High-density targeting of a viral multifunctional nanoplatform to a pathogenic, biofilm-forming bacterium.

Nanomedicine directed at diagnosis and treatment of infections can benefit from innovations that have substantially increased the variety of available multifunctional nanoplatforms. Here, we targeted a spherical, icosahedral viral nanoplatform to a pathogenic, biofilm-forming bacterium, Staphylococcus aureus. Density of binding mediated through specific protein-ligand interactions exceeded the density expected for a planar, hexagonally close-packed array. A multifunctionalized viral protein cage was used to load imaging agents (fluorophore and MRI contrast agent) onto cells. The fluorescence-imaging capability allowed for direct observation of penetration of the nanoplatform into an S. aureus biofilm. These results demonstrate that multifunctional nanoplatforms based on protein cage architectures have significant potential as tools for both diagnosis and targeted treatment of recalcitrant bacterial infections.