By Gesa Junge, PhD
If you have ever been inside a lab you will know that centrifuges and microscopes come in various shapes and sizes and degrees of sophistication, but in some form they are used every day in most research labs around the world. Microscopes and centrifuges are pretty basic lab equipment, although some versions can be very high-end, for example high-speed centrifuges that can cool down to fridge temperatures, or electron microscopes that can magnify structures up to 2 million times. But even basic centrifuges and microscopes cost a few thousand dollars, and they require electricity and maintenance. These are not big issues for most universities and established research institutes, but for scientists working in the field, or in developing countries, money and electricity can be hard to come by.
With this in mind, Manu Prakash from Stanford University developed a centrifuge and a microscope made of paper. Yes, you read that right. The centrifuge is basically a paper disk on two strings that you pull to make the disk spin (kind of like a whirligig Saw Mill, remember those?) – check out this video from Wired Magazine. The whole thing costs 20 cents and fits into a jacket pocket, but it can spin samples up to 12500rpm, which is fast. Fast enough, for example, to separate blood into blood cells and plasma, which is a key step in many diagnostic procedures.
And the foldscope is basically origami. It is printed on paper, you cut out the parts and fold them up and insert a lens. The microscope does need electricity, but it can run on a battery for up to 50 hours, and the sample can be mounted on a piece of tape, as opposed to a glass slide. The lens determines the magnification, and they can go up to 2000x. For reference, we can distinguish individual human cells easily at 10x, nuclei become clearly visible at 20x and bacteria at 40x. Using different color LEDs, this can even be converted into a fluorescent microscope, meaning it can be used to analyse different stains of tissues.
The paperfuge and the foldscope are the implementation of an emerging concept called “frugal science”, and aim to bring scientific advances to inaccessible and under-developed regions. And while Manu Prakash’s ideas are very low-tech approaches, the idea of making science useful to everyone also benefits from innovation and advanced technology. For example, Dr Samuel Sia at Columbia University has developed a smart phone dongle technology called mChip which can diagnose HIV from a finger prick’s worth of blood. This device contains all the necessary reagents which mix at the push of a button, and it plugs into the headphone jack of a phone as a power supply. Testing takes about 15 minutes and costs about $1 (the dongle is $100), which is a huge improvement over current methods. In a similar concept, a company called QuantumMDx in Newcastle in the UK is developing a handheld DNA testing tool, which could be used to identify strains of pathogens. And electronics company Phillips has come up with the MiniCare I-20, a handheld device that can measure troponin I levels from a single drop of blood taken from a pinprick. Troponin I is a marker of a damaged heart muscle, and is often measured in emergency departments.
All of these innovations address a really important, and sometimes overlooked, point: science and technology, in all their greatness and cool fascination, will only benefit humanity if applied in the community in a way that leads to real-life changes. As with so many resources, scientific expertise and technology, and therefore the benefit of science, are distributed incredibly unevenly among the world’s society. For example, malaria and AIDS drugs are still not reaching many of the people who need them, be it for financial, infrastructural, political, or organisational reasons. Diagnostic tests often require well-equipped labs and trained technicians. And while they are limited in their applications for research, the paperfuge and the foldscope have the potential to revolutionize diagnostics as well as education around the world. Cutting-edge research may require more sophisticated centrifuges that spin faster, microscopes that have better resolution, computers to store the images, and teams of scientists analyzing the data. But the frugal science approach is well-suited for the diagnosis of diseases, or to help a high school science class understand what cells are.