基于核酸适配体的比色传感策略用于牛奶中沙门氏菌的快速检测

以鼠伤寒沙门氏菌作为研究模式菌，开发一种基于核酸适配体的可用于食品安全检测的可视化生物传感器。当待测分析物中有鼠伤寒沙门氏菌时，适配体与鼠伤寒沙门氏菌发生特异性结合，释放出的捕获探针吸附在纳米金表面避免其在后续盐诱导作用下发生聚集；当待测分析物中不含鼠伤寒沙门氏菌时，纳米金粒子在盐的诱导下发生团聚，通过裸眼观察溶液的颜色变化来实现对沙门氏菌的快速、便捷检测。对该方法的可行性、检测性能以及特异性进行表征，结果表明该适配体传感器对浓度为10～109 CFU/mL范围内的鼠伤寒沙门氏菌有良好的响应性能，线性方程为y=－0.129 98x＋1.244 11（R2=0.992 62），检出限可达124 CFU/mL，同时也具备良好检测特异性。该方法检测灵敏度高、操作简便、快速、且成本低，在食品安全的现场快速检测应用中具有良好应用前景。

Rapid Visual Detection of Salmonella typhimurium Using a Colormetric Aptamer Sensor Based on Gold Nanoparticles

An aptamer sensor (aptasensor) based on gold nanoparticles (AuNPs) was developed for the rapid visual detection of Salmonella typhimurium in foods. The aptamer specifically bound to S. typhimurium in samples to be analyzed, and a capturing probe that could adsorb onto the surface of AuNPs was released, avoiding subsequent aggregation of AuNPs induced by salts. In the absence of S. typhimurium, salts induced the aggregation of AuNPs, leading to color changes visible to the naked eye in the solution, thus allowing for the rapid and simple detection of S. typhimurium. The feasibility, detection performance, and specificity of the developed aptasensor were characterized. The aptasensor had a good response performance to S. typhimurium in the range of 10–109 CFU/mL. A linear regression model equation was fitted as follows: y = ?0.129 98x + 1.244 11 (R2 = 0.992 62), and the detection limit was as low as 124 CFU/mL. Four kinds of non-target bacteria were detected by this aptasensor with good specificity. Because of its high sensitivity, simple operation, rapidity and low cost, it holds great promise for rapid and in situ food safety detection.