The paper fuge: the paper fuge a 20 cent device that could transform health care the loose assemblage of paper and string. An inexpensive, hand-powered centrifuge that’s based on an ancient toy could help doctors working in developing countries.
Manu Prakash polls from his pocket doesn’t look like much and in a way it’s not just twenty cents worth of materials you can buy at an art supply store but in another way the Stanford bioengineers tangle of stuff is a minor miracle Prakash calls, it a paper fuge and like the piece of lab equipment. its name for the centrifuge it can spin biological samples at thousands of revolutions per minute that’s a critical step in the diagnosis of infections like malaria and HIV but unlike a centrifuge the paper future doesn’t need electricity complicated machinery expensive replacement parts or even much money to operate there are a billion people on this planet who live with no electricity no infrastructure no roads and they have the same kind of healthcare needs that you and I have.
Manu Prakash says his lab developed the paper future with these people in mind inspired by the design of a millennia-old toy the paper future is a hand-powered centrifuge made of paper string and plastic that can with biological samples in circles and up to 125 thousands RPM that’s enough of two separate plasma from a blood sample a standard diagnostic procedure in 90 seconds for reference a stats been MP centrifuge the kind of commercial centrifuge that you’ll find in diagnostic and research labs around the world tops out at 15000 and 800 RPM and can take up to two minutes to perform a plasma separation the stats been also weighs 5.5 pounds requires electricity and cost thousands of dollars the paper future weighs about 2 grams and costs less than a quarter to make that is and less than quarter to make that is and this is scientific term freaking ridiculous.
Manu Prakash is no stranger to innovative paper technology in 2012 he unveiled the foldscope a folding paper microscope inspired by Origami, that costs less than dollar to produce and is powerful enough to see microorganisms the tool embodied Prakash’s frugal science philosophy the ideas, that access to affordable yet power equipment can have a profound impact on science and medicine around the globe.
The paper future expands on that philosophy a year after the fold scopes debut Prakash was visiting a health center in Torah, Uganda when he spotted someone using centrifuge as a door stop he had spent the past few weeks and remote clinics throughout the country familiarizing himself with the needs of doctors and technicians he had seen plenty of instrument graveyards in his travels piles of equipment in disrepair but this was the first time he’s seen anyone use a busted device to prop open a door when I returned from Uganda. I know this was the next thing we were going to build his lab wasn’t the first to try to create a cheap human –powered centrifuge in 208 researchers in George white sides lab at Harvard repurposed an eggbeater to spin biological samples as fast 1200 RPM in 2011 researchers out of Rebecca Richards courtrooms lab at Rice University got knock so salad spinner to hit 600 RPM both options were bigger, heavier more expensive and far less effective than the paper fuge we wanted a much bigger jump, Prakash says; for us it wasn’t about finding the first thing that worked it was about pushing the limit we wanted an absolute solution precautious team found that solution enjoys the best ones.
He says the ones that have stood the test of time still physical properties into approachable forms there’s a sense of simplicity to their mechanisms that cause me to not only enjoy using them but thinking about them.
Prakash says his team started by experimenting with tops but they didn’t spin fast enough for long enough to separate biological samples.
The researchers tried yo-yos with some success but the learning was way too steep the problem is you got know how to throw a yo-yo. Prakash says and not just any throw the best throw consistently and ideally you have to be able to set the yo-yo spinning again without it returning to your hand this is called looping and it looks very hard been after more than a year of practice Prakash says he’s never been able to beat the lap record of 4000RPM set by a visiting researcher a former circus performer and yo-yo master the breakthrough came at the beginning of 2016.
when Bhamla a postdoc in Prakash’s lab and by his own admission allows easy yo were decided to analyze the spin of a toy from his childhood in India called a whirligig the design dates back thousands of years suspend a button or discount a loop of string and pull the loop tends to set the button spinning successive rounds of pulling cause the string to wind and unwind and the button to spend quickly In one direction and then another turns out that even though lab grade centrifuges spin up the world in the direction and then spin down you can get the same results with something that spins one-way stops and then spins back it’s a simple design.
So one night, I made one myself my girlfriend left me a thread from her sewing kit and me strong it through a button Bhalla says he positioned the toy in front of a high-speed camera and started spinning later when I analyze the footage I realized that the button was spinning between 10,000 and fifteen thousand rpm’s.
I remember feeling that this was it this what we’ve been looking for family knew that if he understood the whirligigs mechanics he could optimize it for speed but when he searched for whether anybody had ever modeled were like dynamics he found only basic simulations that were a beautiful paper.
Prakash says but the authors weren’t thinking about the toys fundamental limits the papers mathematical models in other words were too simple for their purposes we wanted to understand the entire design space of the toy the team spend the next few months studying the complexities the of whirligigs system and converting them into a theoretical model the details of which they model the details of which they recount in the latest issue of the journal nature biomedical engineering they discovered that much of the toys power hinges on a phenomenon call supercoiling. When the string coils beyond a certain threshold it starts to form another coil on top of itself you can reproduce this phenomenon yourself by twisting your shoelace or a length of telephone cord a supercoiled string stores or energy which helps accelerate the disc higher and higher RPM the researchers use this and other observations to simulate a wide range of whirligigs physical prototypes came next they tweak the length of the string and the radius of the disk and tried a variety of materials from balsa wood to acrylics in the end though the groups settled on the same stuff, Prakash used to build his fold scopes.
Its synthetic paper the same thing many countries use in their currency Prakash says, it has polymer films on both front and back that make it waterproof and it’s incredibly strong as well plus they still had plenty of the stuff lying around now people are just starting to get access to paper fog this is a great example of how extremely creative people can originate important new ideas by relaxing and observing the world around them says Ray Bowman director of the Nanotech Institute at the university of Texas in Dallas, who was unaffiliated with the research his lab figured out that you can build artificial muscles by supercoiling fishing lines like the strings on the paper fuge and the applications of the described technology for resource-limited parts of the world might provide enormous human health benefits Prakash and Bama think so too the pier recently returned from a trip to Madagascar, where they’ve been coordinating with local healthcare worker on testing the paper future in the field the first people. we met with I thought they would laugh at me when I showed it to them Bhalla says he was wrong he remembers one woman, in particular, a diagnostic technician of 15 years who specializes in malaria. She told us, you think you know, you think you understand; the need for this tool but you don’t understand it like I do I’ve been looking for something like this for years in the past. She told him transporting centrifuges to remote villages required jeeps to haul them there and generators to power them now all she needed were her pockets thanks.