Light-Mediated Directed Placement of Different DNA Sequences on Single Gold Nanoparticles

This paper describes the light-directed functionalization of anisotropic gold nanoparticles with different thiolated-DNA oligomer (oligo) sequences. The starting nanoconstructs are gold nanostars (AuNS) uniformly grafted with one oligo sequence that are then exposed to fs-laser pulses at the plasmon resonance of the branches. The excitation selectively cleaves Au-S bonds at the tips of the branches to create vacant areas for functionalization with a different thiolated oligo sequence. Nanoconstructs synthesized by this approach present one oligo sequence on the AuNS body and branches and a different sequence at the tips. This process enables the formation of nanoparticle superstructures consisting of AuNS cores and small Au satellite nanoparticles at controlled locations after DNA hybridization. Our strategy enables selective oligo presentation at the single-particle level and opens prospects for sophisticated design of nanoscale assemblies that are important in a wide range of biological applications.