Fe^(3+)掺杂聚多巴胺纳米球荧光适配体传感器对小麦中脱氧雪腐镰刀菌烯醇的检测

A Fluorescent Aptasensor Based on Fe^(3+) Doped Polydopamine Nanospheres for Detection of Deoxynivalenol in Wheat

目的:构建一种基于荧光共振能量转移(fluorescence resonance energy transfer,FRET)原理的荧光适配体传感器,用于检测小麦中的脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)。通过掺入Fe^(3+)提高传感器中聚多巴胺纳米球(polydopamine nanospheres,PDANS)对6-羧基荧光素(6-carboxyuorescein,FAM)的猝灭能力。方法:标记有FAM的DON核酸适配体(P_(DON))通过π-π堆积的非共价作用吸附到Fe^(3+)掺杂聚多巴胺纳米球(Fe-PDANS)上,由于FRET,FAM的荧光被Fe-PDANS猝灭。在DON存在的情况下,P_(DON)可以和DON特异性结合,改变P_(DON)的构象,使其难以吸附到Fe-PDANS上,从而增强传感器的荧光信号,实现对DON的检测。结果:该传感器在DON质量浓度0.266 7~133.3 ng/mL范围内具有良好的线性关系,其检出限为0.118 2 ng/mL;同时,对阳性小麦中的DON进行检测,其检测结果与酶联免疫检测法所得结果无显著差异(P>0.05)。结论:所构建的荧光适配体传感器反应快速、灵敏,且具有良好的特异性和重复性,提供了检测小麦中DON的新方法。

Objective:A fluorescent aptasensor based on fluorescence resonance energy transfer (FRET) was constructed for the detection of deoxynivalenol (DON) in wheat.The ability of polydopamine nanospheres (PDANS) in the sensor to quench 6-carboxyuorescein (FAM) was improved by doping with Fe^(3+).Methods:FAM labeled DON aptamer (P_(DON)) was adsorbed on the surface of PDANS (Fe-PDANS) doped with Fe^(3+)viaπ-πstacking non-covalent interactions,and Fe-PDANS quenched the fluorescence of FAM through FRET.In the presence of DON,P_(DON)could specifically combine with DON,changing the conformation of P_(DON),making it difficult to adsorb onto Fe-PDANS,and finally enhancing the fluorescence signal of the sensor for the detection of DON.Results:The aptasensor exhibited a linear range from 0.266 7 to 133.3 ng/mL for DON,and the detection limit was 0.118 2 ng/mL.The results of this aptasensor for DON in positive wheat samples were not significantly different (P>0.05) from those obtained by enzyme-linked immunosorbent assay (ELISA).Conclusion:The fluorescent aptasensor is characterized by rapid detection,excellent sensitivity,high specificity and good repeatability,which will provide a new method for the detection of DON in wheat.