Rapid Detection of SARS-CoV-2 Spike Glycoprotein Using An Electrochemical Impedance Sensor

Faculty-development competitive research grants program for 2021-2022 (Covid-19 project)

Viral infections caused by e.g. influenza virus or norovirus have well-developed internationally approved protocols and procedures to identify and isolate the causative agent. The situation with COVID-19 is opposite since SARS-CoV-2 is an emerging virus. There are no vaccines and certain drugs available to treat COVID-19 patients yet, therefore, early diagnosis and detection of SARS-CoV-2 are important to contain the outbreak. In the proposed study, two types recognition elements, Spike S1 monoclonal mouse IgG1 and aptamers targeting SARS-CoV-2 RBD will be used and the binding efficiency will be evaluated using ELISA, ELONA, and SPRi techniques. The most sensitive recognition element will be further evaluated in the development of a biosensor based on an electrochemical impedance spectroscopy (EIS) incorporated with an interdigitated electrode (IDE) for the rapid detection of SARS-CoV-2 S glycoprotein. EIS is a simple, sensitive, and non-destructive technique. Moreover, EIS- based biosensors are well-suited to the detection of binding events happening on the transducer surface since minute changes in analytes that can be easily and rapidly detected. There is no information in the literature on an employment of aptamers for the detection of SARS-CoV-2 and development of a SARS-CoV-2 aptasensor. The proposed study will try to close this gap by having aptamers as biorecognition elements in the SARS-CoV-2 sensor development that will drastically decrease the cost of the technology as well as bring following advantages such as rapid detection, reusability, stability, as they can be selected and used under any pre-defined conditions. The capability to regenerate the function of immobilized aptamers on the surface of an electrode would be the most attractive characteristic of aptamers. Different surface chemistries will be investigated for their antifouling properties with combination of different aptamer linker type for the surface functionalization of an IDE. The performance of the SARS-CoV-2 S glycoprotein sensor will be further evaluated in artificial nasal fluid sample spiked with SARS-CoV-2 spike protein and/or heat inactivated SARS-CoV-2 strain. Based on available data we will also examine different putative molecular models of SARS-CoV-2 spike glycoproteins and their complexes, using mainly geometrical and physical approaches to (i) evaluate the quality of existing molecular structures, (ii) to generate putative molecular models for target molecular structures, (iii) to estimate physical interaction parameters and to verify physical forces/energies in protein-protein interactions, using known atomic force fields. We believe that the outcome of this proposed study will have a high social and economic impact not only in Kazakhstan, but also at a global scale as the development of rapid and sensitive detection tools has become increasingly critical nowadays. Moreover, the methodology and sensor that will be developed in the proposed study could be adapted to other emerging infectious diseases.The success of the methodology will also give us an opportunity to further explore the area by making the sensor commercially available device as a good way to diagnose COVID-19 at early or latent stages in the future. The results will be compared with the standard methods employed currently.