Paperfuge: The ultralow-cost centrifuge

When people hear the word “centrifuge”, the first thing that comes to their mind is a costly, and bulky piece of equipment powered by electricity. It is an indispensable tool in any laboratory or diagnostic institution. But can the same thing be imagined rotating at high speeds without electricity in between your palms? This is what was achieved by Dr. Manu Prakash and his colleagues at the Department of Mechanical Engineering, Stanford University. They have created a centrifuge made out of paper, which the cheapest raw material possible and named it “paperfuge”. Paperfuge is a lightweight human-powered centrifuge capable of achieving speeds up to 1,25,000 r.p.m (or 30,000g of centrifugal force). The main reason that makes the paperfuge stand apart is its manufacturing cost. A single paperfuge is just 20 cents (around ₹13) to build which is an ultralow-cost feature exclusively for this device. The design mechanics of paperfuge is based on the concept of the whirligig. The buzzer toy which has been around since 3,000 BC uses the same principle which was the inspiration to develop the paperfuge. 

Dr. Manu Prakash demonstrating how to use a paperfuge.

https://www.youtube.com/watch?v=L5ppD07DMKQ

The practical applications of this device are enormous but cost-effective. Achieving a centrifugal force of 30,000g using a centrifuge can make many interesting phenomena happen. One such example is the achievement of hematocrit (complete separation of whole blood into plasma and RBCs) within 1.5 min of centrifugation inside the paperfuge. Another major application is the diagnosis of malaria using quantitative buffy coat (QBC) analysis. In QBC analysis, the high centrifugal force causes the blood components to get separated and stratified. This makes the schizonts (a matured parasitic stage) of Plasmodium falciparum (malarial parasite) to separate out from the red blood cells (RBCs; as shown in figure 1). In the least developed countries, where lack of electricity and proper healthcare systems are still in existence, carrying a bulky centrifuge is not an option. This is where the paperfuge comes into action. Blood samples can be diagnosed at the same place of collection to facilitate an early disease detection by reducing the transportation and diagnostic costs. An early disease detection always comes with better response to treatment and healthy recovery. 

This not the first time that researchers have tried to build a low-cost centrifuge but the centrifugal force and cost-effectiveness attained by the paperfuge precedes any of its predecessors.  The creators of paperfuge believe in “frugal science”, a concept of inspiration to develop affordable scientific tools to people all over the globe. It is through creativity and imagination that such ideas are developed into such effective tools. Let this be a foundation for all of us to get inspired and think.

The article about paperfuge was published in the journal, Nature Biomedical Engineering in 2017

Reference

The paperfuge: A 20-cent device