Figure 8.

Reagent‐free SARS‐CoV‐2 biosensor. a) Receptor binding with viral particles increases the hydrodynamic diameter and subsequently influences the required time for the redox tag to contact the electrode's surface. b) Biosensor architecture based on immobilized DNA linker with a redox tag, conjugated with antibody against spike proteins and c) negatively charged bioreceptor swings across the electrode when a positive potential is applied, which cause a shift in the hydrodynamic drag force detected by chronoamperometric methods. Adapted with permission.^{[ 66 ]} Copyright 2021, American Chemical Society.