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Analysis of one-dimensional structures using Kelvin Probe Force Microscopy
Kovařík, Martin ; Bartošík, Miroslav (referee) ; Kolíbal, Miroslav (advisor)
This bachelor's thesis deals with the use of Kelvin probe force microscopy (KPFM) for analysis of 1D nanostructures, namely germanium nanowires and tungsten disulfide (WS2) nanotubes. First part of this thesis is dedicated to the possibility of gold nanoparticles detection on germanium nanowires and also to the analysis of relevance of the KPFM method to measurements performed at various humidity. Second part deals with the measurement of surface potential changes on WS2 nanotubes induced by interaction with light. We have concluded, that relative surface potential changes can be measured at various humidity. This conclusion is also applied to study the interaction of WS2 nanotubes with monochromatic light. The experiment has revealed, that when exposed to light with defined wavelength, nanotubes coated with gold nanoparticles show opposite surface-potential changes as compared to pristine nanotubes, which indicates different physical processes under way.
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Analysis of Nanostructures by ToF-LEIS
Duda, Radek ; Král, Jaroslav (referee) ; Mašek, Karel (referee) ; Dub, Petr (advisor)
The presented thesis deals with the utilization of TOF-LEIS analytical method in the area of nanostructure analysis. A new procedure for depth profiling of the elemental composition of the sample, based on the alternate measurement with the DSIMS method, was established. The TOF-LEIS method is able to detect the interface between the layers before its mixing by the ion beam of the DSIMS method. Furthermore, a procedure of TOF-LEIS spektra modification was established to obtain the actual concentration of elements in the sample by reduction of a multiple collision contribution. By comparison of TOF-LEIS spectra with the results received by the DSIMS method the ratio of molybdenum and silicon ion yields was obtained. In the next section advantages of the TOF-LEIS method in combination with XPS during analysis of thermal stability of gold nanoparticles are presented. The mutual complementarity of both methods is shown and final conclusions are supported by electron microscopy images. The final section deals with a newly assembled apparatus for the TOF-SARS analytical method and shows its possibilities regarding the detection of hydrogen on the graphene.
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The Introduction of Contact Ecotoxicity Tests for the Assessment of Terrestrial Ecosystems
Modlitbová, Pavlína ; Kráčmar, Stanislav (referee) ; Beklová, Miroslava (referee) ; Demnerová, Kateřina (referee) ; Vávrová, Milada (advisor)
This dissertation thesis is focus on using toxicity tests with testing organism - terrestrial isopod Porcellio scaber. This organism is use for toxicity assessment of selected anorganic compunds which could contaminate terrestrial ecosystem. This organism was selected for several reasons - sophisticated test methodology; well known biology of these animals and their ecological relevance. Besides classical endpoints such as mortality, change in mass of test specimens and the effect of the presence and concentration of contaminants onto food consumption; we monitored changes in the morphometric characteristics at the level of tissues and cells, the cytotoxicity and possibly bioaccumulation in various parts of the body of the organism. Selected test substance in this thesis were nanoparticles and inorganic salts. Wherein for chosen gold nanoparticles was carried out a complete study presents several levels of organization of living matter (organism, tissue, cell). For selected salts compound, this study was carried out on the behavior of organisms and classical endpoints.
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Utilization of porous anodic alumina for fabrication of nanostructured layers and their photoelectrochemical and optical applications
Lednický, Tomáš ; Vanýsek, Petr (referee) ; Sulka, Grzegorz (referee) ; Bendová, Mária (advisor)
Porézní anodická alumina (PAA) je oxidová vrstva vytvořená anodickou oxidací hliníku, která má široké průmyslné využití. Její popularita zaznamenala exponenciální nárůst zejména v oblasti nanotechnologií, k čemu přispělo objevení jejího samouspořádání do struktury o nanorozměrech připomínající včelí plástev. Její jednoduchá příprava a laditelné vlastnosti z ní tvoří levný způsob výroby nanostruktur. Ve stejném duchu se tato disertační práce zabývá metodami přípravy funkčních nanostruktur za využití PAA. První část je zaměřena na výrobu pole nanosloupců z oxidu titaničitého (TiO2) a jejich možné použití jako fotoanody pro štěpení vody. TiO2 nanostloupce jsou tvořeny anodizací hliníkové vrstvy na titanovém substrátu, také nazývanou PAA-asistovaná anodizace. Táto studie demonstruje elektrochemické vlastnosti a fotoelektrochemickou aktivitu nano sloupců vytvořených z dusíkem obohacených substrátů, které byly následně různě termálně modifikovány. Hlavním poznatkem studie je, že špatné vlastnosti jsou způsobeny dutou morfologií nanosloupců. Tento poznatek vedl k rozsáhle studii zabývající se dopadem anodizačných podmínek na morfologii ale i stabilitu vytvořených nanosloupců, jejímž výsledkem byla nová strategie anodizace. Druhá část prezentuje výrobní proces přípravy uspořádané vrstvy zlatých nanočástic na transparentním substrátu pro jejich použití jako optického senzoru využívající efekt rezonance lokalizovaných povrchových plasmonů. Základem této multidisciplinární metody je využití kombinace samouspořádání PAA k výrobě šablony a následného procesu řízeného smáčení v pevné fázi tenké vrstvy zlata. Táto práce detailně popisuje technologické aspekty přípravy; od samotné výroby šablon z hliníku, přes vytváření zlatých nanočástic, až po jejich přenos na transparentní substrát. Na závěr této práce jsou kompozity z nanočástic charakterizovány, přičemž je porovnána jejich citlivost na změnu indexu lomu okolí a jejich stálost. Ze závěrů vyplývá, že tato poměrně velkoplošná a levná metoda je konkurence schopná i v oblasti senzorické citlivosti.
