Fig. 2

Schematic and characterization of the multi-epitope nanoparticles prepared with the SpyTag-SpyCatcher ligase system. A The ferritin sequence was ligated to the C-terminus of SpyCatcher and contained a 8 × His-tag at the C-terminus. The targeting unit (XCL1) was ligated to the C-terminus of SpyTag and the B-cell and T-cell epitopes ligated to the C-terminal of the targeting unit and to each other in tandem using a flexible linker (GGGS). The chimeric sequences were inserted into into pET28a ( +) between the BamHI and XhoI sites. SC: SpyCatcher. ST: SpyTag. B The 3D schematic diagram of nanoparticles. The magenta color represents the targeting molecule, the blue color represents the tandem multi-epitope, and the green color represents ferritin; C SC-Ferritin (lane 1), ST-XME (lane 2), and NanoFVax (lane 3) validated by SDS-PAGE analysis, lane M, protein marker (New Cell & Molecular Biotech, Suzhou, China). D Observation of ferritin nanoparticles by TEM, ferritin (left) and NanoFVax (right). E Size distribution of nanoparticles before and after conjugation by dynamic light scattering (DLS)