Aggregation-induced emission Ru(II) complex nanomaterials: Phosphorescent determination of alkaline phosphatase activity and inhibitors

Alkaline phosphatase (ALP) is a vital protein catalyst that holds a central role in modulating protein metabolism and function throughout organisms, and serves as a reliable foundation for the treatment of human diseases. Thus, the development of a sensitive and selective detection strategy for ALP is considerable scientific and practical significance. In this study, SiO₂ was chosen as the carrier for encapsulating Ru-1 luminophores to effectively prevent the leakage of Ru-1 molecules. Meanwhile, during the preparation process, the introduction of a poor solvent induces aggregation of Ru-1 molecules into nanoparticles, thereby enhancing emission through the aggregation-induced emission effect. Furthermore, using an in-situ growth method，we developed a phosphorescence-based detection strategy, which builds on Ru-SiO₂-MnO₂ nanocomposites. l-ascorbic acid (AA) can be generated by ALP, which catalyzes the hydrolysis of sodium L-ascorbyl-2-phosphate (AAP). This process further breaks down MnO₂ and triggers the phosphorescence sensor through a “turn-on” mechanism. Moreover, by exploiting the capacity of Na₃VO₄ to suppress ALP activity, this phosphorescent method was further employed for the identification of ALP inhibitors. Under the optimized experimental conditions, the phosphorescent intensity displayed a linear association with ALP concentrations ranging from 0.05 to 17 U/L, while the limit of detection was as low as 0.031 U/L. The proposed strategy eliminates the need for complex washing or modification procedures and avoids the aggregation-caused quenching phenomenon of traditional organic dyes, thus standing out as an uncomplicated, economical “turn-on” phosphorescent detection method for ALP. This approach also demonstrated excellent applicability in the analysis of serum samples.