The Technology For Detecting Heavy Metals Based On The Functional Nucleic Acids

At present, we are of great short of water resources, the contamination of water resourceis not optimistic, either. According to the survey,1/5water source is of under standard qualityand half of the urban underground water is seriously contaminated which lead to more andmore restricted water source using in some northern cities which mainly live on undergroundwater. While recently, the heavy metal contamination is becoming a globalizingenvironmental problem which has seriously threatened the humanity healthy and environmentsafty. Since2006, there is many heavy metal pollution event occurred in our country leadingseveral thousand people’s healthy seriously affected. The heavy metal pollution is highlytoxicity, low toxic does, easy to accumulate, hard to refractory and control. Therefore, it is thefocus point of environment monitoring and abatement.The usual detecting methods are ICP-MS, AAS and AFS. All of these methods needlarge-scale instrument and equipment, they have to be operated indoor with specialized people,and they cannot respond rapidly for the emergencies. Lately, the Molecular Biology developsrapidly, providing the new technology for the heavy metal detection which sensitivelyresponded and easily tested and has become the new favourte of detecting heavy matels. Thispapper aims at constructing the optics sensor with the signal of FAM and SYBR Greendetecting Ag+and Hg2+. The main contents are as the follows:Firstly, Where there is Ag+/Hg2+which can combine with Cytosine-Cytosin(C-C)/Thymine-Thymine (T-T) specificly producting double strand DNA (dsDNA) withC-Ag+-C/T-Hg2+-T stablely. Accordingly, we have known that the new nano materialGraphene Oxide is differently approaching the ssDNA and dsDNA, it can quenching thefluorescence of ssDNA. As the Ag+reacting with the aptamer forming the dsDNA structure,the testing fluorescence intensity grows stronger. With the optimal conditions, the systermexhibits a dynamic response range for Ag+from150nM to400nM with detection limit of23nM. This method can be used for fast and sensicitive detection for Ag+.Sceondly, according to the compound T-Hg2+-T produced, this papper employed theC-rich ssDNA as a recgnise probe and SYBR Green as a pointing probe, contructed a sensorfor detecting Ag+and Hg2+sensitively. As the concentration of Ag+/Hg2+increases, they reactwith the C-C/T-T forming the dsDNA structure, making SYBR Green inserting into dsDNAstructure and the flouresence grow stronger, too. We can realize the detection for Ag+andHg2+with fluorospectro photometer. The systerm exhibits a dynamic response range for Ag+and Hg2+from100nM to500nM and5nM to100nM, with detection limit of16nM and 0.68nM. This method is operated easily, sensitively and selectively, it can be used for fast andsensicitive detection for Ag+and Hg2+.