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Electrochemical biosensor for the study of DNA methylation
Petrula, Jakub ; Hrdý, Radim (referee) ; Hynek, David (advisor)
This bachelor’s thesis deals with design and optimalisation of custom biosensor for detection of methylated DNA. Teoretical part explains the mechanism and importance of DNA methylation. Next section describes analytical methods used in connection with DNA methylation and some basic direct and indirect methods of detection. Final part is dedicated to experiment itself, which is divided into several sections. Section one deals witch modification of working electrode and optimalisation of detection method. Second section introduces two different ways of DNA methylation detection. First is based on direct detection and second one on detection through the biosensor. Final part shows determination of methylcytosine from sample based on analysing characteristic attributes of signal and numeric algorithm based on curve fitting.
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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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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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Detection of DNA/RNA fragments using graphene sensor and influence of upper electrolytic gate
Herzánová, Kristína ; Konečný, Martin (referee) ; Bartošík, Miroslav (advisor)
Jedinečné vlastnosti grafenu, jako je biokompatibilita, vysoká mobilita nosičů náboje a povrchová citlivost, z něj činí vhodný materiál pro biosenzory. Cílem této práce je popsat a představit takové senzory a měření provedená za účelem detekce fragmentů DNA, konkrétně látek na bázi cytosinu. Grafen je v polem řízených tranzistorech zapojen jako vodivý snímající kanál. Dopování grafenu vyvolané adsorpcí molekul na vodivém kanálu způsobuje změny transportních vlastností grafenu. Tyto změny se odrážejí v měření elektronických odezev: měření odporu grafenové vrstvy reagujícího v reálném čase na přidávání různých roztoků a závislost odporu na průběžné změně hradlového napětí. Druhou metodu měření lze provádět FET senzorem zapojeným v konfiguraci se spodním nebo elektrolytickým horním hradlem. Je sledován rozdíl mezi oběma konfiguracemi a také vliv vzdálenosti mezi grafenem a horní hradlovou elektrodou na odezvu senzoru. Výsledkem těchto měření jsou transferové křivky vykazující typické píky označující bod neutrality (Diracův bod) grafenu. Různé koncentrace roztoku analytu vedou k různým hodnotám napětí Diracova bodu, což slouží ke kvantifikaci úrovně dopování grafenu.
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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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3D tisknuté sensory pro detekci cukru v nápojích
Zichová, Anežka
Sugars are one of the most common ingredients in food industry, due to their diverse usage as technological component as well as sweetening element. The issue of sugar utilization is not only topic of food industry but plays a key role in human nutrition at the same time. The intake of simple sugars from food, particularly from sweetened beverages, is a major concern from a nutritional standpoint. Carbohydrates can be detected in variety of ways. A literature review was conducted on the methods used in food science, which is based on the previous characterization of the most frequently used sugars in food industry like sucrose, maltose, glucose, fructose, inverted sugar, and glucose-fructose syrup. The chemical, technological and nutritional properties of carbohydrates were described. Considering this examination, 3D printed electrodes were designed for detection of sugar, namely glucose, in beverages. In consideration of the available literature, electrochemical enzymatic biosensors were designed, using glucose oxidase as the sensing element to detect glucose in beverages. The electrodes, carrying the enzyme, were printed from PLA and graphene based conductive filaments. The electrodes were activated in chemical and electrochemical way. To bind the enzyme, a technique based on cross-linking and immobilization was used. Chronoamperometry and cyclic voltammetry were used to test the biosensor. Afterwards the real sample of a fruit juice-based non-alcoholic beverage was examined. The results were interpreted in the context of the applicable legislation of the European Union and, likewise, the legislation of the Czech Republic, in regard to the required data on food labels.
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Graphene dopamine biosensor and gate effect
Krajíčková, Kateřina ; Šimšíková, Michaela (referee) ; Bartošík, Miroslav (advisor)
This bachelor’s thesis focuses on investigating the interaction between biochemical substances (dopamine solutions) and graphene, using field effect transistor (FET) based sensors. Graphene possesses unique properties, including biocompatibility, high charge carrier mobility, and surface sensitivity, making it an ideal material for biosensing devices. In these sensors, graphene is employed as the conductive sensing channel within fieldeffect transistors. By utilizing sensors with an FET arrangement, the doping of graphene induced by adsorbed atoms or molecules can be experimentally determined through the observation of the shift in the position of the Dirac point. The measurements can be performed using either the bottom-gated or electrolytic top-gated configuration of the FET sensor, and the thesis explores the differences between the two setups. Furthermore, it investigates the impact of the distance between the graphene and top-gate electrode on the sensor’s response. The results of these measurements are represented by transfer curves, which exhibit characteristic peaks indicating the charge neutrality point, known as the Dirac point, of graphene.
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Detection of DNA/RNA fragments using graphene sensor and influence of upper electrolytic gate
Herzánová, Kristína ; Konečný, Martin (referee) ; Bartošík, Miroslav (advisor)
Jedinečné vlastnosti grafenu, jako je biokompatibilita, vysoká mobilita nosičů náboje a povrchová citlivost, z něj činí vhodný materiál pro biosenzory. Cílem této práce je popsat a představit takové senzory a měření provedená za účelem detekce fragmentů DNA, konkrétně látek na bázi cytosinu. Grafen je v polem řízených tranzistorech zapojen jako vodivý snímající kanál. Dopování grafenu vyvolané adsorpcí molekul na vodivém kanálu způsobuje změny transportních vlastností grafenu. Tyto změny se odrážejí v měření elektronických odezev: měření odporu grafenové vrstvy reagujícího v reálném čase na přidávání různých roztoků a závislost odporu na průběžné změně hradlového napětí. Druhou metodu měření lze provádět FET senzorem zapojeným v konfiguraci se spodním nebo elektrolytickým horním hradlem. Je sledován rozdíl mezi oběma konfiguracemi a také vliv vzdálenosti mezi grafenem a horní hradlovou elektrodou na odezvu senzoru. Výsledkem těchto měření jsou transferové křivky vykazující typické píky označující bod neutrality (Diracův bod) grafenu. Různé koncentrace roztoku analytu vedou k různým hodnotám napětí Diracova bodu, což slouží ke kvantifikaci úrovně dopování grafenu.
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Study of Biomolecular Interactions with Surface Plasmon Resonance Biosensors
Šípová, Hana ; Homola, Jiří (advisor) ; Houska, Milan (referee) ; Skládal, Petr (referee)
Surface plasmon resonance (SPR) biosensors represent one of the most advanced sensing technologies for real-time studies of biomolecular interactions. In this thesis, methods for functionalization of SPR substrates were optimized and studied via spectroscopic methods. Effects related to the SPR sensor microfluidic interface on the measured biomolecular interactions were analyzed, and furthermore, means to decrease mass-transport limitations were proposed. Several SPR-based assays regarding the detection of nucleic acids were developed, which allow for the detection of physiologically relevant concentrations of nucleic acids as well as point mutations in a nucleic acid sequence. Assays for the determination of the enzymatic activity of HIV integrase and ribonuclease H were developed. These assays can be employed for the design and synthesis of molecules that function either as antiviral drugs or as gene-regulating agents.
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