汞离子功能核酸生物传感器的建立与应用

Establishment and Application of Functional Nucleic Acid Biosensor for Detection of Mercury Ion

利用汞离子(Hg^(2+))特异性功能核酸对Hg^(2+)识别检测,其中模板主要包括与Hg^(2+)特异性结合的识别区、形成G四链体的富G区以及由聚六乙二醇(Spacer18)链接的隔断区;靶序列主要包括5'端配对区和3'端富T区。模板与靶序列只有在Hg^(2+)存在的条件下才能结合并引发延伸,进而使富G序列在模板上剥离下来,但由于Spacer18的隔断作用导致富G序列以单链形式存在,在特定环境下形成具有过氧化物模拟酶活性的G-四链体,催化H_2O_2与2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二胺盐(ABTS)发生肉眼可见的颜色变化,进而对Hg^(2+)进行定量测定。利用构建的Hg^(2+)功能核酸生物传感器,35 min内可完成检测,线性范围为20~500 nmol/L,检出限达到16.5 nmol/L(3σ)。实际水样中的加标回收率为98.5%~103.5%。本方法操作简单、成本低、耗时短,在应急处理、实时环境检测等方面具有良好的应用价值。

Excessive mercury ions have negative effects on individual health.So,it is of great significance to develop a method for rapid,sensitive and specific detection of Hg^（2＋）.In this study,the method for detection of Hg^（2＋）was developed based on specific T-Hg-T mismatche and G-quadruplex.The template sequence mainly included the recognition region which could combine with Hg^（2＋）specifically,the rich G region which could form G-quadruplex,and the speacer 18 partition zone.The target sequence mainly included 5＇ends combining area and 3＇end T-rich region.Templates and targets could be combined and the elongation was triggered only in the presence of Hg^（2＋）.Furthermore,the G-rich sequences were stripped off the templates and could form a singlestranded structure,because Spacer 18 had partition function.The G-quadruplex was formed with the K~＋and hemin,and catalyzed H_2O_2-2,2-azinobis（3-ethylbenzothiozoline）-6-sulfonic acid（ABTS）reaction with color variations.The detection could be done within 35 min,and the Hg^（2＋）concentration exhibited a linear correlation with absorbance at 414 nm within range of 20-500 nmol/L,with a detection limit of 16.5 nmol/L（3σ）.The recoveries of Hg^（2＋）spiked in tap water were 98.5%-103.5%.The method exhibited the advantages such as simple operation,low cost and short time,and operation value in emergency treatment and real-time environmental detection.