Establishment and Application of Functional Nucleic Acid Biosensor for Detection of Mercury Ion / 分析化学

ABSTRACT

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 Hg2+. In this study, the method for detection of Hg2+ was developed based on specific T-Hg-T mismatche and G-quadruplex. The template sequence mainly included the recognition region which could combine with Hg2+ 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 Hg2+. Furthermore, the G-rich sequences were stripped off the templates and could form a single-stranded structure, because Spacer 18 had partition function. The G-quadruplex was formed with the K+and hemin, and catalyzed H2 O2-2,2-azinobis (3-ethylbenzothiozoline)-6-sulfonic acid(ABTS) reaction with color variations. The detection could be done within 35 min, and the Hg2+ 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 Hg2+ 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.