McKenzie Katy J, Marken Frank, Opallo Marcin
Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK.
Bioelectrochemistry. 2005 Apr;66(1-2):41-7. doi: 10.1016/j.bioelechem.2004.03.008.
Cytochrome c is accumulated into a film of TiO(2) nanoparticles and phytate by adsorption from an aqueous solution into the mesoporous structure. Stable voltammetric responses and high concentrations of redox protein within the TiO(2) phytate layer can be achieved. Two types of electrode systems are reported with (i) the modified TiO(2) phytate film between electrode and aqueous solution phase and (ii) the modified TiO(2) phytate film buried under a porous gold electrode ('porotrode'). The electrical conductivity of TiO(2) phytate films is measured and compared in the dry and in the wet state. Although in the dry state essentially insulating, the TiO(2) phytate film turns into an electrical conductor (with approximately 4 Omega cm specific resistivity assuming ohmic behaviour) when immersed in aqueous 0.1 M phosphate buffer solution at pH 7. The redox protein cytochrome c is therefore directly connected to the electrode via diffusion and migration of electrons in the three dimensional mesoporous TiO(2) phytate host structure. Electron transfer from cytochrome c to TiO(2) is proposed to be the rate-determining step for this conduction mechanism.
细胞色素c通过从水溶液吸附进入介孔结构，累积在二氧化钛纳米颗粒和植酸的薄膜中。在二氧化钛植酸层内可实现稳定的伏安响应和高浓度的氧化还原蛋白。报道了两种类型的电极系统：（i）电极与水相之间的修饰二氧化钛植酸薄膜，以及（ii）埋在多孔金电极（“多孔电极”）下的修饰二氧化钛植酸薄膜。测量并比较了二氧化钛植酸薄膜在干燥和湿润状态下的电导率。尽管在干燥状态下基本绝缘，但当浸入pH为7的0.1 M磷酸盐水溶液中时，二氧化钛植酸薄膜会变成电导体（假设为欧姆行为，比电阻率约为4Ω·cm）。因此，氧化还原蛋白细胞色素c通过电子在三维介孔二氧化钛植酸主体结构中的扩散和迁移直接与电极相连。细胞色素c向二氧化钛的电子转移被认为是这种传导机制的速率决定步骤。
