When gold nanoparticles (AuNPs) become extremely small (<2 nm in diameter) as gold nanoclusters (AuNCs), an intriguing issue is whether the interactions of free radicals with AuNCs would be essentially different at sufficiently small size. Herein, we report for the first time that the fluorescence of a polyamidoamine (PAMAM) dendrimer-entrapped Au8-cluster is quenched by the paramagnetic nitroxide radical. Based on an upward curving Stern-Volmer plot, the system shows complex fluorescence quenching with a combination of static and dynamic quenching processes. The quenching mechanism associated with the interactions between Au8-clusters and nitroxide radicals was explored by combined fluorescence and electron paramagnetic resonance (EPR) studies. The controlled quenching of the fluorescent Au8-cluster can be developed as a turn-on fluorescence probe for sensing ascorbic acid (AA) in living cells.
Date:
2015-01
Relation:
Journal of Materials Chemistry B. 2015 Jan;3:191-197.
