A fusion protein, a nanoparticle composed by a plurality of monomers of said fusion protein, and uses thereof. A fusion protein based on the heavy chain of human ferritin is de-scribed, which includes at the N terminus of the protein at least one metalloproteinase cleavage sequence and a modified PAS polypeptide that acts as a masking polymer that in-creases the protein drug stability, as well as a nanoparticle composed of multiple monomers of said fusion protein, a nucleic acid encoding for said fusion protein, and diagnostic and therapeutic applications thereof.