From Serum to Organ: The Amine-Naphthalene Modular Platform Enables Precise Identification and Quantification of...

Accurate detection of alkaline phosphatase (ALP) is critical for clinical diagnosis and mechanistic studies across diverse tissues. Here, we present a modular "off-on" fluorescent probe platform based on 1-naphthol phosphate sodium (1-NPP) and ethylenediamine (EDA), enabling precise, rapid, and cost-effective quantification of ALP activity from serum to whole organs. The probe's mechanism relies on the ALP-catalyzed hydrolysis of 1-NPP to liberate 1-naphthol, which subsequently reacts with EDA to generate a robust fluorescent signal. This system demonstrates high sensitivity, with a detection limit of 0.068 mU/mL, and maintains excellent linearity and stability across complex biological matrices including serum, cell lysates, and tissue homogenates. Application in various cell lines and mice organs revealed organ- and disease-specific ALP activity distributions, highlighting its utility for distinguishing physiological and pathological states. The probe's low cytotoxicity and straightforward preparation offer significant advantages over nanoparticle-based sensors. Overall, this work establishes a versatile and scalable platform for ALP analysis, whose remarkable ability to distinguish ALP activity across cells and organs underpins its broad potential for early disease surveillance, mechanistic exploration, and high-throughput screening.