Gold nanoclusters reversible switches based on aluminum ions-triggered for detection of pyrophosphate and acid phosphatase activity

Gold nanoclusters (AuNCs) were synthesized using glutathione (GSH) as a reducing agent and stabilizer. The aluminum ions could trigger the aggregation of AuNCs, causing a significant fluorescence, owing to the more vital coordination between Al3+ and pyrophosphate (PPi), AuNCs-Al3+ was disaggregated with the addition of PPi, resulting in a considerable fluorescence quench of the system. When acid phosphatase (ACP) was present, PPi was consumed by ACP, which inhibited the disaggregation of AuNCs. Based on the principle of Al3+ and PPi inducing aggregation-disaggregation of AuNCs accompanied by fluorescence enhancement-quenching, a novel method was established for fluorescence turn-on-off-on detection of PPi and ACP activity. The PPi detection limit was determined to be 0.1 mu M in the linear range of 0.3-100 mu M (R-2 = 0.9995). The ACP detection limit was determined to be 4.16 U L-1 in the linear range of 15.0-80.0 U L-1 (R-2 = 0.9970). The proposed GSH-AuNCs biosensor exhibits excellent sensing efficiency and has been introduced to determine PPi and ACP in real samples with satisfactory results. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Gold nanoclusters were synthesized using glutathione as a reducing agent and stabilizer. Aluminum ions triggered the aggregation of AuNCs, leading to significant fluorescence, which can be disaggregated with the addition of pyrophosphate. A novel fluorescence turn-on-off-on detection method for PPi and ACP activity was established, with excellent sensing efficiency in real samples.