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 clots(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 CO increased, which significantly hindered the FRET between CdTe and CO. 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/F-0 and concentration of tDNA is obtained in the range from 7.00x 10(-13) to 2.13x10(-11) mol/L, the detection limit is 7.26x10(-14) mol/L.