population is the main reason for the excessive use of such chemical compounds. The hazardous effects of OP pesticides can be mitigated only through conscientious efforts in detecting them in various food and water resources. In the present study, we developed carbon quantum dots (CQDs) and recombinant Nus-organophosphorus hydrolase (Nus-OPH) enzyme co-immobilized chitosan polymer film-based biosensors for the detection of OP compounds, such as coumaphos (CP), methyl parathion (MP) and ethyl paraoxon (EP), present in river water and household water resources using a fiber optic spectrophotometer. The E. coli strains were utilized for the expression of the Nus-OPH enzyme, purified and subsequently immobilized on the chitosan thin films containing CQDs that were synthesized from triethylene diamine and phthalic acid through microwave irradiation. The thin-film biosensors composed of CQDs-Nus-OPH were characterized utilizing several methods like XRD, XPS, TEM, CLSM, and enzyme activity measurements. The biosensing studies of CP, EP, and MP were performed by recording fluorescence changes using reflectance probe-mediated measurements in a fiber optic spectrophotometer. This study determined that the CQDs-Nus-OPH thin film-based biosensor has the potential to detect/analyze EP, CP, and MP in the 0-100 µM range with the limits of detection of 145 ppb, 178 ppb, and 188 ppb, respectively, within a time frame of 5 minutes. The accuracy of the biosensor in the OP-spiked water matrices was found to be 100%-102%, indicating that the CQDs-Nus-OPH thin-film biosensors can detect the analyte accurately. These results indicate that this biosensor platform shows potential for organophosphate detection, although further studies are needed to improve specificity and analyte discrimination.

Recent studies have demonstrated that terahertz spectroscopy can identify starch absorption peaks in solid pellets containing powdered plant samples with minimal interference of other plant matrices. Here, we applied this analytical method to assess photosynthetic capacity in plant leaves with a relatively low starch content. To monitor starch produced through photosynthesis, rice leaves were measured in the frequency range of 3.0-9.5 THz using a Fourier-transform spectrometer equipped with a bolometer. A starch over-accumulation mutant (α-glucan water dikinase1) and wild type (cv. Nipponbare) were harvested after 2 and 3 months of cultivation. In the terahertz measurements, all leaves exhibited an absorption peak at 9.0 THz attributed to starch and the peak intensities were consistent with starch contents obtained by chemical analysis. Furthermore, correlations were found between second derivative signals and starch content (R² = 0.86-0.87). However, a higher accuracy model was developed using peak height calculated using the peak top at 9.0 THz and a baseline between 8.65 and 9.35 THz (R² = 0.91). These results indicate that just three frequencies are sufficient on behalf of the full range spectra, suggesting the feasibility of a starch sensor for future applications. Therefore, terahertz technology can serve as a valuable analytical method for assessing starch accumulation and photosynthetic capacity in unpurified plant leaves.

The transition from laboratory electroanalytical setups to low-cost electrochemical systems has opened the way for new possibilities for point-of-care diagnostics and environmental monitoring in resource-limited contexts. Recent technologies for material processing, such as additive manufacturing, laser cutting/engraving systems, and open-source electronics, have lowered fabrication costs and expanded access to these devices. However, the electrochemical characterization of low-cost sensors poses challenges when using conventional models, which are useful for characterization under appropriate conditions but may compromise data reliability and complicate comparisons of sensor performance across studies for low-cost materials/platforms. In this review, we provide a critical assessment of the limitations in the electrochemical characterization of low-cost electrochemical devices, along with guidance on estimating electroactive surface area, the use of redox probes, the impact of uncompensated resistance, and the validity of calculating frequency-dependent kinetic parameters. Additionally, the reproducibility and long-term stability of these devices are discussed. Through this, we aim to clarify the factors that lead to miscalculations and misinterpretations in the application of the current literature in low-cost devices characterization and to provide best practices for control experiments and calibration/validation requirements. As a result, we expect that this work will support the development of more reliable standards for the characterization, reproducibility, and validation of low-cost electrochemical sensors for real-world applications.