In this study, a novel fluorescent "turn-on" aptasensor was developed for sensitive and rapid detection of tetracycline (TC) in animal-derived food. It is based on aptamer-functionalized nitrogen-doped graphene quantum dots (N-GQDs-aptamer) coupled with cobalt oxyhydroxide (CoOOH) nanoflakes. The CoOOH nanoflakes are efficient fluorescence quenchers in homogeneous solutions, and this is due to their advantages of excellent optical properties, superior flexibility, and water dispersibility. The proposed method's mechanism is driven by quenching based on the fluorescence resonance energy transfer (FRET) between the donor (N-GQDs) and the acceptor (CoOOH nanoflakes). On the other hand, fluorescence recovery is caused by the structure switching behavior of the aptamer. Compared with previous methods, our developed method exhibits better behavior in terms of being easy to fabricate and being simple in detection procedure and maintains the detection limit low enough in TC determination: a linear range from 1 to 100 ng mL-1 and a detection limit of 0.95 ng mL-1 (S/N = 3). Furthermore, the proposed method was applied to five animal-derived food samples (milk, honey, fish, eggs, and chicken muscle) and demonstrated practical applicability. As well, the method has the advantages of simplicity in pre-treatment and convenience in instruments, saves times, and is cost-effective. Finally, the proposed method demonstrates significant potential for sensitive and rapid detection of specific components in real samples. Graphical abstract.

中文翻译：

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基于氮掺杂石墨烯量子点和六方羟基氧化钴纳米薄片的新型荧光“开启”适体传感器，用于检测四环素。

在这项研究中，开发了一种新型的荧光“开启”适体传感器，用于灵敏，快速地检测动物源食品中的四环素（TC）。它基于适体官能化的氮掺杂石墨烯量子点（N-GQDs-适体）与羟基氧化钴（CoOOH）纳米薄片相结合。CoOOH纳米薄片在均匀溶液中是有效的荧光猝灭剂，这是由于它们具有出色的光学性能，优异的柔韧性和水分散性的优点。所提出的方法的机理是通过基于供体（N-GQDs）与受体（CoOOH纳米薄片）之间的荧光共振能量转移（FRET）进行淬灭来驱动的。另一方面，荧光的恢复是由适体的结构转换行为引起的。与以前的方法相比，我们开发的方法在易于制造和检测程序方面表现出更好的性能，并在TC测定中将检测限保持在足够低的水平：线性范围为1至100 ng mL-1，检测限为0.95 ng mL- 1（S / N = 3）。此外，该方法被应用于五个动物源性食品样本（牛奶，蜂蜜，鱼，蛋和鸡肌肉），并证明了其实际适用性。同样，该方法具有预处理简单和仪器方便的优点，节省了时间，并且具有成本效益。最后，所提出的方法证明了灵敏和快速检测真实样品中特定成分的巨大潜力。图形概要。