Fig. 6.

Detection of SARS-Cov-2 S-RBD using the LF-AOB. (a) Schematic of immunosensing mechanism of SARS-CoV-2 S-RBD using the LF-AOB based on Fresnel reflection and immunoassay. The SARS-CoV-2 S-RBD protein binds with the captured antibody anti-S-RBD antibody immobilized on the fiber bio-probe, which reduces the reflection light intensity. (b) Typical signal curves of S-RBD detection using the LF-AOB; (c) Dose-response curve of S-RBD detection based on bifunctional bio-probe. The error bars corresponded to the standard deviation of the data points in three repeated experiments (n = 3).