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提出了一种可用于Hg2+快速检测的基于磁纳米颗粒与二段对称分裂式G-四分体DNA酶的生物传感器.分别用紫外-可见光谱法,圆二色光谱法和荧光显微镜成像技术对实验设计的DNA酶传感器进行了表征.传感器中磁纳米颗粒的应用不仅可以直接从水样中通过磁分离方法分离和富集被测物Hg2+,并且还能将游离的未与Hg2+结合的DNA酶和hemin等除去,有效地提高检测灵敏度和降低背景信号;此外,二段对称分裂式G-四分体DNA酶的运用还可增强传感器的灵活性和选择性.传感器对Hg2+检测的线性范围为0.8~20 nmol/L,检出限为0.3 nmol/L.当水体中的共存离子大量存在时,传感器对Hg2+的检测仍具有高度特异性.对实际水样的检测回收率在95.3%~104.4%之间.实验设计的DNA酶传感器操作简便,费用低廉,具有良好的再生能力.可用于天然水体和饮用水样品中痕量Hg2+的检测.
A biosensor based on magnetic nanoparticles and two-stage symmetrical cleavage G-tetrad DNAzyme was proposed for rapid detection of Hg2 +. The biosensors were characterized by UV-Vis spectroscopy, circular dichroism spectroscopy and fluorescence microscopy The experimental design of DNAzyme sensor was characterized.The application of magnetic nanoparticles in the sensor not only directly separated from the water sample by magnetic separation method and enrichment of the test substance Hg2 +, but also can be free and not with Hg2 + DNase And hemin and other removal, effectively improve the detection sensitivity and reduce the background signal; In addition, the use of two-stage symmetrical split G-quartile DNase can enhance the flexibility and selectivity of the sensor.The linear range of the sensor for the detection of Hg2 + 0.8 ~ 20 nmol / L and the detection limit was 0.3 nmol / L. The detection of Hg2 + was still highly specific by the sensor when a large amount of coexisting ions were present in the water, and the detection recoveries for the actual water samples ranged from 95.3% to 104.4 % .The experimental design of DNA enzyme sensor is simple, inexpensive, and has good reproducibility.It can be used for the detection of trace Hg2 + in natural water and drinking water samples.