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Applications of nanotechnology in detection of biomolecules
Váňa, Rostislav ; Skladal,, Petr (referee) ; Kolíbal, Miroslav (advisor)
This thesis deals with metal nanostructures and their use in detection of biomolecules. A protocol for stabilizing solutions of gold nanoparticles was developed for better usage in biological samples or biochemical processes, where different pH or salt concentrations can be used. A model of optical properties of the nanoparticles was presented and supported by spectroscopic experiments. A possible utilization of plasmonic nanostructures on surfaces for detection of biomolecules was also demonstrated.
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Low Energy Ion Scattering on Gold Structures
Joch, Vítězslav ; Čech, Vladimír (referee) ; Průša, Stanislav (advisor)
This diploma thesis deals with comparison of experimental and simulated low energy ion scattering spectra. There is a theoretical description of basic principles of low energy ion scattering and description of the spectrometer, which is situated at Institute of physical engineering. It is shown, how to prepare samples using the colloidal gold solution. The deposition of gold nanoparticles is characterized. The usage and meaning of time and energy spectra of low energy ion scattering is explained. There is also shown the effect of channeling in Si substrate.
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Biomedical applications of cationic gold nanoparticles
Žárská, Monika ; Hodný, Zdeněk (advisor) ; Králová, Jarmila (referee) ; Bačáková, Lucie (referee)
Cationic gold nanoparticles (GNPs) represent innovative materials promising for treating severe diseases, including cancer. Due to the unique physical properties of colloidal gold, GNPs have been shown to function as theranostics agents, allowing the diagnosis and treatment of the pathological area simulataneously. In addition, a cationic surface charge of GNPs provides extensive nanoparticle-cell interactions. However, despite the great potential in clinical medicine, various types of GNPs have contradictory results, and the studies dealing with the biological and therapeutic properties of cationic GNPs are inconsistent. This doctoral thesis summarizes the current state of knowledge about the biological properties and medical applications of GNPs focusing specifically on positively charged GNPs. A overview of plasmonic photothermal therapy (PPTT) as a cancer treatment strategy is included. Using a step-by-step research approach, our results then characterize the therapeutic potential of GNPs with a specific shape of nanorods (GNRs) and surface modification with quaternary ammonium salt (QAS). At first, the elementary factors participating in the interaction of cationic GNRs with cells, their transmembrane and intracellular transport, and long-term persistence in cells were described. Subsequently,...
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A novel approach imaging engorged ticks: Micro-CT scanning of Ixodes ricinus fed on blood enriched with gold nanoparticles
ONDRUŠ, Jaroslav
Micro-computed tomography (micro-CT) is an exceptional non-destructive imaging modality, which can be used to visualize both external and internal morphology of arthropods like ticks. The major micro-CT drawback is the soft tissues visualization, which require pre-examination contrasting steps. The commonly employed tick contrasting methods are drying and immersion in a solution containing a high-atomic number element, which both cause major deformation and shrinkage of examined specimens. The aim of this study was to develop a new tick contrasting approach to bypass these limitations. We show that adult Ixodes ricinus females engorged in vitro on blood enriched with gold nanoparticles with polyethylene glycol coating can be scanned with excellent contrast. By utilizing this technique based on the hematophagous nature of the ticks, we were able to observe midgut lumen, midgut epithelium and rectal sac in their natural state. In addition, we were able to precisely calculate the midgut volume.
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Gold nano systems for the detection of molecules using surface-enhanced Raman scattering (SERS)
Benešová, Markéta ; Bernatová,, Silvie (referee) ; Skoumalová, Petra (advisor)
This diploma thesis was focused on the production and use of gold nanosystems to enhance Raman scattering. Metal nanoparticles, when interacting with electromagnetic radiation, form so-called localized plasmons, which can enhance Raman scattering. SERS (surface-enhanced Raman scattering) is a non-destructive analytical technique used in this work to measure the concentration and chemical changes in the rhodamine B molecule. Rhodamine B was subjected to photocatalytic degradation using two types of photocatalysts before measurement: TiO2-(H) and TiO2-(H)-Ag. The quantitative dependence of rhodamine B photodegradation on the presence of photocatalysts in a given period time was sought using photodegradation processes. The results of measurements using the SERS method were compared with the results obtained by UV-VIS spectroscopy. From the measured data, it was found that the photocatalysts significantly accelerate the photodegradation processes, because the Raman signal of rhodamine B decreased, while the signal decrease was most pronounced for the catalyst with added TiO2-(H)-Ag, less prominent but still statistically significant signal decrease was observed for the TiO2-(H) catalyst. In the control sample without the addition of photocatalyst, no decrease in signal was observed. In the next phase of the thesis, a sandwich immunoassay was designed that uses SERS to detect E. coli bacteria or other specific microorganisms in the sample. The first component of the sandwich immunoassay is gold nanoparticles, which carry a so-called Raman reporter, which has a clear Raman response in the spectrum, and gold nanoparticles amplify this signal, and antibodies, thanks to which the particles specifically bind to the microorganism. Another component is either gold layered slides or magnetic nanoparticles, which are modified with antibodies and serve to immobilize microorganisms. This system can be a fast and very accurate way to identify a given microorganism in a sample.
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