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Triggering Mechanism for DNA Electrical Conductivity: Reversible Electron Transfer between DNA and Iron Oxide Nanoparticles
Author(s) -
Magro Massimiliano,
Baratella Davide,
Jakubec Petr,
Zoppellaro Giorgio,
Tucek Jiri,
Aparicio Claudia,
Venerando Rina,
Sartori Geppo,
Francescato Federica,
Mion Fabio,
Gabellini Nadia,
Zboril Radek,
Vianello Fabio
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201404372
Subject(s) - maghemite , materials science , nanoparticle , electron transfer , chemical physics , dna , nanotechnology , oxide , chemical engineering , chemistry , biochemistry , engineering , metallurgy
A new category of iron oxide nanoparticles (surface active maghemite nanoparticles (SAMNs, γ‐Fe 2 O 3 )) allows the intimate chemical and electrical contact with DNA by direct covalent binding. On these basis, different DNA‐nanoparticle architectures are developed and used as platform for studying electrical properties of DNA. The macroscopic 3D nanobioconjugate, constituted of 5% SAMNs, 70% water, and 25% DNA, shows high stability, electrochemical reversibility and, moreover, electrical conductivity (70–80 Ω cm −1 ). Reversible electron transfer at the interface between nanoparticles and DNA is unequivocally demonstrated by Mössbauer spectroscopy, which shows the appearance of Fe(II) atoms on nanoparticles following nanobioconjugate formation. This represents the first example of permanent electron exchange by DNA, as well as, of DNA conductivity at a macroscopic scale. Finally, the most probable configuration of the binding is tentatively modeled by density functional theory (DFT/UBP86/6‐31+G*), showing the occurrence of electron transfer from the organic orbitals of DNA to surface exposed Fe(III) on nanoparticles, as well as the generation of defects (holes) on the DNA bases. The unequivocal demonstration of DNA conduction provides a new perspective in the five decades long debate about electrical properties of this biopolymer, further suggesting novel approaches for DNA exploitation in nanoelectronics.