Enhancing the colorimetric detection of H2O2 and ascorbic acid on polypyrrole coated fluconazole-functionalized POMOFs

A new fluconazole-functionalized polyoxometalate-based metal-organic framework (POMOF) [Ag-3(FKZ)(2)(H2O)(2)][H3SiW12O40] (AgFKZSiW(12)) was successfully constructed, and its polypyrrole (PPy) coated composite AgFKZSiW(12)@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, AgFKZSiW(12)@PPy exhibits the fastest response time (30 s) among all the reported peroxidase mimics to date, including the pristine AgFKZSiW12 (2 min). Moreover, the AgFKZSiW(12)@PPy-based colorimetric biosensing platform towards H2O2 and ascorbic acid (AA) exhibits limits of detection (LOD) as low as 0.12 mu M and 2.7 mu M, respectively. This work reveals a promising prospect in medical diagnosis and biotechnology for colorimetric biosensor fabrication with high performance through the introduction of PPy.