Novel Electrochemical Biosensor for the Detection of DNA Damage Caused by Chemical Carcinogens

Presented Bachelor Thesis is focused on the development and utilization of a simple and inexpensive electrochemical DNA biosensor for the detection of DNA damage caused by chemical carcinogens. A glassy carbon electrode (GCE), having several advantages such as broad potential window and well-renewable surface, was used for its preparation. A low- molecular-weight DNA isolated from salmon sperm was used. The initial part of the work is devoted to the optimization of the biosensor preparation and to its characterization, which was performed using several electrochemical techniques - cyclic voltammetry (CV), square-wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS). The influence of the DNA immobilization type on the quality of the biosensor response was also investigated. Two approaches were tested: (i) spontaneous adsorption of DNA by leaving the DNA stock solution to dry on the GCE surface and (ii) adsorptive accumulation of DNA on the GCE surface from the solution (selected as the optimum one). The second part of this Thesis deals with the detection of DNA damage by various chemical carcinogens. Four model substances were tested: flutamide (an antiandrogen antitumor drug), 4-nitro-3-(trifluoromethyl)aniline (NTMA; a metabolite of flutamide), 2-aminoanthracene (a genotoxic..

The Use of a Simple Electrochemical DNA Biosensor for the Determination of Environmental Pollutants and Investigation of Their Interaction with DNA

The interaction between three selected representatives of environmental pollutants - naphthalene, anthracene, and 2-aminoanthracene - and DNA was investigated using an electrochemical DNA biosensor based on a glassy carbon electrode (GCE) and low molecular weight DNA from salmon sperm (DNA/GCE). The interactions with DNA were monitored using square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS). For naphthalene, there was no DNA damaging interaction observed. In the case of anthracene, the formation of an intercalation complex [DNA-anthracene] was observed. However, its formation does not cause DNA strand breaks. The formation of similar intercalation complex was observed for 2-aminoanthracene [DNA-2-aminoanthracene], where we suppose on the basis of the results obtained that the intercalation of 2-aminoanthracene into the DNA double helix induces a tension and subsequent formation of single-strand breaks, which cause that the fragments of DNA fall away from the electrode surface. The intercalative interaction of DNA with anthracene a 2-aminoanthracene was used in the development of electrochemical methods for determination of these compounds at the GCE and DNA/GCE. At the development of the methods, DC voltammetry (DCV) and differential pulse voltammetry (DPV) were used...

Electrochemical DNA biosensors – useful diagnostic tools for the detection of damage to DNA caused by organic xenobiotics (a review)

Supramolecular interactions of various organic xenobiotic compounds with DNA are among the most important aspects of biological studies in clinical analysis, drug discovery, and pharmaceutical development processes. In recent years, there has been a growing interest in the electrochemical investigation of interactions between studied analytes and DNA. Observing the pre- and post-electrochemical signals of DNA or monitoring its interaction with xenobiotics provides good evidence for the interaction mechanism to be elucidated. Such interaction can also be used for sensitive determination of these compounds. This short review should provide evidence that the electrochemical approach brings new insight into human health protection or rational drug design and leads to further understanding of the interaction mechanism between organic xenobiotic compounds and DNA