Peptide-based biosensor for express diagnostics of coronavirus respiratory infections

At the end of 2019 the first reports appeared of a new coronavirus and WHO announced a pandemic of COVID-19. To date, the new coronavirus, now called SARS-CoV-2, has infected more than 25, 000,000 people and killed about 900, 000 worldwide. It is extremely important to develop means for express diagnostics to ensure prompt action to limit the spread of infection. One of the diagnostic approaches is the detection of viral particles in swabs. This approach can be realized using biosensor with specific ligands, based on peptide molecules complementary to surface viral proteins. The concept of the so-called Systems of Conjugated Ionic-Hydrogen Bonds (abbreviated - SSIVS, CIHBS) implemented in the Protein-3D computer program, was applied to analyze the spatial structures of the bonds between the SARS-CoV-2 spike protein and the ACE-2 receptor, in order to reveal the perspective peptide sequences. There are two clearly marked areas of contact of the spike with the cell receptor - upper and lower, which are visualized in the SSIVS form, and the complex formed at this site is strong enough to ensure its attachment to the coronavirus spike and can compete for binding with the ACE-2 receptor. Two peptides were developed that form a spatial structure complementary to the coronavirus spike: of 8 (No 1) and of 15 (No 2) amino acid residues. The peptides were covalently bound to biochip platforms via neutral linkers to form two sites, including: peptide No1, No 2. The third site has a neutral hydrophilic surface to serve as a reference. The platform was integrated with microfluidic channel and was used as a flow through device. The detection of bound viral particles was carried out using UV excitation and direct registration of viral proteins fluorescence. The preliminary laboratory tests demonstrated the efficiency of the biosensor.