School of Public Health, Jilin University, Changchun, 130021, Jilin, China.
College of Food Engineering, Ludong University, Yantai, 264025, Shandong, China.
Anal Bioanal Chem. 2020 May;412(13):3135-3140. doi: 10.1007/s00216-020-02563-2. Epub 2020 Apr 13.
The authors describe a rapid enzyme-free colorimetric assay for food- and water-borne pathogens by using the multi-functional MnO-doped magnetic ferrite nanoparticles (MCDs-MnO NPs). These nanoparticles not only can recognize, absorb, and separate the analyte from the matrix efficiently but also can directly catalyze the oxidation of TMB into a blue colored product without HO. In the presence of target, the nanoparticles preferentially bind to the target surface and the interaction between nanoparticles and TMB can be blocked, providing turn-off sensing of bacteria. By combining the superior capture efficiency of magnetic beads with the high catalytic activity of the enzyme mimic, the turn-off colorimetric assay can detect the gram-positive bacterium and the gram-negative bacterium by the naked eye at a low detection limit (10 cfu mL) with a wide line arrange from 10 to 10 cfu mL. With the advantage of simplicity, sensitivity, and specificity, this proposed approach showed promise in rapid instrumental and on-site visual detection of bacteria for determination of water contamination. Graphical abstract.
作者描述了一种利用多功能 Mn 掺杂磁性铁氧体纳米粒子（MCDs-MnO NPs）快速进行食源性和水源性病原体酶免比色分析的方法。这些纳米粒子不仅可以有效地识别、吸收和从基质中分离分析物，而且可以在没有 HO 的情况下直接催化 TMB 氧化为蓝色产物。在存在靶标的情况下，纳米粒子优先与靶标表面结合，纳米粒子与 TMB 之间的相互作用可以被阻断，从而提供细菌的关闭感应。通过将磁珠的优异捕获效率与酶模拟物的高催化活性相结合，该关闭比色分析可以通过肉眼在低检测限（10 cfu mL）下检测革兰氏阳性菌和革兰氏阴性菌，检测范围从 10 到 10 cfu mL。该方法具有简单、灵敏和特异性的优点，有望用于快速仪器和现场可视化检测水中的细菌，以确定水污染情况。
