Polymer encapsulated AuNP SERS probes and ligand exchange kinetics monitored by SERS

A new series of simple while effective SERS nanoprobes were prepared by encapsulating poly-pyridine ligand capped AuNPs with amphiphilic diblock copolymer (polystyrene-block-poly(acrylic acid) (PS₁₅₄-b-PAA₆₀)) through one-pot synthesis method. The resulting well-defined core-shell nanoprobes possess of high sensitivity and high stability in aqueous solution and can be used under high PH value and high ion strength conditions. In order to better control the ligand capping process, ligand exchange kinetics of poly-pyridine and other Raman active ligand on the surface of large (60 nm) AuNPs were studied, where SERS was firstly used to in situ monitor the ligands coordination and dissociation on the surface of AuNPs.