MALDI-ToF Protein Profiling as Potential Rapid Diagnostic Platform for COVID-19

Chivte, P.; LaCasse, Z.; Seethi, V. D. R.; Bharti, P.; Gaillard, E. R.

More than a year after the COVID-19 pandemic has been declared, the need still exists for accurate, rapid, inexpensive and non-invasive diagnostic methods that yield high specificity towards the current and newly emerging SARS-CoV-2 strains. Several studies have since established saliva as a more amenable specimen type in early detection and viral load quantitation as compared to the nasopharyngeal swabs. Considering the limitations and high demand for COVID-19 testing, we have employed MALDI-ToF mass spectrometry for the analysis of 60 gargle samples from human donors and compared the spectra with their respective RT-PCR results. Several standards including isolated human serum immunoglobulins and controls such as pre-COVID-19 saliva and heat inactivated SARS-CoV-2 virus were simultaneously analyzed to provide a relative view of the saliva and viral proteome as they would appear in this works methodology. Five potential biomarker peaks were established that demonstrated high consistency with PCR positive samples. Overall, the agreement of these results with RT-PCR testing was no less than 90% for the studied cohort, which consisted of young and largely asymptomatic student athletes. Further investigation of the potential biomarker peaks is necessary, however, from a clinical standpoint, these results are promising for a rapid and inexpensive COVID-19 assay.