When diagnosing people in the developing world, health workers often go into the field lugging bulky, fragile, and expensive microscopes. “We ship research equipment and hope it’ll survive,” says Manu Prakash, a biophysicist. While traveling in Thailand, the scientist dreamt up a lightweight, low-cost alternative: a pocket-sized paper microscope made from a single sheet of folded paper, a pair of lenses, and an LED. Approximate cost: $1.
Prakash’s Foldscope could have a big impact on diagnosing disease in remote or resource-poor regions of the world. The microscope is not only cheap to produce, it’s also relatively sophisticated, achieving a magnification of 2,000 times—equal to the power of a desktop instrument costing $1,000. Prakash, a 34-year-old assistant professor at Stanford, is currently working on refining the optics to improve the resolution from 700 nanometers, which is sharp enough for diagnosing African sleeping sickness, shistosomiasis, loiasis, and many other diarrheal diseases. Malaria and tuberculosis are next, he says.
Foldscopes take about five minutes to fold into shape from a color-coded sheet. They require no external power, weigh less than two nickels, and are waterproof. They’re also extremely robust, capable of surviving being trampled or dropped from a three-story building.
If, for whatever reason, a part does fail, it is easily and cheaply replaced—all the components, lenses included, are modular. That also means that any Foldscope can be modified depending on the disease being diagnosed and lighting conditions. Attaching a bright LED can even transform the microscope into a projector for teaching children or training health workers.
For those accustomed to lab microscopes, a Foldscope might take some getting used to. Users insert samples prepared on standard glass slides and then focus by sliding paper tabs right or left with their thumbs.
Prakash’s lab received $100,000 from the Bill and Melinda Gates Foundation for initial development, and a four-year, $700,000 grant from the Gordon and Betty Moore Foundation to distribute 10,000 Foldscopes to beta-testers who are chosen based on the scientific questions they’d like to study. Prakash is producing the first batch of 50,000 microscopes with a manufacturer of greeting cards using a traditional die-cutting process.
Foldscope isn’t commercially available yet, though Prakash imagines a day when every child carries one, much as their parents keep ballpoint pens in their pockets. By seeing organisms invisible to the naked eye, children could develop a better understanding of how good hygiene plays a part in stemming the spread of disease. “Try explaining to a kid who has never seen anything microscopic why he should wash his hands,” he says. “A microscope completely changes the dialogue of sanitation.”