核酸外切酶III辅助的荧光适体传感器免标记检测卡那霉素

A label-free fluorescent aptamer sensor for kanamycin detection based on exonuclease III-aided signal amplification

随着抗生素的广泛使用,一些负面影响也随之出现.食品和生态环境中残留的抗生素极大威胁着人类的身心健康与生存环境.因此,发展快速、便捷的抗生素检测方法对进一步控制抗生素污染有着非常重要的意义.该文利用核酸外切酶III能特异性催化dsDNA的特性,构建了核酸外切酶III辅助信号放大的荧光适体传感器用于卡那霉素(Kana)检测.当目标物不存在时,双链DNA被核酸外切酶III切成短的寡核苷片段,不能嵌入核酸染料从而表现出低的荧光.当卡那霉素存在时,它与相应的核酸适体链结合,从而将双链转变成单链DNA.游离的单链DNA不能被核酸外切酶III切割,嵌入核酸染料后表现出很高的荧光信号.在最佳实验条件下,该方法对卡那霉素浓度在0.01~50 ng/mL范围内呈线性相关,最低检测限为8.12×10^(-3) ng/mL.废水样品中的加标回收率为96.05%~105.04%,表明该策略可用于实际环境中卡那霉素的检测.

The abuse of antibiotics is alarming and leads to the existence of antibiotic residues in food and ecological environment,which is a great threat to not only the physical and mental health but also the living environment of human beings.The development of rapid and convenient detection methods for antibiotics is importance to further control of antibiotic contamination.In this work,a label-free fluorescent aptasensor was developed for kanamycin(Kana)detection based on exonuclease III-aided signal amplification.In the absence of analyte,the dsDNA was hydrolyzed into short oligonucleotide,which fail to enhance the fluorescence of SYBR Gold,thereby resulting in a low background signal.When the kanamycin-included samples were added,the DNA probe formed an aptamer-Kana complex,thereby separating from the dsDNA and inducing the fluorescence of SYBR Gold.Under optimal conditions,the proposed strategy could detect kanamycin concentrations of less than 0.01-50 ng/mL,with the detection limit was 8.12×10^(-3) ng/mL.The content of the added Kana in wastewater samples was analyzed and the average recovery ranged from 96.05%to 105.04%,which indicated the proposed strategy is expected to be a superior alternative for Kana detection in wastewater samples.