【摘要】 根据纳米金对ss DNA和G-四联体结构的DNA的不同吸附能力,设计了一种简单的Pb2+比色传感器。富含G的无标记ss DNA可以通过静电作用吸附于Au NPs表面,保护Au NPs在高盐浓度溶液中仍呈分散态;当Pb2+存在时,DNA与Pb2+结合形成Pb2+-G-四联体结构,使得Au NPs失去DNA的保护而发生聚集,溶液颜色由红色变成蓝色,最大吸收峰发生红移。通过优化条件,得到溶液吸光度比值(A630/A520)与Pb2+浓度在0.1~10μmol/L范围内呈良好的线性关系,检出限可达50 nmol/L。其他金属离子对Pb2+的检测几乎无干扰。该方法灵敏度高,选择性好,且无需复杂的Au NPs表面修饰过程及DNA标记,制备和操作简便、成本低、响应快(<1 min),非常适合于现场实时应用。更多还原

【Abstract】 A simple colorimetric biosensor based on the different adsorption ability of gold nanoparticles(AuNPs) on single-strand DNA(ssDNA) and G-quartet was presented to determine Pb2 +concentration in water. The guanine-rich ss DNA can be easily adsorbed onto the surface of AuNPs preventing them from aggregation in high ionic strength solution. In the presence of Pb2 +,the conformation of ssDNA was changed from random coil to rigid G-quartet structure which could not bind to Au NPs,leading to the aggregation of Au NPs,accompanied by color changing from red to blue and red shift of the maximum absorption wavelength. Under the optimal conditions,the absorption ratio of A630/ A520 was proportional to Pb2 +concentration in the range of 0. 1-10 μmol/L with a detection limit(3σ) of 50 nmol/L. There were almost no interference from other metal ions. With the advantages of high sensitivity and selectivity,simplicity of preparation and manipulation,lowcost,fast response(within 1 min),the presented method is very suitable for real-time and on-site application in environmental protection.更多还原