Analyst最新文献

Sensitive and rapid detection methods for rare earth elements (REEs), including lanthanides (Lns), will facilitate the mining and recovery of these elements. Here, we innovated a rapid, highly selective and sensitive fluorescence detection method for Lns, based on Hans-Lanmodulin, a newly discovered protein with high selectivity and binding affinity for rare earth elements. By labelling the fluorescein moiety FITC onto Hans-Lanmodulin, named as FITC-Hans-LanM. When rare earth ions are present in solution, FITC-Hans-LanM will specifically bind rare earth ions undergoing a conformational change from a disordered state to a dimer, in which the FITC molecules come close to each other, resulting in decreasing fluorescence intensity or even quenching. The assay was responsive to light, medium and heavy rare earth ions. The fluorescence signal has a good linear relationship with Nd³⁺ concentration in the range of 1–20 nM. The detection limit of the method was 0.512 nM, within 1 min. This method could become a useful technique for the detection and quantification of rare earth elements in environmental and industrial samples.

Various technical methodologies are required to accurately detect substances of different chemical and pharmacological properties in biological samples, which are increasing in number and variety daily. Therefore, laboratories where many samples and different factors are analyzed simultaneously need methods with easy sample preparation, short analysis times and low analysis costs. In this study, the objective was to scan substances susceptible to chemical degradation, amenable to analysis without hydrolysis, and exhibiting short-term stability by employing a straightforward, expeditious, and cost-efficient method. For this purpose, a high-throughput dilute and shoot screening protocol was developed and validated utilizing high-performance liquid chromatography coupled with high-resolution mass spectrometry to analyze various pharmacological compounds in horse urine and plasma. Over 200 prohibited substances across multiple categories were scanned within a 13 minute run. Chromatographic separation was performed on a C18 column using an elution gradient of mobile phase A, 5 mM ammonium bicarbonate at pH 9, and mobile phase B, methanol, at a flow rate of 0.3 mL min⁻¹. The method was validated according to the specifications of 2002/657/EC multi-screening requirements. The detection capability ranged from ≤1 to 200 ng mL⁻¹ for prohibited substances. The implementation of the screening method in doping analysis, and the analysis of real positive case samples served to underscore the practical applicability of the developed method. To the best of our knowledge, this is a rare method that can be applied to both urine and plasma samples and provides a rapid, practical, broad-spectrum, and high-throughput analysis of prohibited substances in horse plasma and urine cost-effectively.

Most current nucleic acid-responsive fluorescent probes are enhanced ones with short emission wavelengths. Therefore, the development of novel near-infrared, turn-on response nucleic acid fluorescent probes is of great significance. Herein, three cationic fluorescent dyes 1a–1c were synthesized by reacting naphthalidine salt with suitable aldehydes. These probes exhibited excellent photostability, maintaining over 95% of their absorption rate after 5 h of irradiation. Notably, probes 1a–1c exhibited an OFF–ON fluorescence response to DNA and RNA. The maximum emission wavelength could reach the near-infrared region (661–762 nm), with large Stokes shifts (153–222 nm) upon binding to DNA/RNA. The fluorescence intensity was enhanced 143 fold and 127 fold for 1b upon interaction with DNA and RNA, respectively. Co-staining and nucleic acid digestion assays showed that probes 1a–1c could target the mitochondria of fixed cells with low cytotoxicity. These findings may be useful for the early screening of genetic mutations related to mitochondrial diseases.

Tetramethylpyrazine (TMP) is a compound known for its natural health benefits, but current detection methods for TMP are overly expensive and time-consuming. In this study, we developed functional materials with TMP molecular recognition properties using molecularly imprinted technology. As TMP does not produce electrochemical signals in the detection potential range, hexacyanoferrate was selected as a redox probe, combined with the highly conductive polymer PEDOT:PSS to enhance electrode conductivity. When coupled with the TMP-specific functional materials prepared through molecular imprinting, an electrochemical sensor specifically recognizing TMP was successfully developed, and this was confirmed through characterization techniques such as ultraviolet spectroscopy and scanning electron microscopy. Additionally, the crucial experimental parameters were optimized for improved performance. Under optimal conditions, the use of differential pulse voltammetry (DPV) to measure the peak currents of hexacyanoferrate showed a linear relationship with TMP concentrations from 0.50 × 10⁻⁶ to 5.00 × 10⁻³ M, achieving a detection limit of 2.1 × 10⁻⁷ M. This method proved effective for quantifying TMP in Baijiu samples, demonstrating good precision with relative standard deviations (RSD) ranging from 2.71% to 3.28%, and recovery percentages between 95.77% and 101.88%. These results indicate the potential of the molecularly imprinted polymer (MIP) sensor for accurately measuring TMP in actual samples.

