Charge transport at the protein–electrode interface in the emerging field of BioMolecular Electronics

What Can We Learn from Protein-Based Electron Transport Junctions?

“…On the longer time scales, charge balance is maintained by rearrangement of protein-bound ions, or exposure to the liquid electrolyte. This is also the case in electrochemical experiments (e.g., refs − ), be they nano-, micro-, or macroscopic, because in all of those, part of the protein is exposed to the electrolyte. The same holds for recent work, where the electrical potential, applied via a reference electrode in solution, was kept well below that needed for a possible redox process, which is unlikely in this case because nonredox proteins were studied …”

RNA BioMolecular Electronics: towards new tools for biophysics and biomedicine

“…This constituted a proof of concept transistor based on a single protein. Further research helped to obtain other parameters, like the transition voltage, 43,44 studying azurin mutants, 14,45 and azurin interacting with the redox partner. 46 Developments over the last decades show that STM-assisted molecular junctions are a vital tool for molecular and bioelectronics.…”

“…Theories for how charges transfer and transport in molecules developed [2][3][4][5][6][7][8] in parallel with the experimental developments. The multiple theoretical and experimental methods used during the years, beyond the scope of this perspective, can be found in review papers [9][10][11][12][13][14] and books. [15][16][17][18] The field experienced a boom when the electronic conductance of individual molecules bound between electrodes could be measured reliably.…”

Distance and Potential Dependence of Charge Transport Through the P700 Reaction Center of Photosystem I

“…In protein junctions where the macromolecule contacts both electrodes, the charge exchange is driven by the potential drop between the electrodes rather than by the redox potential responsible for ET 14 . This charge exchange mechanism through a biased electrode, known as electron transport (ETp) can be achieved in ECSTM (break junction and blinking modes), conductive atomic force microscopy (C-AFM), liquid metal contacts, microfabricated gold nano wire set-ups 15 . A growing amount of evidence 14,[16][17][18] shows that ETp is a ubiquitous charge conduction mechanism through the protein matrix, and that it confers conductivities to redox and non-redox proteins outperforming molecular wires beyond 5 nm distances 19 .…”