In a global-health context, commercial centrifuges are expensive, bulky and electricity-powered, and thus constitute a critical bottleneck in the development of decentralized, battery-free point-of-care diagnostic devices. Here, we report an ultralow-cost (20 cents), lightweight (2 g), human-powered paper centrifuge (which we name ‘paperfuge’) designed on the basis of a theoretical model inspired by the fundamental mechanics of an ancient whirligig (or buzzer toy; 3,300 bc). The paperfuge achieves speeds of 125,000 r.p.m. (and equivalent centrifugal forces of 30,000 g), with theoretical limits predicting 1,000,000 r.p.m. We demonstrate that the paperfuge can separate pure plasma from whole blood in less than 1.5 min, and isolate malaria parasites in 15 min. We also show that paperfuge-like centrifugal microfluidic devices can be made of polydimethylsiloxane, plastic and 3D-printed polymeric materials. Ultracheap, power-free centrifuges should open up opportunities for point-of-care diagnostics in resource-poor settings and for applications in science education and field ecology.
We thank all members of the PrakashLab for their feedback. We thank J. Cybulski and D. Ott for their discussions and engagement in the early phases of this project; F. Hol for his assistance with the soft-lithography fabrication; and K. Hong (Yeh Lab, Stanford University) for her assistance with the malaria samples. M.S.B. acknowledges fellowship support from the Stanford School of Medicine Dean’s Postdoctoral Fellowship. M.P. acknowledges support from the Pew Foundation, Moore Foundation, National Science Foundation Career Award and the National Institutes of Health (NIH) New Innovator Award. This work was supported by the Stanford Clinical and Translational Science Award (CTSA) to Spectrum (UL1 TR001085). The CTSA programme is led by the National Center for Advancing Translational Sciences (NCATS) at the NIH. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.