The invention provides a fusion ferritin protein wherein a ferritin heavy chain polypeptide is fused to a peptide, wherein the peptide is fused to the C-terminal end of the ferritin heavy chain; and the peptide includes at least a portion of a Mms6 protein sequence and at least one heterologous amino acid at its N-terminal end. The invention further provides methods of use of the ferritin fusion protein for Magnetic Resonance Imaging.