Just Curious

How a boy who played with fire (and mercury, and bleach) became a bioengineer who brought $1 origami microscopes (and paper centrifuges, and snorkel-mask PPE) to the world.

July 2021

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Just Curious

Linda A. Cicero/Stanford News Service (main photo); courtesy Foldscope Instruments, Inc. (insets)

A pencil on the sidewalk. Among our earliest childhood memories is one of the most iconic human tools lying in the dust, waiting to be picked up. But what if microscopy were as common as writing, and we had as many recollections: finding not a nub of pencil but a well-worn microscope; rummaging through a bookbag for that microscope you might have left in there; asking the kid at the next desk over if they happen to have an extra; or, in college, pulling one from your purse between tequila shots to peer at the speck crawling across the dive bar’s counter? This is Manu Prakash’s vision—not only of the microscope but of other heavy and dauntingly complex lab equipment: to shrink them until they fit in your pocket, to make them as cheap and ubiquitous as pencils. 

‘I love the small world. I feel I can escape in it. It’s just so beautiful, and everything around us is built out of it.’

Prakash, an associate professor of bioengineering and a senior fellow at the Woods Institute for the Environment, came up with this idea in 2011, in the Thai rainforest, at a rabies clinic equipped with a single high-grade Nikon microscope. “I had this really strange epiphany in which I could see this beautiful, expensive scientific instrument sitting in the middle of nowhere, but anybody who would want to touch it or do anything with it would literally be scared because one of the [lenses] on it is more than your annual salary,” Prakash says. He began contemplating not only how to create tools that would invite people to experience the science shaping their lives but also how such instruments might change the larger culture, much as the pencil has. “Access to tools,” he says, “can mean an incredible transformation in an individual’s capacity.”

The result of Prakash’s insight was the Foldscope, an origami microscope ingeniously crimped from a sheet of cardstock—with sliders to focus and adjust the view—and manufactured for less than a dollar. Its tiny lens has 140x magnification, similar to that of many research microscopes, allowing users to see objects as small as 2 microns. (A run-of-the-mill bacterium can be 1 to 2 microns thick and 5 to 10 microns long.) Prakash has since expanded on his vision of frugal science, at the core of which is his belief that education, human health and environmental stewardship are inextricably linked, requiring that people be given the means not only to understand but also to care for the earth and themselves. To this end, he has created an ever-growing repertoire of accessible tools, including a paper centrifuge called, appropriately, the Paperfuge and a programmable chemistry kit inspired by a hand-cranked music box. More recently, COVID-19 has pushed him to new innovative extremes: among them, upgrading full-face snorkel masks into reusable personal protective equipment and—vindicating the sweet-tooths among us—repurposing cotton-candy machines to spin polypropylene for DIY high-filtration masks. 

 EXPLORATIONS: Prakash  fell in love with the tiny miracles of nature on childhood walks with his cousins (far left). Through the Foldscope, he has enabled 1.5 million people around the globe to make their own discoveries.EXPLORATIONS: Prakash fell in love with the tiny miracles of nature on childhood walks with his cousins (bottom center, at left in tree). Through the Foldscope, he has enabled 1.5 million people around the globe to make their own discoveries. (Photos from bottom center: Courtesy Manu Prakash; Courtesy Foldscope instruments, Inc. (4))


But Prakash’s inspiration in many ways predates seeing the costly microscope in 2011. He first encountered microscopes as a schoolboy in India. “Only the senior students got access to the lab microscopes,” he recalls. Eager to share their experience, he took home one of the cardboard tubes holding the school’s badminton shuttlecocks and, after furtively disassembling his brother’s glasses, inserted the lenses into it. The microscope didn’t work, but within a few years, Prakash would find a source from which to buy proper lenses. “I revived that subconsciously many years later,” he says. “I love the small world. I feel I can escape in it. I can get lost in it. It’s just so beautiful, and everything around us is built out of it.”

