New method to detect Covid-19 in less than five minutes detected by researchers

December 13, 2020 6:26 PM IST

Illinois [US]Dec. 13 (ANI): An ultrasensitive test using a paper electrochemical sensor has been developed that is capable of detecting the presence of the coronavirus in as little as five minutes, said researchers from the University of Illinois Grainger College of Engineering.
As the Covid-19 pandemic continues to spread around the world, researchers from various labs have come up with different strategies that can help track the virus.
The new study shows the possibility of detecting the virus through a rapid method with the use of a graphene biosensor adaptable to other viruses.
A team led by Professor Dipanjan Pan reported their findings in ACS Nano, which shows that a bioengineering graduate student, Maha Alafeef at the University of Illinois Grainger, has jointly developed a rapid, ultrasensitive test using a paper-based electrochemical sensor that can detect presence. of the virus in less than five minutes.
“Currently, we are experiencing a life-changing event once in a century. We are responding to this global need from a holistic approach by developing multidisciplinary tools for the early detection, diagnosis and treatment of SARS-CoV-2.” Alafeef said.
The two broad categories of Covid-19 tests on the market use real-time reverse transcriptase polymerase chain reaction (RT-PCR) and nucleic acid hybridization strategies to identify viral RNA, or focus on detection of antibodies. However, there may be a delay of a few days to a few weeks after a person has been exposed to the virus for them to produce detectable antibodies.
In recent years, researchers have had some success creating point-of-care biosensors using 2D nanomaterials like graphene to detect disease. The main advantages of graphene-based biosensors are their sensitivity, low production cost, and rapid detection response.

“The discovery of graphene opened a new era in sensor development due to its properties. Graphene exhibits unique mechanical and electrochemical properties that make it ideal for the development of sensitive electrochemical sensors,” said Alafeef.
This biosensor has two components, according to the study, which are: a platform to measure an electrical reading and probes to detect the presence of viral RNA. To create the platform, the researchers first coated filter paper with a layer of graphene nanoplatelets to create a conductive film. They then placed a gold electrode with a predefined pattern on top of the graphene as a contact pad for electrical reading. Both gold and graphene have high sensitivity and conductivity, which makes this platform ultrasensitive to detect changes in electrical signals.
Current RNA-based Covid-19 tests detect the presence of the N (nucleocapsid phosphoprotein) gene in the SARS-CoV-2 virus. In this research, the team designed antisense oligonucleotide (ASO) probes to target two regions of the N gene. Targeting two regions ensures sensor reliability should one region suffer a genetic mutation.
Furthermore, gold nanoparticles (AuNP) are coated with these single stranded nucleic acids (ssDNA), which represent an ultrasensitive detection probe for SARS-CoV-2 RNA.
The researchers demonstrated that hybridization of the viral RNA with these probes causes a change in the electrical response of the sensor. AuNP plugs accelerate electron transfer and, when transmitted through the detection platform, increase the output signal and indicate the presence of the virus.
The team tested the performance of this sensor using positive and negative Covid-19 samples. The sensor showed a significant increase in the voltage of the positive samples compared to the negative ones and confirmed the presence of viral genetic material in less than five minutes. In addition, the sensor was able to differentiate the viral RNA loads in these samples. “Viral load is an important quantitative indicator of the progress of infection and a challenge to measure using existing diagnostic methods,” the researchers stated.
Not only this, but this platform has powerful applications due to its portability and low cost. The sensor, when integrated with microcontrollers and LED displays or with a smartphone via Bluetooth or Wi-Fi, could be used at the point of care in a doctor’s office or even at home. (AND ME)