Adsorption of peptide nucleic acid and DNA decamers at electrically charged surfaces

Abstract

Adsorption behavior of peptide nucleic acid (PNA) and DNA decamers (GTAGATCACT and the complementary sequence) on a mercury surface was studied by means of AC impedance measurements at a hanging mercury drop electrode. The nucleic acid was first attached to the electrode by adsorption from a 5-microliter drop of PNA (or DNA) solution, and the electrode with the adsorbed nucleic acid layer was then washed and immersed in the blank background electrolyte where the differential capacity C of the electrode double layer was measured as a function of the applied potential E. It was found that the adsorption behavior of the PNA with an electrically neutral backbone differs greatly from that of the DNA (with a negatively charged backbone), whereas the DNA-PNA hybrid shows intermediate behavior. At higher surface coverage PNA molecules associate at the surface, and the minimum value of C is shifted to negative potentials because of intermolecular interactions of PNA at the surface. Prolonged exposure of PNA to highly negative potentials does not result in PNA desorption, whereas almost all of the DNA is removed from the surface at these potentials. Adsorption of PNA decreases with increasing NaCl concentration in the range from 0 to 50 mM NaCl, in contrast to DNA, the adsorption of which increases under the same conditions.

Peer Reviewed: Detecting DNA Hybridization and Damage

“…Prolonged exposure to highly negative potentials does not desorb PNA molecules; although, under these conditions, almost all DNA molecules are removed from the surface. PNA adsorption increases with decreasing salt concentration, whereas DNA adsorption decreases under the same conditions (13). For DNA hybridization detectors, PNAs may serve as better probes than DNA.…”

Constant Current Chronopotentiometric Stripping Analysis of Bioactive Peptides at Mercury and Carbon Electrodes

“…The main purpose of this article is to show that electrochemical methods and particularly CPSA may provide information about the presence and accessibility of tyrosine, tryptophan and cystine/cysteine residues in peptides and proteins at nanomolar concentrations. In addition measurements of the adsorption/desorption signals [4,45,46] and AC impedance spectra [47] may provide information about the interaction of the biomolecule at the electrode surface. Studies of DNA protein interaction may be particularly interesting as it has been shown that not only peptides and proteins but also DNA yields its own reduction, oxidation and adsorption/desorption signals [33,36,38,45,48] which might change upon the formation of the DNA-protein complexes.…”

Electrical and interface properties of Au/DNA/n-Si organic-on-inorganic structures

“…A DNA molecule (a genetic information carrier) is a double-stranded negatively charged polymer. DNA adsorption at negatively charged surface using self-assembled molecular monolayer or Peptide Nucleic Acid treatments are also investigated [9]. DNA changes its conformation through environmental interactions with the other components of the living cells [10,11].…”