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

Abstract

This chapter reports 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. It is well established that the size of a nano-object significantly affects its physical properties. However, recent interest has centered around the concept of nanoparticle shape and the properties that arise from geometric anisotropy. In addition, DNA-functionalized gold nanoparticles (DNA-AuNPs) have been shown to exhibit unique properties that can be directly linked to a dense surface coverage of oligonucleotides. These include sharp melting transitions when hybridized to complementary particles, elevated binding constants for the capture of free DNA, and the ability to naturally transfect cells.