基于DNA和小沟结合染料DAPI快速检测水样中Hg^(2+)

Rapid Detection of Hg^(2+) in Aqueous Solution Based on DNA and the Minor Groove Binding Dye DAPI

设计了一条DNA序列作为专一识别Hg2+的探针,结合小沟结合染料DAPI,构建了一种新型无标记荧光降低型核酸适体传感器。无Hg2+时DNA折叠成稳定的茎-环结构,DAPI插入茎部位有强荧光发射;Hg2+存在时DNA发生结构转变,DAPI释放荧光降低。结果表明:在最佳实验条件下,体系荧光降低百分数和Hg2+浓度正相关,在较低的浓度范围(0.5~50 nmol/L)仍呈良好的线性关系,实际检出限为0.5 nmol/L。该方法操作简单、对于环境水样中Hg2+的快速实时检测具有潜在的应用前景。

A DNA sequence was designed as a specific probe for Hg2 ＋and a novel label-free fluorescent aptasensor was constructed with the help of the minor groove binding dye DAPI. In the absence of Hg2 ＋,DNA folds into a stable stem- loop structure and DAPI inserts into the stem portion causing strong fluorescence emission, and in the presence of Hg2 ＋,the configuration of DNA produces change and DAPI could release,which results in the decrease of fluorescence. The experiment results showed that the percentage of fluorescence decrease is proportionally correlated with concentration of Hg2 ＋at the optimal experimental conditions,and a good linear relationship was obtained even in the low concentration of 0. 5- 50 nmol / L. The actual detection limit is 0. 5 nmol / L. With the advantages of short detection time and simple operation,the method has a potential application for the rapid real- time detection of Hg2 ＋in environmental water samples.