A DNA-Based Method for Rationally Assembling Nanoparticles into Macroscopic Materials*
Chad A. Mirkin, Robert L. Letsinger, Robert C. Mucic, James J. Storhoff
Abstract
The chemistry proposed focuses on merging the chemistry of DNA with the chemistry of inorganic colloidal materials. In contrast, the DNA-modified Au nanoparticles reported here are stable at elevated temperatures and in aqueous 0.1 M NaC1 solutions for days, presumably because their DNA-modified surfaces prohibit them from getting close enough to undergo particle growth. An advantage of the DNA/colloid hybrid materials reported herein is that the assemblies can be characterized easily by transmission electron microscopy (TEM) and/or atomic force microscopy as well as spectroscopic methods conventionally used with DNA. TEM images of the colloids linked with hybridized DNA show large assembled networks of the Au colloids. In the absence of DNA, the ultraviolet-visible spectrum for the naked Au colloids is much less temperature-dependent. There is a substantial optical change when the polymeric DNA—colloid precipitate is heated its melting point.