Ferritin (Fa a cage-protein composed of 24 subunits, may carry small molecules inside the core of cage. To enhance the potential of FT as a more functional drug carrier, FT genetically-fused with silaffin R5 peptide at N-terminus (R5FT) and silica-enveloped cage protein (SiO2/R5FT) were developed. Doxorubicin (Dox) can be loaded into cage interior by re-assembly of R5FT. The release of Dox loaded in internal cages was retarded by the silica-coated matrix and showed the pH-controlled behavior, in which the release amount is larger in acidic environments than neutral. R5FT provides a biocompatible and eco-friendly manufacturing process for the drug laden silica nanoparticles over conventional production methods.