Tuning the properties of atomically precise gold nanoclusters for biolabeling and drug delivery

A structure-determined gold-levonorgestrel nanocluster, Au₁₀(C₂₁H₂₇O₂)₁₀ (Au₁₀NC), has been obtained via solvent induced crystal transformation from Au₈(C₂₁H₂₇O₂)₈ (Au₈NC), accompanied by a fluorescence color change from green to yellow. A cationic polymer, poly(allylamine hydrochloride) (PAH), was chosen to assemble with Au₁₀NC to prepare monodisperse and stable particles (Au₁₀NC-PAH) with an increased quantum yield of 49.8%. The as-fabricated Au₁₀NC-PAH realized effective antibody-mediated actin imaging and sustained drug release.