Peptide-mediated reduction of silver ions on engineered biological scaffolds

Herein we report the spontaneous reduction of silver ions into nanostructures by yeast surface-displayed glutamic acid (E(6)) and aspartic acid (D(6)) peptides. Light spectroscopy and electron microscopy reveal that silver ions are photoreduced in the presence of the polycarboxylic acid-containing peptides and ambient light, with an increase in reduction capability of E(6) expressing yeast over D(6) yeast. The importance of tethering peptides to a biological scaffold was inferred by observing the reduced particle forming capacity of soluble peptides with respect to corresponding yeast-displayed peptides. This principle was further extended to the M13 virus for fabrication of crystalline silver nanowires. These insights into the spontaneous reduction of metal ions on biological scaffolds should help further the formation of novel nanomaterials in biological systems.