Key Lab of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, China, 150030.
Key Lab of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, China, 150030.
J Dairy Sci. 2020 Sep;103(9):7879-7889. doi: 10.3168/jds.2020-18344. Epub 2020 Jun 26.
Escherichia coli O157:H7 is an extremely serious foodborne pathogen accounting for a vast number of hospitalizations. In this system, a simple, rapid, and safe compound method was developed based on carbonyl iron powder (CIP) and multiwalled carbon nanotubes (MWCNT). Then, the CIP@MWCNT-based aptasensor was constructed by strong π-stacking between nanocomposite and aptamer, single-strand DNA, causing fluorescent quenching of the dye-labeled aptamer. The restoration of dye fluorescence could be achieved when aptamer came off the surface of the CIP@MWCNT nanocomposite due to the presence of target bacteria. To the best of our knowledge, this fabrication of magnetic carbon nanotubes without irritating and corrosive reagents is described for the first time. The sensing platform was also an improvement on the conventional formation of the aptasensor between carbon materials and DNA aptamer. The nanocomposite was verified by diverse characterization of zeta potential, Fourier-transform infrared spectroscopy, transmission electron microscopy, and energy dispersive x-ray analysis. The CIP@MWCNT-based aptasensor was an effective nanoplatform for quantitative detection of E. coli O157:H7, and was measured to have high specificity, good reproducibility, and strong stability. The aptasensor's capacity to quantify E. coli O157:H7 was as low as 7.15 × 10 cfu/mL in pure culture. The detection limit of E. coli O157:H7 was 3.15 × 10 cfu/mL in contaminated milk after 1 h of pre-incubation. Hence, the developed assay is a new possibility for effective synthesis of nanocomposites and sensitive tests of foodborne pathogens in the dairy industry.
大肠杆菌 O157:H7 是一种极其严重的食源性致病菌，导致了大量的住院治疗。在该系统中，基于羰基铁粉（CIP）和多壁碳纳米管（MWCNT）开发了一种简单、快速且安全的复合方法。然后，通过纳米复合材料和适体之间的强π堆积，构建了基于 CIP@MWCNT 的适体传感器，导致染料标记的适体荧光猝灭。当由于存在靶细菌而使适体从 CIP@MWCNT 纳米复合材料表面脱离时，可以实现染料荧光的恢复。据我们所知，这是首次描述在没有刺激性和腐蚀性试剂的情况下制造磁性碳纳米管。该传感平台还改进了传统的碳材料和 DNA 适体之间的适体传感器的形成。纳米复合材料通过各种特性进行了验证，包括 ζ 电位、傅里叶变换红外光谱、透射电子显微镜和能量色散 X 射线分析。基于 CIP@MWCNT 的适体传感器是一种用于定量检测大肠杆菌 O157:H7 的有效纳米平台，具有高特异性、良好的重现性和强稳定性。该适体传感器能够在纯培养物中定量检测低至 7.15×10 cfu/mL 的大肠杆菌 O157:H7。经过 1 小时的预孵育，污染牛奶中大肠杆菌 O157:H7 的检测限低至 3.15×10 cfu/mL。因此，该开发的检测方法为有效合成纳米复合材料和对乳制品行业中的食源性致病菌进行敏感测试提供了新的可能性。