At the root of Prakash’s creativity is a childhood of freedom and scarcity—an origin story in rural India. “All of us have some superpower,” he says. “I’ve always felt this is observation for me. Observing the world is really powerful. I get so much joy out of just watching what literally unfolds right in front of our noses.” But for Prakash, there’s also empathy: a second superpower that he sees complementing the first. “I grew up in environments where I didn’t have much,” he says, “and I carry that burden on my shoulders and in my heart.” He wants others to have the tools to share his joy at science and nature—the sense of wonder that has empowered him and carried him far: from the child manically tinkering and inventing, risking his life to test ideas, to the boy genius celebrated for his gifts despite less-than-perfect grades, and, finally, to his own lab at Stanford, where his inventions have brought him full circle. The tools he now creates are, in many ways, those he searched for as a child intent on explaining the world’s mysteries. 

Prakash was born in 1980, in Mawana, a village known for sugar cane production, in Uttar Pradesh, one of India’s northern provinces. “This is where, to go from one place to another,” he says, “you would hop on a bullock cart and just hitch a ride.” His earliest memories are of the summers he spent at the house of his grandfather, Sukhvir Singh Shastry (Shastry being an honorific for those who teach Sanskrit), of whose seven children six became teachers. Every morning at dawn, Prakash and his 15 or so cousins had to rouse themselves from their rooftop slumber to join their grandfather on a walk. “Even if we were so little, he would take all of us all the way to the river and back, which was a solid two-hour walk for a kid,” Prakash says. “Every single plant that we could point a finger at, he could say what it was. He could point every single bird, and he could tell what it was. And he would weave these really complex stories about what it means. It was a ritual.” The walks were unlike anything Prakash experienced at school, where the focus was on achievement, not observation. “My first memory of nature,” he says, “and the idea of connecting that with knowledge itself and observation really follows from those long walks.”

During those years, Prakash moved often; first, shortly after his birth, to Shamli, the hometown of his father, Brij, and then, so that his father could start a business as a general contractor, to Delhi, the crowded capital that made Prakash feel the intensity of the world. “Your senses are exploding,” he says. “You can smell the carburetors and the plastic being burned in one corner, and you can smell the sweets on the other end, and you can feel the mosquitoes on your skin, and you can feel the nice breeze coming from the peepul tree.” A few years later, when Prakash was 8, Brij suffered a serious brain injury in a motorcycle accident and was unable to work for months. Prakash’s mother, Sushma, had recently finished a PhD in political science and suddenly had to support the family. The first job offer came from a community college in Rampur—a town 120 miles east of Delhi. For a year, she took the Monday train that reached Rampur in the afternoon and she didn’t return until the weekend. After Brij recovered and began struggling to rebuild his business, Sushma and the two boys moved to a small house in Rampur, a place that would nourish Prakash’s love of experimentation. In the backyard, he and his brother, Anurag, came upon a little room attached to the landlord’s cow barn. “We opened it and found these beautiful instruments, like analytical balances and rheostats and things that are used in undergraduate laboratories, that were completely covered with spiderwebs,” he says. They learned that a previous tenant had given chemistry tutorials from the house and the landlord had claimed his laboratory in lieu of unpaid rent. Each day, while Sushma commuted to work and taught, the boys were alone. “As long as we would be back home for dinner, there was just this freedom to explore,” Prakash says. “I think that has really just been at the core of who I am.” 

One after another, Prakash’s projects obsessed him, and four years in a row, his team won the school science competition—most memorably for making a gasoline-filled model of the Mega Borg, a Norwegian oil tanker that caught fire and broke apart. As the judges inspected the meticulously crafted metal ship, Prakash flicked a switch, causing it to break in half and ignite the gasoline. (“Of course,” he says, “I should have anticipated that this would have made really a lot of people upset.”) To Prakash, fire was a subject more of curiosity than of danger. “You can’t really hold it in your hand, and that makes it fascinating,” he says. The morning after the Diwali festival, he collected firecracker duds littering the streets and split them, examining the gunpowder with a magnifying glass to determine whether finely or coarsely milled grains produced a different quality of fire. He then amassed gunpowder on a sheet of newsprint. “The question was what will happen if I combined the gunpowder from all of them,” he says. A plume of fire scorched off his hair and burned his hand, resulting in a hospital stay and a scar that he bears to this day. 

