基于双发射免标记核酸探针的比率型荧光传感器用于银的检测

构建了一种新型免标记的双发射荧光比率核酸探针(GelRed/G40]/Tb^3+)并用于Ag+的检测。对于GelRed/G40]/Tb^3+探针,GelRed作为一种核酸染料嵌入到单链DNA-G40]中,形成的GelRed/G40]作为稳定的内置参照标准,在激发波长290 nm处,发射荧光强度固定不变的红色荧光(发射波长为635 nm),而G40]/Tb^3+作为敏感的响应信号,随着Ag^+浓度的增加,产生的绿色荧光逐渐增强(发射波长为545 nm),G40]/Tb3+与GelRed/G40]发射的荧光强度比值也发生相应的改变,从而实现对Ag^+的定量检测。在优化的实验条件下,G40]/Tb^3+与GelRed/G40]荧光强度比值和Ag^+浓度在0~7.5μmol/L的范围内具有较好的线性关系,Ag^+检出限为0.156μmol/L。本传感器在10 min内就可完成对Ag^+的分析。方法已用于自来水样中Ag^+的检测,与ICP-MS法检测结果一致。

A silver ionratiometric fluorescence sensor by using label-free dual emission DNA probe

A novel method based on label-free dual-emission ratiometric fluorescent probe(GelRed/G40]/Tb^3+)for Ag+detection was presented.For GelRed/G40]/Tb3+probe,the excitation wavelength was set at290 nm,GelRed/G40](GelRed as nucleic acid dye intercalated into the single-stranded DNAG40])acted as a stable build-in reference standard with red emission(emission wavelength at 635 nm),G40]/Tb^3+acted as sensitive response signal with green emission(emission wavelength at 545 nm).The fluorescence intensity ratio ofG40]/Tb^3+and GelRed/G40]can be used to precisely detect the concentration of Ag^+,because Ag+can increased significantly the green fluorescence ofG40]/Tb^3+,where as the inner red fluorescence of GelRed/G40]remained unchangeable.Under the optimum experimental conditions,the ratio of fluorescence intensity increased gradually with Ag^+concentration increasing in the range of 0-7.5μmol/L,exhibiting good linearity.The detection limit of Ag^+was 0.156μmol/L.The detection of Ag^+can be accomplished within 10 min using this ratiometric fluorescence sensor.This detection platform was applied for determination of Ag^+in tap water samples,and the results of this method were in good agreement with that obtained from the inductively couded plasma mass spectrometry.