Hybrid polyoxometalate/silver nanoparticles decorated three-dimensional graphene foam for electrochemical detection of hydrogen peroxide in living cells

Intracellular hydrogen peroxide (H 2 O 2 ) plays a crucial role in regulating various biological processes including cell proliferation, apoptosis, and immune response. Driven by the remarkable need for determination of intracellular H 2 O 2 with higher precision and sensitivity, a novel ternary nanocomposite electrode integrating silver nanoparticles (AgNPs)/Polyoxometalates (POMs)/three-dimensional graphene foam (3DGF) was fabricated for real-time detection of H 2 O 2 generated in MCF-7 cells. POMs acted like an artificial peroxidase, together with AgNPs that served as electron mediator to amplify the electrochemical signal were successfully loaded on the surface of 3DGF, which significantly improved the detection sensitivity due to synergistic advantages. The tricomponent nanohybrids modified glass carbon electrode (AgNPs@POMs-3DGF/GCE) showed a high sensitivity toward reduction of H 2 O 2 , and meanwhile had good long-term stability, wide linear range and low detection limit. Real-time detection of H 2 O 2 released from MCF-7 cells stimulated by N-formyl-L-methionyl-L-leucyl-phenylalanine (fMLP) had been demonstrated using the chronoamperometry based on AgNPs@POMs-3DGF/GCE, which showed a quick response and excellent specificity to H 2 O 2. It was expected that the AgNPs@POMs-3DGF/GCE was able to monitor H 2 O 2 during the dynamic biological process involving H 2 O 2 metabolism.