Could a simple salad spinner help save lives?
Two Rice University undergrads turn a simple salad spinner into a centrifuge that can be used to separate blood in settings without electricity to diagnose anemia on the cheap.
Challenged to find a way to diagnose anemia that's affordable, mobile, and requires no electricity, Rice University undergrads Lila Kerr and Lauren Theis turned to an old-fashioned salad spinner.
They call it the Sally Centrifuge and are taking it to Ecuador in May and Swaziland and Malawi in June, all as part of Rice's Beyond Traditional Borders global health initiative, which is aimed at creating innovations in biotechnology.
The centrifuge is, the students admit, a pretty simple idea. "There was a whole range of projects to take on this year, and luckily we got one that wasn't terribly engineering-intensive," says Kerr, a sociology major and global health technologies minor from Dayton, Ohio.
When little capillary tubes containing 15 microliters of blood are spun in a salad spinner for 10 minutes, the blood separates into heavier red blood cells and lighter plasma.
The resulting hematocrit--the proportion of total blood volume taken up by red blood cells that they measure with a simple gauge held up to the tube--determines whether that patient is anemic. That in turn help diagnose issues such as HIV/AIDS, tuberculosis, malaria, and malnutrition.
Rice already has a mini centrifuge called the ZIPocrit, which spins up to 10,000rpm and takes just four to five minutes. And while the Sally Centrifuge only spins up to 950rpm and takes twice as long, it has several advantages over the ZIPocrit, the first of which is that the ZIPocrit requires batteries. Also, the Sally Centrifuge can spin up to 30 tubes at a time, compared to the ZIPocrit's max of four. And it costs a fraction of the ZIPocrit's $300 price tag.
Named after a Rice campus landmark called the Sally Port, the centrifuge totals just $30 in parts, including the spinner itself, plastic lids, cut-up combs, yogurt containers, and a hot-glue gun for assembly. (Click here for a list of friendly Rice traditions, which may soon include assembling the Sally Centrifuge under said port, and probably, due to the nature of other Rice traditions, done in the nude. But I digress.)
"It's all plastic and pretty durable," Kerr says. "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."
So next time you go to throw away your salad spinner, yogurt containers, plastic lids, or broken combs, consider their centrifugal potential, powered by the best of Rice tradition.