‘He told me I should ignore all of the thoughtful, articulate ones and I should take the difficult one, and that was Manu.’

Other schemes followed. Having found an English translation of a Russian book containing a diagram of the mercury motor created by 19th-century inventor Michael Faraday, Prakash asked a teacher for some mercury and was directed to its location in the lab. (“I thought he meant take [the entire bottle],” Prakash recalls. “When I think about it, it gives me chills that I had in my backpack a liter of mercury.”) Another time, after learning that rabbits have a similar number of bones to humans, Prakash bought one from a butcher and boiled its flesh off in bleach, stinking up his house. “My parents are vegetarian strictly by religion, and this is a huge no-no to be messing around with a dead animal in the house,” he says. As he spent months carefully reassembling the bones, he recalls being astounded that many were nearly too small to see—his first realization that the world is made up of ever-smaller components. 

In fifth grade, an experience at school galvanized Prakash’s attitude toward learning. As his teacher talked about rockets, Prakash asked for clarification on how they worked. “The teacher walked to me and slapped me,” he says. “When I look at education in a more philosophical way, I feel that when you don’t give kids the freedom to explore, it’s that slap, like shutting a door.” A sense of defiance took root. “After that,” he recalls, “I kind of was in charge.” Studying for university entrance exams—16-hour days under a kerosene lamp—he felt his creative self being stripped away. (“You become a machine,” he says.) But once accepted to the computer science program at the Indian Institute of Technology in Kanpur, he gave himself over to his creativity, pouring himself into designing an artificial intelligence program that could draw like a child. “I read a lot of psychology books,” he says. “I spent time in schools in the nearby areas just watching how kids draw.” He also started a popular club in which students made robots from trash. But he maintained only passable grades, and prospects for grad school were slim.  

But then, Neil Gershenfeld, the director of MIT’s Center for Bits and Atoms, gave a talk to an overflowing hall at IIT. “Afterwards, I was swarmed by students,” Gershenfeld recalls. “Generally, as a group, they were thoughtful, articulate, very impressive, but there was one outlier. There was this cranky, intrusive, difficult student who wouldn’t shut up, who wouldn’t leave me alone, who kept following me. While all the others were asking questions, this student was kind of telling me things rather than asking me things, and just sort of all in all very annoying.” Not long afterward, when Gershenfeld was evaluating graduate applications back at MIT, he spoke with the director of IIT Kanpur. “He told me I should ignore all of the thoughtful, articulate ones and I should take the difficult one,” Gershenfeld says, “and that was Manu.”

Prakash’s transcripts didn’t worry Gershenfeld. The Bits and Atoms initiative—focused on the boundaries of the physical and digital—attracted outliers. “Manu in no way tried to accommodate to what you needed to do to rate highly,” Gershenfeld says. “He did what he needed to learn and process things on his terms.” As part of its outreach, the center sets up fab labs—community labs equipped for digital fabrication—around the world. Prakash traveled to several countries with Sherry Lassiter, the director of that effort, to establish labs. “It started back then—his interest in empowering communities both to understand technology and science and to have the power to create that technology for their own purposes,” Lassiter says. She recalls how he designed a thermometer made by lamination that could be manufactured for less than a penny. But Prakash also stood out for the passion with which he shared what he learned. “He was a model for us,” she says. 

Nadya Peek, an assistant professor in human centered design and engineering at the University of Washington, overlapped briefly with Prakash in their doctoral program at MIT. She recalls how he became obsessed with their lab’s new CT scanner (which used X-rays to create 3D reconstructions) and repeatedly scanned insects and water droplets in an attempt to observe how the bugs drank, since their small size necessitates a strategy to overcome water’s surface tension. Once, when she complained of seeing a cockroach in her part of the lab, he ran off to find it and scan it. She recalls that with each new obsession, he worked days on end, taking brief naps and showing no sign of having gone home. “He’s intensely focused on the thing that he wants to figure out and everything else he’s just like, ‘I don’t care,’” she says. Prakash was also constantly looking for calipers, intent on measuring much of what he saw. When Peek cleaned out Prakash’s lab area after he graduated, she found more than 70 of them. 

