Biotinylated bionanocapsules for displaying diverse ligands toward cell-specific delivery

Bionanocapsule (BNC) is hollow nanoparticle composed of the l-protein of the hepatitis B virus surface antigen. BNC allows targeted delivery of either genes or drugs only to hepatocytes, but not to other cell types. In this study, we attempted to alter the specificity of BNC by insertion of biotin-acceptor peptide (BAP), which is efficiently biotinylated using biotin ligase BirA from Escherichia coli. Using streptavidin as a linker, biotinylated BNC could be display various biotinylated ligands that are otherwise difficult to fuse with BNC, such as antibodies, synthetic peptides and functional molecules. BAP-fused BNC was efficiently biotinylated and effectively displayed streptavidin. Furthermore, we demonstrated that biotinylated BNC was internalized into targeted cells via biotinylated Nanobody displayed on the BNC surface. Biotinylated BNC permit display of diverse ligands, and thus have potential as a versatile carrier for drug delivery to a variety of target cells.