Infectious diseases remain the world’s top contributors to human death and disability, and with recent outbreaks of Zika virus infections, there is a keen need for simple, sensitive, and easily translatable point-of-care tests. Since Zika virus infection shares symptoms with other diseases such as Dengue and Chikungunya, quick, accurate diagnosis is required to differentiate these infections and determine the need for aggressive treatment or quarantine.
A useful capability for human point-of-care (POC) diagnosis is to simultaneously test for the presence of more than one pathogen with a single test protocol, which lowers cost, saves time and effort, and allows for a panel of pathogens that may cause similar symptoms to be identified.
A low-cost, portable, smartphone-integrated system provides a promising solution to address the challenges of infectious disease diagnostics, especially in resource-limited settings or in situations where a result is needed immediately. The diagnostic tool’s integration with mobile communications technology allows personalized patient care and facilitates information management for both healthcare providers and epidemiological surveillance efforts. Importantly, the system achieves detection limits comparable to those obtained by laboratory-based methods and instruments, in about 30 minutes.
The system uses a commercial smartphone to acquire and interpret realtime images of an enzymatic amplification reaction that takes place in a silicon microfluidic chip that generates green fluorescence and displays a visual readout 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 application operating 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.
The system was used to demonstrate detection of four horse respiratory diseases, where the system was used to detect and quantify the presence of Zika, Dengue, and Chikungunya viruses in a droplet of whole blood. The horses were used as an animal model for respiratory disease in man and food animals, as many diseases show up first in animals.
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. An important prerequisite for the widespread adoption of point-of-care tests at the patient’s side is the availability of detection instruments that are inexpensive, portable, and able to share data wirelessly over the Internet.