Separation and detection of E. coli O157:H7 using a SERS-based microfluidic immunosensor
Separation and detection of E. coli O157:H7 using a SERS-based microfluidic immunosensor
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DOI：
10.1007/s00604-022-05187-8
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发表时间：
2022-03-01
影响因子：
5.7
通讯作者：
Lin, Mengshi
中科院分区：
文献类型：
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作者：
Asgari, Sara;Dhital, Rajiv;Lin, Mengshi
建立了一种基于表面增强拉曼光谱（SERS）的微流控免疫传感器，用于分离和检测生菜中的大肠杆菌O 157：H7。Sers纳米探针，含有金纳米粒子和针对E。coliO 157：H7，选择性地将其锚在E. coli O 157：H7细胞，并从生菜样品中分离它们。然后使用拉曼光谱仪在类似于35 mW的785 nm激发激光下在流体动力学流动聚焦微流体装置内检测分离的细胞。在不到60 min的富集后，成功检测到100、10、1和0.5 CFU .mL（-1）的细菌浓度。E.大肠杆菌O 157：H7在生菜中的检出率为0.5CFU·mL（-1），验证了该方法对食品中致病菌检测的灵敏度。E的标准曲线线性良好（R-2 > 0.93）。coliO 157：H7富集30 min后，可观察到明显的噬菌斑。该方法将单细胞检测的分析时间缩短到仅1小时，这比传统方法所需的天数明显缩短。总之，将流体动力学流动聚焦微流体装置与Sers纳米探针相结合，为检测复杂食品样品中的各种病原体提供了可靠、选择性和灵敏的方法。
A sensitive SERS-based microfluidic immunosensor was developed to separate and detect Escherichia coli O157:H7 in romaine lettuce. SERS nanoprobes, containing gold nanoparticles and specific antibodies against E. coli O157:H7, were used to selectively anchor onto the E. coli O157:H7 cells and separate them from lettuce samples. Separated cells were then detected within a hydrodynamic flow-focusing microfluidic device using the Raman spectroscope with an excitation laser of 785 nm at similar to 35 mW. Bacterial concentrations of 100, 10, 1, and 0.5 CFU .mL(-1) were successfully detected after less than 60 min of enrichment. The limit of detection of E. coli O157:H7 in romaine lettuce was found to be 0.5 CFU.mL(-1), verifying the sensitivity of our protocol for detection of pathogens in food samples. High linearity (R-2 > 0.93) in the calibration curves for E. coli O157:H7 was observed after 30 min of enrichment. The method reduced the analysis time for single-cell detection to only 1 h, which is significantly shorter than the days required in conventional methods. In summary, combining the hydrodynamic flow-focusing microfluidic device with SERS nanoprobes provides a reliable, selective, and sensitive approach for the detection of various pathogens in complex food samples.