Synthesis And Property Research Of DNA-guided Quantum Dots/graphene Oxide Composite

Graphene oxide?GO?,as an important derivative of Graphene?GR?,has the 2D carbon nanostructure and abundant reactive oxygen-containing groups,so graphene oxide-based composites have attracted tremendous attention in electronics,solar cell and sensor due to its outstanding properties.However,the synthesis of QDs/GO in a facile route for us still remains a challenge.In this paper,a facile and universal route to synthesis DNA-Guided II-VI QDs/GO nanostructure was designed,and DNA-CdTe QDs/GO was used to develop a sensitive sensor using for detecting ascorbic acid.My work provided a new method for the synthesis and application of II-VI QDs/GO composites.The mainly research is as follows:?1?Based on?–?stacking between DNA and GO,a facile,novel and universal route for the preparation of II-VI QDs/GO composite was reported.The synthetic route resulted from the structural modification in phosophodiester backbone of DNA.Compared with the oxygen element,phosphorothioates?ps?as the sulphur-containing variants of the usual phosophodiester backbone,exhibited a higher preference for Cd²⁺in DNA,so that it served as ligand for the growth of quantum dots,which would guide the programmed and in situ growth of QDs after ssDNA adsorbed on surface of GO.The best reaction conditions were found by optimizing reaction time,reaction pH and precursor concentration.The stable QDs/GO was successfully synthesized,including CdS,CdSe,CdTe and CdTeSe QDs under simple environmental,time-saving and universal conditions,which would provide a new direction for the synthesis of QDs/GO composites.?2?Based on electronic transfer between ascorbic acid and DNA-CdTe QDs/GO,resulting in the PL quench of DNA-CdTe QDs/GO,a novel sensor for the detection of ascorbic acid was fabricated.In this sensing system,the PL intensity of DNA-CdTe QDs/GO evolved with ascorbic acid concentration and showed a good linear relationship with a correlation coefficient of 0.9996.The sensor displayed a wide range of linear response and low detection limitation.Meanwhile,it showed a highly selective and stability to ascorbic acid over the potential interferences.This technique further promoted the applications of QDs/GO nanostructure in analysis fields.