Abstract：
Overuse of enrofloxacin (ENR) has posed a potential threat to ecosystems and public health, so it is critical to sensitive and accurate determination of ENR residues. In this work, a novel ultra-sensitive and specific electrochemical aptasensor was fabricated based on the cobalt diselenide loaded gold and platinum nanoflowers (Au@Pt NFs/ CoSe2) and Exonuclease III (Exo III)-assisted cycle amplification strategy for the detection of ENR. Au@Pt NFs/ CoSe2 nanosheets as the substrate material, with large surface area, accelerate electron transfer and attach more DNA probes on the electrode substrate, have effectively enhanced the electrochemical performance of the electrode. With the existence of Enrofloxacin (ENR), the aptamer recognizes and binds to ENR, thus the signal probe cDNA was released and immobilized onto the electrode surface to hybridized with methylene blue (MB) labelled DNA (MB-DNA), thereby triggering the Exo III-assisted cycle for further signal amplification. As expected, the prepared aptasensor demonstrated excellent sensitivity and selectivity, with a wide linear range from 5.0 × 10-6 ng/mL to 1.0 × 10-2 ng/mL for ENR, a low detection limit of 1.59 × 10-6 ng/mL. Consequently, this strategy provided a promising avenue for ultrasensitive and accurate detection of ENR in milk samples.
摘要：
过度使用恩诺沙星(ENR)对生态系统和公众健康构成了潜在威胁,因此灵敏、准确地测定ENR的残留量至关重要。在这项工作中,基于负载二硒化钴的金和铂纳米花（Au@PtNFs/CoSe2）和核酸外切酶III（ExoIII）辅助循环扩增策略，制造了一种新型的超灵敏和特异性电化学传感器，用于检测ENR。Au@PtNFs/CoSe2纳米片作为衬底材料,表面积大，加速电子转移并将更多的DNA探针附着在电极基板上，有效地增强了电极的电化学性能。随着恩诺沙星（ENR）的存在，适体识别并结合到ENR，因此，信号探针cDNA被释放并固定在电极表面，以与亚甲基蓝（MB）标记的DNA（MB-DNA）杂交，从而触发ExoIII辅助循环以进行进一步的信号放大。不出所料,制备的aptasensor表现出优异的灵敏度和选择性，ENR的线性范围从5.0×10-6ng/mL到1.0×10-2ng/mL，低检测限为1.59×10-6ng/mL。因此,该策略为牛奶样品中ENR的超灵敏和准确检测提供了有希望的途径.
