Newly designed porter proteins, which catch gold nanoparticles and deliver the nanoparticles selectively to a silicon dioxide (SiO(2)) surface under the specific conditions were reported. Recombinant apoferritin subunits, each of which has gold-binding peptide and titanium-binding peptide at the C- and N-terminus, respectively, can efficiently encapsulate a gold nanoparticle. The bio-conjugate, a nanogold and surrounding mutant protein subunits, had a property which can deliver itself to the SiO(2) surface through the interaction. In theory, our genetically manipulated apoferritin subunits can encapsulate gold nanoparticles of various sizes, which is a promising property for applications involving surface plasmon resonance.