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Detection of Oxidative Stress Using Electrochemical DNA Biosensors
Jurečková, Zuzana ; Vyskočil, Vlastimil (advisor) ; Fischer, Jan (referee)
Presented Diploma Thesis is focused on the development, characterization, and utilization of simple and inexpensive electrochemical DNA biosensor for the detection of DNA damage caused by oxidative stress. The initial part of the work is devoted to preparation and characterization of a large-surface carbon film electrode (ls-CFE) modified with carbon nanotubes (CNT/ls-CFE). Carbon nanotubes improve electrochemical properties of the transducer and increase the amount of adsorbed DNA on the electrode surface. Testing of the electrode surface modified with multiwalled carbon nanotubes (MWCNT) was performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using a redox system [Fe(CN)6]4-/3- and using square wave voltammetry without any redox indicator. Carbon nanotubes have proved to be unsuitable material for our type of biosensor, but it can be used inanalytical chemistry for the determination of electroactive substances. The second part of this Thesis deals with the application of the prepared DNA biosensor for the detection of DNA damage by oxidative stress. The biosensor based on the ls-CFE was chosen for this purpose, having several advantages, such as its fast preparation, a simple mechanical renewal of the electrode surface, a good reproducibility of measurements,...
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Novel Voltammetric DNA Biosensor for the Detection of the DNA Damage Caused by Oncological Drugs
Hrochová, Zuzana ; Vyskočil, Vlastimil (advisor) ; Zima, Jiří (referee)
This Bachelor Thesis is focused on the optimization of conditions for the use of a simple voltammetric DNA biosensor, based on a large-surface carbon film electrode (ls-CFE), for the detection of the DNA damage caused by oncological drugs. ls-CFE was used for its advantageous properties, such as its fast preparation, a simple mechanical renewal of the electrode surface, a good reproducibility of results, a simple chemical modification, and, last but not least, low preparation costs. A content of ethanol in the solution, in which the biosensor was incubated together with the damaging agent, was the main optimization parameter investigated in this Thesis. The contents of ethanol in the range from 0 to 50 % (v/v) of ethanol in 0.1 mol/l phosphate buffer of pH 7.15 (PBS) were tested. After the incubation of the biosensor, the measurements were performed using cyclic voltammetry (CV) in the presence of the redox indicator [Fe(CN)6]4-/3- in PBS. The optimum content of ethanol was found as 5 %. Afterwards, the DNA biosensor, which preparation was optimized in a previous Bachelor Thesis, was used for the detection of the DNA damage caused by model cytostatic agent - Ellipticine (5,11-dimethyl-6H-pyrido[4,3-b]carbazol). Using the CV technique and the redox indicator [Fe(CN)6]4-/3- , the response of the biosensor to...
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Study of 2-Nitrofluorene Interaction with DNA at a Glassy Carbon Electrode
Skalová, Štěpánka ; Stávková, K. ; Vyskočil, V. ; Barek, J.
2-Nitrofluorene (2-NF) is a nitrated polycyclic aromatic hydrocarbon (NPAH) which occurs as the environmental pollutant. It is a potential carcinogen and mutagen. Interaction of deoxyribonucleic acid (DNA) with 2-NF was monitored using an electrochemical DNA biosensor prepared from a glassy carbon electrode (GCE) and low-molecular-weight DNA by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and square-wave voltammetry (SWV).\nThere were no damaging interactions observed between DNA and 2-NF using EIS. However, CV shows intercalation of this substance into the DNA structure to form the complex 2-NF–DNA. Intercalation was also observed by SWV, confirming intercalation to reduce the number of electroactive sites and thus reducing the peak heights of adenosine and guanosine.
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