Gongke Li

The quality characteristics of wine were strongly influenced by mercaptans, which were key flavor substances contributing to the characteristic aroma profile of wines. Although the wide usages of chromatography and mass spectrography in mercaptan analysis, the complex sample pretreatment and time-consuming analysis processes limited their application in rapid detection. In this work, the rapid sensing method of cyclic cataluminescence (CCTL) was extended to mercaptan analysis by introducing La₂O₃ as a catalyst, and a dynamic response strategy for wine discrimination was established. The La₂O₃ catalyst was synthesized by a simple hydrothermal method and possessed a layered structure and exhibited excellent catalytic activity toward the luminescence reaction of mercaptan substances. The characteristic attenuation coefficient (k) was derived by fitting the decay of peak intensity of the CCTL curve over time. The obtained k values were found to depend on both the concentration and composition of the composite sample. The CCTL method was successfully applied to 55 wine samples, including 12 different wine brands from various production areas. Each wine brand exhibited a characteristic k value, while the same brand showed high consistency. Furthermore, when combined with linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA), the method achieved 100% classification accuracy, demonstrating its great potential for rapid, reliable, and cost-effective wine authentication. Graphical abstract

Chiral separation and detection remain challenging areas in analytical science. Herein, we report a mild and rapid preparation of versatile dual-chiral covalent organic framework (D-CCOF) microspheres that can be directly employed as both a chiral stationary phase and a Raman substrate for the chiral separation and detection of polar chiral compounds. Based on the rapid synthesis of three-component COF microspheres at room temperature, uniform D-CCOF microspheres were prepared through two-step mild post-modification, including an ultraviolet-assisted thiol−ene click reaction for precise chiral site modification. The integration of two chiral functional groups (thiolated β-cyclodextrin and glutathione) into the skeleton of COF with low energy consumption provided abundant chiral sites. When employed as a chiral stationary phase in HPLC, D-CCOF demonstrated enantioseparation performance for hydroxyl-containing drug intermediates that was superior to that of single-chiral COFs and comparable to that of commercial chiral columns. D-CCOF was also used as a Raman chiral substrate for the detection of six carboxyl-containing chiral metabolites by monitoring the intensity ratio variations of two characteristic Raman bands at ∼1133 and ∼1146 cm−1. Furthermore, it demonstrated the potential for chiral qualitative analysis in complex matrices. Molecular simulations revealed that the interactions between the two chiral groups on the dual-chiral COF and the enantiomers are dominated by hydrogen bonds and van der Waals interactions and that the synergistic effect of the dual chiral groups contributes to chiral recognition. This work offers a green and facile route to the rapid synthesis of dual-chiral COF microspheres and illustrates the potential of this dual-chirality design for both chromatographic enantioseparation and Raman-based chiral detection.

Traditional nanozymes suffer from inefficient catalytic kinetics and slow signal response, limiting their use in rapid-response sensors for real-sample analysis. Herein, we developed an external electrical stimulation regulation strategy that directly drives valence cycling in bimetallic MOF nanozymes. This approach reduces the activation energy and promotes the generation of reactive oxygen species, thereby synergistically enhancing the peroxidase-like activity of the MOF nanozyme system, which also shortens the reaction time. By overcoming the inherent electron-transfer rate limitation in conventional enzyme catalysis, it enables rapid cycling of active valence states. Consequently, the application of an external electrical stimulation enables the rapid oxidation of leuco-malachite green to surface-enhanced Raman scattering (SERS)-active malachite green (MG) within 45 s, drastically shortening the reaction time from 45 min and enabling rapid sensor response. The accelerated kinetics minimize intermediate dissipation and maximize analyte utilization, facilitating rapid and pronounced accumulation of the Raman reporter MG for highly sensitive detection. Based on this mechanism, a target-triggered hybridization-assisted SERS sensor was constructed for alternariol toxin detection, achieving a wide linear range of 0.2–100 ng/mL (R2 = 0.9996) and a low limit of detection of 0.074 ng/mL. The sensor demonstrates high selectivity, stability, and applicability in complex food matrices. This work provides an effective acceleration strategy to overcome the kinetic limitations of nanozyme-based sensors, enabling rapid and sensitive detection of trace mycotoxins for food safety monitoring.

