NIR-Emitting Gold Nanoclusters Encapsulated in PS- b -PEG Polymer Micelles.

Gold nanoclusters (AuNCs) are an emerging type of luminescent probe, featuring good biocompatibility, high photostability, and large Stoke shifts. Their lack of colloidal stability is, however, a drawback for many applications. Here, we report the stabilization of AuNCs emitting in the NIR by a thiol-terminated polystyrene chain ( M n = 5000 g mol -1 ). The optical properties of this nanocomposite remain invariant for 2 years in THF. To use the PS 5k -AuNCs in an aqueous environment, these were encapsulated into polymer micelles using a polystyrene- b -poly(ethylene glycol) copolymer. The resulting hierarchical constructs, with diameters of ca. 125 to 215 nm, have promising properties for applications as luminescent probes such as contrast agents for biomedical imaging.