Diagnose yourself by spitting on your touchscreen

The remarkable sensitivity of touchscreens can distinguish between different concentrations of liquids. Could phones one day identify ailments with just tiny drops of saliva?
Written by Janet Fang, Contributor on

Sure, you could collect a saliva sample and send it off to a lab for analysis, easy enough. But what if you could just spit on your screen, and then have your phone or tablet do all the lab work?

Byoung Yeon Won and Hyun Gyu Park from Korea Advanced Institute for Science and Technology suggest that all you need to do is press a tiny droplet of the sample against a phone’s touchscreen, and then an app would figure out whether you have food poisoning, strep throat, or the flu, for example. New Scientist reports.

Touchscreens sense a fingertip’s ability to store electric charge – known as its capacitance.

Turns out, the capacitive sensitivity of touchscreens is much higher than what we need on a daily basis (that is, playing games on the subway doesn’t require much sensitivity). "Since these touchscreens can detect very small capacitance changes, we thought they could serve as highly sensitive detection platforms for disease biomarkers," Park says.

So, the duo devised a way to harness touchscreen power into a lab-on-a-chip and tried to provide some proof-of-concept.

They put drops of 3 different solutions – each containing varying concentrations of DNA from the chlamydia bacteria – onto a multitouch display the size of an iPhone’s.

With drops as small as 10 microliters, the screen was able to distinguish between the capacitances caused by each of the different concentrations of bacteria DNA.

For now, the tech can’t identify specific viruses or bacteria from the sample – but the ability to tell the difference between concentrations is a promising step.

However, any changes to current production-line touchscreens would need to demonstrate huge financial benefits before they’re implemented.

Also, the team’ll need to figure out how to eliminate false-touch signals from sweat and other kinds of moisture. And they also want to make a film that will stick on the screen: "Nobody wants direct application of bio-samples onto their phone," Park says.

The work was published in Angewandte Chemie International Edition.

From New Scientist.

Image from Won and Park

This post was originally published on Smartplanet.com

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