Norovirus (NoV) is a leading global cause of foodborne illness, necessitating the development of rapid and sensitive detection methods. However, conventional proximity ligation assays (PLA) often suffer from limited sensitivity and poor compatibility with array-based analysis. Here, we present a novel detection strategy that integrates a proximity-ligation hybridization chain reaction with catalytic hairpin assembly (NPLA-HCR/CHA) and a multidirectional cyclic fluorescence detection system (MDCFS). In this design, protein targets are first converted into amplifiable DNA barcodes via NPLA-HCR/CHA, enabling exponential signal amplification. The MDCFS device, employing electronic fluorinated liquid spacers, enables cyclic array-based readout with enhanced sensitivity. Specific lectin- and antibody-based probes were designed to ensure selective recognition of NoV capsid protein VP1. Signal amplification is achieved through proximity-activated hybridization chain reaction and catalytic hairpin assembly. For practical samples, this method demonstrated a detection limit of 0.15 pg·mL^-1 (approximately 8.51 × 10³ copies·mL^-1) and a linear range of 0.50-50 pg·mL^-1 (approximately 2.84 × 10⁴ to 2.84 × 10⁶ copies·mL^-1), exhibiting high selectivity and accuracy comparable to those of real-time polymerase chain reaction (RT-PCR). The combination of NPLA-HCR/CHA with MDCFS thus provides a powerful platform for ultrasensitive, multiplexed, and array-compatible detection of NoV, offering significant potential for applications in public health monitoring and food safety assurance.

Cyclic cataluminescence (CCTL) is an emerging strategy that extends the principles of cataluminescence (CTL). The catalyst constitutes a critical component in CTL sensing systems. Currently, the development of innovative sensing systems and the elucidation of sensing mechanisms to enhance CTL remain significant challenges. Herein, we designed a heterogeneous electron allocator catalyst and a circulating flow system-assisted CTL for enhancing sensitivity and response speed. MgO/Y₂O₃ heterogeneous catalysts were employed as electron allocators and decorated on CNTs, and the resulting MgO/Y₂O₃/CNT catalyst was coupled with the CCTL method for the catalytic detection of multiple aldehydes. By fitting the variation of the peak intensity (I_n) of CCTL with time (t), the characteristic attenuation coefficient (k) value was calculated, and the k value could be used for qualitative analysis. The comprehensive k values of aldehydes contained characteristic information of tea. The k values of 61 tea samples were obtained by the CCTL method, and the k values of different tea species and origins were different from 2.0 to 41. Moreover, linear discriminant analysis and hierarchical cluster analysis were used to further process the CCTL data. This research provided a new perspective on CTL through designing a heterogeneous electron allocator catalyst and a circulating flow system.

Aiming to meet the critical need for user-friendly and sensitive clinical analysis platforms, an all-in-capillary SERS analytical system integrated with a visible-light-enhanced nanozyme for highly sensitive and convenient biomarker detection was developed. The system employs a hierarchical tandem heterojunction (TiO₂/MoS₂/CoFe₂O₄) as a peroxidase-like nanozyme, which significantly enhances separation and transfer of photogenerated charges under visible light. This nanozyme catalyzes the oxidation of leucocrystal violet to crystal violet, generating a characteristic Raman signal at 923 cm^-1. To ensure analytical reliability, the inner wall of the capillary was modified with TiO₂ as an internal standard, enabling signal self-calibration. This integrated platform allows direct sampling of finger blood without any pretreatment, performing all-in-capillary SERS detection. The proposed method achieves ultrasensitive detection of Alzheimer's disease biomarker Aβ_1-42, with a wide linear range of 1.0 × 10^-3 to 1.0 × 10^-7 μg/mL, a low detection limit of 0.089 pg/mL, and satisfactory recovery of 94.3%-101% in human serum. The method was successfully applied to clinical serum samples from Alzheimer's patients and controls of different groups, revealing statistically significant differences in Aβ_1-42 levels. Furthermore, the results showed excellent agreement with those obtained by the reference ELISA method, demonstrating high accuracy and practical applicability of our assay for early diagnosis and population screening. By combining rational nanozyme design with a miniaturized and calibration-free sampling interface, this work provides a streamlined bioanalytical strategy with great potential for point-of-care testing in early disease diagnosis.

Analytical chemistry is undergoing a transformation from the traditional linear model to a cyclic model, driving separation and detection technologies toward greater efficiency and sustainability.