Electrochemical biosensor based on gold nanoflowers-encapsulated magnetic metal-organic framework nanozymes for drug evaluation with in-situ monitoring of H_2O_2 released from H9C2 cardiac cells

摘要

A novel electrochemical biosensor was fabricated for the determination of hydrogen peroxide (H_2O_2) by electrodeposition of gold nanoflowers (AuNFs) on molybdenum disulfide (MoS_2) nanosheets-supported magnetic metal-organic framework (MMOF) Fe_3O_4@ZIF-8 hybrid nanozymes. Fe_3O_4@ZIF-8 nanomaterial was selected on account of the high peroxidase-mimicking activity of magnetic Fe_3O_4 nanoparticle and the large pore size and surface area of metal-organic framework ZIF-8. However, we found that the MMOF Fe_3O_4@ZIF-8 nanomaterial was easily dissoluted into the electrolyte solution followed by an unreproducible electrochemical response. MoS_2 nanosheets and one-step electrodeposition of gold nanostructures can largely enhance the long-term stability, conductivity and catalytic performance. With the help of MoS_2 nanosheets and electrodeposited gold thin layer, it can have an important impact on the retaining of surface states of Fe_3O_4@ZIF-8 nanomaterials to keep the electrocatalytic activity. The obtained hybrid nanocomposites (AuNFs/Fe_3O_4@ZIF-8-MoS_2) exhibited prominent electrocatalytic activity for the reduction of H_2O_2 and the fabricated biosensor detected H_2O_2 with a low detection limit of 0.9 μM and an ultra-wide linear detection range of 5 μM-120 mM. Moreover, this electrochemical biosensor was successfully performed to detect H_2O_2 concentration released from H9C2 cardiac cells under drug stimulation. These results indicated that this modified electrode can serve as a general and powerful platform to detect other disease biomarkers for drug evaluation.