The effect of particle size and protein content on nanoparticle-gold-nucleated cytochrome c superstructures encapsulated in silica nanoarchitectures

Abstract We recently reported the encapsulation of a heme protein superstructure within a sol–gel-derived material processed to form gas-phase-active bioaerogels. The protein superstructure, nucleated in the liquid phase by colloidal gold, protects cytochrome c protein molecules within the superstructure to the extent that they survive the harsh physical and chemical processing conditions necessary to form the aerogel and retain long-lived stability at room temperature. In this investigation, we report the effects of altering the size of the colloidal metal nanoparticle upon the viability of the aerogel-encapsulated proteins, and examine the number of protein molecules that can be assembled into a gold-nanoparticle-nucleated superstructure. The resultant bioaerogels exhibit stable electronic-state spectra at room temperature for 6 weeks for the protein molecules encapsulated in the biocomposite nanoarchitecture.