Smartphone-Based System Tests Saliva for Infectious Diseases

Engineers at the University of Cincinnati (UC) have created a tiny portable lab that plugs into a smartphone. The lab, which is about the size of a credit card, can diagnose infectious diseases such as coronavirus, malaria, HIV, or Lyme. It can also track hormones related to anxiety or depression. The patient puts a single-use plastic lab chip into his or her mouth and the saliva on the chip is tested. The device automatically transmits test results to a doctor’s office through a custom app developed at UC.

The lab chip uses natural capillary action to draw a sample down a capillary flow assay composed of two microchannels. The functionally designed microchannels, along with adequate hydrophilicity, produce a sequential flow of assay reagents and autonomously perform the ultrasensitive chemiluminescence-based assay for the detection of disease. This assay platform, which has no external flow control and simple chemiluminescence detection, can easily communicate with a smartphone via USB-OTG port using a custom-designed optical detector.

University of Cincinnati professor Chong Ahn developed a portable lab that plugs into your smartphone to diagnose diseases like malaria or coronavirus. The results are transmitted to one's doctor over a custom UC-developed app. Courtesy of Joseph Fuqua II/UC Creative Services.

Professor Chong Ahn and his team used the smartphone device to test for malaria. However, the assay platform could be customized for different biomarkers, opening the way for smart point-of-care testing for various infectious diseases with full networking capability at low cost.

Ahn said the device is accurate, simple to use, and inexpensive. “The performance is comparable to laboratory tests. The cost is cheaper. And it’s user-friendly,” he said. “We wanted to make it simple so anyone could use it without training or support.”

Researcher Sthitodhi Ghosh said the biggest advancement in the device is in the design of its tiny channels that naturally draw the sample through the sensor arrays using capillary flow. “The entire test takes place on the chip automatically. You don't have to do anything. This is the future of personal health care,” he said.

The research was published in Microsystems & Nanoengineering (www.doi.org/10.1038/s41378-019-0108-8).