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基于Pb~(2+)与凝血酶适配体(Thrombin Aptamer,TBA)特异性结合,以及结晶紫(CV)与凝血酶适配体、G-四链体结合后荧光信号的差异,建立了一种简单、灵敏、无需标记检测Pb2+的DNA生物传感器。实验研究了不同浓度的Pb~(2+)引起CV/TBA体系荧光强度变化的规律,考察了DNA序列、TBA与CV浓度比,以及稳定时间等因素对检测灵敏度的影响。实验结果表明:大多数金属离子无明显干扰,在最优实验条件下,Pb~(2+)浓度在5~50nmol/L范围内与体系荧光强度的变化呈良好的线性关系(r=0.9984),检测限(S/N=3)为2.0×10~(-9) mol/L。
Based on the specific binding between Pb 2+ and Thrombin aptamer (TBA) and the difference of fluorescence signals between crystal violet (CV) and thrombin aptamer and G-quadruplex, a A simple, sensitive DNA biosensor that does not require labeled detection of Pb2 +. The changes of fluorescence intensity of CV / TBA system induced by different concentrations of Pb 2+ were studied experimentally. The effects of DNA sequence, concentration ratio of TBA to CV, and stabilization time on the detection sensitivity were investigated. The experimental results show that most of the metal ions have no obvious interference. Under the optimal experimental conditions, there is a good linear relationship between the fluorescence intensity and the concentration of Pb 2+ in the range of 5 ~ 50 nmol / L (r = 0.9984) , The detection limit (S / N = 3) was 2.0 × 10 -9 mol / L.