A Helical Peptide can Mediate Electron over 120 Å by Hopping Mechanism

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We have studied long-range electron transfer through various lengths of helical peptides from 8 mer (24 Å) up to 80 mer (120 Å) in self-assembled monolayers prepared on a gold surface. Helical peptides carrying a redox-active ferrocene unit and a disulfide group at the respective terminals were synthesized and immobilized on gold via a gold-sulfur linkage to form a well-defined monolayer with vertical helix orientation, and the electron transfer from the ferrocene unit to gold through the helical peptides was studied by electrochemistry. The electron transfer showed a very shallow distance dependence and high activation energies, both of which are characteristic of a hopping mechanism. Detailed theoretical calculations successfully demonstrated that a hopping mechanism with the amide groups as hopping sites is responsible for the long-range electron transfer, which enables ultralong-range electron transfer over 120 Å with the 80 mer helical peptide.

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Journal: TechConnect Briefs
Volume: 3, Nanotechnology 2011: Bio Sensors, Instruments, Medical, Environment and Energy
Published: June 13, 2011
Pages: 143 - 146
Industry sectors: Advanced Materials & Manufacturing | Medical & Biotech
Topic: Biomaterials
ISBN: 978-1-4398-7138-6