核酸适体和胶体金检测皮质醇含量的方法与应用

目的通过指数富集配体系统进化（SELEX）技术获得皮质醇特异性核酸适体，应用核酸适体和胶体金建立一种灵敏的定量检测皮质醇含量的方法。方法采用柠檬酸钠还原法和硼氢化钠还原法制备胶体金，用核酸适体、胶体金聚集显色法检测皮质醇含量。结果相比20nm胶体金，采用5nm和13nm胶体金颗粒具有较好的灵敏度、重复性和线性范围，5nm胶体金颗粒用于皮质醇的检测的线性范围为10．1～320μmol／L，标准曲线相关系数r为0．9993，其重复性较好，标准差小于平均值10％。结论本实验建立了一种高灵敏性的能特异性地检测皮质醇标准品含量的方法。

Cortisol tested based on aptamers and colloidal gold

Objective To obtain and identify aptamers which can specifically bind to cortisol by systematic evolution of ligands by exponential enrichment （SELEX） protocol, and to establish a sensitive method of quantitative detection of corti- sol levels by using aptamers and colloidal gold. Methods Colloidal gold was prepared by sodium citrate reduction and so- dium borohydride reduction method. Cortisol levels were measured using the aptamer and colloidal gold aggregation chromo- genic method. Results Compared to 20 nm colloidal gold particles, five and 13 nm colloidal gold particles were of good sensitivity, reproducibility and linear range. Using 5 nm colloidal gold particles, the linear range of detection of cortisol was 10.1 - 320 μmol/L, the linear correlation coefficient r = 0.9993. The standard deviation was less than 10% of the average with good reproducibility. This method is currently suitable for the detection of cortisol standard. Conclusion This experi- ment establishes a highly sensitive specific detection method of cortisol.