基于石墨烯和量子点自组装膜的能量转移构筑的高灵敏度DNA界面荧光传感

以QDs作为荧光探针, HIV1病毒序列DNA为研究对象, 设计了Quartz/PDDA/PSS/PDDA/CdTe/ssDNA自组装膜, 利用氧化石墨烯(GO)猝灭自组装膜上CdTe QDs的荧光, 而靶DNA(tDNA)与自组装膜表面ssDNA的互补配对作用使GO与CdTe QDs的距离增加, 导致自组装膜上量子点的荧光恢复, 由此建立了一种基于GO与QDs自组装膜之间荧光共振能量转移的快速灵敏检测DNA的界面分析方法, 检出限为7.26×10-14 mol/L. 本方法制备的DNA探针操作简单, 自组装膜表面修饰的ssDNA提高了方法的选择性, GO的猝灭作用降低了检测背景, 极大地提高了荧光分析方法的灵敏度.

High Sensitive Interface Fluorescent Sensing for DNA Based on Energy Transfermation Between Graphene and QDs Self-assembly Multilayers

Fluorescent self-assembly multilayers(SAMs) Quartz/PDDA/PSS/PDDA/CdTe/ssDNA,with ssDNA fixed onto the outermost layer were designed.The SAMs were fabricated onto the quartz surface using CdTe quantum dots(QDs) as a fluorescence probe,which can effectively sense biomolecules by fluorescence resonance energy transfer(FRET) from QDs to graphene oxide(GO).GO can quench fluorescence of SAMs.When tDNA was added,upon the strong interaction between ssDNA and tDNA,tDNA was accumulated on the surface of SAMs in place of GO.The distance between the SAMs and GO increased,which significantly hindered the FRET between CdTe and GO.Thus,the fluorescence of CdTe increased with tDNA adding.The constructed ssDNA SAMs could be sensing for tDNA at the solid-liquid interface with extremely high sensitivity.A good linear relationship between the relative fluorescence intensity F/F0 and concentration of tDNA is obtained in the range from 7.00×10-13 to 2.13×10-11 mol/L,the detection limit is 7.26×10-14 mol/L.