School of Public Health, Jilin University, Changchun, 130021, People's Republic of China.
Department of Thyroid Surgery, the First Hospital of Jilin University, Changchun, 130021, People's Republic of China.
Mikrochim Acta. 2022 May 11;189(6):218. doi: 10.1007/s00604-022-05312-7.
A dual-signal photometric/fluorometric assay was established for rapid, qualitative, and quantitative detection of Salmonella typhimurium (S. typhimurium). This method was composed of two parts: (1) a single-step photometric (SSC) assay containing gold nanoparticles (AuNPs), poly-diallyldimethylammonium chloride (PDDA), and S. typhimurium-specific aptamer, and (2) a fluorescence (FL) assay containing carboxyl-modified CdSe/ZnS quantum dots (QDs-). Users just need to drop samples contaminated with S. typhimurium into SSC assay; the apparent color change from red to blue can be observed in a short time (20 min). A smartphone app was developed to read the semiquantitative result. By subsequently adding one drop of FL assay into the reaction mixture, the generated fluorescence intensity reflected the concentration of S. typhimurium. The naked eye limit of detection (LOD) and fluorescent LOD were 10 cfu/mL and 10 cfu/mL, respectively. This method exhibited good selectivity. The reliability and practicability were verified by testing contaminated food, drinking water, and pets' urine.
建立了一种用于快速定性和定量检测鼠伤寒沙门氏菌（S. typhimurium）的双信号比色/荧光测定法。该方法由两部分组成：（1）包含金纳米粒子（AuNPs）、聚二烯丙基二甲基氯化铵（PDDA）和鼠伤寒沙门氏菌特异性适体的单步比色（SSC）测定法；（2）包含羧基修饰的 CdSe/ZnS 量子点（QDs-）的荧光（FL）测定法。用户只需将含有 S. typhimurium 的样品滴入 SSC 测定法中；在短时间（20 分钟）内可以观察到从红色到蓝色的明显颜色变化。开发了一个智能手机应用程序来读取半定量结果。随后向反应混合物中加入一滴 FL 测定法，产生的荧光强度反映了 S. typhimurium 的浓度。肉眼检测限（LOD）和荧光 LOD 分别为 10cfu/mL 和 10cfu/mL。该方法表现出良好的选择性。通过测试污染的食物、饮用水和宠物尿液验证了其可靠性和实用性。
