Researchers in Illinois have used a smartphone in conjunction with a credit-card-sized test kit to diagnose four respiratory diseases in horses.
The low-cost, portable, smartphone-integrated system is said to be able to address the challenges of diagnosing infectious diseases in resource-limited settings, or in situations where a result is needed immediately.
The system has reportedly achieved detection limits comparable to those obtained by laboratory-based methods and instruments, in about 30 minutes.
Findings published in Analytical Chemistry showed the system was able to detect four horse respiratory diseases – equine herpesvirus-1, equine herpesvirus-4, Streptococcus equi, and S. Zooepidemicus. A related report in Biomedical Microdevices explained how the system was used to detect and quantify the presence of Zika, Dengue, and Chikungunya virus in a droplet of whole blood.
For the research effort, horses were used as an animal model for respiratory diseases in man and in food animals. The team of researchers is working on a next-generation chip that will have four more tests available.
“You can often more easily develop diagnostic tools for human use by coming in to development from the animal side of things first,” explains Dr David Nash, a key researcher involved in the project.
“Many diseases show up first in animals, kind of the canary in the coal mine,” says Nash, who is a private practice equine expert and veterinarian in Kentucky.
Discussing the financial impact of infectious disease outbreaks in horses, he says: “It’s costly to horse owners and trainers, and disrupts the business operations of all equine sports.
“Consider this — on December 25, 2016 a single horse stabled at the Fair Grounds Race Course in New Orleans experienced a fever and subsequently developed neurological symptoms.
“The state diagnostic lab was 100 miles away and was closed for the Christmas holiday. The end result was an equine herpesvirus-1 (EHV-1) outbreak that resulted in the quarantine of over 200 horses at the racetrack and a serious financial loss for horse owners and the racetrack owner.
“Imagine the consequences if they ever had to postpone the Kentucky Derby due to a disease outbreak.”
The technology is intended to enable clinicians to rapidly diagnose disease in their office or in the field, resulting in earlier, more informed patient management decisions, while markedly improving the control of disease outbreaks.
The system uses a commercial smartphone to acquire and interpret real-time images of an enzymatic amplification reaction that takes place in a silicon microfluidic chip that generates green fluorescence and displays a visual read-out of the test.
The system is composed of an unmodified smartphone and a portable 3D-printed cradle that supports the optical and electrical components, and interfaces with the rear-facing camera of the smartphone.
The software on the smartphone gathers information about the tests conducted on the microfluidic card, patient-specific information, and the results from the assays, that are then communicated to a cloud storage database.
“This project is a game changer,” says Nash.
“This is the future of medicine – empowered front-line healthcare professionals. We can’t stop viruses and bacteria, but we can diagnose more quickly.
“We were able to demonstrate the clear benefit to humankind, as well as to animals, during the proposal phase of the project, and our results have proved our premise.
“Next, I want to go into the field, multiple sites, multiple geographic locations, and test in real-world situations.”
University of Illinois graduate student and research assistant Fu Sun sees this project as fulfillment of one of her primary career objectives:
“I entered graduate school with the hope to make a better world by developing biomedical devices that can facilitate effective disease prevention, diagnosis, or treatment.”
The system represents the only platform to date that can multiplex detection of viral and other nucleic acid targets on a portable point-of-care setup using one droplet of bodily fluid, including whole blood.
Importantly, the system is capable of detecting multiple nucleic acid targets at the same time and, thus, is capable of identifying coinfections of multiple pathogen strains. By generating a positive/negative determination of the presence of specific pathogens, the mobile system can assist physicians in rapid point-of-care decision-making for treatment and quarantine response that is currently not possible with tests performed at central laboratory facilities.
The multidisciplinary group inolved in the project included personnel from University of Illinois at Urbana-Champaign and the University of Washington at Tacoma.