Depositing gold nanoparticles is of great interest because of the many potential applications of nanoparticle films; however, generating dense surface nanoparticle coverage remains a difficult challenge. Using dual-affinity peptides we have synthesized gold nanoparticles and then pre-aggregated the particles in solution via interactions with metal ions. These nanoparticle aggregates were then deposited onto silicon dioxide surfaces using another dual-affinity peptide to control binding to the substrate. The results demonstrate that when divalent ions like Zn2+ or Ni2+ are used, densely packed gold nanoparticle monolayers are formed on the silicon dioxide substrate, which may have applications in fields like molecular electronics. (C) 2014 Elsevier B.V. All rights reserved.