In this study, a sensitive immunoassay using immunomagnetic nanobeads (MNBs), manganese dioxide nanoflowers (MnO₂ NFs) and quantum dots (QDs) was developed for simultaneous detection of E. coli O157: H7 and Salmonella typhimurium. MnO₂ NFs were synthesized, functionalized and incubated with QDs to obtain QDs@MnO₂ nanocomposites, followed by modification with antibodies (pAbs) to obtain pAb-QDs@MnO₂ 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 MnO₂ to Mn²⁺. 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 × 10¹ to 1.5 × 10⁶ CFU/mL with detection limit of 15 CFU/mL and Salmonella from 4.0 × 10¹ to 4.0 × 10⁶ 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，开发了使用免疫磁性纳米珠（MNB），二氧化锰纳米花（MnO ₂ NFs）和量子点（QDs）的灵敏免疫测定法，用于同时检测大肠杆菌O157：H7和鼠伤寒沙门氏菌。合成MnO ₂ NFs，将其功能化并与QDs孵育以获得QDs @ MnO ₂纳米复合材料，然后用抗体（pAbs）修饰以获得pAb-QDs @ MnO ₂纳米复合材料（QM NCs）。首先将目标细菌与MNB和QM NC偶联，以形成MNB-细菌-QM复合物。然后，使用谷胱甘肽从复合物中快速释放QD，以将MnO ₂还原为Mn ²⁺。最后，通过光学检测器测量特征波长下的荧光强度，以确定目标细菌。该免疫测定可同时定量检测1.5×10 ¹至1.5×10 ⁶  CFU / mL的大肠杆菌（检出限为15 CFU / mL）和沙门氏菌4.0×10 ¹至4.0×10 ⁶  CFU / mL的检出限。 2小时内达到40 CFU / mL。加标鸡肉样品中两种细菌的​​平均回收率约为96％。