Sensitive monitoring and bioimaging intracellular highly reactive oxygen species based on gold nanoclusters@nanoscale metal-organic frameworks

Nanoscale metal-organic frameworks (NMOFs) have been widely employed in biological diagnosis and treatment system. In this work, glutathione stabilized gold nanoclusters (GSH-AuNCs) were successfully encapsulated in NMOFs and the as-obtained nanocomposites (named as AuNCs@NMOFs) showed nearly 10 times enhancement in fluorescence intensity and longer fluorescence lifetime relative to GSH-AuNCs. In addition, the fluorescence intensity of AuNCs@NMOFs was quenched by highly reactive oxygen species (hROS) due to their strong oxidation ability. Based on the fact, the nanocomposites were used for the detection of hROS with a linear range from 80 nM to 1.0 mu M toward hypochlorite (as the representative of hROS). The limit of detection (LOD) was about 30 nM, which was about 30 times lower than that of GSH-AuNCs (LOD = 0.96 mu M). With the features of good biocompatibility, excellent luminescence and efficient cellular uptake, AuNCs@NMOFs were successfully applied in fluorescence imaging of hROS in living cells. (C) 2019 Elsevier B.V. All rights reserved.