Mobile device detects Zika virus via smartphone

Scientists at an American laboratory have developed a prototype for a mobile device that, through the use of a smartphone, is able to simultaneously determine within 30 minutes whether someone has Zika, dengue fever or the chikungunya virus.

The detection method uses pieces of the viral DNA, which are tagged via a fluorophore. A fluorophore is a chemical compound that, when irradiated with light, in turn emits light of a different wavelength. Thanks to a specially developed technology, the samples with viral DNA light up, while non-viral DNA remains dark. The smartphone’s camera sensor photographs the sample, with a specially developed algorithm from the accompanying app being able to measure the brightness and color of the light. A lab technician can also do a visual assessment, but the combination of the camera sensor and the app’s algorithm would be more accurate.

The device works with loop-mediated isothermal amplification. In this diagnostic method, the viral DNA is copied, after which it is heated under a fixed temperature of 65 degrees Celsius for half an hour. It is not necessary to first process the samples of blood, urine or saliva to isolate the DNA or RNA.

This method, which the researchers published in the journal Scientific Reports, is much simpler and cheaper than the traditional way of determining whether someone has such viral DNA, according to the makers. The traditional way involves isolating the DNA or RNA. This is done with a thermocycler, a device that can isolate the DNA from the samples through temperature fluctuations. This process, the polymerase chain reaction, takes a lot of power and time because the thermocycler has to heat and cool the samples more than once. Expensive fluorimeters that measure the intensity of the light must be used. In total, it would soon cost 18,500 euros.

The device is in fact a small mobile laboratory, a box in which the measurements are performed. It can be supplied with power via a USB connection. According to the scientists, this device costs about 93 euros. According to the makers, the total costs are therefore mainly determined by the purchase of the smartphone used. They say they used a smartphone of 18 euros when testing; the phone only needs an optical sensor and must be able to run the app.