Nanoflower Microreactor Based Versatile Enhancer for Recognition Cofactor-Dependent Enzyme Biocatalysis toward Saxitoxin Detection.

Investigating organic carriers' utilization efficiency and bioactivity within organic-inorganic hybrid nanoflowers is critical to constructing sensitive immunosensors. Nevertheless, the sensitivity of immunosensors is interactively regulated by different classes of biomolecules such as antibodies and enzymes. In this work, we introduced a new alkaline phosphatase-antibody-CaHPO4 hybrid nanoflowers (AAHNFs) microreactor based colorimetric immunoprobe. This system integrates a biometric unit (antibody) with a signal amplification element (enzyme) through the biomineralization process. Specifically, the critical factors affecting antibody recognition activity in the formation mechanism of AAHNFs are investigated. The designed AAHNFs retain antibody recognition ability with enhanced protection for encapsulated proteins against high temperature, organic solvents, and long-term storage, facilitating the selective construction of lock structures against antigens. Additionally, a colorimetric immunosensor based on AAHNFs was developed. After ascorbic acid 2-phosphate hydrolysis by alkaline phosphatase (ALP), the generated ascorbic acid decomposes I2 to I-, inducing the localized surface plasmon resonance in the silver nanoplate, which is effectively tuned through shape conversion to develop the sensor. Further, a 3D-printed portable device is fabricated, integrated with a smartphone sensing platform, and applied to the data of collection and analysis. Notably, the immunosensor exhibits improved analytical performance with a 0.1-6.25 ng·mL-1 detection range and a 0.06 ng·mL-1 detection limit for quantitative saxitoxin (STX) analysis. The average recoveries of STX in real samples ranged from 85.9% to 105.9%. This study presents a more in-depth investigation of the recognition element performance, providing insights for improved antibody performance in practical applications.

Identification and verification of key taste components in wampee using widely targeted metabolomics.

Due to the lack of comprehensive evaluation of all metabolites in wampee, the metabolic reasons for taste differences are unclear. Here, two local varieties YF1 (sweet taste) and YF2 (sweet-sour taste), were selected for quality analysis, followed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) based widely targeted metabolomic analysis. YF1 and YF2 were clearly separated by principal component analysis (PCA) and cluster analysis, and 449 metabolites were different between the cultivars, including 29 carbohydrates and 29 organic acids. Among them, d-galactose, d-mannose, and d-fructose 6-phosphate contributed mainly to the sweet taste of the YF1 wampee. l-citramalic acid, 2-hydroxyglutaric acid, and 3-methylmalic acid were the dominant organic acids in YF2 wampee, and therefore, contributed primarily to the sweet-sour taste. The differential metabolites were significantly enriched in the "ascorbate and aldarate metabolism" and "C5-branched dibasic acid metabolism" pathways. Ascorbate played a crucial role in the regulation of sugars and organic acids through those pathways. In addition, high-performance liquid chromatography (HPLC) based quantitative verification exhibited the same specific cultivar variations.