Amperometric H2O2 biosensor based on poly-thionine nanowire/HRP/nano-Au-modified glassy carbon electrode

Poly-thionine nanowire/HRP/nano-Au composite nanomaterial was developed to fabricate the H2O2 biosensor. Poly-thionine nanowires (PTHNWs) have been synthesized by electrodeposition in porous anodic aluminum oxide (AAO) template. The morphological characterization of PTHNWs was examined by scanning electron microscopy (SEM) and transmission electron microscope (TEM). The nanowires prepared by this method can be used to encapsulate horseradish peroxidase (HRP) and nano-Au by in situ electrochemical copolymerization. The resulting PTHNWs–HRP–nano-Au material facilitates electron-transfer process in electrochemical sensor design. The PTHNWs–HRP–nano-Au film-modified electrode showed to be excellent amperometric sensors for H2O2. In pH 6.98 phosphate buffer, almost interference-free determination of H2O2 is realized at −0.1 V versus SCE with a linear range of 5 × 10−7 to 1.3 × 10−2 M, a correlation coefficient of 0.998 and response time <5 s. The sensitivity of the H2O2 biosensor is up to 168 μA mM−1 cm−2 and the detection limit is 0.3 μM. Furthermore, the biosensor exhibited long-term stability, and good reproducibility.