AUTHOR=Lin Xiaofeng , Mei Yanqiu , He Chen , Luo Yan , Yang Min , Kuang Ying , Ma Xiaoming , Zhang Huifang , Huang Qitong 

TITLE=Electrochemical Biosensing Interface Based on Carbon Dots-Fe3O4 Nanomaterial for the Determination of Escherichia coli O157:H7

JOURNAL=Frontiers in Chemistry

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.769648

DOI=10.3389/fchem.2021.769648

ISSN=2296-2646

ABSTRACT=<p><italic>Escherichia coli</italic> (<italic>E. coli</italic>) O157:H7 can cause many food safety incidents, which seriously affect human health and economic development. Therefore, the sensitive, accurate, and rapid determination of <italic>E. coli</italic> O157:H7 is of great significance for preventing the outbreak and spread of foodborne diseases. In this study, a carbon dots-Fe<sub>3</sub>O<sub>4</sub> nanomaterial (CDs-Fe<sub>3</sub>O<sub>4</sub>)-based sensitive electrochemical biosensor for <italic>E. coli</italic> O157:H7 detection was developed. The CDs have good electrical conductivity, and the surface of carbon dots contains abundant carboxyl groups, which can be used to immobilize probe DNA. Meanwhile, the CDs can be used as a reducing agent to prepare CDs-Fe<sub>3</sub>O<sub>4</sub> nanomaterial. The Fe<sub>3</sub>O<sub>4</sub> nanomaterial can improve the performance of the electrochemical biosensor; it also can realize the recovery of CDs-Fe<sub>3</sub>O<sub>4</sub> due to its magnetism. As expected, the electrochemical biosensor has excellent specificity of <italic>E. coli</italic> O157:H7 among other bacteria. The electrochemical biosensor also exhibited good performance for detecting <italic>E. coli</italic> O157:H7 with the detection range of 10–10<sup>8</sup> CFU/ml, and the detection limit of this electrochemical biosensor was 6.88 CFU/ml (3S/N). Furthermore, this electrochemical biosensor was successfully used for monitoring <italic>E. coli</italic> O157:H7 in milk and water samples, indicating that this electrochemical biosensor has good application prospect. More importantly, this research can provide a new idea for the detection of other bacteria and viruses.</p>