Janus-like protein cages. Spatially controlled dual-functional surface modifications of protein cages.

Protein cages have been used both as size-constrained reaction vessels for nanomaterials synthesis and as nanoscale building blocks for higher order nanostructures. We generated Janus-like protein cages, which are dual functionalized with a fluorescent and an affinity label, and demonstrated control over both the stoichiometry and spatial distribution of the functional groups. The capability to toposelectively functionalize protein cages has allowed us to manipulate hierarchical assembly using the layer-by-layer assembly process. Janus-like protein cages expand the toolkit of nanoplatforms that can be used for directed assembly of nanostructured materials.