Zinc ion-triggered aggregation induced emission enhancement of dual ligand co-functionalized gold nanoclusters based novel fluorescent nanoswitch for multi-component detection

Abstract

Herein, a zinc ion (Zn2+)-triggered aggregation induced emission enhancement (AIEE) fluorescence “on-off-on” nanoswitch was fabricated for inorganic pyrophosphate (PPi) and inorganic pyrophosphatase (PPase) activity detection. Dual ligand functionalized Au NCs were utilized as the substrate of the AIEE nanoswitch. The introduction of Zn2+ can cause Au NCs aggregated along with the enhanced fluorescence. After the addition of PPi, aggregated Au NCs disaggregated along with decreased fluorescence due to the competitive combination between PPi and Zn2+ (on-off). When PPase was introduced, PPi was hydrolyzed and release Zn2+, resulting in aggregated Au NCs along with enhanced fluorescence again (off-on). On the basis of this, highly selective and sensitive detection PPi (liner range from 0.1 to 300 μM) and PPase activity (liner range from 0.1 to 10 mU) can be achieved. The detection limits are 0.04 μM for PPi and 0.03 mU for PPase, respectively. Furthermore, the as-prepared Zn2+-triggered AIEE nanoswitch was successfully used for quantitative analysis of PPase activity in human serum with satisfactory spiked recoveries, and applied for the inhibitors screening.