Bacteriology
Scientists develop biosensor to detect E. Coli bacteria
By IANS
Feb 25, 2006, 10:03

Scientists have developed a fast working biosensor that can accurately and rapidly detect an infectious agent that causes food borne illness, including the dangerous E. Coli bacteria.

The unique technology developed by the University of Rochester Medical Centre uses a protein from the suspect bacteria as part of the sensing system that includes a silicon chip and a digital camera.

"Traditional methods of detection of bacteria can take days but the biosensor developed by them could take as much time as it takes for a snapshot," said lead researcher Benjamin Miller.

The Rochester team called the technology "arrayed imaging reflectometry".

The system utilises a silicon chip that is made in a manner so that laser light reflected off the chip is invisible unless the target bacteria are present.

A protein from the bacteria, Translocated Intimin Receptor or Tir, is placed on the chip. The Tir can be seen as a "molecular harpoon", Miller said.

The E. Coli sends out the harpoon into a cell. Once it is in, the Tir binds with an E. Coli protein called Intimin. A similar process occurs between the Tir placed on the chip and any E. Coli in the sample.

The binding of the probed sample and the bacteria alters the surface of the chip. A digital camera image of the chip captures the changes for analysis and confirmation of detection.

Describing the new technology as inexpensive, Miller said that a physician some day could use it in his office to confirm a streptococcal infection in a patient with a sore throat.

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