Counting Cells in Seconds

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The counter has high throughput--while it's capable of detecting small numbers of cells, it can image as many as 100,000 cells in a 20-centimeter-squared field of view in one second. The counter can, for example, determine the concentration of red blood cells in an unprocessed blood sample with 90 percent accuracy. Red blood cell count can be used to diagnose anemia, to monitor malaria, and to monitor patients' responses to chemotherapy.

"What [Ozcan] is doing has potential for hand-held devices that work in the field," says Alexander Revzin, an assistant professor of biomedical engineering at the University of California, Davis. Rezvin has begun a collaboration with Ozcan to develop a cheap, diffraction-based test for counting T cells in HIV patients--a measure of the health of the immune system that's used to determine when to start drug treatment and whether it's working. "Obviously a poor-resource setting is one target, but it doesn't just need to be used in Africa if this is a robust technology," says Rezvin.

"This is a very practical technique," says Mehmet Fatih Yanik, an assistant professor in the Research Laboratory of Electronics at MIT. "Ozcan's work can significantly reduce the cost and effort required for cell counting, allowing its commonplace use even in Third World countries for a variety of medical applications."

So far, Ozcan's group has developed protype cell counters on the lab benchtop. Next, he says, he'll convert a cell phone into a mobile diagnostic lab by taking out the camera lens and putting in the imaging chip and a mechanical system to load microscope slides.