A Microscope Out of a Smartphone

Evergreen faculty member and Berkeley team contribute to river blindness eradication project.

Neil Switz with a variety of lenses.

Neil Switz with a variety of lenses. Photo by Shauna Bittle ‘98.

In the world of tropical parasites, relationships can get complicated.

Take, for example, onchocerciasis, a parasite passed to humans through black fly bites and a major cause of avoidable blindness.

A few years ago a veterinary drug called Ivermectin was found to be an effective treatment for river blindness, and mass drug administration efforts (involving the World Health Organization, the Bill & Melinda Gates Foundation, and others) helped eliminate the disease in many areas.

However, in some places, such as Cameroon, a second parasitic worm known as loa loa is also present, and people with sufficiently bad loa loa infections can die if treated with Ivermectin. As a result, a mass drug administration effort there had to be halted.

A microscopic view of loa loa—microfilaria.

Loa loa—microfilaria. Photo by Stefan Walkowski 3.0 via Wikimedia Commons.

Neil Switz, a biophysicist, finished his doctorate at UC Berkeley, working on similar technology for use in tuberculosis diagnosis. When National Institutes of Health (NIH) researcher Thomas Nutman brought the problem to the attention of Berkeley professor Dan Fletcher, members of the team in Fletcher’s lab thought they could provide a solution.

Switz designed a novel optical system to provide an extremely large field of view in a compact format for easy portability. Colleagues took this design and produced an elegant, miniaturized system with motorized sample handling, based around a custom iPhone® app. The system is a small box that attaches to an iPhone. In addition to special lenses for the phone camera, the box contains a Bluetooth®-enabled controller for LEDs and a tiny motor that moves blood samples under the lens. “You can see a lot of blood this way,” explained Switz, “which dramatically improves sensitivity.”

A cellscope attached to a smartphone is used to scan a blood sample for onchocerciasis and loa loa parasites.

A cellscope attached to a smartphone is used to scan a blood sample for onchocerciasis and loa loa parasites. Photo courtesy of Berkeley Fletcher Lab.

The team finished the first model in 2012, and a second-generation cellscope has already diminished the size of the box, making the system more nimble. Each test takes three minutes to process, with up to 40 tests during the time-window each day. “It is cheap, fast, takes no sample preparation, and little training,” said Switz, noting that the phone, an iPhone or Android®, is the scope’s most expensive component.

A new faculty member at Evergreen, Switz attended the college before transitioning to Stanford and later Berkeley. He called his time as an Evergreen student, “a transformative experience,” and is happy to be back in a teaching role. He said “Evergreen’s emphasis on the connections between theory and practice make it a fantastic fit for me and the sort of research I engage in.” Switz is currently teaching a program called The Science of Sensory Perception covering links between physics and biology.

A worker uses the cellscope at a hospital in Cameroon.

A worker uses the cellscope at a hospital in Cameroon. Photo courtesy of the National Institute of Allergy and Infectious Diseases.

“Evergreen taught me to take ownership of my learning. That lesson has been invaluable, both in school and out,” said Switz. He said he was especially lucky to take what was then a radical new computer-data-acquisition-based lab sequence, created by founding faculty member Fred Tabbutt and others, which allowed him to thrive. “That experience, and the emphasis at Evergreen on independent learning, served me very well at Stanford,” said Switz.

Evergreen’s interdisciplinary education model had real-world applications in the cell phone scope project, according to Switz.

“A project like this requires significant teamwork. You can’t do anything important like this without a team of people who have different skills and come from different perspectives,” he said.

He credited excellent collaborators, including the NIH and his colleagues in the Fletcher Lab, of whom he said, “they don’t just develop things—they try to get them into the field and into use.”

Switz would not go so far as to say this invention is revolutionary, but he holds hope that such scopes could be widely used in the future. “This scope is tightly tailored for this use,” he said, “but you can imagine a similar device being broadly applied.” As examples, he cited the possibility that a cell phone microscope could show white blood cell counts or diagnose parasites from stool samples. He also said data gathered by the software can provide a real-time map to chart the geographical spread of disease. “Location-enabled phones can immediately give you that information,” he said.

Though he realizes new medical devices can take years to achieve mass production and use, Switz said, “We hope that the use of low-cost optics for diagnostics can extend healthcare to underserved populations nationally and worldwide.”