By Benjamin Ross
March 13, 2020 | Engineers at the University of Cincinnati have developed a portable device that brings the capabilities of a diagnostics lab to the smartphone. The credit card-sized device, developed by Chong Ahn and his research team, was used to diagnose malaria in a study published in the Nature journal Microsystems & Nanoengineering (DOI: https://doi.org/10.1038/s41378-019-0108-8).
Ahn, Distinguished Research Professor and Director of the Microsystem and Biomedical Microelectromechanical Systems (Bio-MEMS) Laboratory, told Diagnostics World News that the focus of his team at the University of Cincinnati was to bring point-of-care testing (POCT) to patients by utilizing a readily available tool: the smartphone.
Over two and a half billion people own a smartphone as of 2018, Ahn says. “I’ve been thinking for a long time about how to bring a personalized lab-on-a-chip [LOC] to these people that can communicate with a mobile phone easily for the end-user’s convenience.”
Researchers and companies have been attempting to tap into the promise of smartphones as detection tools for years, understanding the power of handheld technology as POCT.
“The realization of an ideal POCT system largely relies on the development of cheap and disposable microfluidic devices that can be easily integrated to low power electronics with a user- friendly interface,” Ahn and his co-authors write.
While the smartphone is the ideal device for POCT, Ahn says the device by itself has certain limitations. For instance, smartphones offer a low power source, making it difficult to develop a functional microfluidic lab at a small scale.
Ahn’s solution was to develop a microchannel capillary flow assay (MCFA) platform that serves as its own power source. The to-be-named platform consists of a MCFA lab chip, a high-sensitive optical detector that attached to the smartphone, and a smartphone analyzer used for data display, data transfer, data storage, and analysis.
The platform connects to the smartphone via USB On-The-Go (OTG) ports, which, Ahn says, works as a communicator and power source for the platform’s optical detector. Unfortunately, the design of the USB OTG protocol limits the number of smartphones and tablets that can support the platform. Apple, for instance, hasn’t provided “an explicit way to provide a similar function,” according to Ahn.
Patients will either place the lab chip in their mouth for a saliva sample or prick their finger to collect a blood sample and place it directly on the chip. A natural capillary action built into the chip will separate the sample into two channels within the assay. One channel mixes the sample with freeze-dried detection antibodies. The other contains a freeze-dried luminescent material to read the results when the split samples combine again on three sensors.
“The developed whole system... is portable, user friendly, can perform fast and sensitive measurements and can be viewed as an ideal POCT analyzer with minimum intervention of end-users,” Ahn and his co-authors write.
The system is supported by a smartphone application, which provides users the ability to adjust test parameters and save results in order to present them to either medical practitioners such as their primary care physicians (PCPs) or to store for future analysis.
The platform produces results in 15-20 minutes, Ahn and his co-authors report. “The developed POCT based on smartphone thus greatly reduces the time and complexity associated with disease diagnostics, and for the first time a new concept of [MCFA] platform using lyophilized chemiluminescence substrate has been fully developed and reported.”
While initially used as a malaria diagnostic, the platform can be configured to diagnose other infectious diseases, such as Lyme disease and—more timely—coronavirus, in 3-4 weeks, Ahn says. He even foresees the platform being used to diagnose mental health conditions such as anxiety or depression, though he admits that capability won’t be attainable for a while.
For now, Ahn and his team are currently looking to make the platform commercially available, which Ahn hopes to be possible in the next year depending on the clinical trial and regulatory process.