An Integrated 3D-Printed Portable Device Coupling Bimetallic FeCo-MOF Nanozymes with Freeze-Dried Hydrogel Carriers for Point-of-Care Testing of Serum Acid Phosphatase

Acid phosphatase (ACP) is a key biomarker for prostate disorders, hyperparathyroidism, and other metabolic diseases. However, current ACP assays are limited by complex protocols, bulky instrumentation, and poor stability under resource-limited conditions. Herein, we report a portable, smartphone-readable point-of-care testing (POCT) platform integrating bimetallic FeCo-MOF nanozymes entrapped in freeze-dried agarose hydrogel carriers for dual-mode (colorimetric-fluorometric) quantification of ACP in human serum. The FeCo-MOF catalyzes glucose oxidation to generate H 2 O 2 and reactive oxygen species, converting o-phenylenediamine (OPD) to the chromogenic/fluorogenic product 2,3-diaminophenazine (DPA). ACP-mediated hydrolysis of sodium pyrophosphate (PPi) restores FeCo-MOF activity, enabling signal readout proportional to ACP concentration. Encapsulation of reagents within freeze-dried hydrogels significantly enhances substrate stability (89–100% activity retained at 4 °C for 30 days) and facilitates rapid reagent diffusion (