基于G-四链体构象转换免标记荧光法用于Ag^(+)的检测

A label-free fluorescence method based on G-quadruplex conformation switching for Ag^(+)de⁃tection

目的:基于银离子(Ag^(+))介导的G-四链体构象转换策略建立免标记的荧光传感法用于Ag^(+)定量分析。方法:首先,荧光染料吖啶橙嵌入G-四链体后可使其荧光显著增强。其次,当体系加入Ag^(+)后,Ag^(+)可螯合G-四链体中的鸟嘌呤进而抑制G-四链体空间结构形成使得荧光降低。最后,根据荧光强度的变化进行Ag^(+)的定量检测。样品的荧光光谱分析以480 nm为激发波长,检测500~700 nm的荧光发射光谱,并记录最大发射波长525 nm处的荧光强度。结果:本研究设计的荧光传感器对Ag^(+)的检测呈现出较宽的检测线性范围(0.1~2.0μmol/L)和较低的检测限(43.5 nmol/L)。此外,该方法在复杂的实际环境样品回收率分析中取得了满意的结果。结论:本研究构建的Ag^(+)检测方法操作简单,无需任何荧光标记,成本低,分析速度快,选择性好,在环境分析中具有广泛的实际应用前景。

Objective:To develop a label-free fluorescence sensing method for quantitative detection of Ag^(+)based on silver ion(Ag^(+))-mediated G-quadruplex conformation switching strategy.Methods:Firstly,the fluorescent dye acridine orange was embedded into the G-quadruplex,resulting in a significantly enhance fluorescent signal.Secondly,when Ag^(+)was added to the system,Ag^(+)could chelate guanine in G-quadruplex,thus inhibiting the formation of G-quadruplex spatial structure to reduce the fluorescence intensity.Finally,the quantitative detection of Ag^(+)was conducted according to the fluorescence intensity change.The fluorescence emission spectra of the samples were analyzed with 480 nm as the excitation wavelength,the fluorescence emission spectra of 500-700 nm were detected,and the fluorescence intensity at the maximum emission wavelength of 525 nm was recorded.Results:The fluorescence sensor designed in this study had a wide linear range(0.1μmol/L-2.0μmol/L)and a low detection limit(43.5 nmol/L)for the detection of Ag^(+).In addition,this method achieved satisfactory experimental results in the analysis of recovery rates in complex environmental samples.Conclusion:The Ag^(+)detection method developed in this study has the advantages of simple operation,no need for any fluorescent labeling,low cost,fast analysis speed and good selectivity,and has broad prospects for practical applications in environmental analysis.