Apoferritin-camouflaged Pt nanoparticles: surface effects on cellular uptake and cytotoxicity

Apoferritin-encapsulated Pt nanoparticles (AFt-Pt) were bio-mimetically prepared by an in situ reduction method in the unique 8 nm spherical cage of apoferritin. The average size of AFt-Pt was 4.3 +/- 0.9 nm. The spherical structure of apoferritin remained intact after loading Pt particles in its cavity. Apoferritin coating increased the amount of Pt internalized in HepG2 cells by about three times via receptor-mediated endocytosis. AFt-Pt showed greatly improved biocompatibility compared with polyvinylpyrrolidone stabilized Pt nanoparticles (PVP-Pt). More than 80% of cells survived after treatment with 100 mM AFt-Pt for 48 h. By camouflaging the particles with a protein corona, apoferritin conferred a cell-recognizable identity to the particles, which strikingly ameliorated the bio-effects of the nanoparticles.