Analytical Sciences

Quantification of Enterohemorrhagic Escherichia coli via Optical Nanoantenna and Temperature-responsive Artificial Antibodies

So TANABE,* Satohiro ITAGAKI,* Shuyi SUN,* Kyohei MATSUI,* Takamasa KINOSHITA,* Shigeki NISHII,* Yojiro YAMAMOTO,*,** Yasuhiro SADANAGA,* and Hiroshi SHIIGI*

*Department of Applied Chemistry, Osaka Prefecture University, 1-2 Gakuen, Naka, Sakai, Osaka 599-8570, Japan
**GreenChem. Inc., 19-19 Tsuruta, Nishi, Sakai, Osaka 593-8323, Japan

Enterohemorrhagic Escherichia coli are a dangerous bacterium known to be harmful to the human body, with some infections even resulting in death. Given this danger, food factories are required to perform a quick bacterial test to confirm the absence of this pathogen prior to shipping. We have developed a novel molecular imprinting polymer (MIP) particle that has encapsulated gold nanoparticles (AuNPs) and which can function as both a receptor and an optical signal transmitter in biological systems. This MIP particle is artificially synthesized and can be engineered to specifically recognize and capture antigens on the bacterial cell membrane. In addition, MIP particles containing AuNPs generate strong scattered light signals, and binding of the MIP particles improves the optical intensity of the target bacterial cells. This enables clear visualization under a dark-field microscope and quantification of the target bacteria using the scattering light intensity. Here we describe the successful quantification of Escherichia coli O157 cells in real meat samples using this technology in conjunction with a simple labelling step.

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