Electronic Transport in Molecular Wires of Precisely Controlled Length Built from Modular Proteins

Bintian Zhang, Eathen Ryan, Xu Wang, Weisi Song, Stuart Lindsay

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


DNA molecular wires have been studied extensively because of the ease with which molecules of controlled length and composition can be synthesized. The same has not been true for proteins. Here, we have synthesized and studied a series of consensus tetratricopeptide repeat (CTPR) proteins, spanning 4 to 20 nm in length, in increments of 4 nm. For lengths in excess of 6 nm, their conductance exceeds that of the canonical molecular wire, oligo(phenylene-ethylenene), because of the more gradual decay of conductance with length in the protein. We show that, while the conductance decay fits an exponential (characteristic of quantum tunneling) and not a linear increase of resistance with length (characteristic of hopping transport), it is also accounted for by a square-law dependence on length (characteristic of weakly driven hopping). Measurements of the energy dependence of the decay length rule out the quantum tunneling case. A resonance in the carrier injection energy shows that allowed states in the protein align with the Fermi energy of the electrodes. Both the energy of these states and the long-range of hopping suggest that the reorganization induced by hole formation is greatly reduced inside the protein. We outline a model for calculating the molecular-electronic properties of proteins.

Original languageEnglish (US)
Pages (from-to)1671-1680
Number of pages10
JournalACS nano
Issue number1
StatePublished - Jan 25 2022


  • bioelectronics
  • hopping transport
  • molecular electronics
  • molecular wires
  • protein electronics
  • protein wires
  • tunneling transport

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy


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