Figure 2. Synthesis of scFv Ab-conjugated aUCNPs.
(A) Expression and reaction of SpyCatcher (SC) and SpyTag-scFv Ab (ST-scFv), monitored by SDS-PAGE. Partially purified His-tagged scFv were incubated with an excess of SC. (B) MALDI mass spectra of purified SC and ST-scFv before and after conjugation. (C) High-angle annular dark field transmission electron micrograph of core/shell NaEr0.8Yb0.2F4 @ NaY0.8Gd0.2F4 aUCNPs. Scale bar is 50 nm. (D) Diameters of nanoparticles determined by dynamic light scattering (DLS), of hydrophobic (blue), PMAO-encapsulated (teal), SpyCatcher-functionalized (yellow), and scFv-conjugated (red) UCNPs. Mean diameters (n = 5) are 19, 21, 24, and 28 nm, respectively.