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Biosensors based on modified carbon nanotubes
Ferdusová, Helena ; Majzlík, Petr (referee) ; Hubálek, Jaromír (advisor)
The aim of this work is to describe biosensors for detection of substances in liquids using modified carbon nanotubes. This work reports on knowledge about nanotubes and electrochemical analysis methods which were used. The matter of direct electrochemical detection of insulin using CNTs modified thick layer planar carbon nanotubes is discussed. The elementary working electrodes were created by using of commercial carbon paste and were modified by thin film CNTs, CNTs/ruthenium oxide and CNTs/chitosan then. The best results of the insulin detection were achieved with the working electrodes modified by low concentration non-purified CNTs which had low elementary response in electrolyte and good response to increasing concentration of insulin in the concentration range from 0, 25 to 10 mol/L. The other modifications caused increasing of the electrode elementary response, but they did not significantly affect the detection.
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Organic tranistors for sensorics
Marková, Aneta ; Omasta, Lukáš (referee) ; Vala, Martin (advisor)
The aim was to find the best available commercial formulation of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and methods and subsequent treatment of thin films for organic electrochemical transistors (OECT). These films will be used in bioelectronic sensors to measure the physiological function of cardiomyocytes. Studied material was PEDOT:PSS in six different formulations. Thin layers prepared by spin coating were modified in three ways, namely (i) immersion in ethylene glycol, (ii) drying and (iii) a combination of drying and ethylene glycol. The layers were then tested for the influence of ethylene glycol, thermal stability, the impact of storage, influence of aqueous medium, and additional thermal annealing. According to the results obtained, the most suitable treatment of most materials was immersion in ethylene glycol followed by thermal annealing of the layer. It was found that the most appropriate material formulation was Sigma Aldrich 739 316 treated by the combination of drying, immersion in ethylene glycol and thermal annealing.
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Electrochemical biosensor for glucose detection
Matula, Tomáš ; Majzlíková, Petra (referee) ; Prášek, Jan (advisor)
This thesis pays attention to electrochemical sensors for the detection of glucose. The theoretical part deals with the technology of thick film, their application and firing. It is further described electrochemistry, electrodes used in electrochemistry and analytical methods based on electrochemical reaction. End of theoretical part deals with electrochemical biosensors for detection glucose using special electrodes based on enzyme glucose oxidase. In the experimental part is processed amperometric measure for detection glucose using screenprinted sensors S10 and S8 with immobilized enzyme glucose oxidase. Next was studied effect of plasma, dissolved potassium chloride, storage, ascorbic acid and the reproducibility of the sensors.
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Analysis of Thick Film Amperometrical Sensors Signal and Its Usage for Measurement and Characterization of Enzymes
Ondruch, Vít ; Kizek, René (referee) ; Masojídek,, Jiří (referee) ; Vrba, Radimír (advisor)
V práci je popsán princip synchronní detekce (SD), který byl uplatněn při měření s biosenzory. Metoda SD umožňuje dosažení výrazně lepšího poměru signálu k šumu, vyššího limitu detekce a celkové zlepšení robustnosti měření. Uplatnění SD při měření s biosenzory umožní zlepšit analýzu jeho odezvy a umožní odstranění nežádoucích interferencí nebo šumů, které mohou být způsobeny například mícháním roztoku, elektromagnetickými vlivy nebo parazitními proudy. SD také umožňuje rozložit získaný signál na odezvu stimulace a na dlouhodobý signál jiného procesu, a dále také identifikovat jevy druhého řádu. Pro identifikaci stimulačního signálu ve výstupním signálu měření byl na základě lineárního statistického modelu vyvinut specializovaný software. SD byla ověřena na modelovém případu výstupního signálu biosenzoru s aplikovaným komplexem fotosystému II (PSII) a jeho odezvě na stimulaci světlem. Odezva PSII se řídí kinetikou prvního řádu a může být také ovlivněna inhibitory. Kinetické konstanty vazby herbicidu na PSII závisí lineárně na koncentraci herbicidu. To umožňuje jejich měření také při nízkých koncentracích herbicidu.
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Application of metal and semiconductor nanostructures for biodetection
Kejík, Lukáš ; Skládal, Petr (referee) ; Kolíbal, Miroslav (advisor)
The master’s thesis deals with two applications of gold discoidal nanostructures exhibiting plasmon resonance for biodetection. The first approach considers the detection of changes in the phase on plasmonic antennas using coherence-controlled holography microscope. It was found that the steepness of the phase is increasing with the illumination wavelength when plasmon resonance is excited in larger antennas. The sensitivity of the phase to refractive-index changes of the surrounding media was observed when the largest response was given by antennas in resonance with wavelength of illumination. Next part deals with plasmon resonance detection by means of optical spectroscopy combined with voltametry which characterizes the electrochemical activity. Changes in resonance wavelength induced by the presence of SSC buffer were observed, although this influence seems to diminish in time. Conducted experiments have also shown that oxygen-plasma cleaning is not suitable for sample surface cleaning because of oxidation of metals including gold as well.
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Nanostructured surfaces for electrochemical detection
Dzuro, Matej ; Hrdý, Radim (referee) ; Drbohlavová, Jana (advisor)
This work deals with the preparation of gold nanostructures for future usage in electrochemical sensors and biosensors, methods for their characterization and production. The emphasis is focused on the template-based electrodeposition method of gold and on study of the effect of manufacturing conditions on physical properties, mainly electrical and topological of nanostructures. Thesis is focused also on overall function and sensitivity of the gold nanostructured electrode.
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Biosensor of halogenated substances as device using fluorescence method
Sedláček, Jiří ; Prokop,, Zbyněk (referee) ; Hubálek, Jaromír (advisor)
This master thesis deals with design and construction of device for optic biosensor. The device are using for detected halogen compound in the water. For excitation testing sample is used LED diode about wave length 590 nm. Photocounter is used for detection of the emitted light after fluorescence Such as fluorescent marker are 5(6)-carboxynaphthofluorescein. The thesis is divided into three head parts. The first part includes the theory needed for realization; the second part takes in detail description of the construction and function of the device and the last part describes measurements with the device.
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Reliability analysis of substance measurements using biosensors - limit of detection robust method design
Láznička, Jan ; Brno, Karel Lacina, MU (referee) ; Grosmanová, Zuzana (advisor)
Detection limit of any method is affected by device (electronics, noise), evaluation, software (timing inaccuracy, rounding mistakes, errors determination of parameters using measured values by numerical methods) and by a chemical reaction (diluting errors, the reaction mixture design, chemical interferents, temperature, the accuracy of pipetting). In this work was proposed a metod for determination of detection limit for measuring of inhibitors of acetylcholine esterase by biosensor analysator of toxicity (BTA). The analysator was developed by BVT Technologies a.s. in 2004. To determine the exact detection limit a calibration of output signal was done. Presently the analysator is able to detect only presence of toxins, not their concentration. Not least are mentioned all founded errors of software, which are continuously eliminated.
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