Introduction: Diagnosis of COVID-19 is based upon clinical and in vitro approaches. Sensitive diagnostics are of major importance for rapid and accurate detection of infectious agents including the SARS-CoV-2. In this regard, the current study was designed to develop a sensitive Sandwich ELISA (S-ELISA) kit for the detection of SARS-CoV-2 whole particles as a serious threat to human beings.
Methods: For the development of a sensitive S-ELISA platform, our recombinant scFv antibody (which is developed by in-depth bioinformatics studies) was used as a primary antibody for coating the microtiter ELISA plates. Thereafter, the washing step was performed and blocking was done with the tween 20 in PBS buffer. The whole viral particles were added to ELISA plates in 20µg/well concentration. Incubation was done and the secondary antibody (the positive serum samples from COVID-19 patients) was applied as a detection antibody to each well. After the addition of HRP-conjugated A+G antibody and three times washing with PBST, reactions were developed through the addition of TMB (3, 3', 5, 5'- tetramethyl benzidine).
Results: The gathered results showed the specific binding capacity and high affinity of the purified scFv for the detection of SARS-CoV-2.
Conclusion: In the current study, the potent in-vitro reaction of the introduced recombinant scFv turns it into a possible candidate for diagnostics and by further investigations, it may be utilized as potent therapeutics.