Ancient Toy Inspires Low-Cost Medical Diagnostic Tool

Modern medicine often feels like magic: A technician pricks your skin, draws a drop of blood and whisks it away into another room. Oftentimes, this gives the doctor enough information to make a diagnosis and prescribe a treatment. But for people in developing countries, these kinds of diagnostics can be more science fiction than reality.

Modern medicine relies heavily on technology, like centrifuges, that are costly, bulky and require electricity. In many places around the world, this kind of equipment can be hard to come by. But in a new study published online today (Jan. 10) in the journal Nature Biomedical Engineering, researchers described an inexpensive, hand-powered centrifuge that's based on an ancient toy and could help doctors working in developing countries.

The centrifuge is the workhorse of modern medical laboratories. The device spins samples at high speeds to separate particles or cells based on size and density, effectively concentrating specific components. Most diagnostics "are like looking for a needle in a haystack," said Manu Prakash, lead researcher on the new study and an assistant professor of bioengineering at Stanford University. A centrifuge, Prakash said, puts all the needles in one place, making them easier to find. [10 Technologies That Will Transform Your Life]

Unfortunately, even the simplest modern centrifuges are burdensome for doctors in the field. Prakash, who won a 2016 MacArthur "genius" award, is a leader in the so-called frugal science movement, which aims to devise low-cost solutions for complex technologies. Prakash is best known for developing the Foldscope, an origami-like paper microscope that costs about $1.50.

In the past, researchers explored common household items, such as egg beaters and salad spinners, as alternatives to the centrifuge, but these devices gave poorer results than modern diagnostic tests. A simple blood test using these tools required more than 10 minutes to separate cells, compared with 2 minutes for commercial centrifuges. So instead of using these items, Prakash and his colleagues focused on spinning toys.

"We tested many toys, like the top and yo-yo," study lead author M. Saad Bhamla, a postdoctoral researcher at Stanford University, told Live Science. "We wanted to find the most effective way of converting physical energy into rotational energy."