Selective functionalization and spectral identification of gold nanopyramids

This paper reports the selective functionalization of gold nanopyramids and spectral identification of their orientation on a surface. Facile asymmetric functionalization of the nanopyramids with different thiol-terminated ligands was achieved by controlling the etching conditions of the nanopyramidal template. We confirmed this differential modification by attaching gold colloids to either the inner or outer surfaces of the Au nanopyramids using hybridized DNA. Significantly, we have also demonstrated that the relative orientation of the nanopyramids can be identified by measuring their scattering spectra only. This unique capability of these three-dimensional, asymmetric particles enables their orientation to be determined in condensed media without the need for direct and destructive imaging tools.