DNA-mediated patterning of gold nanoparticles into discrete structures: modularity, write/erase and structural switching

摘要

Nanoparticle assemblies hold great promise as new materials in catalysis, nanoelectronic and nanophotonic applications. Many of their properties, which depend on the relative arrangement of the individual nanoparticles within the assembly, are not sufficiently well-understood because of a lack of methods to systematically assemble them into well-defined discrete model systems. In here we discuss a method for the ready access to a large number of discrete nanoparticle assemblies using a small number of single-stranded and cyclic DNA templates that are also dynamic. A triangular template and a square template are used to generate gold nanoparticle assemblies with geometrical control by the simple tagging of each particle to be organized with a DNA sequence that serves to dictate its final position within the construct. The same triangular template is used to access all the possible triangular combinations that two gold nanoparticles of different sizes may be organized in (I.e. three larger, two larger / one smaller, one larger/ two smaller, all smaller). The same square template is used to generate nanoparticle assemblies in which four gold nanoparticles are organized into square, trapezoidal and rectangular arrangements. Post-assembly addressability is demonstrated by a write/erase experiment in which three gold nanoparticles of a single size are assembled into a triangular arrangement, a specific particle is erased using an external eraser strand, and the empty position is re-written with a smaller sized particle. Our approach could be generalized to easily generate large sets of nanoparticle groupings with control over the position, size, type and addressability of each nanoparticle within the construct.