Yttrium vanadates based ratiometric fluorescence probe for alkaline phosphatase activity sensing.

Alkaline phosphatase (ALP) is an important biomarker for diagnosis, and the abnormal level of serum ALP is closely related to a variety of diseases. In present work, a ratiometric fluorescence probe based on hybrid nanoparticles CDs@YVO: Dy nanoparticle is introduced for alkaline phosphatase (ALP) activity determination. The CDs@YVO: Dy probe is constructed by the carbon dots (CDs) and YVO: Dy through a simple mixing method, in which the blue emission of CDs at 405 nm acts as the calibrated signal, the green emission of YVO: Dy at 574 nm decreased with the increasing targets ALP, and used as the output signal. In addition, the Cu and pyrophosphate (PPi) were also employed in this strategy to utilize the excellent fluorescnece quenching efficiency of Cu to the Dy ions emission of CDs@YVO: Dy, as well as the strong affinity of PPi for Cu. In the presence of analyts ALP, ALP catalyzes the hydrolysis of PPi, causing the release of Cu, resulting in the Dy ions emission quenched, while the CDs emission at 405 nm retained unchanged, based on this, we designed the off-on-off ratiometric fluorescence platform for ALP sensing. The experiment result shows that the ratio of F/F is linear to the concentration of ALP in arange of 0.05∼3000 U/L with a detection limit of 0.04 U/L, which is comparable or better than those reported fluorescence probe, especially the calibrated signal introduction of CDs can eliminate the background interference, improve the accuracy of proposed probe greatly. Furthermore, the discrimination of ALP enzyme inhibitor with the IC of 26 μM, and ALP concentration in real human serum sample has also demonstrated the applicability of CDs@YVO: Dy fluorescence sensor well.