Chen Sihan, Zong Xinran, Zheng Jiapeng, Zhang Jiaxin, Zhou Mengyao, Chen Qing, Man Chaoxin, Jiang Yujun
Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China.
Foods. 2021 Oct 22;10(11):2539. doi: 10.3390/foods10112539.
() is a foodborne pathogen that has caused numerous outbreaks worldwide, necessitating the development of on-site strategy to prevent early contamination. Here, we set up an enzyme-free strategy for aptamer-catalyzed hairpin assembly in which salt-induced aggregation of unmodified gold nanoparticles (AuNPs) served as a colorimetric signal output, allowing on-site detection of in milk. The aptamer-functionalized magnetic beads were used as a vehicle of specifically enriching target bacteria which conjugated with target aptamer to trigger the "Y" shape catalytic hairpin assembly (Y-CHA) circuit. Due to the hairpins desorbing from the surface of AuNPs to the formation of a large amount of double-stranded DNA (dsDNA), AuNPs turned from dispersion to aggregation in the presence of , resulting in a change of the colorimetric signal from red to blue-gray. The signal output showed a linear relationship for over a concentration range of 10 to 10 CFU/mL, with a sensitivity of 2.4 × 10 CFU/mL under optimal conditions. The visual protocol has excellent selectivity even in the presence of other competitive bacteria and has been validated in real milk samples with a sensitivity of 2.8 × 10 CFU/mL.
（）是一种食源性病原体，已在全球范围内引发了众多疫情，因此需要制定现场预防早期污染的策略。在此，我们建立了一种用于适体催化发夹组装的无酶策略，其中未修饰的金纳米颗粒（AuNPs）的盐诱导聚集作为比色信号输出，可实现牛奶中（）的现场检测。适体功能化磁珠用作特异性富集目标细菌的载体，该细菌与目标适体结合以触发“Y”形催化发夹组装（Y-CHA）回路。由于发夹从AuNPs表面解吸形成大量双链DNA（dsDNA），在（）存在的情况下，AuNPs从分散状态转变为聚集状态，导致比色信号从红色变为蓝灰色。信号输出在10至10 CFU/mL的浓度范围内与（）呈线性关系，在最佳条件下灵敏度为2.4×10 CFU/mL。该可视化方案即使在存在其他竞争性细菌的情况下也具有出色的选择性，并且已在实际牛奶样品中得到验证，灵敏度为2.8×10 CFU/mL。
