Determination of hydrogen peroxide released from cancer cells by a Fe-Organic framework/horseradish peroxidase-modified electrode.

Multi-walled carbon nanotubes (MWCNTs) were used as conductive carrier on the glassy carbon electrode (GCE), and the hybrid of metal organic framework [NH-MIL-53(Fe)] and horseradish peroxidase (HRP) was prepared by simple physical mechanical mixture. The GCE modified by the above material with immobilization, namely NH-MIL-53(Fe)/HRP/MWCNTs/GCE, was used to construct an electrochemical biosensor toward HO. The results indicated that the addition of NH-MIL-53(Fe) had a good synergistic effect on the electron transfer of HRP and the detection of HO. Under the optimized condition, the biosensor exhibited excellent electrochemical performances such as low detection limit, high sensitivity, good stability and so on. The HO biosensor showed two linear ranges of 0.1-1 μM and 1-600 μM with a calculated detection limit of 0.028 μM (signal-to-noise ratio, S/N = 3). In addition, the stability of the hybrid of NH-MIL-53(Fe) and HRP were discussed by SEM, XRD and UV-vis methods. Furthermore, the reported biosensors were practically used in direct detection of HO released from HeLa and HepG2 cells successfully. Thus, this work provides a new strategy to fabricate electrochemical biosensors using MOFs and biomolecules.