Fast and efficient charge transport across a lipid bilayer is electronically mediated by C{sub 70} fullerene aggregates
- Rockefeller Univ., New York, NY (United States)
Fullerene anions, made by photoreduction in a lipid bilayer, produce the largest trans-membrane steady state photocurrents yet observed, nearly 6.0 {mu}A/cm{sup 2}. Since these photocurrents are not light saturated, their maximum value is considerably larger. Dithionite was used as electron donor for its ability to reduce photoexcited fullerenes at the donor interface on a time scale faster than 15 ns. Both photovoltage and photocurrent increase 15-fold on adding the acceptor ferricyanide trans to the donor. There are two components to the transit time of negative charge across the bilayer, <100 ns and 6 {mu}s, in the 100 mM dithionite 0.6 mM C{sub 70} 5 mM ferricyanide system, where stands for the water-bilayer interface. This is strong evidence that the conduction is electronic and not diffusive-ionic. The plot of the ratio of photovoltage for the dithionite C{sub 70} system to that of the dithionite C{sub 70} ferricyanide system versus concentration of C{sub 70} in the lipid-forming solution is highly monlinear. This suggests that aggregates of the fullerene are responsible for the fast negative charge transport. The action spectrum of the photocurrent further supports the existence of photoactive C{sub 70} aggregates in the lipid bilayer. These aggregates may form the conductive path for electrons across the lipid bilayer. 23 refs., 5 figs., 1 tab.
- OSTI ID:
- 282948
- Journal Information:
- Journal of the American Chemical Society, Vol. 118, Issue 24; Other Information: PBD: 19 Jun 1996
- Country of Publication:
- United States
- Language:
- English
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