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Switchable fluorescence immunoassay using gold nanoclusters anchored cobalt oxyhydroxide composite for sensitive detection of imidacloprid
摘要： The fabrication of a convenient fluorescence-based immunoassay (FIA) for specific antigen attract increasing concern but remains a considerable challenge, especially the laborious synthesis of nanomaterials-antibody conjugates. Herein, we circumvent this drawback by introducing a specific fluorescence signal response procedure to commercially available alkaline phosphatase (ALP)-labeled conventional immunoassay for imidacloprid detection. In this FIA protocol, gold nanoclusters (AuNCs) can anchor on the surface of two-dimensional cobalt oxyhydroxide (CoOOH) nanoflakes to form nanocomposite, resulting in remarkable decrease of fluorescence intensity. The quenching effects can be effectively reversed by introducing ascorbic acid that can trigger the decomposition of CoOOH nanoflakes. Notably, the corresponding fluorescence response induced by ascorbic acid was related to ALP activities labeled on antibody. After competitive immunoreaction, the ALP-labeled antibodies were bounded to immobilized antigen, which can regulate the fluorescence change. Utilizing fluorescence switching of system, the 50% inhibition concentration (IC50) value of FIA toward imidacloprid was obtained at 1.3 ng mL?1 which was 60-fold-of-magnitude more sensitive than that of conventional ELISA (86.4 ng mL?1). This FIA protocol not only develops new prospects for pesticide detection, but also opens up potent strategy of fluorogenic immunoassay.
关键词： Immunoassay,Composite,Alkaline phosphatase,Fluorescence,Imidacloprid
更新于2025-09-23 15:22:29
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Fast sensing of imidacloprid residue in tea using surface-enhanced Raman scattering by comparative multivariate calibration
摘要： This study focused on the fabrication of a rapid, highly sensitive and inexpensive technique for the quantification of imidacloprid residue in green tea, based on surface-enhanced Raman scattering (SERS) using highly roughed surface flower shaped silver nanostructure (as SERS substrate) coupled with the chemometric algorithm. The basic principle of this method is imidacloprid yielded SERS signal after adsorption on Ag-NF under laser excitation by the electromagnetic enhancement and the intensity of the peak is proportional to the concentration ranging from 1.0×103 to 1.0×10-4 μg/mL. Among the models used, the GA-PLS (Genetic algorithm-partial least square) exhibited superiority to quantify imidacloprid residue in green tea. The model achieved Rp (correlation coefficient) of 0.9702 with RPD of 4.95 % in the test set and RSD for precision recorded up to 4.50 %. Therefore, the proposed sensor could be employed to quantify imidacloprid residue in green tea for the safeguarding of quality and human health.
关键词： Different PLS algorithm,Green tea,Flower-shaped silver nanostructure,Surface-enhanced Raman scattering,Imidacloprid residue
更新于2025-09-10 09:29:36