Nanoreactors via encapsulation of catalytic gold nanoparticles within cowpea chlorotic mottle virus protein cages

Viral protein cage-based nanoreactors can be generated by encapsulation of catalytic metal nanoparticles within the capsid structure. In this method, coat proteins of the cowpea chlorotic mottle virus (CCMV) are used to sequester gold nanoparticles (Au NPs) in buffered solutions at neutral pH to form CCMV-Au hybrid nanoparticles. This chapter describes detailed methods for the encapsulation of Au NPs into CCMV protein cages. Protocols for the reduction of nitroarenes by using CCMV-Au NPs as catalyst are described as an example for the catalytic activity of Au NPs in the protein cages.