What Controls the Melting Properties of DNA-Linked Gold Nanoparticle Assemblies?*

Abstract

In this chapter, the author reports a series of experiments and a theoretical model designed to systematically define and evaluates the relative importance of nanoparticle, oligonucleotide, and environmental variables that contribute to the observed sharp melting transitions associated with DNA-linked nanoparticle structures. These variables include the size of the nanoparticles, the surface density of the oligonucleotides on the nanoparticles, the dielectric constant of the surrounding medium, target concentration, and the position of the nanoparticles with respect to one another within the aggregate. Understanding the fundamental origins of the melting properties of DNA-linked nanoparticle aggregates (or monolayers) is of paramount importance because these properties directly impact one's ability to formulate high sensitivity and selectivity DNA detection systems and construct materials from these novel nanoparticle materials. Nanoparticles heavily functionalized with oligonucleotides have been used as probes in a variety of DNA detection methods and as elemental building blocks in materials synthesis schemes based upon the sequence-specific hybridization properties of DNA.