Synergistic Pt@PCN-224(FeⅢ) nanocomposite for rapid naked-eye simultaneous detection of ascorbic acid and alkaline phosphatase

Ascorbic acid (AA) and alkaline phosphatase (ALP) are important biomarkers for diagnosing scurvy, liver dysfunction, and bone metabolic disorders. In this work, we have synthesized Pt@PCN-224(Fe Ⅲ ), a metal-organic framework (MOF) doped with Fe 3+ and decorated with Pt nanoparticles for sensitive detection of AA and ALP. By synergistically integrating Fe 3+ and Pt into the PCN-224 framework, the material exhibits a 2-fold enhancement in peroxidase-like activity over pristine PCN-224. Using H 2 O 2 as an oxidant, Pt@PCN-224(Fe Ⅲ ) efficiently catalyzes the conversion of colorless TMB to generate blue ox-TMB. AA suppresses blue signal generation by reducing ox-TMB to colorless state. This enables AA detection with a good linear response over the range of 5-60 μM and a detection limit of 0.13 μM. For ALP analysis, ALP-mediated hydrolysis of L-ascorbic acid 2-phosphate trisodium (AA2P) generates AA, which reduces ox-TMB. ALP concentration thus inversely correlates with ox-TMB absorbance, showing a linear range of 1-150 U/L with a detection limit of 0.75 U/L. The detection platform demonstrates robust performance in complex biological matrices, with spiked recoveries of 96.5-103.8%. Therefore, this work presents a portable, low-cost point-of-care testing solution that completes the entire detection process within 15 min without sophisticated instrumentation.