At MIT, Prakash did his dissertation on building a computer out of air bubbles, demonstrating that computing can be applied to the processing of materials as well as information. He continues to explore the idea that humans might someday learn from nature how to program matter to self-organize, the way, as a hand grows, it attains its “immense complexity,” he says. “Your hand has on the order of a trillion or half a trillion cells. To build an object of that same complexity with a 3D printer–type approach would take multiple decades, but biology does it because of an algorithmic approach.” This obsession created an immediate bond when he met his future wife, Sophie Dumont, a biophysicist from Quebec and now an associate professor of bioengineering at UCSF. Both were junior fellows at Harvard’s Society of Fellows, a three-year program that allows time to pursue studies however one might choose. “When I asked her what she works on,” Prakash recalls, “she said something in a very cryptic but beautiful way. She said, ‘I figure out how cells count.’” The idea captured his imagination—cells counting when replicating billions of times, segregating new chromosomes into new cells, rarely making errors. 

Not long after they began dating, Dumont learned that Prakash wouldn’t receive his doctorate due to unpaid library fines, the result of six years of driving his car to the library, loading it with 50 or 60 books and not returning them on time, or ever. “He had bought his parents their first tickets from India to visit for his graduation,” Dumont recalls. “The entire goal of their trip was to see him get his degree, but then, maybe a week before, he was told he wasn’t going to graduate.” The symbolism of the moment, if not the money spent on tickets and visas, made her want to help. She asked her brother for a loan to cover the fines—around $10,000. (Prakash hasn’t entirely changed his ways: “One thing I feel glad about at Stanford is that as faculty you don’t get fined, or at least I’m not aware of it . . . I don’t know, but I should check.”)

Prakash joined Stanford’s faculty in 2011. Since his lab wouldn’t be ready for nine months, he embarked on fieldwork with infectious disease institutes in India and Thailand. During that time, he had the inspiration for the Foldscope, which he would later design with one of his first grad students, Jim Cybulski, PhD ’15. “I decided to make 50,000 of them in a lab at Stanford and ship them for free to anybody who would ask for it,” Prakash says—the best choice of his career, he believes. A $100,000 grant from the Moore Foundation enabled him to realize his vision, supplying not only $1 for each Foldscope but also funds to set up manufacturing in the lab and to ship worldwide. “That was the seed of what is now known as the Foldscope community,” Prakash says. 

Today, Foldscopes are easily available online, and 1.5 million have shipped. More than 500 peer-reviewed papers have been published on uses including environmental research, animal health, agriculture and education. Daily, users upload photos—taken with the Foldscope’s smartphone attachment—to the Microcosmos, an online forum. While Prakash admits to having 120,000 unread emails, he frequently peruses the images: fern rhizomes, onion peel cells, bioluminescent microbes, the barbs of a pigeon feather, the pitted lunar surface of Vicks VapoRub. 

Prakash himself often uses the Foldscope to inspect the world around him. In Palo Alto’s Baylands Nature Preserve, he observed the single-celled organisms Spirostomum perform simultaneous ultrafast contractions—a defensive reaction coordinated without any known signaling—and published a paper describing the phenomenon. But while his lab works both to make basic-science discoveries and to develop more tools for frugal science, he also wants to study how the natural world is transforming. “All of us need to become conservationists and see the dramatic changes,” he says. The challenge is giving people the tools. “There are a million Foldscopes out there but 2 billion kids,” he adds. This passion for science and outreach is, Gershenfeld points out, striking. “I’ve been with Manu in state-of-the-art research settings and in labs in remote villages, and he doesn’t draw any distinction. It’s all part of his discovery.” 

