martes, 5 de abril de 2011

Nano-biosensors to boost detection of foodborne pathogens

Carbon nanofibers to detect E. coli and Salmonella are under development by scientists in the US.

Researchers at Kansas State University are using carbon nanofibres (CNF) as part of the biosensors to detect the bacteria, an application which could have a huge take up in the state’s huge meat processing sector, they said.

Jun Li, associate professor of chemistry, and doctoral student Lateef Syed, said they chose CNFs because they are able to form an array of tiny electrodes even smaller than bacteria and viruses. When these microbial particles are captured at the electrode surface, an electric signal can be detected.

Work started at NASA

The CNFs and the circuits underneath are encapsulated with silicon dioxide (SiO2) to provide electrical insulation and mechanical anchoring. Excess SiO2 is removed by mechanical polishing and reactive ion etching so only the very end of the CNF tip is exposed.

“This embedded CNF nanoelectrode array chip is then packaged with counter electrodes and reference electrodes in a microfluidic chip through which the sample solution can be passed through”, said Li.

In-line monitoring

The team aims to calibrate the system to detect specific pathogens. The final system should be able to detect 1 bacterium in 100 mL water (the EPA standard) in less than an hour without going through polymerase chain reaction (PCR) or culture.

The project was initially supported Canadian-based Company Early Warning Inc., which provided the K-State research team with $240,000 for two years as part of the developmental work. Recently, the US Department of Homeland Security Center of Excellence for Emerging and Zoonotic Animal Diseases, or CEEZAD, has come on-board.

"Kansas is a leading state in meat production and the poultry industry," said Sayed. "Any outbreak of pathogens in these industries causes huge financial losses and a lot of health risks. We want to prevent these outbreaks by detecting pathogens at an early stage."

Source: Food Quality

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