A colorimetric immunoassay based on glucose oxidase-induced AuNP aggregation for the detection of fumonisin B1
2018
Chen, Xirui | Liang, Yi | Zhang, Wenjing | Leng, Yuankui | Xiong, Yonghua
Naked-eye readout colorimetric signal-based assays are promising for high-throughput screening detection and point-of-care diagnostics in resource-constrained regions. Here, a novel direct competitive plasmonic enzyme-linked immunosorbent assay (dc-pELISA) based on gold nanoparticle (AuNP) aggregation with highly sensitive and robust naked-eye readout signal was developed and used to detect fumonisin B₁ (FB₁). AuNP aggregation was induced by a horseradish peroxidase (HRP)/hydrogen peroxide (H₂O₂)/tyramine (TYR) system, resulting in a dramatic color change from red to blue. In this system, H₂O₂ was produced via GOx-mediated glucose oxidation reaction, and FB₁–GOx was used as a competitive antigen. The proposed pELISA demonstrated good linear detection of FB₁ from 3.125 ng mL⁻¹ to 25 ng mL⁻¹ with a vivid color change from deep blue to red and a cutoff limit of 12.5 ng mL⁻¹ observed by the naked eye. The average recoveries for FB₁-spiked corn samples ranged from 76.5% to 96.8% with a relative standard derivation of 4.88~ 16.4%. Meanwhile, the proposed method exhibited excellent agreement (R² = 0.927) with the conventional ELISA method in blindly detecting FB₁ spiked corn samples. Additionally, the results of the proposed method for FB₁ positive corn samples also showed a high consistency with those of the ultra performance liquid chromatography method. These results indicated acceptable accuracy and precision of the proposed colorimetric ELISA for quantitative detection of FB₁ in actual corn samples.
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