The Structural Characterization of Oligonucleotide-Modified Gold Nanoparticle Networks Formed by DNA Hybridization

If a solution of DNA-coated nanoparticles is allowed to crystallize, the thermodynamic structure can be predicted by a set of structural design rules analogous to Pauling’s rules for ionic crystallization. The details of the crystallization process, however, have proved more difficult to characterize as they depend on a complex interplay of many factors. This chapter describes that this crystallization process is dictated by the individual DNA bonds and that the effect of changing structural or environmental conditions can be understood by considering the effect of these parameters on free oligonucleotides. The well-defined base-pairing interactions of DNA allow it to behave as a programmable bond on a nanoparticle scaffold and, when designed properly, these systems form crystals through a process that closely mirrors the formation of atomic crystals. However, DNA-directed nanoparticle crystallization also offers a level of programmability that is not achievable in atomic systems as it enables precise and independent control over many components in a given system.