Effect of a Mixed Peptide Ligand Layer on Au Nanoparticles for Optical Control of Catalysis

Inorganic colloidal nanoparticles are known for their efficient catalytic reactivities due to their enhanced surface-to-volume ratio. As an alternative to conventional synthetic methods, bioinspired approaches can sustainably generate stable colloidal nanoparticles where their reactivity can be tuned by the biomolecular overlayer structure. Recent studies have shown that incorporation of light-activated photoswitches into material-binding peptides could be used to optically and reversibly switch the biomolecular overlayer structure on Au nanoparticle surfaces, which has significant ramifications on the material catalytic reactivity. In this contribution, we demonstrate that the optical photoswitching capability and catalytic reactivity in these materials are highly dependent upon the composition of the biomolecular overlayer. For this, mixed monolayer-capped Au nanoparticles were prepared where the ratio of the parent material-binding peptide and the peptide with photoswitch included were varied. Key trends related to the photoswitching capability of the peptides and their overall reactivity were identified, where slower reactivity was noted for materials prepared using only the photoswitchable peptide. Taken together, these results demonstrate that the composition of the overlayer structure on Au nanoparticles is highly important in tuning the overall optical, photoswitching, and catalytic properties of these materials and can be used to refine the properties of the structure for their intended application.