Methods based on enzyme labelling strategies have been widely developed for capacitance immunoassays, but most suffer from low sensitivity and are unfavorable for routine use in the early stages of diagnostics. Herein, we designed a highly efficient capacitance immunosensing method for the low-abundance neuroblastoma biomarker neuron-specific enolase (NSE) using an interdigitated micro-comb electrode. Initially, monoclonal mouse anti-human NSE capture antibodies were immobilized on the interdigitated gold electrodes using bovine serum albumin. Thereafter, a sandwich-type immunoreaction was carried out in the presence of target NSE using horseradish peroxidase (HRP)-labeled secondary antibodies. The labelled HRP subsequently triggered the formation of tyramine–enzyme conjugate repeats with the help of HRP–tyramine and H₂O₂. The concatenated HRP molecules catalyzed the oxidation of 4-chloro-1-naphthol to produce an insoluble precipitate on the interdigitated micro-comb electrode, resulting in a shift in capacitance. Two protocols, with and without tyramine–HRP repeats, were investigated for the detection of NSE, with improved analytical performance achieved through tyramine signal amplification. Under optimum conditions, the interdigitated capacitance immunosensors exhibited good responses to target NSE within a dynamic linear range of 1.0–10 000 pg mL⁻¹, with a low detection limit of 0.78 pg mL⁻¹. An intermediate reproducibility of ≤9.67% was accomplished with batch-to-batch consistency, and good anti-interference capacity against other proteins was acquired. No significant differences at the 0.05 significance level were encountered in the analysis of 12 human serum specimens between the developed capacitance immunosensor and the commercially available enzyme-linked immunosorbent assay (ELISA).

Protein N-glycosylation, as one of the most crucial post-translational modifications, plays a significant role in various biological processes. The structural alterations of N-glycans are closely associated with the onset and progression of numerous diseases. Therefore, the precise and specific identification of disease-related N-glycans in complex biological samples is invaluable for understanding their involvement in physiological and pathological processes, as well as for discovering clinical diagnostic biomarkers. However, protein N-glycosylation suffers from microscopic heterogeneity and low abundance in biological systems, leading to N-glycopeptide signals being overshadowed by those of their non-glycosylated counterparts during mass spectrometry (MS) analysis. Consequently, there is an urgent demand for the development of novel methods for highly efficient N-glycan enrichment. In this study, we introduced a novel hydrophilic nanomaterial, nitrogen-modified reduced graphene oxide (N-rGO), tailored for this purpose, which was formed by a condensation reaction between the amino groups of rGO and the carboxyl groups of Fmoc-Photo-Linker. Compared to other enrichment materials, N-rGO not only supports efficient N-glycans enrichment via hydrophilic interaction (HILIC), but also serves as an effective matrix for direct MALDI-TOF MS analysis combined with DHB, thereby avoiding sample loss during N-glycans release. 76 and 81 serum N-glycans were obtained from 3 healthy individuals and 3 hepatocellular carcinoma (HCC) patients. Notably, relative quantification of serum N-glycans between 20 patients and 20 healthy controls showed significant expression differences, such as H₅N₄F₁S₁, H₆N₅F₁, H₅N₄S₂, H₅N₄F₂S₁ and H₅N₅F₁S₁, indicating the potential of N-rGO for biomarker discovery.

Although the glycosylation of viral proteins plays a critical role in the process of viral invasion into host cells, studies on the glycosylation of monkeypox virus (MPXV) structural proteins have not yet been reported. To investigate the importance of MPXV protein glycosylation, poly Ser-Arg (poly SR) materials capable of simultaneously enriching both N-glycopeptides and O-glycopeptides were synthesized by surface-initiated reversible addition–fragmentation chain transfer (SI-RAFT) polymerization. The poly SR materials were evaluated using the digest mixture of standard proteins containing bovine fetuin and bovine serum albumin, and the digest of complex biological samples including bovine sperm tail lysate, mouse sperm tail lysate, mouse brain lysate, and human serum. The poly SR materials demonstrated excellent glycopeptide enrichment performance. Subsequently, poly SR materials were applied to comprehensively analyze the N-glycosylation and O-glycosylation of the MPXV structural proteins A29, A35, B6R, and H3L, revealing that these proteins are highly sialylated. To further elucidate the mechanism of MPXV protein infection, the strong specific binding of A29 to heparan sulfate and chondroitin sulfate was determined using glycan microarrays. These findings provide a foundation for understanding the viral infection mechanism and developing vaccines and antiviral drugs.

Infrared absorption spectroscopy and surface-enhanced Raman spectroscopy were integrated into three data fusion strategies—hybrid (concatenated spectra), mid-level (extracted features from both datasets) and high-level (fusion of predictions from both models)—to enhance the predictive accuracy for xylazine detection in illicit opioid samples. Three chemometric approaches—random forest, support vector machine, and k-nearest neighbor algorithms—were employed and optimized using a 5-fold cross-validation grid search for all fusion strategies. Validation results identified the random forest classifier as the optimal model for all fusion strategies, achieving high sensitivity (88% for hybrid, 92% for mid-level, and 96% for high-level) and specificity (88% for hybrid, mid-level, and high-level). The enhanced performance of the high-level fusion approach (F1 score of 92%) is demonstrated, effectively leveraging the surface-enhanced Raman data with a 90% voting weight, without compromising prediction accuracy (92%) when combined with infrared spectral data. This highlights the viability of a multi-instrument approach using data fusion and random forest classification to improve the detection of various components in complex opioid samples in a point-of-care setting.