CdTe纳米荧光探针的合成及其与DNA的相互作用

Synthesis of functional CdTe nanofluorescent probe and the interaction between it and the deoxyribonucleic acids

以巯基丙酸（RSH）为稳定剂，采用水相法合成了功能性CdTe纳米晶，并通过X射线衍射（XRD）和透射电镜（TEM）对其粒度和形貌进行表征。建立了一种以水溶性CdTe量子点作为荧光探针测定DNA的方法，当DNA浓度为0．2—40μmol·dm^3时，荧光强度与DNA浓度呈良好的线性关系，检测限为80nmol·dm^-3，11次重复测定含有5．6gmol·dm^-3的小牛胸ctDNA得到的相对标准偏差为3．4％。考察了CdTe量子点浓度、pH值、温度及作用时间等因素对DNA荧光强度的影响。研究发现CdTe纳米粒子与DNA之间存在强烈的相互作用，量子点的荧光猝灭与DNA浓度呈线性关系；作用机理研究表明，CdTe纳米粒子与DNA之间存在静电相互作用，且DNA对CdTe纳米粒子的猝灭为动态猝灭过程。

Functional CdTe nanocrystals were synthesized by a wet chemical method with mercaptopropionic acid （RSH） as stabilizer. The morphology and structure of nanocrystal were characterized by XRD and TEM. The CdTe nanocrystal was used as nanofluroscent probe to determine the contents of DNA. When the concentration of DNA in the range of 0.2 - 40 μmol·dm^3 , there is a nicer linear relationship between fluorescence intensity and concentration of DNA with the limit of detection of 80 nmol. dm^-3. The interaction between CdTe nanofluorescence probe and DNA was investigated in Tris-HCl （ pH = 7.4） by spectra method. The effects of pH, particle concentration, temperature and time were studied in this paper. The results indicated a strong interaction between CdTe nanocrystal and DNA. Further researches on the mechanism of action showed that the interaction between CdTe and DNA was electrostatic action and the quenching of DNA to CdTe was a dynamic quenching process.