Molecularly linked 3D plasmonic nanoparticle core/satellite assemblies: SERS nanotags with single-particle Raman sensitivity.

A fast, generic, and suspension-based route to highly SERS-active assemblies of noble metal nanoparticles (Au, Ag) with small core-satellite gaps and single-particle Raman sensitivity is presented. Rationally designed, heterobifunctional Raman reporters serve as molecular linkers for electrostatic conjugation of the small satellites to the large core.