Tuning Charge Transport of Oligopeptide Junctions via Interfacial Amino Acids

The charge transport through peptides can imitate the corresponding processes in more complicated proteins, enabling us to develop high-performance bioelectronic devices and to understand the mechanisms of biomolecular recognition and information transfer. While charge transport modulation through individual peptides has been achieved via various covalent strategies, the intermolecular modulation is still very challenging, which may capture the charge transport between proteins. To tackle this challenge, we used well-defined self-assembled monolayers (SAMs) of oligopeptides as a model to imitate the interface of proteins and explored an interfacial amino acid strategy for charge transport modulation. We showed that non-covalently interfaced charged amino acids (e.g., arginine) effectively attenuated the charge transport of glutamic acid terminated polyglycine peptide SAMs. By analyzing the relationship of the charge transport with the molecular frontier orbital relative to the Fermi energy level of the electrode, the molecule-electrodes coupling (G), and the trends in skewness and kurtosis with voltage and the dielectric constant (e(r)), we showed that the attenuation was from the decreased G and the reduced polarizability. We present an efficient strategy to modulate the charge transport of oligopeptide-SAM junctions by intermolecular interactions, which will advance our understanding of charge transport in biological systems and facilitate developing future electronics.

Automated summary

Charge transport through peptides can mimic complex protein processes, allowing for the development of high-performance bioelectronic devices and the understanding of biomolecular recognition and information transfer mechanisms. Modulating charge transport through individual peptides has been achieved, but intermolecular modulation remains challenging. To address this challenge, we used self-assembled monolayers (SAMs) of oligopeptides as models and explored an interfacial amino acid strategy for charge transport modulation. Our results showed that non-covalently interfaced, charged amino acids effectively attenuated charge transport. Analysis revealed that the attenuation was due to decreased molecule-electrodes coupling and reduced polarizability. This efficient strategy advances our understanding of charge transport in biological systems and facilitates the development of future electronics.