Fig. 2From: Development of multivalent nanobodies blocking SARS-CoV-2 infection by targeting RBD of spike proteinExpression, purification and binding ability determination of monovalent nanobodies. a Schematic presentation of the vector for nanobody expression in mammalian cells. b SDS-PAGE detection of the expression and purification of recombinant nanobody-hFc fusions (55Â kDa). M: Marker; lane 1: Nb82-hFc; lane 2: Nb91-hFc; lane 3: Nb3-hFc; lane 4: Nb35-hFc. c Measurement the binding ability of recombinant monovalent nanobodies using indirect ELISABack to article page