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Differential Electrochemical Conductance Imaging at the Nanoscale
Author(s) -
LópezMartínez Montserrat,
Artés Juan Manuel,
Sarasso Veronica,
Carminati Marco,
DíezPérez Ismael,
Sanz Fausto,
Gorostiza Pau
Publication year - 2017
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201700958
Subject(s) - electron transfer , nanotechnology , electrochemistry , nanobiotechnology , materials science , conductance , electrode , nanoscopic scale , redox , scanning tunneling microscope , electron transport chain , chemical physics , chemistry , nanoparticle , physics , biochemistry , organic chemistry , condensed matter physics , metallurgy
Electron transfer in proteins is essential in crucial biological processes. Although the fundamental aspects of biological electron transfer are well characterized, currently there are no experimental tools to determine the atomic‐scale electronic pathways in redox proteins, and thus to fully understand their outstanding efficiency and environmental adaptability. This knowledge is also required to design and optimize biomolecular electronic devices. In order to measure the local conductance of an electrode surface immersed in an electrolyte, this study builds upon the current–potential spectroscopic capacity of electrochemical scanning tunneling microscopy, by adding an alternating current modulation technique. With this setup, spatially resolved, differential electrochemical conductance images under bipotentiostatic control are recorded. Differential electrochemical conductance imaging allows visualizing the reversible oxidation of an iron electrode in borate buffer and individual azurin proteins immobilized on atomically flat gold surfaces. In particular, this method reveals submolecular regions with high conductance within the protein. The direct observation of nanoscale conduction pathways in redox proteins and complexes enables important advances in biochemistry and bionanotechnology.