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A Tripeptide-Stabilized Nanoemulsion of Oleic Acid

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Published on: February 27, 2019

Polypeptides in alpha-helix conformation perform as diodes.

Dahiyana Cristancho¹, Jorge M Seminario

¹Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122, USA.

The Journal of Chemical Physics

|February 16, 2010

Summary

Researchers discovered intrinsic diode behavior in alpha-helix polypeptides like poly(L-alanine) and polyglycine. Applying electric fields alters molecular orbital gaps, enabling or blocking electron flow, paving the way for molecular electronic devices.

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Area of Science:

Molecular electronics
Organic semiconductors
Computational chemistry

Background:

Molecules with intrinsic electric dipoles were proposed as potential electronic devices mimicking semiconductor diode depletion zones.
Previous attempts were hindered by electron donor-acceptor linkers diminishing diode behavior.

Purpose of the Study:

To identify single-molecule systems exhibiting intrinsic diode behavior.
To investigate the electronic properties of polypeptides in alpha-helix conformation.

Main Methods:

Utilized molecular orbital theory and ab initio computational methods.
Analyzed the electronic band structure of poly(L-alanine) and polyglycine.

Main Results:

Intrinsic diode behavior was observed in alpha-helix poly(L-alanine) and polyglycine.
An antiparallel electric field reduced the energy gap between valence and conduction orbitals, increasing current.
A parallel electric field increased the energy gap, blocking electron flow.

Conclusions:

Polypeptides in alpha-helix conformation exhibit intrinsic molecular diode behavior.
The observed behavior is explained by electric field-induced modulation of molecular orbital energy gaps.
This finding opens new avenues for designing single-molecule electronic devices.