Inspiration for a medical device that could assist doctors in diagnosing malaria in remote locations has come from an unlikely place —a children's toy.
Diagnosing malaria in the field isn't difficult, but it does require a centrifuge, a machine that rapidly spins blood samples, causing different types of cells in the blood to separate. These devices are bulky, costly and require electricity, meaning many field hospitals in developing nations do not have access to one. Manu Prakash, an assistant professor of bioengineering at Stanford University, is trying to change that.
Seeing the need for a cheaper alternative during a trip to Uganda, Prakash began experimenting with anything that could spin, including toys. “Toys hide in them pretty profound physical phenomena that we just take for granted,” Prakash told NPR. Eventually he picked up an ancient children's toy that first appeared in 500 B.C., a whirligig, and, noticing how fast it spun, got to work refashioning the toy into a centrifuge.
The toy consists of a disc that spins when strings that pass through the center of the disc are pulled in opposite directions by hand. Scientists created their device, named the paperfuge, out of paper coated in a polymer film, string and PVC pipe or wood. Blood samples are attached to the center disc, and pulling the strings causes the disc to rapidly spin, causing the blood cells to separate. Samples can then be processed and tested for parasites and malaria.
Researchers have clocked the revolutions of the paperfuge at 125,000 per minute, the fastest recorded rotational speed for a human-powered device. The paperfuge costs only 20 cents per device to make and can be made of paper or plastic. Using a desktop 3-D printer, Prakash and his colleagues printed more than 100 devices in one day. The developers published their results in Nature Biomedical Engineering, indicating that if the device catches on it could be cheaply and easily distributed to resource-poor areas