DNA-wrapped single-walled carbon nanotubes as rigid templates for assembling linear gold nanoparticle arrays

A strategy toward the assembly of gold nanoparticles (AuNPs) onto DNA-wrapped single-walled carbon nanotubes (SWNTs) is reported. DNA has been found to be an ideal supramolecular material for the assembly of gold nanoparticles mainly due to its programmable self-assembly ability. An excess amount of AuNPs was added (the suitable ratio between gold nanoparticles and carbon nanotubes was determined based on a trial-and-error procedure with the help of agarose-gel electrophoresis) to avoid crosslinking between nanotubes induced by the addition of AuNPs. The SWNT-L solution recovered from the 2 % agarose gel was then deposited on a MgCl₂ treated mica substrate and imaged by tapping-mode atomic force microscopy. This strategy can also be easily adapted for the assembly of other materials by introducing suitable chemical groups into the DNA strands, and this can be done either during DNA synthesis or by post-modification using well-developed bio-conjugation chemistry.