Calvo Ernesto J, Rothacher M Silvina, Bonazzola Cecilia, Wheeldon Ian R, Salvarezza Roberto C, Vela Maria Elena, Benitez Guillermo
Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, INQUIMAE, Ciudad Universitaria, AR-1428 Buenos Aires, Argentina.
Langmuir. 2005 Aug 16;21(17):7907-11. doi: 10.1021/la050695n.
A new biomimetic nanostructured electrocatalyst comprised of a self-assembled monolayer (SAM) of flavin covalently attached to Au by reaction of methylformylisoalloxazine with chemisorbed cysteamine is introduced. Examinations by Fourier transform infrared spectroscopy and scanning tunneling microscopy (STM) show that the flavin molecules are oriented perpendicular to the surface with a 2 nm separation between flavin molecules. As a result of the contrast observed in the STM profiles between areas only covered by unreacted cysteamine and those covered by flavin-cysteamine moieties, it can be seen that the flavin molecules rise 0.7 nm above the chemisorbed cysteamines. The SAM flavin electrocatalyst undergoes fast electron transfer with the underlying Au and shows activity toward the oxidation of enzymatically active beta-NADH at pH 7 and very low potential (-0.2 V vs Ag/AgCl), a requirement for use in an enzymatic biofuel cell, and a 100-fold increase in activity with respect to the collisional reaction in solution.
介绍了一种新型的仿生纳米结构电催化剂，它由通过甲基甲酰异咯嗪与化学吸附的半胱胺反应而共价连接到金上的黄素自组装单层（SAM）组成。傅里叶变换红外光谱和扫描隧道显微镜（STM）检查表明，黄素分子垂直于表面取向，黄素分子之间的间距为2纳米。由于在STM图谱中观察到未反应的半胱胺覆盖区域与黄素-半胱胺部分覆盖区域之间的对比度，可以看出黄素分子比化学吸附的半胱胺高出0.7纳米。SAM黄素电催化剂与底层金之间发生快速电子转移，并在pH 7和非常低的电位（相对于Ag/AgCl为-0.2 V）下对酶活性β-NADH的氧化表现出活性，这是酶促生物燃料电池使用的一个要求，并且相对于溶液中的碰撞反应，活性增加了100倍。
