Sensitive detection of SARS-CoV2 spike antibodies by a paper-based polypyrrole/reduced graphene oxide sensor

The presence of antibodies (Abs) in the body is an indicator of the individual immune response to an infection. In the post-pandemic era, an accurate, cheap, and rapid antibiotic sensor is critically needed to monitor Ab levels. Therefore, we present a simple fabrication method for a highly sensitive electrochemical sensor that detects SARS-CoV2 spike Abs. The sensor comprises filter paper with a composite made of polypyrrole (PPy) and reduced graphene oxide (rGO). The rGO structure is observed using a scanning electron microscope and Fourier-transform infrared spectra (FTIR). The presence of rGO improves protein conjugation which is identified using a fluorescent microscope and FTIR. The sensitivity test performs high selectivity and reproducibility in two different SARS-CoV2 Abs separately and shows the range of detection limits between 10 and 1000 fg/mL. The results demonstrate an advancement in developing PPy/rGO composite sensors for SARS-CoV2 Ab detection and as a promising sensor for monitoring COVID-19 exposures and infections.