Cameroon, Africa.
Cameroon, Africa. Courtesy of Prakash Lab/ Stanford University

Throughout the world, in places like Africa, Latin America and Asia, millions of poor people suffer from infectious diseases, many of which disappeared long ago in the United States. Diseases like malaria and African sleeping sickness sap energy and cause vomiting, diarrhea, bleeding and even death. These diseases are caused by tiny microbes that are invisible to the naked eye. They’re often transmitted by unclean water, insects or poor sanitation.

Mosquito biting someone
Malaria is a disease that is transmitted by certain mosquitos that carry a microscopic parasite. If an infected mosquito bites someone, it can transfer the parasite to that person causing malaria. Courtesy of CDC/ Dr. William Collins

In just one example, more than a million people, mostly children under five years old, are killed by malaria each year, and more than a billion are at risk of infection. If people can be tested and helped in time, many of them can be treated or cured.

Doctors and health-care workers often use microscopes to figure out what is causing a disease so they can treat it with the proper medication. The problem is that there aren’t enough microscopes in poor and remote areas of developing countries, which results in many people going untreated or receiving the wrong medication.

Microscope and blood sample
Healthcare workers often take a sample of blood and look at it under a microscope to see what disease someone has. On the right is a blood sample that has the parasite that causes malaria (circled). Courtesy of Prakash Lab/ Stanford University (left) and CDC/ Dr. Mae Melvin (right).

There are many reasons why there aren’t a lot of microscopes in these parts of the world. Traditional microscopes are expensive, and these areas often don’t have the money or resources to buy or maintain such equipment. They’re heavy and cumbersome to carry on dirt roads to distant villages in slums, deserts and jungles. Over time, mold can grow on the microscopes’ lenses. The microscopes are also fragile and easily broken. Once a microscope is damaged it can be hard to find replacement parts.

Even a clinic that has a microscope may not use it. The tool is so precious that it often sits safely locked away in storage. Sick patients wait, but who — and where — is the expert who can use the tool?

Manu Prakash
Manu Prakash (left) traveling. Courtesy of Prakash Lab/ Stanford University

Manu Prakash, an assistant professor of bioengineering at Stanford University, knows about the lack of microscopes and access to health-care in these regions. He grew up in small towns in India and has traveled extensively throughout Africa, Asia and Latin America. Prakash dreamed of tackling this problem by building a simple, low-cost microscope that could diagnose diseases on the spot, a tool that was so sturdy, cheap and easy to use that it could help poor and sick people all over the world.

“Just saying, ‘Let’s buy microscopes and ship them around the world’ is a terrible idea,” he says. “We put them out in the field and they just die. And then we don’t have a way to fix them…. There is fungus growing on the lenses…. We saw an insect colony come out of a microscope…. So you really have to reinvent from the ground up.” 

In the end, he came up with the Foldscope. A Foldscope is a print-and-fold optical microscope that can be assembled from a single flat sheet of paper.

Manu Prakash and his lab at Stanford University have designed an origami based paper microscope, called a Foldscope. Having trouble viewing the video? Stream or download it here.

Sketch of matchstick microscope design
This is a sketch from Prakash’s lab book. One of the original ideas was to use a matchstick and matchstick box to build a portable microscope. Courtesy of Prakash Lab/ Stanford University.

When Prakash set out to design a fully functional, inexpensive microscope, he had many constraints.  It had to be lightweight and durable. It needed to be cheaply produced to keep the cost of each device to less than a dollar. It couldn’t rely on outside electricity, rare in many places. It had to be easy to use and replace. And, like a fancy microscope, it had to be able to examine a specimen on a glass slide, the traditional way to detect microbes.

Prakash calls his approach “frugal science.” He conceived of the idea in a rainforest in Thailand and a remote public hospital in Africa. When he returned to Stanford, he and his team turned his idea into a real thing.

Original sketch of Foldscope design
Early sketches for the look and feel of the Foldscope. The team realized that folding paper like origami could allow for precise alignment of parts of the microscope. Courtesy of Prakash Lab/ Stanford University

According to colleague Jim Cybulski, they tried many different versions using simple tools like a utility knife, rulers and Scotch tape before finding something that worked. They first tried using sturdy manila folder paper, and then they tried black paper because it blocked unwanted light, but each had its problems. The early designs let them see a microscopic image, but they weren’t easy to use. Finally, they found a solution using computer software, smooth printable plastic paper instead of plain paper, and a laser to precisely-cut the paper.

They developed a way to mount tiny lenses on paper and fold the paper so that the user can view a sample on a microscope slide. The pieces of the microscope are printed on a single sheet of thick, waterproof plastic paper. The paper also holds the tiny lens. The pieces are punched out, folded and assembled by following a diagram printed on the sheet — no written instructions necessary.

The microscope can be tweaked into a more sophisticated device, too. With added combinations of components, such as a watch battery, multiple lenses, stains or fluorescent filters, it gets even better at detecting specific organisms.

Different versions of the Foldscope
Evolution of the Foldscope design starting from the first prototype using a matchstick box (left) to the current design. Courtesy of Prakash Lab/ Stanford University

How well does the Foldscope work? It is now being used in clinical trials to earn official approval as a diagnostic tool. The Bill & Melinda Gates Foundation was so impressed that it awarded Prakash a $100,000 grant to test the Foldscope in India, Thailand and Uganda. His team is now busy designing Foldscopes to help diagnose 30 different diseases. Prakash also hopes to mass produce the Foldscopes so that everyone around the world can have access to this powerful scientific tool.

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