4 May 2010
Centrifuge made from a salad spinner for developing countries
by Kate Melville
A salad spinner, plastic lids, yogurt containers and a hot-glue gun could be saving lives in the developing world this summer, thanks to two Rice University undergraduates. Their rudimentary blood centrifuge, which can separate blood without electricity, will be taken abroad for nearly two months this summer as part of Beyond Traditional Borders (BTB), Rice's global health initiative that brings new ideas and technologies to underdeveloped countries. The students, Lila Kerr (right) and freshman Lauren Theis, will take a spinner to Ecuador in late May, one to Swaziland in early June and a third BTB team will take one to Malawi, also in June.
"There was a whole range of projects to take on this year, and luckily we got one that wasn't terribly engineering-intensive," said Kerr. "We were essentially told we need to find a way to diagnose anemia without power, without it being very costly and with a portable device," added Theis.
They found that a salad spinner met those criteria. When tiny capillary tubes that contain about 15 microliters of blood are spun in the device for 10 minutes, the blood separates into heavier red blood cells and lighter plasma. The hematocrit, or ratio of red blood cells to the total volume, measured with a gauge held up to the tube, can tell clinicians if a patient is anemic. That detail is critical for diagnosing malnutrition, tuberculosis, HIV/AIDS and other diseases.
"The students really did an amazing job of taking very simple, low-cost materials and creating a device their research shows correlates nicely with hematocrit levels in the blood," said Rice's Maria Oden, the team's co-adviser with Richards-Kortum. "Many of the patients seen in developing world clinics are anemic, and it's a severe health problem. Being able to diagnose it with no power, with a device that's extremely lightweight, is very valuable."
Kerr said the device spins tubes at up to 950 rpm and can spin up to 30 tubes at a time. It has also proven to be fairly robust. "It's all plastic and pretty durable," Kerr said. "We haven't brought it overseas yet, of course, but we've trekked it back and forth across campus in our backpacks and grocery bags and it's held up fine." The centrifuge costs about $30 in parts, including the spinner. The students expect to continue work on the device after their summer treks.
Source: Rice University
Pic courtesy Jeff Fitlow/Rice University