Fidget-spinner centrifuge separates blood from plasma

A fidget spinner, the toy twirled endlessly between the fingers of schoolkids, can act as a makeshift centrifuge and separate blood plasma sufficiently for an HIV test (Anal. Chem. 2018, DOI: 10.1021/acs.analchem.8b04860). For blood tests, red blood cells must be separated from the plasma, usually with a fast-spinning centrifuge, but these are expensive and require electricity to operate, which may not be feasible in resource-limited regions of the world, says Chien-Fu Chen of the Institute of Applied Mechanics at National Taiwan University. Along with Chien-Cheng Chang and colleagues, Chen put human blood spiked with a common HIV-1 diagnostic protein in 50 mm long plastic tubes, sealed them, and taped them to each of the three spinning arms of a commercially available fidget spinner. After spinning the device for 4–7 min, the team separated about 30% of the plasma from the blood sample—with 99% purity. A paper-based HIV test detected the