In Situ Synthesis of Horseradish Peroxidase Nanoflower@Carbon Nanotube Hybrid Nanobiocatalysts with Greatly Enhanced Catalytic Activity

Abstract

High Resolution Image Download MS PowerPoint Slide Organic–inorganic hybrid nanoflowers (NFs) consisting of horseradish peroxidase (HRP) and copper II (Cu 2+ ) are successfully synthesized with the involvement of carbon nanotubes (CNTs) by in situ and post-modification methods. Catalytic activities of in situ synthesized [email protected] ( [email protected] ) and post-modification-synthesized [email protected] ( [email protected] ) are systematically examined. The 30 mg CNTs incorporated [email protected] ( [email protected] ) exhibits greatly increased catalytic activity and stability toward 3,3′,5,5′-tetramethylbenzidine (TMB), thanks to the synergistic effect between HRP-NF and CNTs and the peroxidase-like activity of CNTs in the presence of hydrogen peroxide (H 2 O 2 ). While [email protected] retains almost 85% of its initial activity even after 10 cycles, HRP-NF (without CNTs) loses half of its initial activity at the same experimental conditions. We study how two experimental parameters, the pH values and temperatures, influence the catalytic activity of [email protected], in addition to the fact that [email protected] is employed to detect the presence of H 2 O 2 and glutathione (GSH) with colorimetric and spectrophotometric readouts. For instance, [email protected] is used to sensitively detect H 2 O 2 in the range of 20 to 300 μM with an LOD of 2.26 μM. The catalytic activity of [email protected] is suppressed in the presence of GSH, and then an obvious color change from blue to nearly colorless is observed. Using this strategy, GSH is also sensitively determined in the range of 20–200 μM with an LOD of 11.2 μM. We expect that [email protected] can be used as a promising and novel nanobiocatalyst for various biomedical and industrial applications in the near future.

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