Nanoparticle Shape Anisotropy Dictates the Collective Behavior of Surface-Bound Ligands

TitleNanoparticle Shape Anisotropy Dictates the Collective Behavior of Surface-Bound Ligands
Publication TypeJournal Article
Year of Publication2011
AuthorsJones, MR, Macfarlane, RJ, Prigodich, AE, Patel, PC, Mirkin, CA
JournalJournal of the American Chemical Society
Volume133
Issue46
Pagination18865 - 18869
Date Published2011/11/23/
ISBN Number0002-7863
Abstract

We report on the modification of the properties of surface-confined ligands in nanoparticle systems through the introduction of shape anisotropy. Specifically, triangular gold nanoprisms, densely functionalized with oligonucleotide ligands, hybridize to complementary particles with an affinity that is several million times higher than that of spherical nanoparticle conjugates functionalized with the same amount of DNA. In addition, they exhibit association rates that are 2 orders of magnitude greater than those of their spherical counterparts. This phenomenon stems from the ability of the flat, extended facets of nonspherical nanoparticles to (1) support more numerous ligand interactions through greater surface contact with complementary particles, (2) increase the effective local concentration of terminal DNA nucleotides that mediate hybridization, and (3) relieve the conformational stresses imposed on nanoparticle-bound ligands participating in interactions between curved surfaces. Finally, these same trends are observed for the pH-mediated association of nanoparticles functionalized with carboxylate ligands, demonstrating the generality of these findings.