Shan Wenjing, Liu Hongyun, Shi Jiantao, Yang Lingzhu, Hu Naifei
Department of Chemistry, Beijing Normal University, Beijing 100875, China.
Biophys Chem. 2008 Apr;134(1-2):101-9. doi: 10.1016/j.bpc.2008.01.008. Epub 2008 Feb 6.
Anionic surfactant dihexadecyl phosphate (DHP) with two hydrocarbon chains can be self-assembled into a double-layer structure with tail-to-tail configuration and negatively charged head groups toward outside in its aqueous dispersion. Due to this unique biomembrane-like structure, the "charge reversal" in DHP adsorption on solid surface was realized, and the DHP was successfully assembled with positively charged myoglobin (Mb) or hemoglobin (Hb) into {DHP/protein}(n) layer-by-layer films. Quartz crystal microbalance (QCM), UV-vis spectroscopy, and cyclic voltammetry (CV) were used to monitor or confirm the film assembly process. The {DHP/protein}(n) films grown on pyrolytic graphite (PG) electrodes showed a pair of well-defined and nearly reversible CV peaks at about -0.35 V vs SCE in pH 7.0 buffers, characteristic of the protein heme Fe(III)/Fe(II) redox couples. Based on the direct electrochemistry of heme proteins, the {DHP/protein}(n) films could also be used to electrochemically catalyze reduction of oxygen, hydrogen peroxide and nitrite with significant lowering of reduction overpotentials. Scanning electron microscopy (SEM), UV-vis spectroscopy, and reflectance absorption infrared (RAIR) spectroscopy were employed to characterize the {DHP/protein}(n) films, suggesting that the proteins in the films retain their near-native structure.
具有两条烃链的阴离子表面活性剂磷酸二己酯（DHP）在其水分散体中可自组装成尾对尾构型且带负电荷的头基朝向外部的双层结构。由于这种独特的类生物膜结构，实现了DHP在固体表面吸附的“电荷反转”，并且DHP成功地与带正电荷的肌红蛋白（Mb）或血红蛋白（Hb）组装成{DHP/蛋白质}(n)层层膜。使用石英晶体微天平（QCM）、紫外可见光谱和循环伏安法（CV）来监测或确认膜组装过程。在热解石墨（PG）电极上生长的{DHP/蛋白质}(n)膜在pH 7.0缓冲液中相对于饱和甘汞电极（SCE）在约-0.35 V处显示出一对定义明确且近乎可逆的CV峰，这是蛋白质血红素Fe(III)/Fe(II)氧化还原对的特征。基于血红素蛋白的直接电化学，{DHP/蛋白质}(n)膜还可用于电化学催化氧气、过氧化氢和亚硝酸盐的还原，显著降低还原过电位。采用扫描电子显微镜（SEM）、紫外可见光谱和反射吸收红外（RAIR）光谱对{DHP/蛋白质}(n)膜进行表征，表明膜中的蛋白质保留了其近乎天然的结构。
