One-pot synthesis of tyrosine-stabilized fluorescent gold nanoclusters and their application as turn-on sensors for Al3+ ions and turn-off sensors for Fe3+ ions

The simplicity of the one-pot green synthesis routine and the capability of surface modification of various bioactive molecules make gold nanoclusters (Au NCs) highly suitable as scaffolds for the construction of novel chemical and biological sensors. In this work, we report a novel strategy to prepare amino acid stabilized fluorescent Au NCs via a green one-pot process. The obtained Au NCs possessed light green fluorescence with maximum emission at 498 nm and their quantum yield (QY) was evaluated to be 1.68%. Subsequently, the developed fluorescent Au NC biosensor allowed sensitive and selective detection of Fe3+ ions based on fluorescence quenching with a detection limit of 0.2 μM and Al3+ ions based on enhanced fluorescence with a detection limit of 0.3 μM, respectively. Furthermore, we testified the feasibility of applying this fluorescent probe for real sample analysis through the detection of Al3+ ions and Fe3+ ions in lake water, pond water and tap water. These results indicated that the as-prepared Au NCs had great potential to be developed as the favorable sensor for detection of metal ions in real samples.