Ligand exchange based water-soluble, surface-enhanced Raman scattering-tagged gold nanorod probes with improved stability

► Raman-tagged water soluble polymer (PEG) is synthesized. ► The Raman-active PEG adsorbs onto gold nanorods upon a simple ligand exchange reaction, resulting in surface-enhanced Raman scattering (SERS)-tagged gold nanorod probes. ► The SERS-tagged gold nanorod probes exhibit excellent SERS activity and improved stability.