A self-assembly lanthanide nanoparticle for ratiometric fluorescence determination of alkaline phosphatase activity

The Ce-Tb@GMP are prepared via the self-assembly of guanine monophosphate (GMP) with terbium and cerium ions (Ce3+, Tb3+). The Ce-Tb@GMP nanoparticles exhibit strong green fluorescence emissions of Tb3+ and weak characteristic peaks of Ce3+ with 260nm excitation wavelength. In the present of ALP, the phosphate ester of GMP is hydrolyzed, which leads the coordination of polymer suffering from destroying and the energy transfer efficiency from Ce3+, GMP to Tb3+ is reduced. Thus, the fluorescence intensity of Ce-Tb@GMP remarkably quenched. Based on this, we designed a ratiometric fluorescent strategy for the determination of ALP. [Display omitted] •A ratiometric fluorescent sensor was designed for the determination of ALP.•The hydrolysis of phosphate ester leads the destruction of the Ce-Tb@GMP structure and the decline of fluorescence intensity.•The fluorescent sensor shows high sensitivity and selectivity for quantitative analysis of ALP. Alkaline phosphatase (ALP) has been known to participate in the multiple pathways of cell metabolism. Here, a ratiometric fluorescent probe was designed for determination of ALP activity based on Ce-Tb@GMP. The Ce-Tb@GMP nanoparticles were prepared via the self-assembly of guanosine monophosphate (GMP) with terbium and cerium ions (Ce3+, Tb3+). The Ce-Tb@GMP nanoparticles own two luminescent centers, Tb and Ce, respectively. In presence of ALP, the phosphate ester in GMP was hydrolyzed and the structure of Ce-Tb@GMP was destroyed. Moreover, the coordination effect of Ce3+, Tb3+ and ligand GMP was significantly declined and the energy transfer efficiency from Ce3+, GMP to Tb3+ was reduced. Therefore, the fluorescence emission of Tb3+ and Ce3+ was quenched and the fluorescence intensity ratio (F552/F384) gradually decreased. This probe displayed low limit detection 0.12 mU/mL under the concentration range of 0.2–60 mU/mL. Meanwhile, the method accomplished the detection of ALP in a diluted serum sample of 5%. This strategy will make a construction for the application of fluorescent probes in bioanalytical sciences.