Cytochrome c self-assembly on alkanethiol monolayer electrodes as characterized by AFM, IR, QCM, and direct electrochemistry

Koji Nakano, Tadateru Yoshitake, Yasunori Yamashita, Edmond F. Bowden

    研究成果: ジャーナルへの寄稿学術誌査読

    89 被引用数 (Scopus)


    With the advantage of carbodiimide coupling chemistry, horse heart cytochrome c (cyt c) has been covalently immobilized onto self-assembled monolayers (SAMs) from 11-mercaptoundecanoic acid (MUDA) developed on single-crystal or polycrystalline gold substrate surfaces. The cyt c immobilized substrates thus prepared have been characterized by atomic force microscopy (AFM); we have succeeded in obtaining surface topographical images down to single-protein resolution. AFM imaging has also shown densely packed, uniform protein monolayer formation that is highly suggestive of self-assembly of cyt c molecules on MUDA SAMs. Covalent attachment of cyt c has been further evidenced by reflection-absorption FT-IR as well as microgravimetric analysis using a quartz crystal microbalance (QCM). In the latter, the specific MUDA and cyt c surface concentrations were determined to be 0.86 ± 0.11 nmol cm -2 (n = 5) and 28 ± 12 pmol cm-2 (n = 5), both of which agree fairly well with their theoretical counterparts. The obtained QCM chips having the cyt c/MUDA/Au interfacial structure were found to be capable of the direct electrochemistry of the surface-attached cyt c molecules. Cyclic voltammetric measurements on the chips gave particular redox waves showing characteristics of surface process. The electroactive protein surface concentration was determined to be 7.2 ± 4.8 pmol cm-2 (n -6); it was almost consistent with values found in literature, while it was limited to 26% in magnitude for the QCM data. This was deemed to have arisen from the orientation variation of the surface-confined cyt c molecules and is discussed briefly.

    出版ステータス出版済み - 5月 22 2007

    !!!All Science Journal Classification (ASJC) codes

    • 材料科学(全般)
    • 凝縮系物理学
    • 表面および界面
    • 分光学
    • 電気化学


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