Key Laboratory of Agricultural Information Acquisition Technology, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing 100083, China.
Key Laboratory of Modern Precision Agriculture System Integration Research, Ministry of Education, China Agricultural University, Beijing, China.
Food Chem. 2020 Aug 30;322:126719. doi: 10.1016/j.foodchem.2020.126719. Epub 2020 Mar 31.
In this study, a sensitive immunoassay using immunomagnetic nanobeads (MNBs), manganese dioxide nanoflowers (MnO NFs) and quantum dots (QDs) was developed for simultaneous detection of E. coli O157: H7 and Salmonella typhimurium. MnO NFs were synthesized, functionalized and incubated with QDs to obtain QDs@MnO nanocomposites, followed by modification with antibodies (pAbs) to obtain pAb-QDs@MnO nanocomposites (QM NCs). Target bacteria were first conjugated with MNBs and QM NCs to form MNB-bacteria-QM complexes. Then, QDs were quickly released from the complexes using glutathione to reduce MnO to Mn. Finally, fluorescent intensity at characteristic wavelength was measured by optical detector to determine target bacteria. This immunoassay could simultaneously and quantitatively detect E. coli from 1.5 × 10 to 1.5 × 10 CFU/mL with detection limit of 15 CFU/mL and Salmonella from 4.0 × 10 to 4.0 × 10 CFU/mL with detection limit of 40 CFU/mL in 2 h. The mean recovery for both bacteria in spiked chicken samples was ∼96%.
在这项研究中，开发了一种使用免疫磁纳米珠（MNBs）、二氧化锰纳米花（MnO NFs）和量子点（QDs）的敏感免疫分析方法，用于同时检测大肠杆菌 O157：H7 和鼠伤寒沙门氏菌。合成、功能化和孵育 MnO NFs 以获得 QDs@MnO 纳米复合材料，然后用抗体（pAb）修饰以获得 pAb-QDs@MnO 纳米复合材料（QM NCs）。目标细菌首先与 MNBs 和 QM NCs 缀合以形成 MNB-细菌-QM 复合物。然后，使用谷胱甘肽将 MnO 快速还原为 Mn，从复合物中释放出 QDs。最后，通过光学检测器测量特征波长处的荧光强度来确定目标细菌。该免疫分析方法可以同时定量检测 1.5×10 至 1.5×10 CFU/mL 的大肠杆菌，检测限为 15 CFU/mL，在 2 小时内可以检测 4.0×10 至 4.0×10 CFU/mL 的沙门氏菌，检测限为 40 CFU/mL。在添加的鸡样中的两种细菌的平均回收率约为 96%。
