Ultrasensitive detection and quantification of E-coli O157:H7 using a giant magnetoimpedance sensor in an open-surface microfluidic cavity covered with an antibody-modified gold surface

作者：Yang, Zhen^*; Liu, Yan; Lei, Chong^*; Sun, Xue-cheng; Zhou, Yong^*

来源：Microchimica Acta, 2016, 183(6): 1831-1837.

DOI：10.1007/s00604-016-1818-3

• Dynabeads
• Escherichia coli O157:H7
• Giant magnetoimpedance sensor
• Microfluidic cavity
• MEMS
• SEM
• AFM

We report on a method for ultrasensitive detection and quantification of the pathogen Escherichia coli (E. coli), type O157:H7. It is using a tortuous-shaped giant magnetoimpedance (GMI) sensor in combination with an open-surface microfluidic system coated with a gold film for performing the sandwich immunobinding on its surface. Streptavidin-coated super magnetic Dynabeads were loaded with biotinylated polyclonal antibody to capture E. coli O157:H7. The E. coli-loaded Dynabeads are then injected into the microfluidics system where it comes into contact with the surface of gold nanofilm carrying the monoclonal antibody to form the immunocomplex. As a result, the GMI ratio is strongly reduced at high frequencies if E. coli O157:H7 is present. The sensor has a linear response in the 50 to 500 cfu center dot mL(-1) concentration range, and the detection limit is 50 cfu center dot mL(-1) at a working frequency of 2.2 MHz. In our perception, this method provides a valuable tool for developing GMI-based microfluidic sensors systems for ultrasensitive and quantitative analysis of pathogenic bacteria. The method may also be extended to other sensing applications by employing respective immunoreagents.

• 出版日期2016-6
• 单位上海交通大学