Exploiting pH-Regulated Dimer-Tetramer Transformation of Concanavalin A to Develop Colorimetric Biosensing of Bacteria

文献类型： 外文期刊

第一作者： Xu, Xiahong

作者： Xu, Xiahong;Yuan, Yuwei;Hu, Guixian;Wang, Xiangyun;Qi, Peipei;Wang, Zhiwei;Wang, Qiang;Wang, Xinquan;Yang, Hua;Xu, Xiahong;Yuan, Yuwei;Hu, Guixian;Wang, Xiangyun;Qi, Peipei;Wang, Zhiwei;Wang, Qiang;Wang, Xinquan;Yang, Hua;Xu, Xiahong;Yuan, Yuwei;Hu, Guixian;Wang, Xiangyun;Qi, Peipei;Wang, Zhiwei;Wang, Qiang;Wang, Xinquan;Yang, Hua;Fu, Yingchun;Li, Yanbin

作者机构：

期刊名称：SCIENTIFIC REPORTS （ 影响因子：4.379； 五年影响因子：5.133 ）

ISSN： 2045-2322

年卷期： 2017 年 7 卷

页码：

收录情况： SCI

摘要： Gold nanoparticles (AuNPs) aggregation-based colorimetric biosensing remains a challenge for bacteria due to their large size. Here we propose a novel colorimetric biosensor for rapid detection of Escherichia coli O157:H7 (E.coli O157: H7) in milk samples based on pH-regulated transformation of dimer/tetramer of Concanavalin A (Con A) and the Con A-glycosyl recognition. Briefly, antibody-modified magnetic nanoparticles was used to capture and concentrate E.coli O157: H7 and then to label with Con A; pH adjusted to 5 was then applied to dissociate Con A tetramer to release dimer, which was collected and re-formed tetramer at pH of 7 to cause the aggregation of dextran-modified AuNPs. The interesting pH-dependent conformation-transformation behavior of Con A innovated the design of the release from the bacteria surface and then the reconstruction of Con A. Therefore, we realized the sensitive colorimetric biosensing of bacteria, which are much larger than AuNPs that is generally not suitable for this kind of method. The proposed biosensor exhibited a limit of detection down to 41 CFU/mL, short assay time (similar to 95 min) and satisfactory specificity. The biosensor also worked well for the detection in milk sample, and may provide a universal concept for the design of colorimetric biosensors for bacteria and virus.

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