Rapid smartphone test could diagnose mosquito-borne viruses in minutes
In areas affected by mosquito-borne viruses like Zika, dengue and chikungunya, rapid detection of the viruses is incredibly important for treatment and for preventing the spread of the disease. Typically, the lab equipment needed to diagnose these illnesses is the size of a microwave and costs up to $20,000.
The high cost and bulky size makes it hard to get these instruments to clinics in developing countries where these viruses are more widespread. Additionally, it often takes days to get results back to patients.
Researchers at Sandia National Laboratories have developed a battery-operated device that works with a smartphone app to detect these illnesses within 30 minutes. The small device weighs less than a pound and only costs $100. This is a major improvement over an MIT device that came out last year that could diagnose Zika in hours instead of days.
"In addition to creating an app that serves as a simple interface to operate the device, we were able to adapt smartphone camera sensors to replace traditional laboratory sample analysis tools, allowing for unprecedented mobility," said chemical engineer and lead author Aashish Priye.
The device uses the loop-mediated isothermal amplification (LAMP) diagnostic method, a rapid testing method. Conventional tests require that biological samples be processed by heating and cooling the sample many times to replicate the DNA or RNA in order to detect a virus.
The LAMP method uses biochemical agents so that the sample only needs to be heated once to about 150 degrees Fahrenheit for 30 minutes in order to test it. This means that a much lower power source can be used, like a battery.
The researchers combined that process with a technique that allows them to test for multiple viruses simultaneously. The user just places the smartphone on top of the device containing the sample and opens the app. The app turns on the heater for the LAMP reaction and after 30 minutes the smartphone takes a picture of the sample. An image analysis algorithm then scans the image determining the color and brightness of the glow from the reaction which will mean either a positive or negative diagnosis.
The system could help clinics quickly test and diagnose patients in one appointment, which gives them more time to treat and take measures to prevent the viruses from spreading. If Zika is detected in an area, doctors and government officials can quickly inform people to take precautions to prevent mosquito bites.
The low cost of the smartphone based device makes it accessible to clinics that don't have the resources for more expensive and power-hungry lab equipment.
"There are billions of smartphones in the world, even in developing countries, and this tool doesn't require the highest-end smartphone on the market," said Priye. "It only needs to have an optical sensor and be able to run the app."
To illustrate the point, the smartphones used in the testing of the device only cost $20.