The Paperfuge is a human powered centrifuge made of paper and string that could revolutionise pathology in developing countries

How people power plus paper makes a 20-cent centrifuge

A centrifuge is a highly important tool in pathology laboratories. The instrument spins samples very fast and the centrifugal force created separates different cells, such as red blood cells from plasma. This is an important step in many pathology tests.

The types of centrifuges most commonly used in pathology labs require power and can cost thousands of dollars to buy, which creates a barrier to healthcare in developing countries or poorly resourced areas.

Now scientists from Stanford University have created a prototype they are calling a “Paperfuge” – a simple device based on a child’s toy that doesn’t require electricity and costs only twenty cents.

The device is able to perform the same task as a powered centrifuge but using human power and is constructed like an old child’s toy known as a whirligig.

Made only of string, paper and plastic piping the Paperfuge is simple and cheap to make. The Stanford team are already embarking on trials with developing communities in Madagascar to test the device’s application in the field.

Their research showed they could separate parasites in blood samples facilitating diagnosis of serious conditions. Details of the work are published in Nature Biomedical Engineering.

Creator Manu Prakash said the team looked at a lot of toys in the development of the Paperfuge, including yoyos and spinning tops, before coming across the whirligig.

“We realized that nobody actually understood the mathematics and the physics behind the toy, which can’t move fast enough. But when you understand the parameters, you can adjust them and achieve all the way up to 125,000 revolutions per minute. So you can actually pull out malaria parasites, African sleeping sickness, and all kinds of other different parasites from blood,” he said.

Still in the early stages, the device is a ray of hope for millions of people in the developing world with poor access to healthcare.