How a children's toy could help fight malaria
One of the most basic and necessary pieces of equipment in medical labs is a centrifuge. Often bulky and expensive, this device (in the most simple terms) spins things. And spinning things like blood can separate out its components. It allows doctors to diagnose diseases like malaria. But the lack of electricity and resources in rural regions around the world means no centrifuge. Now, a simple new 20-cent gadget could change all that. It's based on an unusual source of inspiration. That is the whirligig.
"There are more than a billion people around the world who have no infrastructure. No roads. No electricity," says Manu Prakash. He is a physical biologist at Stanford. He is the inventor of the new gadget. When he visited Uganda in 2013, he found that clinics either did not have centrifuges or didn't have the juice to power them. "One clinic used its broken centrifuge as a doorstop," Prakash tells Devin Powell at Nature.
"I realized that if we wanted to solve a critical problem like malaria diagnosis, we needed to design a human-powered centrifuge that costs less than a cup of coffee," Prakash says in a press release.
When he returned to Stanford, Prakash began brainstorming ideas with one of his post-docs, Saad Bhamla. They examined all sorts of spinning things, reports Madeline K. Sofia at NPR. They quickly began focusing on old-school, preindustrial toys like yo-yos and whirligigs.
"One night I was playing with a button and string. And out of curiosity, I set up a high-speed camera to see how fast a button whirligig would spin. I couldn't believe my eyes," Bhamla says in the press release. The button was rotating at 10,000 to 15,000 rpms.
The pair began prototyping small hand-powered centrifuges based on the whirligig principle. Their final model was the Paperfuge. It spins at 125,000 rpm. That's equal to a centrifuge costing $1,000 to $5,000, according to the press release.
The Paperfuge is made of a disk of paper coated in a polymer, reports Sofia. The disk is attached to two pieces of wood or PVC pipe via string. When the strings are pulled, the disc in the middle spins. This acts as a centrifuge for a blood sample attached to the center of the disk. The team describes their work in the journal Nature Biomedical Engineering.
Prakash and Bhamla recently returned from successful field trials of the Paperfuge in Madagascar. They used it to test for malaria. While the gadget only takes two minutes to separate blood, reports The Economist, it takes 15 minutes of whirligigging for malaria-diagnosing separations.
Once the blood is separated it needs to be examined by a microscope. Luckily, several years ago Prakash also created the Foldscope. It is a $1 paper microscope. It has optical quality similar to conventional microscopes. It will begin distribution in 2018.
CRITICAL THINKING QUESTION
How can a microscope only cost $1?
Write your answers in the comments section below