We demonstrate a selective nanoscale positioning of targeted Au nanoparticles (NPs) through a bifunctional protein-based encapsulation/delivery system. The newly designed recombinant bifunctional protein, appended with both gold-binding peptide (GBP) and Ti/Si-binding peptide (TBP) at the C-and N-termini efficiently encapsulated 15-20 nm-diameter Au NPs during the pH-controlled reversible reassembly process, and showed the ability of the internalized Au NPs in selective binding to nanometer-scale Ti islands without overshooting. This highly controlled placement of the Au NPs on substrates can be employed to make both large scale devices and point-contact devices. (C) 2011 Elsevier B.V. All rights reserved.