Smartphone-based device can test for Zika at point of care
Researchers at Sandia National Laboratories have developed a smartphone-based diagnostic device that can detect Zika and other mosquito-borne viruses in 30 minutes or less, replacing expensive laboratory testing equipment that can take days for patients to receive test results.
The low-cost portable solution could help clinicians make faster decisions about patient care—particularly in resource-limited clinics—and enable them to rapidly alert public health officials so they can take action to prevent the spread of Zika among pregnant women, who are at risk of passing the illness to fetuses and causing congenital birth defects.
“I would describe it as a portable, handheld instrument that is capable of running the diagnostic assay for Zika,” says chemical engineer and project lead Robert Meagher of Sandia, which operates under the federal Department of Energy. “The operation of the device, which weighs less than a pound, is completely controlled by a smartphone.”
Researchers developed the prototype, which costs as little as $100 for the device and $20 for the smartphone, by creating an app that serves as a simple interface to operate the diagnostic device that leverages the smartphone’s camera sensors to replace conventional laboratory sample analysis tools.
“Detecting the Zika virus in 30 minutes is kind of the upper limit. Depending on how high the concentration of the virus is, you can start seeing positive results in as little as 5 minutes,” adds Meagher.
Traditional viral testing involves transporting a sample to a laboratory, extracting DNA or RNA from it and then multiplying the genetic materials through a process called polymerase chain reaction. However, Sandia researchers were able to successfully test their prototype through a process that involves heating and cooling a sample many times, so that any viral DNA/RNA in the sample is replicated enough to be detected.
“The kind of chemistry we’re employing right now is more of a yes/no detection, which detects if the virus is present or not,” says Sandia chemical engineer Aashish Priye, who was lead author of a study involving the device that was published online March 20 in the journal Scientific Reports.
According to Meagher, the research team “made it just good enough to do what it needs to do.” He adds that the chemistry involved is based on the loop-mediated isothermal amplification (LAMP) diagnostic method, which eliminates the need to process a biological sample before testing. As a result, Meagher contends that Sandia researchers have made the test simple enough that it could be performed in a point-of-care setting.
“Insufficient diagnostic capabilities are a key limitation facing current Zika outbreak management strategies,” states the paper. “The ability to detect Zika virus directly from crude human sample matrices (blood, urine and saliva) demonstrates our device’s utility for widespread clinical deployment. Together, these advances enable our system to host the key components necessary to expand the use of nucleic acid amplification-based detection assays towards point-of-care settings where they are needed most.”
Meagher points out that, during the height of the Zika transmission in South Florida last year, people were waiting weeks to get their laboratory tests “just because there was a backlog of samples waiting to be tested at a lab.” However, he acknowledges that Sandia’s device will not be available in the field anytime soon.
“We would need a commercial partner to help us do the technology transition,” Meagher concludes. “We’re a Department of Energy national lab. We’re not ourselves going to go into the business of manufacturing thousands of these and commercializing them.”
In addition, he says ultimately the diagnostic device would require regulatory approval by the Food and Drug Administration. “That’s where a commercial partner who has experience with clinical trials for diagnostics would come into play.”