Silver–Gold Alloy Nanoclusters as a Fluorescence-Enhanced Probe for Aluminum Ion Sensing

In this paper, the development of a simple method is described for preparing highly red fluorescent mercaptosuccinic acid stabilized AgAu alloy nanoclusters (MSA–AgAu NCs) through the core etching of Ag nanoparticles (NPs) and a galvanic exchange reaction using nonorganic solvent and no multistep centrifuge washing. The as-prepared MSA–AgAu NCs were characterized using spectroscopic and microscopic techniques. After covalently attaching methoxy-poly(ethylene glycol)-NH2 (m-PEG-NH2), PEGylated MSA–AgAu NCs were still stable even in 1 M NaCl. Probably based on the deposition of Al3+-enhanced fluorescence, the PEGylated MSA–AgAu NCs offered highly selective and sensitive sensing of Al3+ in aqueous solution with a detection limit of 0.8 μM.