Synergistic catalysis and detection of hydrogen peroxide based on a 3D-dimensional molybdenum disulfide interspersed carbon nanotubes nanonetwork immobilized chloroperoxidase biosensor

Abstract

Enzyme-based electrochemical biosensors are promising for a wide range of applications due to their unique specificity and high sensitivity. In this work, we present a novel enzyme bioelectrode for the sensing of hydrogen peroxide (H₂O₂). The molybdenum disulfide nanoflowers (MoS₂) is self-assembled on carboxylated carbon nanotubes (CNT) to form a three-dimensional conductive network (3D-CNT@MoS₂), which is modified with 1-ethyl-3-methylimidazolium bromide (IL_EMB), and followed by anchoring chloroperoxidase (CPO) onto the nanocomposite (3D-CNT@MoS₂/IL_EMB) through covalent binding to form a bioconjugate (3D-CNT@MoS₂/IL_EMB/CPO). The IL_EMB modified 3D-CNT@MoS₂/IL_EMB has good hydrophilicity and conductivity, which not only provides a suitable microenvironment for the immobilization of CPO but also facilitates the direct electron transfer (DET) of CPO at the electrode. The 3D-CNT@MoS₂/IL_EMB/CPO bioconjugate modified electrode has a high catalytic efficiency for H₂O₂. Through electroenzymatic synergistic catalysis for H₂O₂ detection by 3D-CNT@MoS₂/IL_EMB/CPO-GCE, a wide detection range of 0.2 μmol·L^-1 to 997 μmol·L^-1 and a low detection limit of 0.097 μmol･L^-1 with high sensitivity of 1050 µA·mmol·L^-1·cm^-2 were achieved. Additionally, the 3D-CNT@MoS₂/IL_EMB/CPO-GCE displayed exceptional stability, selectivity, and reproducibility. Furthermore, 3D-CNT@MoS₂/IL_EMB/CPO-GCE is suitable for sensing of H₂O₂ in human urine s with good recovery, suggesting its potential application for the detection of H₂O₂ in biomedical field.

Keywords: Biosensor; Chloroperoxidase; Detection of hydrogen peroxide; Electroenzymatic synergistic catalysis; Ionic liquid.