Cytochrome c Self-Assembly on Alkanethiol Monolayer Electrodes as Characterized by AFM, IR, QCM, and Direct Electrochemistry
| Autor: | Edmond F. Bowden, Tadateru Yoshitake, Yasunori Yamashita, Koji Nakano |
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| Rok vydání: | 2007 |
| Předmět: |
Models
Molecular Protein Conformation Analytical chemistry Infrared spectroscopy Biosensing Techniques In Vitro Techniques Microscopy Atomic Force Electrochemistry Alkanes Spectroscopy Fourier Transform Infrared Monolayer Animals General Materials Science Horses Sulfhydryl Compounds Electrodes Spectroscopy biology Chemistry Cytochrome c Cytochromes c Substrate (chemistry) Surfaces and Interfaces Quartz crystal microbalance Condensed Matter Physics Crystallography Covalent bond Multiprotein Complexes biology.protein Self-assembly |
| Zdroj: | Langmuir. 23:6270-6275 |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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