基于封闭链释放型磁性DNA分子机器的化学发光传感体系

A magnetic DNA nanomachine enable unload of blocker DNA for chemiluminescence sensing

以核酸外切酶Ⅲ(EXOⅢ)作为驱动力,构建了一种卸载封闭链激活DNAzyme的磁性DNA分子机器,用于化学发光传感分析。将含有富G序列的DNA固定在磁性微球上,并用封闭链封闭富G片段,当有目标DNA存在时,在EXOⅢ的作用下,目标DNA可以循环地将封闭链从磁性微球上卸载,使磁性微球表面生成G-四链体DNAzyme,催化产生化学发光,定量检测目标DNA。该DNA分子机器仅需30 min便可完成循环过程。通过紫外吸收、分子荧光、化学发光、聚丙烯酰胺凝胶电泳等方法验证了DNA分子机器的工作原理。最佳条件下,该分子机器检测DNA的线性范围为10~200 pmol/L,检出限3.2 pmol/L。该磁性DNA分子机器在低丰度DNA检测中具有良好的应用前景。

A magnetic DNA molecular machine that can unload the blocker DNA to activate DNAzyme was developed for chemiluminescence(CL)sensing assays.The G-rich DNA was immobilized on the magnetic microspheres,and blocked with the blocker DNA.When the target DNA was present,it could catalytically unload the blocker to activate G-quadruplex DNAzyme on the surface of magnetic microspheres via driving by EXOⅢ.Then the activated DNAzyme catalyzed the CL reaction between luminol and H2O2.The experiments demonstrated that the DNA walker can complete the entire cycle in 30 min.Additionally,the working principle of DNA walker was verified by UV spectra,fluorescence,CL,polyacrylamide gel electrophoresis.Under the optimal conditions,the linearity for detection of target DNA was in the range of 10-200 pmol/L,and the detection limit was calculated to be 3.2 pmol/L.The DNA nanomachine will be promising for detection of low abundance DNA.