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

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: 0.5-100μM (R(2)=0.9983) and 100-250μM (R(2)=0.9981), as well as an extremely low method detection limit of 0.18μM.