基于末端脱氧核苷酸转移酶协同G-四链体核酶的恩诺沙星检测新方法

A sensitive method for enrofloxacin detection based on collaborative signal amplification by terminal deoxynucleotidyl transferase with G-quadruplex ribozyme

摘要:

恩诺沙星因抗菌活性强、抗菌谱广而广泛应用于动植物疾病治疗，但过度使用甚至滥用会导致其在动植物食品中的残留量超标，因此发展高效的恩诺沙星检测方法至关重要。本工作基于末端脱氧核苷酸转移酶（TdT）协同G-四链体核酶设计信号放大策略，建立了一种新型恩诺沙星（ENR）电化学检测方法。目标物恩诺沙星与特异性核酸适体的结合触发TdT在电极表面的扩增反应，产生G-四链体核酶纳米线结构，进而发挥辣根过氧化物酶活性催化信号放大，实现恩诺沙星的高灵敏和高特异性检测。本方法对恩诺沙星的线性检测范围为0.5 ~ 50 ng/mL，检测限低至0.043 ng/mL。此外，该无标记电化学生物传感器简单快速，成本低，并成功应用于对实际食品样本的分析检测，显示出较好的应用潜能。

Abstract:

Enrofloxacin is widely used in the treatment of animal and plant diseases due to its strong antibacterial activity and broad antibacterial spectrum. However, overuse and even abuse of enrofloxacin can lead to excessive residues in animal and plant food and harm human health through the food chain, so it is crucial to develop efficient methods for enrofloxacin detection. In this work, a novel electrochemical method for enrofloxacin detection is established based on the signal amplification strategy designed by collaborating terminal deoxynucleotidyl transferase (TdT) with G-quadruplex ribozyme. The binding of target enrofloxacin with specific aptamer triggers the extension reaction of TdT on the electrode surface, resulting in the formation of G-quadruplex ribozyme nanowires, which can play horseradish peroxidase activity to catalyze signal amplification, finally achieving highly sensitive and specific detection of enrofloxacin. The linear detection range of enrofloxacin is 0.5 ~ 50 ng/mL, and the limit of detection is as low as 0.043 ng/mL. In addition, the label free electrochemical biosensor is simple, fast and low cost, and has been successfully applied to the analysis of real food samples, showing good application potential.