XPS Analysis of Enzyme and Mediator at the Surface of a Layer-by-Layer Self-Assembled Wired Enzyme Electrode
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- 作者：Pablo Scodeller ; Federico J. Williams ; Ernesto J. Calvo
- 刊名：Analytical Chemistry
- 出版年：2014
- 出版时间：December 16, 2014
- 年：2014
- 卷：86
- 期：24
- 页码：12180-12184
- 全文大小：277K
- ISSN：1520-6882
文摘
High potential purified Trametes trogii laccase has been deposited in mono- and multilayer thin films on gold surfaces by layer-by-layer electrostatic adsorption self-assembly. The osmium bipyridil redox relay sites on polycation poly(allylamine) backbone efficiently work as a molecular 鈥渨ire鈥?in oxygen cathodes for biofuel cells. X-ray photoelectron spectroscopy of Cu 2p3/2 and Os 4f signals provided chemical information on the enzyme and redox mediator surface concentrations after different adsorption steps. The electrical charge involved in oxidation鈥搑eduction cycles of the osmium sites, the ellipsometric enzyme film thickness, and the mass uptake from quartz crystal microbalance experiments, correlate with the XPS surface concentration, which provides unique evidence on the chemical identity of the composition in the topmost layers. XPS is shown to be an important analytical tool to investigate stratified copper and osmium distribution in LbL thin films relevant to biosensors and biofuel cells.