Synthesis of PB@FePt hybrid nanoparticles with peroxidase-mimicking activity for colorimetric determination of hydrogen peroxide in living cells

The rapid determination of H2O2 is important in a series of areas, such as bioanalysis, food safety and clinical diagnosis. Here, we describe a novel colorimetric sensing platform, based on Prussian blue nanocubes supporting FePt (PB@FePt HNPs), for the rapid and sensitive determination of H2O2. The hybrid nanoparticles exhibited efficient peroxidase-mimicking activities that were verified by the oxidation reaction of 4,4′-bis-2,6-xylidine accompanied with H2O2. Under optimized conditions, the linear range for H2O2 determination was 20 μM to 800 μM. A relatively low detection limit was acquired reaching 8.27 μM. The principle of these peroxidase-mimicking activities was investigated by the fluorometric spectroscopy method with terephthalic acid as the indicator. Furthermore, the colorimetric sensing platform was successfully utilized to determine the intracellular H2O2 in human breast adenocarcinoma (MCF-7) cells. This indicated that the as-constructed PB@FePt-TMB-H2O2 system provided a potential approach for H2O2 detection in living cells.