Gold nanostructure orchestrated electrochemical immunosensor integrated with Antibody-Electroactive Probe Conjugate for rapid detection of SARS-CoV2 antibody

Nanomaterials play a major role in the development of both advanced and conventional diagnostic devices. Gold nanomaterials (Au nanoparticles, nano-flowers, magnetic nanobeads, nano-composites, etc) have been widely reported in various sensing technologies, owing to their distinct morphological, optical, electrical, chemical, and physical properties to improve the overall sensing quality. Apart from improving the interface properties they can also be easily functionalized and conjugated to bio-molecules to act as a reporter in colorimetric sensors. Herein, the presented work reports the fabrication of the electrochemical immunosensor for rapid SARS-CoV2 antibody (CoV2-Ab) detection in the blood serum samples with a linear detection range of 10-100ng/ml, linearity R²=0.96, sensitivity 0.013µA(ng/ml)^-1cm^-2, LOD=3.59ng/ml and LOQ=11.84ng/ml. For the fabrication of the immunosensor, the electrode base was modified with a bio-polymeric layer and then coated with gold nanostructures to enhance the electron charge transfer. The SARS-CoV2 antibody capturing probe was then immobilized to the electrode to detect different concentrations of SARS-CoV2 antibody. To further enhance the readability, electroactive material tagged secondary antibody was used as the reporter, that also amplifies the electrochemical signal in presence of its mediator. The present immunosensor demonstrates a nano structure-based platform for rapid detection of viral antibodies (SARS-CoV2 Ab) and the concept can be used for the development of rapid sensing platforms for different viruses.