关键词: 辣根过氧化物酶, 凹土, 过氧化氢, 巨噬细胞

Abstract: The nanostructured attapulgite clay was employed as a support matrix for immobilizing horseradish peroxidase (HRP). FTIR and electrochemical methods demonstrated that HRP had been effectively assembled on attapulgite surface with the formation of HRP-attapulgite nanocomposites. The HRP-attapulgite hybrid was deposited on the glassy carbon (GC) electrode forming the HRP-attapulgite/GC electrode. Cyclic voltammetric results showed a pair of well-defined redox peaks, which were ascribed to direct electron transfer (DET) of HRP, with the formal potential E₀′ = -335 mV (vs. SCE) in the phosphate buffer solution (PBS, pH 7.0). The dependence of E₀′ on solution pH indicated that DET reaction of HRP was coupled with proton transfer. The developed electrode revealed a good electrocatalytical activity toward the reduction of H₂O₂. The electrocatalyic current was linear to the concentration of H₂O₂ in the concentration range of 0.3 to 75 μmol·L^-1 with high sensitivity ((53 ± 2) μA·(mmol·L^-1)^-1·cm^-2) and low detection limit ((0.10 ± 0.05) μmol·L^-1). Moreover, the HRP-attapulgite/GC electrode was used to detect the level cellular H₂O₂ released from the Macrophages cells (RAW 264.7). Therefore, an electrochemical approach for detection of cellular H₂O₂ based on HRP-attapulgite hybrid was developed. This study has not only established a novel approach to detect cellular H₂O₂, but also provided a general route for fabricating attapulgite-based biosensing platform via assembling enzymes/proteins on attapulgite surface, expanded the scope of attapulgite applications to the field of bioelectroanalytical chemistry and cellular biology.

Key words: horseradish peroxidase, attapulgite, hydrogen peroxide, macrophages cell