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Nanoporous Enzyme-Based Impedimetric Biosensor
Košelová, Z.
The ordered nanopores surfaces has been studied in the field of biosensors for the detection of affinity interactions such as antigen-antibody or nucleic acid hybridization. Nanopores are frequently fabricated by anodic oxidation of aluminium. This method is practically simple method of highly ordered pore formation, but is not suitable for massive production. The principle of detection is usually based on the degree of pore blockage by biomolecular interaction that allows a sensitive electrochemical response. Here we show the development and characterization of the nanopore-based enzymatic biosensor for the detection of analytes. We performed and tested the concept of the simple and versatile method of nanopores formation on the electrode using non-conductive polystyrene nanoparticles. The variability in pore size was modulated by nanoparticles diameter (40 and 80 nm). We measured response of our designed biosensor using electrochemical impedance spectroscopy in presence of redox mediator at low potential. The smaller diameter of nanopores increases charge transfer resistance. Biosensors with 80 nm nanoparticles had behaviour similar to reference without nanoparticles, therefore the pore was too wide for this design. The limit of detection from Rct showed to be at most 0.01 mM for every sample type. This proposed biosensor contributes to the basic knowledge about nanopores sensors, and it could have a potential, for example, in the development of ―point of care‖ devices.
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Electrochemical Characterization of Self-Assembled Monolayers Containing Redox Switching Element
Nováková Lachmanová, Štěpánka ; Kocábová, Jana ; Vavrek, František ; Sebechlebská, Táňa ; Šebera, Jakub ; Kolivoška, Viliam ; Lukášek, J. ; Balzer, N. ; Valášek, M. ; Hromadová, Magdaléna
Adsorption properties of molecules containing [Ru(terpy)2]2+ and [Os(terpy)2]2+ redox switching element connected to the electrode surface by tripodal thiolate anchoring groups have been studied together with their charge transfer properties in the adsorbed form. STM-based current-voltage measurements confirmed that the conductance of self-assembled monolayer containing [Os(terpy)2]2+ redox switching element is lower than that containing [Ru(terpy)2]2+ element. This observation agrees with previously observed differences in the electron transfer rate constants of these molecules in their adsorbed state.
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Analysis of liquid electrolyte electrical parameters using impedance spectroscopy
Brabenec, Josef ; Pikula, Stanislav (referee) ; Havránek, Zdeněk (advisor)
The bachelor thesis deals with impedance spectroscopy of electrochemical systems, especially liquid electrolytes. The method of impedance spectroscopy is widely used to describe electrochemical cells, batteries and electrolytes for diagnostic purposes over a wide range of frequencies. This thesis presents the main types of impedance imaging in the complex and frequency domain, as well as basic information on the measurement methods used and the methods for impedance analysis. The main part of the thesis was the development of software for automated impedance measurements and estimation of equivalent circuit parameters using basic and specialized circuit elements. A workplace with fabricated electrodes for liquid electrolyte measurements was prepared for the application. The functionality of the application was verified by real measurements of different concentrations of water and salt solutions. The validity of the estimated equivalent circuit parameters was verified on measured simple circuits connected from basic circuit elements and was also verified using the commercially used ZView software.
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The effect of temperature on the charging and discharging characteristics of lithium-ion batteries
Doleželová, Eva ; Máca, Josef (referee) ; Libich, Jiří (advisor)
This thesis deals with operation principles of lithium-ion batteries, its degradation principles, capacity fade, materials used, formats, main characteristics, development, uses and mid to high temperature behaviour. The thesis aims to study aging characteristics of commercially available lithium-ion batteries. In the practical part of the thesis, the key parameters of selected types of commercially available lithium-ion batteries were measured under normal temperature conditions. The measurement was repeated at an elevated temperature. Results were analysed and effects of different temperatures on the selected characteristics were concluded both verbally and graphically. A conclusion evaluates short-term and long-term impacts of ambient temperature on rate capability, ageing, capacity fade and longevity.
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Development of Novel Electrochemical Methods Using Various Membrane Materials for Monitoring of Selected Anticancer Drugs and Phytochelatins
Skalová, Štěpánka ; Barek, Jiří (advisor) ; Labuda, Ján (referee) ; Trnková, Libuše (referee)
Present Ph.D. Thesis is focused on the development of electrochemical methods for determination of anticancer drugs using various types of membranes for their preliminary separation. Furthermore, this Thesis reports the study of transport mechanisms of heavy metals in the presence of phytochelatins across biological membranes. Sodium anthraquinone-2-sulphonate (AQS) was used as a model compound for its similar structure with anthraquinone-based (AQ-based) anticancer drugs (doxo/daunorubicin) and also due to its better availability. All these compounds can be easily electrochemically oxidized and/or reduced. Redox behaviour of AQS was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in a cathodic region on mercury meniscus modified (m-AgSAE) and polished silver solid amalgam (p-AgSAE) electrodes, Obtained results were used for the development of a micro-volume voltammetric cell (MVVC). Its applicability for voltammetric determination of anticancer drugs was verified by using doxorubicin (DX) as a model substance. The second part of this Thesis deals with therapeutic monitoring of anticancer drugs in the blood circulation of the patients. For pilot experiments, a liquid-flow system with dialysis catheter and amperometric detection was used. The flow rate of carrier...
