Bovine serum albumin decorated gold nanoclusters: A fluorescence-based nanoprobe for detection of intracellular hydrogen peroxide

Gold nanoclusters are well studied due to their facile synthesis, biocompatibility, limited photobleaching, and bright fluorescence properties. Monitoring the reactive oxygen species (ROS) level in mammalian cells is required to assess the healthy metabolism of oxygen, cell signaling, and homeostasis. ROS are also known to cause several human diseases including cancer, neurodegenerative disease, diabetes, and cardiovascular disorders, therefore, following the ROS status could provide important information about the critical pathophysiology of the diseased cells/tissues. Among different ROS, hydrogen peroxide is a well-reported stable oxidative stress biomarker for several diseases. In this work, we report the synthesis of BSA coated AuNCs (BSA-AuNCs) displaying bright red fluorescence (Ex./Em. 511/651 nm), which utilized for the degradation of hydrogen peroxide with concomitant loss of fluorescence of BSA-AuNCs. The fluorescence property of this nanoprobe was used for the detection of hydrogen peroxide levels in liver cells (WRL-68). The accumulation of hydrogen peroxide in WRL-68 cells was artificially induced by 3-amino-1,2,4-triazole (catalase inhibitor) treatment, which leads to a decrease in the fluorescence intensity of BSA-AuNCs to enable fluorescence-based sensing of hydrogen peroxide. Thus, the synthesized fluorescent BSA-AuNCs could be used for the detection of intracellular hydrogen peroxide.