Voltammetric study of interaction between polymers (PEI and TMO) and pDNA on a hanging mercury drop electrode.

Electrochemical DNA biosensors can become a powerful tool for the investigation of potent changes on the plasmid DNA structure caused by polymers used as non-viral vectors in gene delivery. Trimethylated chitosan oligomer (TMO) and polyethylenimine (PEI), offering biocompatibility, low immunogenicity and minimal cytotoxicity, are being studied as model non-viral carriers. The information obtained is intended to serve as a basis for developing a new analytical system for the study of the effect of any physically or chemically synthesized polymer on DNA structure.

DNA-modified carbon paste electrode applied to the study of interaction between rifampicin (RIF) and DNA in solution and at the electrode surface.

Rifampicin (RIF) is an antibiotic widely used against tuberculosis and a DNA intercalator. The interaction of RIF with double-stranded (ds) and single-stranded (ss) calf thymus DNA was studied in solution as well as at the electrode surface by means of transfer voltammetry using differential pulse as stripping mode with carbon paste electrode (CPE) at 0.2M acetate buffer at pH 5.0 and at 0.2M phosphate buffer pH 7.4. Differentiations in the above-mentioned interaction at different pH values are presented and compared in order to optimize the detection of Rifampicin (RIF).

Study of interactions between actinomycin D and DNA on carbon paste electrode (CPE) and on the hanging mercury drop (HMDE) surface.

The interaction of actinomycin (ACTD) with double stranded (ds) calf thymus DNA and single stranded (ss) DNA was studied at the carbon paste electrode surface by means of transfer voltammetry in 0.2 M phosphate buffer solution (pH 7.4). Accordingly the interaction of actinomycin (ACTD) with ds calf thymus DNA, ss DNA and supercoiled (sc) DNA was studied using hanging mercury drop electrode in 0.3 M NaCl, and 50 mM sodium phosphate buffer (pH 8.5). The different electrochemical behaviours are presented and compared in the article.

Study of interactions between DNA-ethidium bromide (EB) and DNA-acridine orange (AO), in solution, using hanging mercury drop electrode (HMDE).

The interaction of ethidium bromide (EB) and acridine orange (AO) with double stranded (ds), thermally denatured (ss) and supercoiled (sc) DNA, in solution, was studied by alternating current voltammetry (AC voltammetry) at the hanging mercury drop electrode (HMDE) in 0.3 M NaCl+50 mM sodium phosphate buffer (pH 8.5). Their interaction with DNA is shown to be time dependent and completely different. The changes at peak 2 (peak at -1.20 V) of dsDNA form and the appearance of peak 3 (peak at -1.42 V) in scDNA form are presented as criteria declaring the different mechanism of interaction of EB and AO with DNA. Additionally, the appearance of a new peak at around -0.44 V as a result of DNA and AO interaction, differentiates the studied behaviors. The comparison of the electrochemical behaviors of these compounds highlights the differences in the mechanism of interaction.