Scientists at the University of Rochester Medical Center have developed a fast-working sensor that picks up on the presence of E. coli bacteria. The system bounces a laser off of a chip with the sample on board. In the presence of E. coli, the reflected laser light becomes visible.
The Rochester research team calls the technology “arrayed imaging reflectometry.” The system utilizes a silicon chip that is made 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 cell, the Tir then 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 being tested. The binding of the probe 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.
Traditional methods of detection of bacteria can take days. “This takes as much time as it takes for a snapshot,” Miller said.
The scientists currently are defining the sensitivity levels of the technology, previously called reflective interferometry, and extending the system to other biological targets.