Probing
the Nature of Charge Transfer at Nano–Bio
Interfaces: Peptides on Metal Oxide Nanoparticles
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Abstract
Characterizing the nano–bio
interface has been a long-standing
endeavor in the quest for novel biosensors, biophotovoltaics, and
biocompatible electronic devices. In this context, the present computational
work on the interaction of two peptides, A6K (Ac-AAAAAAK-NH<sub>2</sub>) and A7 (Ac-AAAAAAA-NH<sub>2</sub>) with semiconducting
TiO<sub>2</sub> nanoparticles is an effort to understand the peptide–metal
oxide nanointerface. These investigations were spurred by recent experimental
observations that nanostructured semiconducting metal oxides templated
with A6K peptides not only stabilize large proteins like photosystem-I
(PS-I) but also exhibit enhanced charge-transfer characteristics.
Our results indicate that α-helical structures of A6K are not
only energetically more stabilized on TiO<sub>2</sub> nanoparticles,
but the resulting hybrids also exhibit enhanced electron transfer
characteristics. This enhancement can be attributed to substantial
changes in the electronic characteristics at the peptide-TiO<sub>2</sub> interface. Apart from understanding the mechanism of electron transfer
(ET) in peptide-stabilized PS-I on metal oxide nanoparticles, the
current work also has implications in the development of novel solar
cells and photocatalysts