Probing the Nature of Charge Transfer at Nano–Bio Interfaces: Peptides on Metal Oxide Nanoparticles

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-NH2) and A7 (Ac-AAAAAAA-NH2) with semiconducting TiO2 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 TiO2 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-TiO2 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.

A pH‐Induced Reversible Conformational Switch Able to Control the Photocurrent Efficiency in a Peptide Supramolecular System

“…Specifically,C ahen and co-workersd emonstrated experimentally that the electronic transportthrough protonated peptides can lead to an increase in conduction comparedt on egatively or uncharged peptides, because of the decrease of the energy of both occupieda nd unoccupied electronic levels. [51] The same conclusion was reported by at heoretical investigation by Ta rakeshwar et al [52] In our system, by decreasing the pH the photocurrent value increases, confirming that protonation improves the photocurrent value;o nt he other hand, the highest photocurrentd ifference between film 1 and 2 is obtained at pH 11.S ince the described effects are in contrast, our resultsd emonstrate that the effect of the conformational transition (betterE Tp roperties of a-helix compared to 3 10 -helix) is predominant on that of the charged residues.…”

Superior methanol electrooxidation activity and CO tolerance of mesoporous helical nanospindle-like CeO2modified Pt/C

“…As shown in Fig. 35,36 The electrochemical surface characteristics of Pt@Heli-CeO 2 /C are compared with Pt@Octa-CeO 2 /C and Pt/C catalysts using cyclic voltammetry (Fig. 33,34 This remarkable enhancement in the electron transmission may be attributed to the helical structure, which is more conductive with better electron transfer than that of the corresponding octahedral structures.…”

“…33,34 This remarkable enhancement in the electron transmission may be attributed to the helical structure, which is more conductive with better electron transfer than that of the corresponding octahedral structures. 35,36 The electrochemical surface characteristics of Pt@Heli-CeO 2 /C are compared with Pt@Octa-CeO 2 /C and Pt/C catalysts using cyclic voltammetry (Fig. 5b).…”

Self-Assembling Behavior of pH-Responsive Peptide A6K without End-Capping

“…In addition, A 6 K can promote the selective adsorption of specific substrates and enhance photovoltaic performance in the application of biological photovoltaic cells. These studies have great significance for the development of new solar cells and photocatalysts [16,17].…”