A novel biosensor based on the direct electrochemistry of horseradish peroxidase immobilized in the three-dimensional flower-like Bi2WO6 microspheres

• 3D-Bi2WO6 microspheres are used to fabricate a mediator-free biosensor firstly.
• The biosensor displays a wide linear range of 0.5–250 μM for H2O2.
• The biosensor exhibits a low detection limit of 0.18 μM for H2O2.

Three-dimensional flower-like Bi2WO6 microspheres (3D-Bi2WO6 MSs) have been synthesized through a simple hydrothermal method. The morphology and structure of 3D-Bi2WO6 MSs were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The 3D-Bi2WO6 MSs subsequently were used to immobilize horseradish peroxidase (HRP) and fabricate a mediator-free biosensor for the detection of H2O2. Spectroscopic and electrochemical results reveal that 3D-Bi2WO6 MSs constitute an excellent immobilization matrix with biocompatibility for enzymes. Meanwhile, due to unique morphology of the flower-like microspheres, the direct electron transfer of HRP is facilitated and the prepared biosensors display good performances for the detection of H2O2 with a wide linear range, including two linear sections: 0.5–100 μM (R2 = 0.9983) and 100–250 μM (R2 = 0.9981), as well as an extremely low method detection limit of 0.18 μM.

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