Key Laboratory of Agricultural Information Acquisition Technology, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, 100083, China.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
Biosens Bioelectron. 2021 Apr 15;178:113020. doi: 10.1016/j.bios.2021.113020. Epub 2021 Jan 21.
Rapid screening of pathogenic bacteria contaminated foods is crucial to prevent food poisoning. However, available methods for bacterial detection are still not ready for in-field screening because culture is time-consuming; PCR requires complex DNA extraction and ELISA lacks sensitivity. In this study, a microfluidic biosensor was developed for rapid, sensitive and automatic detection of Salmonella using metal-organic framework (MOF) NH-MIL-101(Fe) with mimic peroxidase activity to amplify biological signal and Raspberry Pi with self-developed App to analyze color image. First, the target bacteria were separated and concentrated with the immune magnetic nanobeads (MNBs), and labeled with the immune MOFs to form MNB-Salmonella-MOF complexes. Then, the complexes were used to catalyze colorless o-phenylenediamine and HO to produce yellow 2,3-diaminophenazine (DAP). Finally, the image of the catalysate was collected under the narrow-band blue light and analyzed using the Raspberry Pi App to determine the bacterial concentration. The experimental results showed that this biosensor was able to detect Salmonella Typhimurium from 1.5 × 10 to 1.5 × 10 CFU/mL in 1 h with the lower detection limit of 14 CFU/mL. The mean recovery for Salmonella in spiked chicken meats was ~112%. This biosensor integrating mixing, separation, labelling and detection onto a single microfluidic chip has demonstrated the merits of automatic operation, fast reaction, less reagent and small size, and is promising for in-field detection of foodborne bacteria.
快速筛选污染食品的致病菌对于预防食物中毒至关重要。然而，现有的细菌检测方法仍然不适用于现场筛选，因为培养法耗时较长；PCR 需要复杂的 DNA 提取，ELISA 则缺乏灵敏度。在本研究中，我们开发了一种基于金属有机框架（MOF）NH-MIL-101(Fe)模拟过氧化物酶活性的微流控生物传感器，用于快速、灵敏和自动检测沙门氏菌。该传感器利用 MOF 对生物信号进行放大，并用 Raspberry Pi 及其自主开发的 App 分析彩色图像。首先，用免疫磁性纳米珠（MNBs）分离和浓缩目标细菌，并将其与免疫 MOF 标记形成 MNB-沙门氏菌-MOF 复合物。然后，复合物用于催化无色邻苯二胺和 HO 生成黄色 2,3-二氨基吩嗪（DAP）。最后，在窄带蓝光下收集催化产物的图像，并使用 Raspberry Pi App 进行分析，以确定细菌浓度。实验结果表明，该生物传感器能够在 1 小时内检测到 1.5×10 至 1.5×10 CFU/mL 的鼠伤寒沙门氏菌，检测下限为 14 CFU/mL。鸡肉中添加沙门氏菌的平均回收率约为 112%。这种将混合、分离、标记和检测集成到单个微流控芯片上的生物传感器具有自动操作、快速反应、试剂用量少和体积小的优点，有望用于现场检测食源性细菌。