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Catalytic and adsorption properties of papain and its derivatives
Lachmanová, Štěpánka ; Hudeček, Jiří (advisor) ; Karpenko, Vladimír (referee)
The aminoacid sequence of papain (EC 3.4.22.2) consists of 212 aminoacids. It has only one free sulfhydryl group, which is located in the active site of the protein. Some organometallic complexes could be bonded only to this free -SH group due to their structure. The artificial metalloproteins synthesised by this way may have different electrochemical properties. In this work, we have studied the electrochemical properties of papain and its derivatives. We compared the ability of papain and its three artificial derivatives to catalyse the hydrogen evolution by the chronopotenciometry. The work was completed by the study of the electrochemical properties of the organometallic complexes of ruthenium, which were used for the artificial metalloprotein preparation. The electrochemical properties of the compounds were never studied before. The process of the hydrogen evolution catalysed by the proteins is held in the adsorbed state of the catalyst. Due to this fact we have also studied the adsorption properties of papain on the substrates with different level of hydrofobicity. (In Czech)
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Simple Electrochemical DNA Biosensor for Detection of DNA Damage Caused by UV Radiation
Arustamian, Daria ; Vyskočil, Vlastimil (advisor) ; Dejmková, Hana (referee)
Ultraviolet (UV) radiation is a common DNA damaging agent. Major DNA lesions, such as cyclobutane pyrimidine dimers (CPDs) and pyrimidine-(6-4)-pyrimidone (6-4PPs) photoproducts, are carcinogenic and mutagenic. UV induced DNA damage was investigated using a simple electrochemical DNA biosensor based on an ultra-trace graphite electrode (UTGE) and low molecular weight doble-stranded DNA (dsDNA) from salmon sperm. Biosensor was prepared using adsorption of dsDNA on a surface of the UTGE and then used to detect UV-induced DNA damage. Effects of UV radiation were investigated using a combination of several electrochemical technics: square-wave voltammetry (SWV) for direct monitoring of DNA base oxidation and cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), as non-direct methods, using redox-active indicator [Fe(CN)6]4-/3- . CV and EIS, which allow characterization of electrode surface, were used to optimize preparation of the dsDNA/UTGE biosensor. Prepared dsDNA/UTGE biosensor was exposed to UV radiation using UV lamp with two set wavelengths: UVC of 254 nm and UVA of 365 nm. UVC radiation was used to damage DNA. Relative signal decrease was 50% after 20 minutes of exposure to UVC radiation. UVA radiation was used to compare effects of different types of UV radiation. Obtained...
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Nanopatterned alumina-based materials for electrochemical sensors and biosensors
Kynclová, Hana ; Hynek, David (referee) ; Trnková, Libuše (referee) ; Prášek, Jan (advisor)
The doctoral thesis is focused on basic research and development of nanostructured surfaces prepared using anodic alumina material. Various types of gold nanostructured surfaces and nanoporous aluminum membranes for electrochemical sensors and biosensors were prepared using the anodic oxidation method. Nanostructured surfaces were prepared by electrochemical anodization of aluminum material to form hexagonally arranged nanopores. Gold was then deposited into the nanoporous masks by electrochemical reduction from potassium dicyanoaurate solution using a pulse deposition method. The prepared nanostructured gold surfaces were electrochemically characterized by electrochemical impedance spectroscopy and voltammetry. Temperature stability and the effect of annealing on their electrochemical behavior at atmospheric pressure as well as in the vacuum were investigated. Then, gold nanostructures of various dimensions were prepared and the influence of their shape and dimensions on the electrochemical behavior was studied. Nanostructured surfaces were also modified with 11–mercaptoundecanoic acid, and the effect of this modification on the electrochemical results was studied. In the last part of the work, nanoporous aluminum membranes were prepared, and their permeability was studied.
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Development of Novel Electrochemical Methods Using Various Membrane Materials for Monitoring of Selected Anticancer Drugs and Phytochelatins
Skalová, Štěpánka
Present Ph.D. Thesis is focused on the development of electrochemical methods for determination of anticancer drugs using various types of membranes for their preliminary separation. Furthermore, this Thesis reports the study of transport mechanisms of heavy metals in the presence of phytochelatins across biological membranes. Sodium anthraquinone-2-sulphonate (AQS) was used as a model compound for its similar structure with anthraquinone-based (AQ-based) anticancer drugs (doxo/daunorubicin) and also due to its better availability. All these compounds can be easily electrochemically oxidized and/or reduced. Redox behaviour of AQS was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in a cathodic region on mercury meniscus modified (m-AgSAE) and polished silver solid amalgam (p-AgSAE) electrodes, Obtained results were used for the development of a micro-volume voltammetric cell (MVVC). Its applicability for voltammetric determination of anticancer drugs was verified by using doxorubicin (DX) as a model substance. The second part of this Thesis deals with therapeutic monitoring of anticancer drugs in the blood circulation of the patients. For pilot experiments, a liquid-flow system with dialysis catheter and amperometric detection was used. The flow rate of carrier...
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Development of Novel Electrochemical Methods Using Various Membrane Materials for Monitoring of Selected Anticancer Drugs and Phytochelatins
Skalová, Štěpánka
Present Ph.D. Thesis is focused on the development of electrochemical methods for determination of anticancer drugs using various types of membranes for their preliminary separation. Furthermore, this Thesis reports the study of transport mechanisms of heavy metals in the presence of phytochelatins across biological membranes. Sodium anthraquinone-2-sulphonate (AQS) was used as a model compound for its similar structure with anthraquinone-based (AQ-based) anticancer drugs (doxo/daunorubicin) and also due to its better availability. All these compounds can be easily electrochemically oxidized and/or reduced. Redox behaviour of AQS was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in a cathodic region on mercury meniscus modified (m-AgSAE) and polished silver solid amalgam (p-AgSAE) electrodes, Obtained results were used for the development of a micro-volume voltammetric cell (MVVC). Its applicability for voltammetric determination of anticancer drugs was verified by using doxorubicin (DX) as a model substance. The second part of this Thesis deals with therapeutic monitoring of anticancer drugs in the blood circulation of the patients. For pilot experiments, a liquid-flow system with dialysis catheter and amperometric detection was used. The flow rate of carrier...
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