A Self-Unlocking Biocatalytic Cascade Enabled by a Laccase-Entrapping Metal-Organic Framework for Point-of-Care Detection of Alkaline Phosphatase.

Authors

Rui Gao, Xiaoxue Kou, Weiyu Ye, Yizhang Li, Jing Li, Siming Huang, Hao Wang, Fang Zhu, Guosheng Chen, Gangfeng Ouyang

Published in

ACS sensors. Oct 05, 2026. Epub Oct 05, 2026.

Abstract

The point-of-care testing (POCT) for alkaline phosphatase (ALP), a critical biomarker for hepatobiliary diseases, bone disorders, and specific malignancies, remains analytically challenging due to signal interference from complex biological matrices. Herein, we report the development of a laccase-entrapping zeolitic imidazolate framework-8 nanoprobe (LAC@ZIF-8) that enables a self-unlocking biocatalytic cascade (SUBC) for the selective colorimetric detection of ALP. The SUBC mechanism proceeds via three discrete steps: (1) ALP-catalyzed hydrolysis of disodium phenyl phosphate yields phenol and inorganic phosphate (Pi); (2) Pi induces the structural collapse of the ZIF-8 scaffold via competitive coordination, thereby, releasing the encapsulated LAC which is otherwise sterically locked by intact ZIF-8 with a narrow microporous aperture (ca. 3.4 Å) and inaccessible to consequent bioreaction; (3) the cogenerated phenol is subsequently oxidized by the released LAC in the presence of 4-aminoantipyrine to generate a quantifiable red quinoneimine chromophore. By requiring the concerted presence of both Pi and phenol, the dual products of ALP catalysis, this LAC@ZIF-8-mediated SUBC design effectively suppresses false-positive signals originating from endogenous phosphate-containing compounds or phenolic interferents. This biosensor exhibits exceptional specificity for ALP activity, demonstrating negligible cross-reactivity with common ionic species (K+, Na+, Ca2+, CO32-), glucose, amino acids, proteins, phosphate-containing compounds, and endogenous phenols. The assay achieves a linear dynamic range of 0.5-50 U/L with a detection limit of 0.43 U/L. Furthermore, a smartphone-coupled POCT hydrogel kit was developed, facilitating on-site, instrument-free visual detection of ALP activity and its inhibitor Na3VO4. This work presents a generalized strategy for the design of highly specific biosensors through the integration of metal-organic framework (MOF)-gated selectivity with biocatalytic signal amplification.

PMID:
42833856
Bibliographic data and abstract were imported from PubMed on 06 Oct 2026.

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