A comprehensive overview on alkaline phosphatase targeting and reporting assays

Alkaline phosphatase (ALP) is an enzyme that catalyzes the dephosphorylation of various vital nucleic acids and proteins. A broad range of physiological and pathological processes thus inevitably accompany ALP activities, rendering it an essential biomarker in clinical and industrial applications. In this regard, numerous ALP assays and immunoassay strategies have been intensively investigated to improve their sensitivity and selectivity in various biological environments and meet point-of-care testing requirements. This review provides the first comprehensive overview of recent advances in all the major schemes of ALP-targeting and reporting assays, including colorimetric, fluorometric, electrochemical, and chemiluminescence techniques. We also discussed the advancements in ALP bioassay strategies stemming from the feasibility of ALP as a label for immunoassay systems and other current assay strategies involving ALP non-enzymatic catalytic activities. In-depth comparison studies among these techniques resulted in new subclassifications of ALP assays and mechanisms, providing a facile route to developing more advanced ALP sensors. Ultimately, we discuss potential challenges and prospects for developing advanced future ALP sensor technology.