DNA-Origami-Directed Self-Assembly of Discrete Silver-Nanoparticle Architectures

摘要

The bottom-up organization of noble-metal nanoparticles (NPs) with nanometer-scale precision is an important goal in nanotechnology.The DNA-guided self-assembly of these nanoparticles has shown significant progress to meet this challenge. Enormous progress has been, made in the DNA-guided organization of nanoparticles into discrete, one-dimensional, two-dimensional, and three-dimensional architectures. Facile DNA-functionalization strategies for gold nanoparticles (AuNPs) are now available, making AuNPs preferred (easier) candidates for subsequent self-assembly to form higher-order structures. In contrast, the mediation by DNA self-assembly of the assembly of silver nanoparticles (AgNPs) into higher-order, well-defined discrete nanoarchitectures has not been well explored, mainly as a result of the relative instability of these systems. Ag undergoes oxidization more readily than Au; therefore, the conjugated ligands on the surface of AgNPs are more labile, and AgNPs tend to aggregate irreversibly in solutions with a high salt concentration. However, a high salt concentration is crucial for efficient DNA self-assembly. Recently, we and others started to address this problem by attaching multiple sulfur moieties to DNA to form stable AgNP-DNA conjugates that resist aggregation in buffers with a high salt concentration.