Reversible aggregation of DNA-decorated gold nanoparticles controlled by molecular recognition.

The programmable assembly of functional nanomaterials has been extensively addressed; however, their selective reversible assembly in response to an external stimulus has been more difficult to realize. The specificity and programmable interactions of DNA have been exploited for the rational self-assembly of DNA-conjugated nanoparticles, and here we demonstrate the sequence-controlled disaggregation of DNA-modified gold nanoparticles simply by employing two complementary oligonucleotides. Target oligonucleotides with perfectly matching sequence enabled dissociation of aggregated nanoparticles, whereas oligonucleotides differing by one nucleotide did not cause disassembly of the aggregated nanoparticles. Physical aspects of this process were characterized by UV-vis absorption, light scattering, and transmission electron microscopy. This strategy for programmed disassembly of gold nanoparticles in response to biological stimuli demonstrates a fundamentally important concept anticipated to be useful for diverse applications involving molecular recognition.