Clip-on detector enhances Zika virus testing

By Aarushi Aggrwal, Staff Writer

Following the COVID-19 pandemic, many have forgotten about Zika fever, a mosquito-borne disease that spreads through the Zika virus. For most, symptoms include a fever and cold for a few days, but for pregnant women, Zika can mean congenital disabilities.

Since the large Zika outbreaks in the Americas during 2015 and 2016, the number of cases has been on the decline. However, the virus has not been eradicated, spreading in Africa, Brazil and other underdeveloped countries; 2021 alone saw over 20,000 cases of Zika fever.

For pregnant women, the Zika virus may cause miscarriages, stillbirths and other congenital disabilities in children, including microcephaly — being born with an atypically small head.

Testing is expensive and time-consuming, and existing methods include Enzyme-Linked Immunosorbent Assay, or ELISA, and PCR testing. These tests require highly-trained personnel, purification of the test samples and bulky equipment.

A team of researchers at the University have developed a simple and inexpensive smartphone clip-on Zika virus detector. The team was led by Brian Cunningham, professor in Engineering, who guided PhD students that worked on the detector.

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“We’ve been developing this method for several years,” Cunningham said. “We used it initially for HIV, then more recently, we’ve pivoted toward Zika, Dengue and Chikungunya (viruses). During the pandemic, we adapted the test for COVID diagnosis from viral swab media.”

The device is small, user-friendly and can be used at home without any laboratory equipment. One test can be done with about one droplet of blood (12.5 microliters), and the samples do not need processing. 

To test, the user mixes their blood and transfers it into a separate chip on the core module. The module is inserted into the device, where an app on the smartphone captures and processes images of the reaction site.

Han-Keun Lee, a graduate student studying electrical and computer engineering, is one of the main faces of the project. He highlighted the advantages his teams’ device has over traditional methods.

“Our device requires very minimal training and is much cheaper than the laboratory tests,” Lee said. “Once factory manufacturing starts, it shouldn’t cost over $5. Additionally, the test is amazingly fast. The sample-to-answer time for PCR is usually more than two hours, and the results come in about half a day. But for now, our device can complete the test in 40 minutes.”

The team is still developing a more compact, smaller version of the instrument that people can carry around in a pocket, without the hefty price tag.

Weijing Wang, a graduate student studying bioengineering, is one of the main researchers with Lee. She explained how the image-processing app works.

“Our image-processing app allows us to shorten the whole detection time as compared to the desktop PCR,” Wang said. “One can see the little balloons forming in the channels. We’ll be able to shorten the time even more, around 5 (to) 10 minutes, because of those images.”

The device can be extended to many more diseases and infections. For instance, swine flu in pigs can be detected using a modification of the device.

Lee said a major part of the project was collaboration with people from varying fields.

“This project came about through a lot of collaboration, so it is important to be able to work with other people to achieve something better,” Lee said. “Modern research requires a lot of interdisciplinary studies.”

Wang noted it was a pleasure to work with such students from so many fields. She gave insight into how the work was divided in the team.

“If you look at the authorship, some of us were developing the assay, some on the cartridge and others working on image processing,” Wang said. “Everyone worked their part, and we produced an exemplary outcome together.”


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