Enhancing the colorimetric detection of H2O2and ascorbic acid on polypyrrole coated fluconazole-functionalized POMOFs

A new fluconazole-functionalized polyoxometalate-based metal-organic framework (POMOF) [Ag₃(FKZ)₂(H₂O)₂][H₃SiW₁₂O₄₀] (AgFKZSiW₁₂) was successfully constructed, and its polypyrrole (PPy) coated composite AgFKZSiW₁₂@PPy was also obtained via a facile 'in situ' oxidation polymerization process. The peroxidase-like activity evaluation indicates that the maximized synergistic effect from the integration of PPy, SiW₁₂ clusters, HFKZ drug molecules, and Ag ions deeply enhanced the overall performance. More importantly, AgFKZSiW₁₂@PPy exhibits the fastest response time (30 s) among all the reported peroxidase mimics to date, including the pristine AgFKZSiW₁₂ (2 min). Moreover, the AgFKZSiW₁₂@PPy-based colorimetric biosensing platform towards H₂O₂ and ascorbic acid (AA) exhibits limits of detection (LOD) as low as 0.12 μM and 2.7 μM, respectively. This work reveals a promising prospect in medical diagnosis and biotechnology for colorimetric biosensor fabrication with high performance through the introduction of PPy.