Green Synthesis of Fluorescent Ag Nanoclusters for Detecting Cu2+ Ions and Its “Switch-On” Sensing Application for GSH

Abstract

Herein, we prepared the L-histidine- (His-) protected silver nanoclusters (Ag NCs) by the microwave synthesis method. The synthesis process was rapid, facile, and environmentally friendly. Under 356 nm excitation, the as-prepared Ag NCs exhibited the blue fluorescence, and the fluorescence emission peak was located at 440 nm. The Ag NCs could successfully detect trace copper (Cu2+) ions in the aqueous solution and the limit of detection (LOD) was as low as 0.6 pM. Interestingly, the Ag NCs showed a different pH-dependent selectivity for both Cu2+ and iron (Fe3+) ions with no responses to other heavy metal ions. Furthermore, the as-fabricated fluorescent sensing system was utilized to detect glutathione (GSH, the LOD was 0.8 nM) by using the “switch-on” fluorescence recovery of Ag NCs through adding glutathione (GSH) to the Cu2+-Ag NCs solution.

Self-Cascade Nanoenzyme of Cupric Oxide Nanoparticles (CuO NPs) Induced in Situ Catalysis Formation of Polyelectrolyte as Template for the Synthesis of Near-Infrared Fluorescent Silver Nanoclusters and the Application in Glutathione Detection and Bioimaging

“…10 Therefore, developing an alternative method for the efficient synthesis of Ag NCs in sensing is important and of great interest. In the past decades, strategies such as radiolytic, 11 microwave synthesis, 12 and chemical reduction approaches 13 have been reported.…”