Interactions of nitroxide radicals with dendrimer-entrapped Au8-clusters: a fluorescent nanosensor for intracellular imaging of ascorbic acid. Issue 2 (7th November 2014)

• Record Type: Journal Article
• Authors: Liu, Ching-Ping; Wu, Te-Haw; Liu, Chia-Yeh; Cheng, Hsien-Jen; Lin, Shu-Yi
• Is Part Of: Journal of materials chemistry. Volume 3:Issue 2(2015)
• Page Start: 191
• Page End: 197
• Publication Date: 2014-11-07
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Biomedical materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c4tb01657b
• Languages: English
• ISSNs: 2050-750X

Abstract

Abstract : The fluorescence of the dendrimer-entrapped Au8 -cluster is quenched by the paramagnetic nitroxide radical and then restored by AA, which can be applied for intracellular imaging of AA in living cells. Abstract : 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.