Silica Nanoarchitectures Incorporating Self-Organized Protein Superstructures with Gas-Phase Bioactivity

We have encapsulated self-organized protein superstructures containing cytochrome c into a mesoporous silica-based nanoarchitecture. The protein superstructure, nucleated by colloidal gold in buffered medium and nanoglued with silica sol, remains intact upon supercritical drying of the wet composite gel and exhibits rapid gas-phase recognition of NO. We posit that specific adsorption of the heme edge at nanoparticulate Au creates a high radius-of-curvature nanoscale hybrid that induces protein−protein self-directed assembly. We also have evidence that an outer “skin” of protein is damaged upon experiencing the chemical and physical denaturants necessary to create an aerogel but that this sacrificial layer shields the proteins within the superstructure. Transmission electron microscopy verifies that objects on the order of 102 nm are present in the biocomposite silica aerogel. The temperature−pressure stability exhibited by the protein in the biocomposite nanoarchitecture may provide an experimental, sea-level analogy to prebiotic hypotheses, which propose that cellular evolution occurred in hydrothermal vents within porous minerals that stabilized precellular progenitors.