State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin, 300457, China.
Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, 300071, China.
Anal Bioanal Chem. 2020 Jan;412(3):611-620. doi: 10.1007/s00216-019-02208-z. Epub 2020 Jan 3.
Infections caused by foodborne microorganisms are a great threat to the global environment and public healthcare today. Thus, rapid, portable and sensitive assays that can realize the identification of foodborne bacteria are highly desired. In this study, a smart fluorescent and colorimetric dual-readout sensing system has been established for simple and rapid E. coli determination by utilizing the Cu-triggered oxidation of o-phenylenediamine (OPD). Initially, Cu can oxidize OPD to OPDox, resulting in an orange-yellow fluorescence and visible pale-yellow color. However, E. coli can effectively reduce Cu into Cu, inhibiting the Cu-triggered oxidation of OPD to OPDox. Consequently, the introduction of E. coli can turn off both the fluorescence and the UV-vis absorbance signals of the OPD-Cu system, illustrating an original mechanism for fluorescent and colorimetric dual-channel detection of E. coli. Moreover, a filter paper-based visual sensor was built and coupled with OPD-Cu solution under the assistance of a UV lamp. The as-prepared sensor can detect E. coli quantitatively with the help of a typical smartphone color-scanning application (APP). Thus, this study offers a valid dual-mode assay for sensitive and on-site visible detection of E. coli, guaranteeing the reliability of the results and is more attractive for practical use. Graphical Abstract Schematic illustration of the smartphone-integrated sensing system for fluorescent and colorimetric dual-channel detection of E. coli based on the Cu-OPD system.
食源性病原体感染对全球环境和公共卫生健康构成了严重威胁。因此，人们迫切需要开发快速、便携且灵敏的方法来检测食源性病原体。本研究利用邻苯二胺（OPD）与 Cu 的氧化还原反应，建立了一种智能型荧光和比色双读值传感体系，用于简单快速地检测大肠杆菌。在该体系中，Cu 可以将 OPD 氧化为 OPDox，从而产生橙色荧光和浅黄色颜色。然而，大肠杆菌可以有效地将 Cu 还原为 Cu，从而抑制 OPD 的 Cu 引发氧化反应。因此，大肠杆菌的引入可以同时关闭 OPD-Cu 体系的荧光和紫外可见吸收信号，提供了一种用于大肠杆菌荧光和比色双通道检测的原始机制。此外，本研究还构建了基于滤纸的可视化传感器，并在紫外灯的辅助下与 OPD-Cu 溶液结合。借助典型的智能手机彩色扫描应用程序（APP），该制备的传感器可以实现对大肠杆菌的定量检测。因此，该研究为大肠杆菌的灵敏、现场可见检测提供了一种有效的双模式分析方法，保证了结果的可靠性，更具实际应用价值。
