Infectious disease is still the biggest causes of human death and disability worldwide, and are a particularly acute problem in developing countries where easy access to clinics equipped with up-to-date diagnostic equipment is often limited. But the rapid spread of smartphones has put advanced technology into the hands of many more people, and leveraging their capabilities for healthcare applications has become a subject of great interest.
The US team, spread across electrical engineering, bioengineering and mathematics departments at the Universities of Illinois at Urbana-Champaign and the University of Washington at Tacoma, developed a lab-on-a-chip system that can be mounted on a very portable credit card-sized carrier and read by the camera on an unmodified smartphone, providing diagnostics almost as sensitive and accurate as those of clinic-based equipment but potentially at a fraction of the cost. Moreover, the team claims, it can distinguish between diseases with similar symptoms, allowing the right treatment — or quarantine, if necessary — to be administered quickly.
The team was led by two Illinois professors, electrical engineer Brian Cunningham and bioengineer Rashid Bashir, and Tacoma Prof David Hirschberg, affiliated with science and mathematics at the School of Interdisciplinary Arts and Sciences. Also on board was Ian Brooks of the National Centre for Supercomputing Applications in Urbana-Champaign, and David Nash, a Kentucky-based specialist in respiratory diseases in horses.
“You can often more easily develop diagnostic tools for human use by coming in to development from the animal side of things first,” Nash explained. “Many diseases show up first in animals, kind of the canary in the coal mine." Moreover, he stressed, disease outbreaks in horses are a major financial drain on a locally-important industry, and as diagnostic labs tend to be far apart, there is a need for this kind of technology.
The lab-on-a-chip is equipped to carry out enzymatic tests on small samples of blood or sputum, and indicates results by inducing a green fluorescence that can be easily detected by a standard phone camera. The card is accompanied by a 3D-printed cradle that contains optics and electronics and holds the card and the phone at the optimum distance with the rear-mounted camera of the phone positioned over the chip’s readout section. Software on the phone gathers information about the tests on the card, patient-specific information, and uploads the test results to a cloud server.
The project's results have been published in two papers. In Analytical Chemistry, the team describes detection of four equine diseases, and in Biomedical Devices, they discuss how the system detected and quantified the presence of three mosquito-borne viruses — Dengue fever, Zika and Chikungunya, which all have similar early symptoms but different outcomes and require specific treatment— from a single drop of whole blood.
“This project is a game changer,” Nash said. “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.”
What’s more, he added, it could not have been done without a multidisciplinary team. “I can't envision going into a project without engineers now,” he said.