DNA-Programmed Bimodal 2D Assembly of Differently Sized Nanoparticles via Folding of Precursory Circular Chains

Abstract

Gold nanoparticle (AuNP) assemblies in two-dimensions (2D) exhibit collective physical/chemical properties that are useful for various devices. However, technical issues still impede the efficient ordering of differently sized AuNPs on solid supports while avoiding phase separation. This paper describes a method to construct binary 2D assemblies by folding precursory circular chains composed of small and large AuNPs. The structural change is caused by a spontaneous, noncross-linking assembly of fully matched double-stranded DNA-modified AuNPs (dsDNA−AuNPs) at a high ionic strength. Since larger dsDNA− AuNPs have a lower critical coagulation concentration of the supporting electrolyte, the spontaneous assembly of large AuNPs precedes that of small AuNPs in the precursory chain during evaporation. Transmission electron microscopy reveals that alternate-type AuNP chains are folded into a binary 2D structure in a mixed mode, whereas blocktype chains are transformed into a binary 2D structure in a core−shell mode. The methodology could potentially be harnessed for the fabrication of binary AuNP arrays for various devices.

DNA Base Pair Stacking Assembly of Anisotropic Nanoparticles for Biosensing and Ordered Assembly

“…For AuNSs that exhibit uniform surface activity, however, it would be much more difficult, even though a multi-step method has been used to prepare bifunctional monomer to construct assemblies with ordered spatial arrangement. [56][57][58][59][60]…”

A Simple Colorimetric Assay of Bleomycin‐Mediated DNA Cleavage Utilizing Double‐Stranded DNA‐Modified Gold Nanoparticles

“…In contrast, dsDNA‐AuNPs with a terminal mismatch sequence remain dispersed under identical conditions and are applicable for several bioassays, including ATP, [44] single‐base substitutions, [45] metal ions,[ 46 , 47 ] liquid foods, [48] and reversible control of interparticle distance on ssDNA‐templated dsDNA‐AuNP oligomers. [ 49 , 50 , 51 , 52 , 53 ] Such behavior may be due to differences between the attractive blunt‐end stacking at the matched dsDNA terminal and the repulsive mismatched dsDNA terminal on the particle. In fact, the analysis of the force‐distance curve between the dsDNA layers in atomic force microscopy supported the assumption.…”

“…dsDNA‐AuNPs with a full‐match sequence can undergo aggregation in ionic aqueous solutions, showing a drastic color change. In contrast, dsDNA‐AuNPs with a terminal mismatch sequence remain dispersed under identical conditions and are applicable for several bioassays, including ATP, [44] single‐base substitutions, [45] metal ions, [46,47] liquid foods, [48] and reversible control of interparticle distance on ssDNA‐templated dsDNA‐AuNP oligomers [49–53] . Such behavior may be due to differences between the attractive blunt‐end stacking at the matched dsDNA terminal and the repulsive mismatched dsDNA terminal on the particle.…”