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Tuesday, May 18, 2010

College students invent salad spinner centrifuge

Rice University undergraduates Lila Kerr and Lauren Theis turned an ordinary salad spinner into a device for diagnosing anemia.

Caption: Rice University students Lauren Theis, left, and Lila Kerr created the Sally Centrifuge as part of a class on global health, and will take it overseas this summer for testing in developing countries.

Credit: Jeff Fitlow/Rice University

Ordinarily, anemia is diagnosed by spinning blood samples in a centrifuge until the heavier red blood cells separate from the rest of the liquid, or plasma. The ratio of red blood cells to total volume (hematocrit) can be used as a tool in diagnosing a number of diseases, such as malaria or HIV/AIDS. However, centrifuges are expensive and require an energy source. Salad spinners are cheap, light, and run solely on muscle power.

The two students were given the task of coming up with an anemia test that didn’t require an external power source by their Introduction to Bioengineering and World Health class professor, Rebecca Richards-Kortum. They assembled the device, named ‘Sally Centrifuge’ (in honor of the Sallyport archway at Rice), from a salad spinner, plastic lids, cut up combs, and yogurt containers. The entire thing cost about $30.

The prototype spinner performed as well as a real centrifuge. Besides the low cost, the Sally Centrifuge has the advantage of being made entirely of plastic, making it light and sturdy. If something does break off of one, you can always hot glue it back in place.

The students will be taking their spinners abroad this summer to test them in the field; Kerr to Ecuador and Theis to Swaziland.