Influence of the Doping Level on the Interactions between Poly(3,4‐ethylenedioxythiophene) and Plasmid DNA

Abstract

The influence of the doping level in the formation of specific interactions between plasmid DNA and PEDOT is investigated using experimental assays and theoretical calculations. Electrochemical methods are used to prepare polymer samples with oxidation degrees ranging from 0.14 to 1.05 positive charges per repeating unit. A combination of experimental and theoretical results are used to propose a mechanism for the formation of DNA/conducting polymer complexes, which consists of the initial stabilization of the adducts through non‐specific interactions followed by small structural re‐arrangements that allow to be established specific hydrogen bonds involving the polar groups of the conducting polymer and selected DNA bases.magnified image

A Conducting Polymer/Protein Composite with Bactericidal and Electroactive Properties

“…The increment of the turn population (12.2%) suggests the possible formation of hydrogen bonding interactions between the enzyme and the oxygen atoms of the polymer chains, which is consistent with a decrease of protein structural integrity. Within this context, it should be mentioned that PEDOT recognizes specific nucleotide sequences in plasmid DNA through the formation of hydrogen bonds,21, 22, 53 which illustrates the capability of this CP to form weak interactions. Results obtained for PEDOT/LZ (data not shown) are practically identical to those displayed in Figure 5a evidencing that, as expected, adsorption does not alter the structure of the enzyme.…”

“…Although the interaction between common CPs (i.e., polyaniline and, specially, polypyrrole derivatives) and bioentities, such as amino acids, proteins, DNA and living cells, has been extensively studied,8–16 it has been only quite recently that polythiophene derivatives have been explored as materials with promising biotechnological and/or biomedical applications 17–33. Within these exciting fields, PEDOT has been used to: recognize specific nucleotide sequences12–24; interact with epithelial, fibroblasts and neuronal cells favoring their adhesion and proliferation25–30; prepare bifunctional films with high bio‐ and electrochemical activities through the incorporation of collagen, which is one of the known constituents of the extracellular matrix of neurons31; construct functionalized devices for protein detection32, 33; etc.…”

Resolving the subnanometric structure of ultrathin films of poly(3,4-ethylenedioxythiophene) on steel surfaces: a molecular modeling approach

“…21,22 Acetonitrile molecules were represented by the standard AMBER03 model, 20 and ClO 4 À parameters were obtain from Baaden et al, 2000.…”

Properties of oligothiophene polycations

“…However, it should be noted that in all cases, calculations on n ‐EDOT were performed considering neutral ( q = 0) and oxidized molecules, the latter exclusively consisting of monocations having doublet ground state ( q = +1, S = 2) and/or dications having singlet ( q = +2, S = 1) or triplet ( q = +2, S = 3) ground states. This represents a limitation because PEDOT typically exhibits doping levels ranging from +0.1 to +0.5 positive charges per repeating unit, depending on the experimental conditions . Moreover, this oxidation degree can be easily increased to values higher than +1.0 positive charges per repeating unit using electrochemical methods …”

“…This represents a limitation because PEDOT typically exhibits doping levels ranging from +0.1 to +0.5 positive charges per repeating unit, depending on the experimental conditions . Moreover, this oxidation degree can be easily increased to values higher than +1.0 positive charges per repeating unit using electrochemical methods …”