基于核酸适配体探针快速检测鼠伤寒沙门氏菌

Rapid Detection of Salmonella Typhimurium Based on Aptamer

以核酸适配体为特异性识别元件,利用金纳米粒子变色效应,对鼠伤寒沙门氏菌进行比色法检测。采用柠檬酸三钠还原法制备金纳米粒子,通过优化氯化钠浓度、核酸适配体浓度,建立核酸适配体比色法进行鼠伤寒沙门氏菌的定量检测。体系最优条件下各种浓度为:氯化钠浓度0.2 mol/L,核酸适配体浓度0.15 mmol/L。在最优条件下,线性范围2.9×10^(3)~2.9×10^(7) cfu/mL内,鼠伤寒沙门氏菌浓度与金纳米粒子在650 nm和525 nm波长吸光度比值(A_(650/525))呈现良好的线性关系,线性方程为Y=0.0233lgX+1.0149(R2=0.9916),检测限为2.9×10^(2) cfu/mL,15 min完成检测;对实际样品做加标回收实验,回收率为90.51%~109.97%。核酸适配体比色法对鼠伤寒沙门氏菌检测具有快速准确、操作简单、可视化等优点,为鼠伤寒沙门氏菌监测提供了新的方法。

In this study,a colorimetric probe was devised and synthesized by coupling an aptamer,which acts as a specific recognition unit,the gold nanoparticles was used as a signal unit for the detection of Salmonella typhimurium.Gold nanoparticles were prepared by sodium citrate reduction method,and an aptamer colorimetry was established by optimizing the concentration of sodium chloride and nucleic acid aptamers.Qualitative and quantitative analysis was carried out according to color change and UVvisible spectrophotometer.Under the optimized conditions,the A_(650/525) ratio of AuNPs had a good linear relationship with the logarithm of Salmonella typhimurium concentration in the range of 2.9×10^(3)~2.9×10^(7) cfu/mL,which was fitted as follows:Y=0.0233lgX+1.0149(R=0.9916).The detection limit was 2.9×10^(2) cfu/mL.The detection time was 15 min.The average recoveries for samples were 90.51%~109.97%.The aptamer colorimetry detection method has the advantages of rapid and accurate detection of Salmonella typhimurium,simple operation and visual inspection,providing a new method for food safety monitoring.