If two South Korean researchers have their way, the days of needing specialized equipment to test whether someone has strep, the flu, or other common illnesses may soon be numbered. The pair want to check for disease markers in a tiny drop of a bodily fluid by pressing it against a touchscreen, so your diagnosis could come straight from your smart phone. While there's no app for that yet, the scientists recently finished a proof-of-concept study showing that a touchscreen could differentiate between various concentrations of bacterial DNA---a first step towards diagnosing your disease by spitting on your iPad. How the Heck:
What's the News:
Touchscreens like those in smartphones and tablets work by detecting changes in capacitance, or how much electric charge a material can store. When you're using your phone, the touchscreen senses the relatively large capacitance change of fingertip vs. no fingertip. But, the researchers knew, touchscreens can detect much smaller differences. Using screens to measure the capacitance of a bodily fluid droplet could reveal the sample's contents, they hypothesized, since the type and amount of a pathogen would change a fluid's capacitance in a particular way.
To test that idea, the researchers made three solutions, each of which contained the DNA of Chlamydia trachomatis, the STD-causing bacteria, at a different concentration. The scientists then pressed 10 microliters of each sample on a touchscreen---and found that the screen could differentiate between the concentrations of bacterial DNA based on changes in capacitance.
What's the Context:
In other efforts to move diagnostics out of the lab, researchers have also been developing a wide range of lab-on-a-chip tests, making diagnostic devices far smaller---and often cheaper---than traditional equipment.
Not So Fast:
This was just a preliminary study; the researchers haven't yet shown that touchscreens can pick out what particular bacteria or viruses are present in a sample.
Personal electronics currently come with software that keeps touchscreens from being too sensitive, since no one wants sweat or other moisture in the environment to accidentally activate their phone. While phones and tablets could be set up to turn off that software during diagnosis, such a change would be expensive---and, therefore, unlikely unless it might prove profitable for electronics companies.
Reference: Byoung Yeon Won & Hyun Gyu Park. "A Touchscreen as a Biomolecule Detection Platform." Angewandte Chemie International Edition, published online October 26, 2011. DOI: 10.1002/anie.201105986 [via New Scientist]
Image courtesy of StrebKR / Flickr