磁性纳米微球-血红蛋白修饰电极的电化学行为及对H_2O_2电催化还原的研究

Immobilization of Hemoglobin on Magnetic Microspheres for Preparation of Hydrogen Peroxide Biosensor

将天然高分子壳聚糖（CS）包裹碳包铁的磁性纳米微球（CFN／CS）修饰于玻碳电极表面，并利用戊二醛将血红蛋白（Hb）交联在CFN／CS上，制备了Hb-CFN／CS-GC电极。循环伏安法和电化学交流阻抗法实验结果表明，Hb在CFN／CS-GC电极表面仍保持较好的生物活性，能稳定有效地进行直接电子转移反应。电化学研究表明该修饰电极对H2O2有良好的电催化还原作用，在pH7．0的磷酸盐（PBS）介质中，H2O2在5．2×10^-5～2．3×10^-3mol／L浓度范围内，其浓度与还原峰电流呈良好线性关系，检出限为8．7×10^-6mol／L。该修饰电极有着良好的重现性和稳定性。

A third-generation hydrogen peroxide biosensor was designed by immobilizing Hb on a glassy carbon electrode modified with natural polymer magnetic microspheres. It was found that the electron transfer between Hb and the underlying electrode was greatly enhanced in the advantageous microenvironment with the natural polymer magnetic microspheres. The fabrication procedures and electrochemical behaviors of protein were characterized by electrochemical impedance spectroscopy and cyclic voltammetry. The modified electrode exhibited excellent electrocatalytic activity and rapid response for H2O2. The electrocatalytic response showed a linear dependence on H2O2 concentration ranging from 5.2×10^-5 mol/L to 2.3×10^-3mol/L with a detection limit of 8. 7×10^-6 mol/L. In addition, the biosensor had good repeatability and long-term stability.