Building fast and portable biosensors to detect E. coli

Washington State University researchers have developed a portable biosensor for quick and easy detection of harmful bacteria

As in the case of several recent food recalls, the harmful pathogens are often only discovered once people have become ill. Tiny numbers of pathogens can create serious health risks, but current technology is unable to quickly and easily detect them in such small quantities. This is why Washington State University researchers have been working to develop better biosensors that could quickly, accurately and automatically detect harmful bacteria in the environment.

The WSU research team has created a simple sensor that is able to detect and amplify the signal of the food pathogen Escherichia coli (E. coli) 0157:H7, which can cause severe diarrhea and kidney damage in people.

The research team, led by Yuehe Lin, professor in the School of Mechanical and Materials Engineering, recently published the work in the journal, Small.1

The key to a better sensor is maintaining a large amount of enzyme activity for detecting antigens in a sample. To address this issue, the researchers developed a particle at the nanoscale that includes organic and inorganic components and looks like a tiny flower. Smaller than a speck of dust and made up of a group of molecules, the nano-sized flower and petals provide a large surface area for immobilising the highly active enzymes that are needed to detect the bacteria at low levels.

The team showed that the nanoflower biosensor reconised and amplified signals from E. coli O157:H7 so they could be picked up easily with a simple handheld pH meter or pH indicator paper strip.

'We want to take these nanoflowers and create a simple-to-use, handheld device that anyone can use anywhere,' said Lin. 'It’ll be as simple as using a pregnancy test strip or a glucose meter.'

The researchers have filed a patent for the handheld device concept and are working to switch out components of the nanoflower to detect disease markers as well as other pathogens such as salmonella.

The team includes Lin and his group at the WSU Voiland College of Engineering and Architecture and his collaborator, associate professor Meijun Zhu from WSU’s School of Food Science.

The work was supported by the US Centers for Disease Control and Prevention/National Institute for Occupational Safety and Health.

1. Ye, R., Zhu, C., Song, Y. et. al. (2016). Small,/i>, 12: 3094–3100. doi:10.1002/smll.201600273