With a lot of ingenuity, some creative engineering and a few off-the-shelf items, a University of Florida team led by a virologist and an engineer have created an inexpensive, quick and accurate handheld device that can detect seven mosquito-borne illnesses.
Their design could help clinicians in low-resource or remote settings — from clinics in rural Haiti to farm animal veterinarians — diagnose patients without the need for a power supply, bulky equipment or extensive training.
John Lednicky , Ph.D., a virologist in the UF College of Public Health and Health Professions whose interests include mosquito-borne viruses, Z. Hugh Fan , Ph.D., a mechanical/biomedical engineer in the Herbert Wertheim College of Engineering , and colleagues describe the device’s development in the journal Analytical Chemistry.
“We wanted to create a diagnostic test that could distinguish between viruses that was relatively quick, cheap and didn’t require expensive instrumentation or a lot of training,” said Lednicky, a research professor in the Department of Environmental and Global Health.
Rapid detection is essential for treating patients as quickly as possible and limiting disease spread. In locations without access to laboratory testing, however, when patients present with classic virus symptoms such as fever, joint pain, fatigue and rash, clinicians may have to make their best diagnostic guess based on which viruses are believed to be circulating in their area.
“Many mosquito-borne viral diseases have similar symptoms, but each viral infection requires different clinical management,” said Fan, a distinguished professor in the Department of Mechanical and Aerospace Engineering . “We had to come up with an approach that differentiates them.”
The researchers, both members of UF’s Emerging Pathogens Institute , first applied the virus testing design in 2019 to answer the call for a rapid, point-of-care test for Zika virus. They later used the same technology to develop a test that distinguishes influenza virus from SARS-CoV-2 in the early stages of the COVID pandemic.
With National Institutes of Health funding, the team’s latest iteration is designed to test for seven viruses that circulate in Haiti, other Caribbean nations and many countries in the Americas: Zika, chikungunya, Mayaro and four types of dengue viruses. When validated with human samples, the device performed as well as a reverse transcription polymerase chain reaction, or RT-PCR, test, considered the gold standard of diagnostic testing for mosquito-borne viruses.
The UF device is based on related technology known as RT-LAMP. Like PCR, RT-LAMP can detect tiny amounts of genetic material from viruses, bacteria and other organisms. But instead of relying on repeated heating and cooling cycles, it works at a single temperature, allowing for simpler equipment and providing results in 30 minutes to an hour, compared with the one- to two-day turnaround often associated with PCR tests.
The team’s device is believed to be the first capable of simultaneously testing for seven viruses with RT-LAMP-based technology.
To scale a whole laboratory’s worth of equipment down to a miniaturized portable kit, the team got creative. The mechanics behind a ballpoint pen inspired their method to dispense liquid reagents needed for testing samples without using traditional pipettes. Expensive thermocyclers or bulky laboratory water baths were off the table, too. Instead, the team used a commercially available coffee mug with a USB port that holds the test samples at a specific temperature. A $12 blue light flashlight can be used to interpret the colors that represent positive or negative results.
The team is seeking patents for their technology and aims to integrate components of the device to make it even more user-friendly and inexpensive. While the USB-rechargeable coffee mug can be purchased for $60 to $100, that may even be too much for some resource-strapped areas, including regions where mosquito-borne illnesses are especially pervasive, such as southeast Asia and South America, Fan said.
With alterations to the chemistry, the researchers say the device could be used to test countless viruses, bacteria and other pathogens in humans, animals and the environment in a host of different settings.
“I’m most excited about the device’s simplicity, cost-effectiveness and that it is based on proven technology,” Lednicky said. “It’s easy to get excited about something that’s cheap and easy to use, but if it’s not based on effective chemistry, it’s meaningless.”
Experimental study