 WHO’S  ZOOMIN’ WHO:  Foldscope users upload photos of their finds to the Microcosmos online community daily. WHO’S ZOOMIN’ WHO: Foldscope users upload photos of their finds to the Microcosmos online community daily. (Photos: Courtesy Foldscope instruments, Inc. (2))


As Prakash’s frugal science projects expand, the minuscule world remains a theme. In 2020, his lab published the design for the PlanktoScope, a microscope that pumps seawater past lenses and can be easily assembled for a few hundred dollars. Prakash is encouraging the amateur sailing community worldwide to use the PlanktoScope to map the effects of climate change on plankton, which underpin the planet’s food chain and assimilate 30 to 50 percent of its carbon dioxide. “We can really be measuring the planet at the scale that changes are happening,” he says.

Prakash’s lab has also built the Octopi (open configurable high-throughput platform for infectious disease diagnosis in the field), a device that scans blood for malaria 120 times faster than a person can using a traditional microscope. With components also costing a few hundred dollars, it doesn’t use conventional optics (no one stares into an eyepiece) but rather a neural network trained to recognize malaria from 20,000 images. “Diagnostics is the key, because we actually have a cure for malaria,” he says. “But the methods used to detect it are literally 100 years old.” 

Not long after Prakash released the Octopi, the global inequities driving him to make cheap tools for science and health care were thrown into stark relief with COVID-19, which disproportionately harmed low-income communities. “In delivering and building health care, if we don’t plan actively for access, we will always end up in these situations no matter how much or how hard we try,” Prakash says. “If you’re going to think about health for all, you have to account for the affordability of it. Otherwise, it’s almost as if it doesn’t exist.”

Prakash immediately set to work. Since the pandemic’s start, 23,534 Pneumasks—full-face snorkel masks converted to reusable PPE—have been deployed around the world, and the PufferFish, a cheap, open-source ventilator on which he collaborated, is being manufactured in India and Kenya. He has worked on decontaminating N95 masks and invented a COVID-19 saliva test that could retail for as little as $1. And one day, while pausing to gaze through a Foldscope at cotton candy—sugar spun into the sweet fibers so popular in his youth—he realized that it resembled filtration material. He ordered several cotton candy machines off Amazon, and his lab began spinning polypropylene like that used in N95 masks to show that this approach could be deployed in a pinch. 

Today, Prakash and Dumont live in San Francisco and have twin 4-year-old daughters. He travels to India once or twice a year, visiting his parents, who offered him the freedom to explore, and his grandfather, who opened his mind to observation—two passions that have led him to believe that we have much to learn from nature. “I am of the opinion that we don’t even know in the 21st century what is possible, what biology can do,” Prakash says. He believes that by building new tools and making them widely available, more and more organisms will be studied, though the revelations won’t be obvious. “Nature has its way of hiding its secrets, and sometimes the fundamental work of making discoveries in biology is underappreciated and only the work of translating it to give a certain value is valued,” he says. “I want to flip that argument. These are both equally important, and we are lacking in the discovery piece.” 

While many of Prakash’s projects may seem distinct, they revolve around the three interwoven threads of his vision: education, health and the environment. “If you cannot provide opportunities and a healthy livelihood for people, they will always have to live lives that will have environmental impacts,” he says. “If you cannot create environments that nurture, you will always have health impacts degrading the environment. If you cannot build infrastructure around education, people will neither believe in the health systems and the health services that are available, nor value the environment as much as we should.” 

Despite time spent encouraging governments to equip schools with affordable scientific tools, he doesn’t see his role as the person shouting from the rooftops. “I want to turn stones,” he says. He is most passionate about imparting the curiosity that sends him back into nature. “I don’t see many students walking around the campus—it’s a beautiful campus with tons of nature—just exploring the environment,” he says. “If I was transported 50 or 100 years ago, my intuition is that I would have seen students poking at what’s growing in the backyards or in Lake Lagunita. We really have to make sure that we are getting out of the labs.”

Deni Ellis Béchard was a senior writer at Stanford. Email him at stanford.magazine@stanford.edu.

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