Manufacture of stable palladium and gold nanoparticles on native and genetically engineered flagella scaffolds

Abstract

The use of bacterial flagella as templates for the immobilization of Pd and Au nanoparticles is described. Complete coverage of D. desulfuricans flagellar filaments by Pd(0) nanoparticles was obtained via the H₂-mediated reduction of [Pd(NH₃)₄]Cl₂ but similar results were not obtained using HAuCl₄. The introduction of additional cysteine-derived thiol residues in the E. coli FliC protein increased Au(III) sorption and reduction onto the surface of the flagellar filament and resulted in the production of stabilized Au(0) nanoparticles of ∼20–50 nm diameter. We demonstrate the application of molecular engineering techniques to manufacture biologically passivated Au(0) nanoparticles of a size suitable for catalytic applications. Biotechnol. Bioeng.