A Conversation with Manu Prakash

S tanford bioengineer Manu Prakash specializes in frugal science: engineering cheap, easy-to-use diagnostic tools for the developing world, especially remote areas where bulky, electric-powered lab equipment is impractical. In 2014, Prakash debuted the Foldscopea foldable paper microscope designed to detect blood-borne pathogensas well as a chemistry kit-on-a-chip to carry out diagnostic assays. The Prakash group’s most recent device is a humanpowered centrifuge, capable of isolating malaria parasites in blood. Inspired by a twirling toy known as a whirligig, the team built the device, called the paperfuge, by stringing paper disks together with twine running through the center. Rhythmically pulling the twine spins the disks, loaded with blood samples in attached capillary tubes, at up to 125,000 rpm. Health workers can then examine the samples, which are treated with a fluorescent stain that binds to the parasites, under a microscope to diagnose malaria using the telltale glow at the right layer in the tube. Prakash spoke to Melissa Pandika about how he developed the paperfuge and the challenges of adapting diagnostic tools to underserved areas.