Selectively fluorescent sensing of Cu2+ based on lysine-functionalized gold nanoclusters

Herein, fluorescent lysine-functionalized gold nanoclusters (AuNCs@Lys) are employed as novel probes for the detection of Cu2+. AuNCs@Lys has been prepared using a simple one-pot method with lysine linking to the Cu2+ ions which leads the fluorescence quenching of the AuNCs@Lys signal. Based on a linear decrease of fluorescence intensity, the Cu2+ ion concentration was determined in the range from 10 nM to 7 μM, with a detection limit of 3 nM with a signal-to-noise ratio of 3. Moreover, the practicality of the probes for detection of Cu2+ in actual samples was further validated, demonstrating their advantage of simplicity, selectivity, sensitivity and low cost. Significantly, the method described here provides an alternative way for assaying the Cu2+ ion concentration.