基于核酸适配体的镉离子可视化检测方法

Aptamer-based colorimetric detection of Cd^(2+)

利用适配体对镉离子的特异性识别作用,以镉离子适配体及互补链为生物识别单元,建立基于核酸适配体的镉离子可视化检测方法,实现对自来水中镉离子痕量检测。该方法将镉离子适配体固定在微孔板上,再与适配体互补链及-辣根过氧化物酶(HRP)复合物进行竞争性结合,通过HRP对底物的催化水解反应引起450nm处特征峰的变化来定量检测镉离子。结果表明:该检测体系在0.1~5.0ng/mL时具有线性关系(R^2=0.995 8),检测限低至0.5ng/mL。该方法选择性良好、操作简单、灵敏度高,并且具有较好的实用性,可用于食品安全分析和环境监测中金属离子镉的检测。

In this study, we presented a simple, rapid and sensitive colorimetric assay for the detection of cadmium （Cd） based on en- zyme linked oligonucleotides. The specific binding of aptamer to Cd2＋ led to the decrease of horseradish peroxidase（HRP） on the mi- crotiter plate, since HRP could not be bind onto through the hybrid- ization of the aptamer and complementary DNA strand. It resulted in the change of characteristic peaks at 450 nm, helping to quantitatively detect Cd-＋. Under the optimal conditions, the detec- tion limit could be as low as 0.05 ng/mL, and the linear response for Cd2＋ in a concentration range from 0.1 to 5 ng/mL（S/N 3）. This method was simple and rapid, resulting in high sensitivity and speci- ficity, and could be used in food safety analysis and environment mo- nitoring.