Ratiometric fluorescence determination of alkaline phosphatase activity based on dual emission of bovine serum albumin-stabilized gold nanoclusters and the inner filter effect

• Published in: Analyst (London) 2021-02, Vol.146 (3), p.943-948
• Main Authors: Pu, Li, Xia, Mengfan, Sun, Pengyue, Zhang, Yaodong
• Format: Article
• Language: English
• Subjects: Alkaline Phosphatase; Emission; Fluorescence; Gold; Linearity; Metal Nanoparticles; Nanoclusters; Nitrophenol; Phosphatase; Reference signals; Serum albumin; Serum Albumin, Bovine; Spectrometry, Fluorescence; Substrates
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/d0an01978j

A novel and convenient method for the ratiometric fluorescence detection of alkaline phosphatase (ALP) activity was proposed based on dual emission of bovine serum albumin-templated gold nanoclusters (BSA-AuNCs) and the mechanism of the inner filter effect between BSA-AuNCs and p -nitrophenol (PNP). First, ALP catalyzed the hydrolysis of the substrate p -nitrophenyl phosphate (PNPP) to produce PNP. PNP effectively quenched the emission peak of BSA-AuNCs at 410 nm because of the overlap in absorbance feature of PNP and the fluorescence spectrum of BSA-AuNCs, and the peak at 650 nm was almost unaffected. Thus, a sensitive ratiometric method for detection of ALP activity was developed using the fluorescence intensity of BSA-AuNCs at 650 nm as a reference signal. ALP activity versus the ratio of fluorescence intensities at 410 and 650 nm showed good linearity between 0.2 and 5 mU mL −1 ( R 2 = 0.9931) and high sensitivity with a detection limit of 0.03 mU mL −1 (S/N = 3). The developed sensing method was successfully applied to investigate ALP inhibitors and detect ALP in serum samples. Ratiometric fluorescence assay of alkaline phosphatase based on dual emission of bovine serum albumin-templated gold nanoclusters and inner filter effect.