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A portable and antibody-free sandwich assay for determination of chloramphenicol in food based on a personal glucose meter

Chen, Si, Gan, Ning, Zhang, Huairong, Hu, Futao, Li, Tianhua, Cui, Huan, Cao, Yuting, Jiang, Qianli
Analytical and bioanalytical chemistry 2015 v.407 no.9 pp. 2499-2507
beta-fructofuranosidase, chloramphenicol, detection limit, enzyme-linked immunosorbent assay, glucose, models, molecular imprinting, nanoparticles, polymers, screening, sucrose
A portable and antibody-free sandwich assay was fabricated for determination of chloramphenicol (CAP) in animal-derived food by a personal glucose meter (PGM). The sandwich-type strategy was developed on the basis of magnetic molecularly imprinted probe (m-MIP) nanoparticles and a β-cyclodextrin/invertase-functionalized signal tag. Firstly, the m-MIPs were fabricated using polydopamine molecularly imprinted film modified Fe₃O₄nanoparticles with 2,2-dichloroacetamide as a template that could capture the 2,2-dichloroacetamide segment of CAP. Secondly, β-cyclodextrin/invertase polymer bioconjungate was synthesized as a signal tag that could recognize the nitrobenzene segment of CAP through host–guest interaction. The dual-specificity recognition model relies on the formation of a sandwich between m-MIPs, different segments of CAP, and the β-cyclodextrin-functionalized signal tag. The sandwich-type complex formed was then subjected to detection with a PGM. The complexes can hydrolyze sucrose to glucose, which can be used for detection with a PGM through invertase. According to our experiment, the concentration of CAP was proportional to the amount of glucose formed, which could quantitatively assess the CAP with a dynamic range of 0.5–50 ng mL⁻¹and a detection limit of 0.16 ng mL⁻¹(signal-to-noise ratio of 3). The detection time of the assay was about 1 h, which was obviously shorter than that of competitive ELISA. More importantly, we have successfully applied this on-site assay for CAP screening in animal-derived food.