Fig. 3: Interference of the ACE2-RBD interaction by the sdAbs.

The recombinant human ACE2 protein was immobilized on CM5 chip using a BIAcore T200 machine and tested for the binding with gradient concentrations of SARS-CoV-2 RBD that were diluted in 100 nM sdAbs, including an isotype control sdAb (a), 1E2 (b), 2F2 (c), 3F11 (d), 4D8 (e), and 5F8 (f).