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Antibacterial activity of photoactive surfaces
Rabenseifnerová, Barbora ; Králová, Marcela (referee) ; Veselá, Mária (advisor)
This master's thesis deals with the antibacterial activity of photoactive surfaces in flia with a known content of zinc pyrithione in combination with the photoactive part. Individual flia were exposed to illumination for a given period of time to confirm photoactive ability and stored for comparison in the dark for the same time. The imprinting method was used and supplemented by a method based on ISO standard 27447:2019.
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Nanofiber membranes with encapsulated photoactive molecules simultaneously generating NO and 1O2 species
Liška, Vojtěch ; Mosinger, Jiří (advisor) ; Kubíček, Vojtěch (referee)
This thesis focuses on the preparation and study of a new type of photoactive polycaprolactone nanofibrous membrane with encapsulated NO photodonor 4-(N- (aminopropyl)-3-(trifluoromethyl)-4-nitrobenzenamine)-7-nitrobenzofurazan and photosensitizer chlorin e6. The electrospun nanofibrous membrane exhibits efficient photogeneration of NO and singlet oxygen molecules, which initiate facial and space photoantibacterial properties. The structure of the prepared NO photodonor was studied by NMR spectroscopy and UV-VIS absorption spectroscopy measurements. The resulting nanofibrous material was studied by scanning electron microscopy, and the successful encapsulation of both photoactive species was studied by absorption and fluorescence spectroscopy. Photogeneration of the NO molecule was studied by direct amperometric detection of NO and by reaction with a chemical substrate. The photogeneration of singlet oxygen O2( Δg 1 ) was studied by time-resolved spectroscopy and by reaction with a chemical substrate. Significant photoantibacterial properties were demonstrated on the bacterial strain Escherichia coli DH5α. Both antibacterial effects were studied by monitoring the number of colony forming units (CFU) using image analysis, and the facial effect by scanning electron microscopy. Keywords: singlet...
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Fluorescence Detection of Skin Tumours
Stíbal, Adam ; Dědic, Roman (advisor) ; Hála, Jan (referee)
This thesis discusses the photodynamic therapy (PDT) and it's application for dia- gnostics of tumours. The PDT is based on production of reactive oxygen species (ROS) from the molecules of photosensitizers (PS). PS are preferentially accumulated in disea- sed tissues, where ROS are produced and cause selective destruction of the target tissue, while surrounding healthy tissue remains intact. The photodynamic diagnostics uses the fluorescence of PS for digital and spectral imaging. This thesis is focused on detection of tumours from spectral characteristics of protoporphyrin IX fluorescence induced in tis- sue by methyl-aminolevulinate. The main part of the research was realised on rats' scars in vivo, the solutions of homogenized mouse fibroblasts were also studied. The way to distinguish between diseased and healthy tissue was found using measurements of fluo- rescence bleaching kinetics.
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Methods of Study of Photosensitizer-Photophysics with Application on Thiazolyl-porphyrins
Scholz, Marek ; Dědic, Roman (advisor) ; Hála, Jan (referee)
Title: Methods of Study of Photosensitizer-photophysics with Application on Thiazolyl-porphyrins Author: Marek Scholz Department: Department of Chemical Physics and Optics Supervisor: RNDr. Roman Dědic, Ph.D. Supervisor's e-mail address: Roman.Dedic@mff.cuni.cz Abstract: Photodynamic therapy for oncologic and various chronic diseases is a rapidly emerging method of treatment. It is based on the production of highly reactive singlet oxygen and free radicals by excitation energy transfer from the molecules of photosensitizers. Photosensitizers are preferentially accumulated in the target tissues and locally illuminated. This way produced reactive species cause apoptosis or necrosis of the cells leading to the desired therapeutic effect. Synthesis and subsequent photophysical characterization of photosensitizing dyes is a fundamental part of the development of photodynamic methods. The main aim of the work is to explain the most widely used methods of photophysical study of photosensitizers and apply them to new synthesized photosensitizers: thiazolyl-porphyrins. Methods of absorption and fluorescence spectroscopy, flash- photolysis, time- and spectral-resolved detection of luminescence, optoacoustic spectroscopy and other spectroscopic methods were used. Thiazolyl-porphyrins proved to be promising new...
