Fluorescent gold nanocluster-based sensor for detection of alkaline phosphatase in human osteosarcoma cells

Gold nanoclusters (AuNCs) have attracted much attention as signal transducers in photoluminescence chemical/biological sensors. Herein, we employ bovine serum albumin/3-mercaptopropionic acid co-modified AuNCs as a fluorescence probe, Fe³⁺ as a quencher, and pyrophosphate as an alkaline phosphatase (ALP) substrate and Fe³⁺ chelator to design a novel biosensor for ALP detection, achieving a detection linear range of 0.8-16 U/L and a detection limit of 0.78 U/L. The developed method is successfully applied to the detection of ALP in human osteosarcoma cells and is shown to be suited for ALP inhibitor screening.