基于纳米金显色的非标记核酸适配体可视化检测重金属镉的方法研究

Visual detection of cadmium based on aggregation of aptamer-modified gold nanoparticles

目的建立以特异性非标记核酸适配体为识别探针的重金属镉可视化检测方法。方法根据适配体与镉的高亲和力结合特性,利用纳米金溶液在盐诱导下凝聚后引起的颜色变化反应,通过分光光度计检测溶液的吸光度来检测镉离子浓度。通过优化适配体DNA浓度、盐离子浓度和纳米金溶液体积,确定最佳反应条件,建立样品溶液中镉离子浓度与吸光度的线性关系。结果该方法的线性范围和检测限分别是0.14~10 ng/m L和0.14 ng/m L,可以满足痕量检测要求。通过对灌溉水样的加标回收实验证明,检测体系具有很好的实用性和复杂基体适应性。结论利用核酸适配体和纳米金显色实现了镉的痕量可视化检测,该方法是一种简单、快速、灵敏的检测方法,在现场快速检测和高通量分析中都具有很好的应用前景。

Objective To establish a visual, rapid, and sensitive method for the detection of Cd based on aptamer and gold nanoparticles. Methods The concentration of cadmium ion was detected indirect by the value of absorbance according to the color changes caused by salt-induced condensation of gold nanoparticles and the high affinity binding of aptamer with cadmium. By optimizing the concentration of aptamers DNA, salt and gold nanoparticles in solution, the optimal determine conditions and linear relationships between the sample absorbance and concentration of cadmium were established. Results This system achieved a superior linear dynamic range from 0.14 ng/m L to 10 μg/m L and a detection limit as low as 0.14 ng/m L. The aptasensor practicability were tested by real sample of irrigating water spiked with a series of concentration of Cd and the results showed a good tolerance to matrix effect. Conclusion The developed approach is a simple, quick and sensitive detection method for Cd monitoring and offers a great potential for on-site and high-throughput analysis in routine control.