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目的应用核酸适体133DNA和N-甲基中卟啉IX(NMM),建立铅离子和放射性惰性气体氡的非标记荧光传感分析新方法。方法以核酸适体133DNA为识别探针,以N-甲基中卟啉IX(NMM)为荧光信使,采集氡辐射稳定的子体铅;用Pb~(2+)离子诱导单链133DNA发生构象转变,形成稳定的G-四链体。G-四链体与NMM键合,导致体系荧光信号敏锐变化,灵敏检测铅和氡。结果 Pb~(2+)离子浓度c_(Pb)为5.0 nmol/L~90 nmol/L时,荧光强度改变量(ΔF)与Pb~(2+)离子浓度之间呈现良好的线性关系,ΔF=1.80c_(Pb)(nmol/L)-2.07,r=0.990 9;氡累积浓度c_(Rn)为2.0×10~4Bq·h/m~3~12.0×10~4Bq·h/m~3时,ΔF值与氡累积浓度之间的数学定量模型为ΔF=7.71c_(Rn)+3.00,r=0.996 5。新方法对铅的检出限为1.67 nmol/L,对氡的检出限为1.19×10~3Bq·h/m~3,低于中国国家标准方法中氡的累积测量的检出限(2.1×10~3Bq·h/m~3)。结论本方法可以灵敏检测铅和氡,K~+离子等干扰小。在氡的采样和检测过程中,避免了辐射危害;氡样品可直接测定,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核酸适体荧光传感检测新领域。
OBJECTIVE: To develop a new method for non-labeled fluorescence sensing analysis of radionuclides with lead ions and radioactive noble gases by using nucleic acid aptamer 133DNA and N-methylporphyrin IX (NMM). Methods Nucleotide aptamer 133 DNA was used as a probe and N-methylporphyrin IX (NMM) was used as a fluorescent messenger to capture radon-stabilized daughter leptin. Pb 2+ ions were used to induce the conformation of single- Transform to form a stable G-quadruplex. G-quadruplex and NMM bond, resulting in a sharp change in fluorescence signal system, sensitive detection of lead and radon. Results When the Pb 2+ ion concentration was 5.0 nmol / L ~ 90 nmol / L, the change of fluorescence intensity (ΔF) showed a good linear relationship with the concentration of Pb 2+ ion. The concentration of ΔF = 1.80c_ (Pb) (nmol / L) -2.07, r = 0.9909; the cumulative concentration of radon is 2.0 × 10 ~ 4Bq · h / m ~ 3 ~ 12.0 × 10 ~ 4Bq · h / m ~ 3 , The mathematical quantitative model between the ΔF value and the cumulative concentration of radon is ΔF = 7.71c_ (Rn) + 3.00 and r = 0.996 5. The new method has a detection limit of 1.67 nmol / L for lead and a detection limit of 1.19 × 10 -3 Bq · h / m 3 for radon, which is lower than the detection limit of cumulative measurement of radon in Chinese national standard method (2.1 × 10 ~ 3Bq · h / m ~ 3). Conclusion The method can sensitively detect lead and radon, K ~ + ions and other small interference. Radon samples are avoided during the sampling and testing process; radon samples can be directly measured, simple to operate and low in cost, thus expanding the new field of nucleic acid aptamer fluorescent sensing detection of nucleic acid aptamers for radioactive materials and gases.