Plasmonic response of DNA-assembled gold nanorods: effect of DNA linker length, temperature and linker/nanoparticles ratio.

Optical properties of gold nanorod (AuNR) particles self-assembled with DNA are systematically investigated. The particles assembly is driven by specific base-pair recognition between single strand (ss) DNA linker and DNA anchored to AuNRs, and it results in the distance- and morphology-dependent plasmonic coupling of AuNRs. The longitudinal plasmon band is distinctly affected by tuning the length of DNA linker, the temperature and linker/AuNRs ratio. We observed that the increase of temperature enhances the interparticle interactions and leads to clear distinguishable plasmonic signals between linker lengths up to 100 bases. Both absorbance decrease and shift of the longitudinal plasmon allow for use of AuNR for the DNA sensing applications.