碳糊电极上无机膜固载血红蛋白的直接电化学

Direct Electrochemistry of Hemoglobin Immobilized on Carbon Paste Electrode by Inorganic Film

报道了用硅溶胶-凝胶(Sol-gel)膜将血红蛋白(Hb)固载于碳糊电极上的直接电化学行为.研究结果表明,Hb-Sol-gel修饰的碳糊电极在pH=7.0的缓冲溶液中于-0.275 V(vs.Ag/AgCl)处有一对可逆的循环伏安氧化-还原峰,为Hb血红素辅基Fe(Ⅲ)/Fe(Ⅱ)电对的特征峰.HbFe(Ⅲ)/Fe(Ⅱ)电对的式量电位在pH5.0～11.0范围内与溶液pH值呈线性关系,表明Hb的电化学还原很可能是一个质子伴随着一个电子的电极过程.FTIR光谱证实,Sol-gel膜对Hb的固载没有破坏其天然结构.Hb-Sol-gel修饰的碳糊电极能够催化还原H_2O_2,可望将其用于制作第三代生物传感器.

Direct electrochemical behavior of hemoglobin (Hb) immobilized on carbon paste electrodes by Sol-gel film derived from tetraethylorthosilicate was investigated for the first time. Hb-Sol-gel-modified electrodes showed a pair of well-defined and nearly reversible cyclic voltammetric peaks for HbFe(Ⅲ )/ Fe( Ⅱ ) redox couple at about -0. 275 V(vs. Ag/AgCl) in pH 7. 0 phosphate buffers. The formal potential of Hb heme Fe( Ⅲ )/Fe( Ⅱ ) couple shifted linearly between pH 5. 0-11. 0 with a slope of 51. 85 mV/ pH, suggesting that one proton was coupled to each electron transfer in the electrochemical reaction. It was demonstrated by FTIR spectra that the structure of Hb was still maintained native-like in the film. The immobilized Hb displayed the features of a peroxidase and gave an excellent electrocatalytic response to the reduction of H2O2. Consequently, this work provides a possible route of using Hb-Sol-gel-modified electrodes as the third generation biosensors.