Build Based On Bismuth Oxide Semiconductor Materials, Biosensors And Sensing Performance

1. Direct electrochemistry and electrocatalysis of hemoglobin based on inorganic semiconductor Bismuth Oxide FilmsImmobilized hemoglobin (Hb) in a high biocompatible composite system based on polycrystalline bismuth oxide films, the direct electron transfer between hemoglobin and the underlying glassy carbon electrode (GCE) can be readily achieved. Cyclic voltammetry of Hb/ polycrystalline bismuth oxide films /GCE showed a pair of stable and quasi-reversible peaks for Hb Fe(III)/Fe(II) redox couple at about -0.410 V versus saturated calomel electrode (SCE) in pH 7.0 buffer, at the scan rate of 150 mVs-1. The electrochemical reaction of Hb immobilized in polycrystalline bismuth oxide films composite matrix exhibited a surface-controlled and nonideal thin-film process with an electron transfer accompanied single proton transportation. The electron transfer rate constant was estimated to be2.34s-1. it is has catalytic ability of oxygen,H2O2.,nitrous acid and trichloroacetic acid .The interaction between Hb and this bio-nano-composite material was also investigated using FT-IR and UV-V is spectroscopy, indicating that Hb remained its native structure in this hybrid matrix.2. Inorganic semiconductor Bismuth Oxide Films for development of amperometric biosensor for phenolic compoundsAn attractive biocomposite based on polycrystalline bismuth oxide film (BiOx) and polyphenol oxidase (PPO) was proposed for the construction of a mediator-free amperometric biosensor for phenolic compounds in environmental water samples. The laboratory prepared bismuth oxide semiconductor consisted polymorphism. Its hydrophilicity provided a favorable microenvironment for retaining the biological activity of the immobilized protein. The proposed PPO/BiOx biosensor provided a linear response to catechol over a concentration range of 4×10-9 M to 1.5×10-5 M with a dramatically developed sensitivity of 11.3 A M-1 cm-2 and a detection limit of 1×10-9 M based on S/N=3. Moreover, the characteristics of PPO/BiOx biocomposite were investigated in detail by scanning electron microscope (SEM), Fourier transform infrared spectra (FTIR) and rotating disk electrode voltammetry.3. Amperometric detection of glucose with Glucose Oxidase immobilized in inorganic semiconductor Bismuth Oxide FilmsA novel cheap and simple amperometric biosensor, based on the immobilization of glucose oxidase(GOD) into polycrystalline bismuth oxide films is presented. The process parameters for the fabrication of the enzyme electrode and various experimental variables such as pH, applied potential and temperature were explored for optimum analytical performance of the enzyme electrode. The biosensor can reach 95% of steady-state current less than 5 s. The enzyme electrode provided a linear response to glucose over a concentration range of 1×10-6～1.5×10-3 mol/L with a sensitivity of 4×10-7 mol/L and a detection limit of 0.1 M based on the signal-to-noise ratio of 3. The activation energy for enzymatic reaction was calculated to be 22.4 kJ mol-1. Meanwhile, the enzyme electrde exhibited wonderful long-term stability, and good reproducibility.