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Updated: Jan 30, 2026

Direct Detection of Isolevuglandins in Tissues Using a D11 scFv-Alkaline Phosphatase Fusion Protein and Immunofluorescence
Published on: July 5, 2021
Development of a one-step immunoassay for triazophos using camel single-domain antibody-alkaline phosphatase fusion
Kai Wang1, Zhiping Liu1, Guochun Ding2
1Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, China.
Abstract:
Triazophos is mainly used in Asian and African countries for the control of insects in agricultural production. Camelid variable domains of heavy-chain antibodies (VHHs) show great promise in monitoring environmental chemicals such as pesticides. To improve the rate of success in the generation of VHHs against triazophos, genes specifically encoding VHH fragments from the unique allotype IgG3a of an immunized Camelus bactrianus were amplified by using a pair of novel primers and introduced to construct a diverse VHH library. Five out of seven isolated positive clones, including the VHH T1 with the highest affinity to triazophos, were derived from the allotype IgG3a. A one-step enzyme-linked immunosorbent assay (ELISA) using VHH T1 genetically fused with alkaline phosphatase (AP) had a half-maximum inhibition concentration of 6.6 ng/mL for triazophos. This assay showed negligible cross-reactivity with a list of important organophosphate pesticides (< 0.1%). The average recoveries of triazophos from water, soil, and apple samples determined by the one-step ELISA ranged from 83 to 108%, having a good correlation with those by a gas chromatography mass spectrometry (R2 = 0.99). The VHH-AP fusion protein shows potential for the analysis of triazophos in various matrices.
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