An Investigation into the Intrinsic Peroxidase-Like Activity of Fe-MOFs and Fe-MOFs/Polymer Composites

The quest for developing materials that provide a perfect trade-off between factors such as enzyme-like response, stability, and low cost has been a long-standing challenge in the field of biosensing. Metal-organic frameworks (MOFs) and their composites have emerged as promising candidates for biosensing applications due to their exceptional properties such as tunable pore size, high specific surface area, and exposed active sites. A comparative study of the intrinsic peroxidase-like activity of five different MOF materials: Fe-BTC, NH2-MIL-101(Fe), composites of Fe-BTC with polymers polydopamine (PDA), poly p-phenylenediamine (PpPDA), and poly(3,4-ethylenedioxythiophene) is reported for the detection of H2O2, an important biomarker in biomedical diagnostics. The response of these materials toward H2O2 via electrochemical and colorimetric techniques is mapped and it is found that, at neutral pH, the Fe-BTC/PEDOT composite exhibits the highest sensitivity and activity compared to other MOF materials in this study. The results indicate that the combination of unique properties of Fe-BTC and conducting polymer PEDOT, improves the peroxidase-like activity of the Fe-BTC/PEDOT composite compared to the individual components. This work presents a new opportunity for easy-to synthesize and low-cost MOFs/conducting polymer composites for biosensing applications and provides significant insights to achieve rational design of composites with desirable functional properties