硫磺素T诱导G-四链体核酸适体的氡累积辐射剂量荧光检测新方法

A new fluorescence method for the determination of radon accumulation radiation dose based on G-quadruplex induced by thioflavine T

目的应用核酸适体9-3-35和硫黄素T,建立放射性惰性气体氡的非标记荧光传感分析新方法。方法用硫磺素T诱导富G序列核酸适配体9-3-35形成稳定的G-四链体结构,产生荧光信号,采集氡辐射得到稳定的子体铅,加入Pb^(2+)后导致体系荧光信号敏锐变化,灵敏检测氡。结果 Pb^(2+)离子浓度为1.0 nmol/L^125.0 nmol/L时,荧光强度改变量(ΔF)与Pb^(2+)离子浓度呈现良好的线性关系,ΔF=9.13cPb+163.40,r=0.995 3;氡累积浓度为3.0×104Bq·h/m^3~2.2×105Bq·h/m^3时,ΔF值与氡累积浓度之间的数学定量模型为ΔF=35.59cRn+229.51,r=0.994 0。新方法对铅的检出限为0.312 nmol/L,对氡的检出限为1.87×103Bq·h/m^3,低于国家标准方法中氡的累积测量的检出限(2.1×103Bq·h/m^3)。结论本方法可以灵敏检测氡,在氡的采样和检测过程中避免了辐射危害;可直接测定氡样品,操作简单,成本低廉,拓展了核酸适体对放射性物质和气体的荧光传感检测新领域。

Objective To establish a new label - free fluorescence method for the determination of radioactive inert gas radon by using the aptamer 9 - 3 - 35 and Thioflavine T. Methods Using Thioflavine T induced G rich nuclei acid sequence 9 - 3 - 35 to form stable conformation G - quadruplex structure, which produced fluorescence signal. Collecting stable daughter lead from radon radiation, after the Pb2＋ was added to the system, a sharp fluorescence signal change emerged, then the radon was sensi- tive detected. Results When the concentration of Pb2＋ concentration was within 1.0 nmol/L - 125.0 nmol/L, the fluores- cence intensity change （AF） and Pb2＋ concentration showed a good linear relationship, AF = 9.13Cpb ＋ 163.40, r = 0. 995 3; When the radon concentration was within 3.0 × 104 Bq · h/m3 - 2.2 × 105 Bq ·h/m3 , AF = 35.59CRn ＋ 229.51, r = 0. 994 0. The detection limit of the new method for lead ions was 0.312 nmol/L and that of radon was 1.87 × 103 Bq · h/m3. This method was far below the detection limit for cumulative radon measurement from the Chinese national standard method（2. 1 ×103 Bq ·h/m3 ）. Conclusion This sensitive method can exclude radiation damage in field testing. Furthermore, it expands a new fluorescence sensing detection field of aptamers for radioactive substances and gases.