The research team led by Professor Hyun Gyu Park of the Department of Chemical and Biomolecular Engineering developed a new technique for detecting biological molecules that uses smartphone touchscreens. This new method allows for the detection of disease-indicating molecules either by the surface capacitive touchscreen or by the projected capacitive touchscreen. The technology is expected to establish a new paradigm of disease diagnostics in which people diagnose common diseases by using personalized diagnostic devices rather than visiting the hospital.

A capacitive touchscreen is an input device commonly used in mobile electronic devices such as smartphones and personal digital assistants. It detects the locations of the touches made within the display area by sensing small capacitance changes that are induced by the contact with users’ fingertips. Researchers noted that DNA has its own capacitance and that the magnitude of the capacitance change on the screen depends on its concentration. Given that fact, researchers devised a touchscreen-based detection platform that utilizes signal information to detect and quantify DNA. The device was tested by applying DNA solutions on the screen and measuring the change in electric capacitance. The results showed that concentrations of unknown DNA samples were accurately determined in a manner that is comparable to results given by the conventional detection method.

Because DNA, as well as most biological molecules such as proteins and nucleic acids, has electric capacitances, this technology can be applied extensively to the detection of various biological substances. As of now, the technique can only detect the presence and concentrations of non-specific biological molecules. Researchers are working to improve the technology in order to enable selective detection of targeted molecules.

Professor Park said, “The study proved for the first time in the world that touchscreens, which have only been used as input devices for electronic equipments, have enough potential to be used for analysis of biomolecules. As this technology lays the groundwork, the times in which individuals can diagnose their diseases with touchscreen-based smart phones and tablet PC will soon arrive.”

The study was published as the cover paper in the January 16 issue of the chemistry journal Angewandte Chemie International Edition.