Simple centrifuge for field science
A new paper looks at the ‘paperfuge’ – a cheap and simple centrifuge for use outside of high-tech labs.
The hand-spun centrifuge made of paper and string, costing about 30 cents, can separate plasma from blood in less than two minutes, according to reports in Nature Biomedical Engineering.
Experts have found that the paperfuge can be used to detect malaria in about 15 minutes, and can also separate the blood fraction that contains white blood cells and platelets.
Commercial centrifuges are standard equipment in any biomedical laboratory. However, in low-income countries with poor access to electricity, consumables and trained healthcare personnel, the cost of acquiring, maintaining and operating a centrifuge can amount to hundreds of dollars per year.
Inspired by an ancient whizzing toy, researchers found that blood can be centrifuged by securing capillary tubes filled with blood in between two paper discs attached with Velcro strips.
The disks are spun by repetitively winding and unwinding (through wooden handles) two strings made of fishing line that run through the centre of the disks.
The authors have shown that the paperfuge can be used to centrifuge blood at about 20,000rpm - a speed comparable to that of high-speed benchtop centrifuges - and that it can even approach speeds up to 125,000rpm, equal to the fastest rotational speed ever reported for a human-powered device.
Finally, the authors also isolated malaria parasites from infected blood samples by hand-spinning their centrifuge for 15 minutes, and demonstrate that the concept can be expanded to make cheap, 3D-printed plastic centrifuges for point-of-care diagnostics.
The paper is available here, followed by videos from the research group.