A novel nanoliposome model platform mimicking SARS-CoV-2 as a bioreceptor to dissect the amperometric response in biosensor applications

In this study, we proposed to investigate the response of an electrochemical-based immunosensor via nanoliposomes carrying the SARS-CoV-2 Spike-S1 protein. In this regard, we prepared RNA encapsulated nanoliposome functionalized with a specific SARS-CoV-2 Spike-S1 protein as a SARS-CoV-2 model. Then, this new nanoliposome mimicking SARS-CoV-2 was used as the bio-recognizing agent of an immunosensor developed to detect the SARS-CoV-2 within the scope of the study. The working electrode of the immunosensor was coated with chitosan polymer, decorated with SARS-CoV-2 Spike antibody, to achieve antibody-antigen matching on the electrode surface. SARS-CoV-2 mimicking nanoliposomes at various concentrations was used to achieve an amperometric response and the analytical parameters of the sensor were calculated from the relationship between the immunosensor's current values depending on the number of these matches with regard to varying antigen concentrations. Linear measurement range, LOD and measurement sensitivity were calculated as 53 pM–8 nM, 3.79 pM and 55.47 μA nM−1 cm−2, respectively. The standard deviation of the same measurements in the developed immunosensor was 0.33 %.