Triggering Mechanism for DNA Electrical Conductivity: Reversible Electron Transfer between DNA and Iron Oxide Nanoparticles

Abstract

A new category of iron oxide nanoparticles (SAMNs, γ-Fe2O3) allows the intimate chemical and electrical contact with DNA by direct covalent binding. On these basis, different DNA-nanoparticle architectures were developed and used as platform for studying electrical properties of DNA. The macroscopic three-dimensional nano-bio-conjugate, constituted of 5% SAMNs, 70% water and 25% DNA, showed high stability, electrochemical reversibility and, moreover, electrical conductivity (70-80 Ω cm-1). Reversible electron transfer at the interface between nanoparticles and DNA was unequivocally demonstrated by Mössbauer spectroscopy, which showed the appearance of Fe(II) atoms on nanoparticles following nano-bio-conjugate formation. This represent 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 was tentatively modelled 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 nano-electronics

Sustainable production of high purity curcuminoids from Curcuma longa by magnetic nanoparticles: A case study in Brazil

“…The SAMN@curcuminoid complex was characterized by UVeVis spectroscopy confirming the binding of the biomolecules onto the surface exposed iron(III) sites on SAMNs, as already observed in previous papers (Magro et al, 2014b(Magro et al, , 2015b. Curcuminoid binding influenced the optical properties of SAMNs as already reported for hybrid nanomaterials, which can display peculiar properties, differently from those inherited from their components.…”

Ternary Hybrid γ‐Fe2O3/CrVI/Amine Oxidase Nanostructure for Electrochemical Sensing: Application for Polyamine Detection in Tumor Tissue

“…Interestingly, as in the case of DNA binding on maghemite nanoparticles, the effect of Cr binding on SAMN recalls the electrochemical behavior produced by the introduction of an ionic liquid, namely, 1‐butyl‐3‐methyl imidazolium hexafluorophosphate, on SAMN‐modified CPEs, which suggests that Cr improved the conductivity of SAMN‐modified CPEs, as already described for ionic liquids . These significantly altered electrochemical properties observed after chromium binding on SAMNs are witness to a strong interaction of dichromate with the nanoparticle surface.…”

Colloidal Surface Active Maghemite Nanoparticles for Biologically Safe CrVI Remediation: from Core‐Shell Nanostructures to Pilot Plant Development

“…After 6 h incubation in PBS, the bacterial cells likely suffered for the lack of nutrients as broken cells or cell debris were detected. Notice that SAMNs, which have a high affinity for nucleic acids, are individually bound to the cellular material of broken cells, which suggests that they were incubated as single particles that aggregated during the sample processing for TEM imaging (Figure , panels C and D). Results indicate that neither naked SAMNs nor SAMN@Cr VI complex display mutagenic effects on Salmonella typhimurium TA100 strain.…”