血红蛋白在二维纳米金Langmuir-Blodgett单层膜修饰电极上的直接电化学

Direct Electrochemistry of Hemoglobin at Two-dimensional Nano-gold Particles Monolayer Deposited by Langmuir-Blodgett Technique

利用Langmuir-Blodgett(LB)技术在氧化铟锡(ITO)电极上制备了分散均匀的二维纳米金单层膜,并将血红蛋白(Hb)直接固定于该修饰电极表面,研究了Hb在电极上的直接电化学行为。实验结果表明:纳米金可以改善Hb和电极间的直接电子传递,提高电子传递效率。Hb/Nano-Au修饰电极在pH5.0～9.0范围内的式电位与溶液pH呈线性关系,斜率为-57mV/pH,说明Hb的电子传递过程伴随质子转移;该修饰电极对H2O2具有良好的催化作用,在0.1mol/LpH7.0的磷酸盐缓冲溶液(PBS)中,H2O2在2.5×10-6～4.1×10-4mol/L浓度范围内与响应电流呈良好的线性关系,检出限为6.2×10-7mol/L;其异相电子转移速率常数为0.66s-1,米氏常数为0.20mmol/L。

Two-dimensional monolayer with well-disseminated nano-gold particles was prepared at a indium-tin oxide （ITO） electrode based on the Langmuir- Blodgett （LB） technique. Hemoglobin （Hb） molecules were directly immobilized on the surface of modified electrode, and direct electrochemistry of Hb was studied by using cyclic vohammetric method. The experimental results indicated that nano-gold particles could improve the direct electron transfer between the electrode surface and Hb and enhance the efficiency of electron transfer. The V^p of modified electrode was linearly dependent on pH value from 5.0 to 9.0 with a linear slope of - 57 mV/pH, which indicated that the electron transfer of Hb was proton-coupled. The modified electrode provided an excellent electrocatalysis activity and rapid response for H2O2 in 0. 1 mol/L pH 7.0 PBS buffer solution. A linear relationship between current response and the concentration of H202 ranging from 2.5 ×10^-6 to 4. 1 ×10^-4 mol/L was obtained with a detection limit of 6.2 ×10^-7 mol/L. RSD of five different electrodes for 3.3 mmol/L H2O2 was 4. 8%. The average reaction rate constant was calculated to be 0. 66 s^-1 and the apparent Michaelis - Menten constant for Hb modified electrode was 0. 20 mmol/L.