Corresponding Author

Chen-xin CAI(cxcai@njnu.edu.cn)


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.

Graphical Abstract


horseradish peroxidase, attapulgite, hydrogen peroxide, macrophages cell

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