Abstract Fluorescence quenching induced by exonuclease, specific target recognition by an aptamer, and host–guest recognition were artfully integrated in this study, and a new nanoscale fluorescent aptasensor for supersensitive recognition of acetamiprid was proposed. In the absence of acetamiprid, the aptamer hybridized with complementary DNA at 3′end-marked ferrocene (Fc) (cDNA-Fc) to form a double-stranded DNA. Fluorescence intensity was nearly unchanged after RecJf exonuclease was added. After the addition of acetamiprid, the aptamer preferentially bound with it to form a new compound; hence, the aptamer could not bind with cDNA-Fc. The single-stranded aptamer and cDNA-Fc were cut off after RecJf exonuclease was added, and the Fc released via host–guest recognition rapidly entered the cavity of cyclodextrin and initiated photoinduced electron transfer. Consequently, fluorescence intensity decreased, and acetamiprid was sensitively detected. The method can be extensively applied to detect various pesticides or additives in agriculture and forestry.

中文翻译：

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RecJf核酸外切酶辅助荧光自组装适体传感器用于食品中农药的超灵敏检测

摘要 本研究巧妙地融合了核酸外切酶诱导的荧光猝灭、适体特异性靶标识别和主客体识别，提出了一种新型纳米级荧光适体传感器，用于超灵敏识别啶虫脒。在不存在啶虫脒的情况下，适体与 3' 端标记的二茂铁 (Fc) (cDNA-Fc) 处的互补 DNA 杂交形成双链 DNA。添加 RecJf 核酸外切酶后，荧光强度几乎没有变化。加入啶虫脒后，适体优先与其结合形成新的化合物；因此，适体不能与 cDNA-Fc 结合。加入RecJf核酸外切酶后切断单链适配体和cDNA-Fc，通过主客体识别释放的 Fc 迅速进入环糊精腔并引发光诱导电子转移。因此，荧光强度降低，并且可以灵敏地检测到啶虫脒。该方法可广泛应用于农林中各种农药或添加剂的检测。