A smartphone app can record and transmit test results from a portable lab that people can plug into their phones. The lab uses saliva from plastic test strips that people put in their mouths like a sucker. (Credit: Joseph Fuqua II/UC Creative Services)

Researchers have designed a tiny portable lab device that plugs into a phone, connecting it automatically to a doctor’s office through a custom app. With a single drop of blood or saliva on a custom plastic lab chip, the device smaller than a credit card can diagnose infectious diseases such as the coronavirus.

While study did not expressly look at coronavirus, the researchers said it would have similar applications in diagnosing infectious diseases or tracking health conditions like depression and anxiety.

The phone provides the power and test protocol to the lab chip. A patient simply puts a single-use plastic lab chip into his or her mouth then plugs that into a slot in the box to test the saliva. The device automatically transmits results to the patient’s doctor through a custom app UC created for nearly instant results.

The research team created a novel lab chip that uses natural capillary action, the tendency for a liquid to adhere to a surface, to draw a sample down two channels called a “microchannel capillary flow 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.