非标记脱氧核酶构象改变荧光法检测铀酰离子

Spectrofluorimetry determination of UO_2^(2+) based on an unlabelled deoxyribozymes conformational switching

在p H 5.5 MES缓冲溶液中,当体系中不存在铀酰离子时,SYBR GreenⅠ(SG)能通过嵌入和小沟结合方式与脱氧核酶作用,导致荧光增强;当铀酰离子存在时,脱氧核酶的r A碱基处断裂,游离出单链,此时SG与单链DNA作用减弱,荧光信号降低,且体系的荧光强度变化值与铀酰离子浓度在1.73×10-9~4.40×10-8mol/L范围内呈良好线性关系,线性回归方程为ΔF=108.99C(×10-8mol/L)+79.22,相关系数r=0.990。根据空白管的标准偏差Sb和标准曲线的斜率k算出LOD为5.2×10-10mol/L。该方法简便、选择性好、灵敏度高。

In MES buffer solution of p H 5. 5,SG can interact with uranyl specific deoxyribozymes through both intercalation and minor groove binding,resulting in fluorescence enhancement in the absence of UO22 ＋. The presence of UO22 ＋causes catalytic cleavage of the DNA substrate strand at the r A position and release of the ss DNA. This leads to the reduction of the interaction of ss DNA with SG,causing a decrease of the fluorescence intensity of the assay system. The decreased fluorescence intensity was proportional to the concentration of uranyl over the range of 1. 73 × 10- 9～ 4. 40 × 10- 8mol / L,and the linear regression equation was ΔF = 108. 99C（ × 10- 8mol / L） ＋ 79. 22 with a correlation coefficient of 0. 990.The limit of detection（ LOD） was 5. 2 × 10- 10 mol / L. The proposed method was simple,selective and sensitive.