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Photoactive chlorophyll nanoparticles
Ludačka, Pavel ; Mosinger, Jiří (advisor) ; Lang, Kamil (referee)
Photoactive sulfonated and non-sulfonated polystyrene nanoparticles (NPs) with encapsulated THF extract from spinach (Spinacia oleracea) were prepared. The preparation of NPs is based on a simple nanoprecipitation method that uses the same solvent (THF) to dissolve the sulfonated or non-sulfonated polystyrene nanofiber membrane and for the extraction itself. Based on spectral and HPLC analysis, it was found that the THF extract and NPs contain chlorophyll a, chlorophyll b, β-carotene and lutein. Time-resolved spectroscopy shows that the extract is a potent source of singlet oxygen O2(1 g) thank to the photosensitizer chlorophyll. The photogeneration of O2(1 g) is partially suppressed by the carotenoids in the extract, which quench O2(1 g). To reduce the quenching effect of carotenoids, it is possible to use dilute extract or pre-irradiated samples with visible light because of carotenoids rapid breakup. A strong photooxidative and antibacterial effect of NPs prepared from an extract generating O2(1 g) was demonstrated on chemical substrates and Escherichia coli. The photoactivity of NPs is initiated by visible light. Key words Chlorophyll, photosensitizer, nanoparticle, singlet oxygen
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Methods of Study of Photosensitizer-Photophysics with Application on Thiazolyl-porphyrins
Scholz, Marek
Title: Methods of Study of Photosensitizer-photophysics with Application on Thiazolyl-porphyrins Author: Marek Scholz Department: Department of Chemical Physics and Optics Supervisor: RNDr. Roman Dědic, Ph.D. Supervisor's e-mail address: Roman.Dedic@mff.cuni.cz Abstract: Photodynamic therapy for oncologic and various chronic diseases is a rapidly emerging method of treatment. It is based on the production of highly reactive singlet oxygen and free radicals by excitation energy transfer from the molecules of photosensitizers. Photosensitizers are preferentially accumulated in the target tissues and locally illuminated. This way produced reactive species cause apoptosis or necrosis of the cells leading to the desired therapeutic effect. Synthesis and subsequent photophysical characterization of photosensitizing dyes is a fundamental part of the development of photodynamic methods. The main aim of the work is to explain the most widely used methods of photophysical study of photosensitizers and apply them to new synthesized photosensitizers: thiazolyl-porphyrins. Methods of absorption and fluorescence spectroscopy, flash- photolysis, time- and spectral-resolved detection of luminescence, optoacoustic spectroscopy and other spectroscopic methods were used. Thiazolyl-porphyrins proved to be promising new...
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Polymer nanoparticles generating singlet oxygen
Berzédiová, Veronika ; Mosinger, Jiří (advisor) ; Tyrpekl, Václav (referee)
This theses focuses on preparation and characterisation and comparison of two types of polymer nanoparticles using photophysical methods. The first type was polystyrene nanoparticles prepared by modified nanoprecipitation method from polymeric sulfonated nanofiber membranes with diffrent content of sulfonated groups. The second type was polymer nanoparticles with diferent lenght of hydrophobic polycaprolactone (PCL) and hydrophilic poly(ethyleneglycol) (PEG) blocks. Both types of nanoparticles conteined encapsulated photosensitizer 5,10,15,20-meso-tetraphenylporphyrin with a high quantum singlet oxygen yield. In the prepared nanoparticles with a photosensitizer, the kinetics of singlet oxygen generation was studied using time resolved spectroscopy. The relative efficiency of photooxidation was studied using external akceptor of singlet oxygen. The effect of temperature, size and matrix (type of polymer) of nanoparticles on photooxidation efficiency was also studied. In the next part of this these was studied the influence of time on the size and stability of nanoparticles and also the effect of solution pH and ionic strength on prepared nanoparticles.
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Spectroscopic Study of Singlet Oxygen in Cells and Model Systems
Scholz, Marek ; Dědic, Roman (advisor) ; Heřman, Petr (referee) ; Kubát, Pavel (referee)
Title: Spectroscopic Study of Singlet Oxygen in Cells and Model Systems Author: Marek Scholz Department: Department of Chemical Physics and Optics Supervisor: doc. RNDr. Roman Dědic, Ph.D., KChFO Abstract: Singlet oxygen (1O2), the first excited state of molecular oxygen, plays many important roles in nature and technology. The work is aimed at development of novel methods for monitoring of 1O2 in cells and other biological samples. Two main ap- proaches were employed: direct detection of the very weak near-infrared phospho- rescence of 1O2, and detection of Singlet Oxygen-Feedback Delayed Fluorescence (SOFDF), which is the emission from the photosensitizer induced by energy transfer from 1O2. The first part of the thesis introduces the basic concepts of photophysics and photochemistry of 1O2: its generation, deactivation, applications, and overview of detection methods. The second part presents the experimental results. Wide-field mi- crospectroscopic detection of 1O2 phosphorescence enabled us to acquire 1O2-based images and near-infrared spectra from single cells incubated with photosensitizers. However, the direct detection suffers from the inherently very low phosphorescence quantum yield. It is shown that SOFDF may overcome this problem and become a promising alternative tool for studies of 1O2 and...
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