New York, Aug 6 : A group of researchers has created a saliva-based, at-home Covid-19 testing device that can detect Covid-causing viruses with the same degree of the sensitivity of PCR tests in only 45 minutes.The study, which was published in the journal ACS Sensors, says the team created a palm-sized testing kit, which a person injects a test substance into a cartridge, then introduces it to the processing platform.
In just 45 minutes, the results of the test are transmitted to a customized Android application created by the team of researchers.
“PCR test results take around an hour to be developed in the lab.However, you need to consider in the time required to send the sample to an lab and then for the lab to take it in,” said principal investigator Weihua Guan, associate professor at Penn State University in the US.
“We wanted to develop an alternative to PCR that people could use at home without the need to endure the uncomfortable nasal test.” Guan added.
The platform utilizes reverse transcription loops that are mediated by isothermal amplification or RT-LAMP , to identify the virus.
The test device first heats the saliva to 203°F, the temperature at which the shells of viral particles break up and let out their genetic material.Genetic material is combined with prepared reagents in microfluidic cartridge.
The sample is then cool to 149 degrees and triggers a chemical reaction in which the viral molecules multiply into billions of copies and makes the virus more difficult to recognize.If the virus is detected in the saliva sample the user will get an positive result in their smartphone application.
To test the system they used human saliva samples purchased commercially with SARS-CoV-2 virus particles that were inactivated and then ran these samples through the test device.They also conducted tests on a few of clinical samples.
The platform accurately identified the positive or not for the virus.
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