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Electro-optical sensor for the detection of extracellular ions
Bellan, Boris ; Salyk, Ota (referee) ; Vala, Martin (advisor)
The aim of this work was to prepare a platform based on electrochemical transistor that would allow both electrical and optical detection of ion exchange between the electrolyte and the layer of organic semiconductor. Semiconductor that have been used in this work was poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate). The main goal was to verify whether the proposed platform meets the requirements of both characterization methods, and whether the sensitivity in the given arrangement is sufficient for the required range of analyte concentrations. The work also dealt with the study of the stability of the prepared platform in selected solvents and culture media, at the same time the method of optimizing the preparation of the photoresist foil and the completion of the OECT measuring cell was studied. A suitable solvent for polymethyl methacrylate was sought so that it did not affect the surrounding parts of the platform. Based on the obtained results, it was found that the selected photoresist for the preparation of the spacer frame is not suitable. However, it was found that the proposed platform satisfies both characterization methods. Therefore, it will be necessary to replace the current photoresist with a new, more chemically stable one.
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Staphylococcus aureus - jeho výskyt a možnosti detekce v mléce a mléčných výrobcích
Fenclová, Denisa
The theoretical part of diploma thesis is focused on summarizing current knowledge about S. aureus, its pathogenesis, occurrence, and possibilities of its detection in milk and dairy products. The experimental part of diploma thesis is aimed at determining S. aureus using various cultivation methods. S. aureus was determined using B-P agar with the addition of RPF, ClearMilku test, MicroFast®, and PetrifilmTM. The determination was evaluated as follows: B-P agar with the addition of RPF > PetrifilmTM > MicroFast® > ClearMilk test. Another part of the experimental diploma thesis deals with the possibility of detecting S. aureus using a newly developed biosensor detection system.
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A comparative study of covalent glucose oxidase and laccase immobilization techniques at powdered supports for biosensors fabrication
Tvorynska, Sofiia ; Barek, J. ; Josypčuk, Bohdan ; Nesměrák, K.
In order to develop the optimal strategy and to deepen the knowledge in the field of enzyme immobilization, three different techniques of covalent binding for two enzymes (glucose oxidase and laccase) at powdered surfaces were compared. Immobilization protocol was optimized by changing supports (two mesoporous silica powders (SBA−15, MCM−41) and a cellulose powder), the functionalized\ngroups introduced at support surfaces (−NH and −COOH), and the methods of activation (glutaraldehyde and carbodiimide). Amino and carboxyl functionalized mesoporous silica and cellulose powders\nwere prepared by silanization using (3-aminopropyl)triethoxysilane and carboxyethylsilanetriol, respectively. It was found that coupling of both enzymes by their –NH groups through glutaraldehyde to -NH functionalized supports, in particular SBA15−NH and cellulose−NH for glucose oxidase, MCM41−NH for laccase, showed the highest activity and the best stability.
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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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Electro-optical sensor for the detection of extracellular ions
Bellan, Boris ; Salyk, Ota (referee) ; Vala, Martin (advisor)
The aim of this work was to prepare a platform based on electrochemical transistor that would allow both electrical and optical detection of ion exchange between the electrolyte and the layer of organic semiconductor. Semiconductor that have been used in this work was poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate). The main goal was to verify whether the proposed platform meets the requirements of both characterization methods, and whether the sensitivity in the given arrangement is sufficient for the required range of analyte concentrations. The work also dealt with the study of the stability of the prepared platform in selected solvents and culture media, at the same time the method of optimizing the preparation of the photoresist foil and the completion of the OECT measuring cell was studied. A suitable solvent for polymethyl methacrylate was sought so that it did not affect the surrounding parts of the platform. Based on the obtained results, it was found that the selected photoresist for the preparation of the spacer frame is not suitable. However, it was found that the proposed platform satisfies both characterization methods. Therefore, it will be necessary to replace the current photoresist with a new, more chemically stable one.
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Real-time monitoring of cellular processes - current approaches
Švecová, Iva ; Hodný, Zdeněk (advisor) ; Groušl, Tomáš (referee)
This thesis aims to provide an overview of real-time live-cell imaging methods with a focus on the signalling pathways. The first, most thorough section is about fluorescence methods and is followed by sections about bioluminescence and label-free methods. In the fluorescence section, we will at first introduce the types of fluorophores and respective labelling approaches. Subsequently, we will go through the individual techniques, starting with single-fluorophore and FRET biosensors, continuing with kinetic modelling approaches, a FLIM method used to detect changes in the cellular environment, and ending with two methods used to improve the resolution. With each technique, we will shortly explain the working principle and look at the examples at which this method was used. Finally, we will look at the example of live-cell imaging of one signalling cascade.
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Methods for monitoring contamination in wastewater
Ravasová, Michaela ; Procházková, Michaela (referee) ; Vondra, Marek (advisor)
Bachelor thesis in the introduction explains the term wastewater. The basic indicators of wastewater pollution are presented and their significance and impact on water quality is explained. Afterwards are explained and described laboratory methods used to measure selected indicators of pollution. Since these methods are unsuitable for continuous wastewater monitoring, following section describes basic sensors for monitoring of wastewater directly at the measuring site. The basic principles which are used in sensors are described and parameters that sensors measure and their influence on environment is explained. Next, three chosen developing methods, i.e., biosensors, electronic noses and fluorescence spectroscopy, which will be applicable for on-line water monitoring in the future. The individual sensors are summarized in final tables. The aim of this work was to create simple overview of methods used for wastewater monitoring.
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Advanced simulations of photonic structures by FDTD method
Vozda, Vojtěch ; Veis, Martin (advisor)
Finite-Difference Time-Domain method (FDTD) is based on numerical solution of Maxwell's equations, nowadays widely used for simulating optical response of photonic structures. This paper provides brief introduction to the FDTD method and several important extensions which make the basic code much more versatile. In order to broaden analysis of photonic structures, transfer matrix method (TMM) is also involved. The code is firstly tested using simple model structures which optical response might be compared with different numerical or even analytical approaches. Debugged code is used to improve photonic crystals for enhanced sensitivity of biosensing devices based on refractive index changes of sensed medium. Last but not the least, properties (sensitivity and Q-factor of resonant peak) of holey waveguide are investigated in one-, two- and three-dimensional simulation. It is shown here, that even this simple structure may compete with complex photonic crystals in the field of biosensors. Powered by TCPDF (www.tcpdf.org)
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Microscopic study of multifunctional drug molecule adhesion to electronic biosensors coated with diamond and gold nanoparticles
Finsterle, T. ; Pilarčíková, I. ; Bláhová, I.A. ; Potocký, Štěpán ; Kromka, Alexander ; Ukraintsev, Egor ; Nepovimová, E. ; Musílek, K. ; Kuča, K. ; Rezek, B.
The easy and fast detection of drug content and concentration levels is demanded in biological research as well as in clinical practice. Here we study on microscopic level how nanodiamonds and gold nanoparticles interact with a multifunctional drug molecule directly on a biosensor surface. The sensors are made of interdigitated Au electrodes coated by 5 nm hydrogenated or oxidized nanodiamonds and further combined with Au colloidal nanoparticles (size 20 nm) providing nanoscale composite (spacing 100 nm). Atomic force microscopy is employed to measure local tip-surface adhesion forces and surface topography. AFM adhesion maps show that the drug binds to all types of nanoparticles and the adhesion is also significantly influenced by the substrates on which the nanoparticles are deposited. Role of local AFM tip interaction with nanostructured surface is also discussed.\n
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