Adding support to the Health Minister’s promise that India will be able to produce RT-PCR and antibody test kits by the end of May, researchers from the National Institute of Animal Biotechnology (NIAB), Hyderabad, have developed a biosensor that can detect the novel coronavirus in saliva samples.
Biosensors have been currently used across the world to detect toxins, narcotic drugs, and are also considered as a reliable tool to detect infectious diseases.
New device
The new portable device named eCovSens, can be used to detect the presence of novel coronavirus antigens in human saliva within 30 seconds using just 20 microlitres of the sample.
The in-house built biosensor consists of a carbon electrode and the coronavirus antibody. The antibody is capable of binding with the spike protein found on the outer layer of the virus. An electrical signal is generated when the antigen and antibody binds.
Electrical components in the device further amplify this signal, process it, convert it to digital readings on an LCD display.
The device can also be connected to a computer or cellphone via Bluetooth and studied. The signal’s intensity was found to be proportional to the concentration of the antigen in the sample.
Battery-operated
The device can also be battery-operated as it uses very low voltage of 1.3V to 3V. The team also compared eCovSens to a regular potentiostat and found the new device to be ultrasensitive and quicker.
“The device is portable and can be taken to the bedside of the patient too. Also, it requires only a very small amount of saliva. The device is stable and when built in bulk can drastically bring down the cost of testing. The validation studies using saliva samples from coronavirus patients are yet to be done,” explains Dr. Sonu Gandhi from DBT-NIAB, Hyderabad, and corresponding author of the paper posted on the preprint server bioRxiv on April 29. It is yet to be peer-reviewed and published in a scientific journal.
Other viral antigens
Cross-reactivity studies were done to check if the antibody in the device binds with any other viral antigen. No electric current was generated when tested with antigens of the Avian influenza virus. The paper adds, “the device can be customised to any target analyte, and can also have other future applications for detection of various other ailments.”
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