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Biocomposite material for 3D print in the field of regenerative medicine
Chaloupková, Kateřina ; Obruča, Stanislav (referee) ; Přikryl, Radek (advisor)
The presented thesis deals with preparation of material for use in regenerative medicine based on poly(3-hydroxybutyrate) and its characterization. In addition to poly (3-hydroxybutyrate), there were used other materials lactic acid (PLA), tricalcium phosphate (TCP) and two types of plasticizers Citroflex®B-6 (CB6) and Syncroflex3114 (S3114). These materials were selected based on their biocompatibility and, in the case of TCP, also bioactivity. TCP allows new bone to grow on the surface of the scaffold. PLA was used to improve the mechanical properties of the material. Both plasticizers have been used to improve the processability of the material. Theoretical part of this work contains a literature review describing basic information about used materials. Aim of the experimental part is to prepare the material, characterization of properties and determination of printability on a 3D printer. The material is examined for thermal properties by thermogravimetric analysis and differential scanning calorimetry. This work also deals with the matter of 3D printing, especially FDM technology. It has been found that materials containing the syncroflex plasticizer are better processed and therefore printed on a 3D printer. The printability tests performed are temperature towers and filling studies. Printed samples were subjected to mechanical tests of tensile and bending tests. Experiments of cytotoxicity and biocompatibility of the material were also performed. Within the work, TCP particles were characterized using a particle size analyzer. The average TCP particle size is 10,76 µm. Using SEM-EDX, the distribution of TCP in sample filaments was subsequently observed, where it was found that by mixing TCP particles with the remaining components of materials, TCP particles agglomerate into formations up to 20 µm in size. Roughness of materials was determined by confocal microscopy. Cytotoxicity was also tested in the extracts of samples on mouse fibroblasts. Cytotoxicity was determined by metabolic activity assay and light microscopy. The metabolic activity test proved the biocompatibility of the observed materials; therefore, it was possible to perform cell proliferation and biocompatibility tests directly on the samples. Assays were performed using human mesenchymal stem cells. DNA quantification was used to determine cell proliferation. Shape of cells was subsequently observed by confocal microscopy. Tests confirmed growth of cells and their appropriate shape. Stem cell differentiation into bone was performed by measuring alkaline phosphatase activity.
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Hydroxyapatite based ceramic composites
Vojtíšek, Jan ; Ptáček, Petr (referee) ; Bartoníčková, Eva (advisor)
This work was focused on the study of hydroxyapatite based bioceramic materials. These materials are generally very important for medical purposes, especially in the reconstruction and replacement of bone material. For medical applications, inert, bioactive or bioresorbable materials can be used. One of the common "bioactive" materials is hydroxyapatite, which forms a large part of human bone. Hydroxyapatite can be prepared by a wide variety of procedures, one of the most common methods is the precipitation reaction used in this work. To improve the biocompatibility of the bone replacement, porous structures with adequate mechanical stability are used. For the initial study of simulation of the behavior of biomaterials in the human body, called in vitro tests are used in solutions based on synthetic body fluids or cell media. The experimental part deals with the synthesis of hydroxyapatite powder and CA phase composite compounds. The reactions between the individual components were studied by thermal analysis and heat microscopy. The resulting products were analyzed for phase composition by X-ray diffraction. The prepared powders were further processed on foam structures by in situ foaming and sintering at a suitable temperature. In vitro tests, following the behavior of the prepared porous products in the synthetic body fluid, were performed for 7, 14 and 28 days. The monitored composites were then studied for biocompatibility by scanning electron microscopy. At the same time, the change in the concentration of Ca2+ and PO43- ions in the body fluids tested was monitored.
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Mapování výskytu (anti-)progestagenních aktivit v povrchových vodách České republiky
KRULOVÁ, Jana
The aim of the bachelor thesis was to map the occurrence of substances with (anti-)progestagenic activity in surface waters of the Czech Republic. Samples were taken at 21 localities using POCIS samplers. Localities included the so-called closure profiles (end of the river basin) and significant sampling points along the profile of the river Elbe. The samples were transported to the laboratory, where they were extracted. (Anti-)PR-CALUX in vitro bioassay was used to detect (anti-)progestagenic activity. First, the cells were plated on a microtiter plate and, after 24 hours of incubation, exposed to a calibration series of the reference substance ORG 2058 for progestagenic activity or the reference substance mifepristone for anti-progestagenic activity and a series of diluted surface water extracts. After 24 hours of exposure, cell luminescence was measured in relative light units. The resulting hormonal activity was expressed in ng/l equivalents of the reference substance (ORG 2058 or mifepristone). Progestagenic activity was below the limit of quantification in the samples from all 21 sampling sites (<6-11 ng/l ORG 2058 equivalents) sampled in the year 2017. Anti-progestagenic activity was detected at 6 localities, ranging from 12 to 33 ng/l mifepristone equivalents. For comparison, 3 samples from the year 2016 were analysed. Anti-progestagenic activity was detected in the range from 14 to 48 ng/l mifepristone equivalents. Progestagenic activity was below the limit of quantification at all 3 localities. The occurrence of anti-progestagenic activity was detected mainly at localities where the chemical industry is in the vicinity. There are companies that can use certain substances with anti-progestagenic activity in the production of their products, such as polycyclic musk compounds, brominated flame retardants or bisphenols. The occurrence of anti-progestagenic activity in these localities could indicate the insufficient ability of industrial wastewater treatment plants to degrade substances exhibiting anti-progestagenic activity. The occurrence of anti-progestagenic activity in surface waters may have a negative impact on aquatic organisms, especially vertebrates. Exposure of these organisms to substances with anti-progestagenic activity could lead to reduced fertility and impaired gonad development.
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Mixture toxicity of estrogenic endocrine disruptors in samples from the Czech Republic
Černá, Tereza ; Cajthaml, Tomáš (advisor) ; Klusoň, Petr (referee) ; Šváb, Marek (referee)
The environment is contaminated by countless toxic chemicals of mainly anthropogenic origin; therefore, elucidating the impact of chemical mixtures is one of the biggest challenges of current research. Endocrine disruptors (EDs) acting through the oestrogenic nuclear receptor are typical representatives of the mixture toxicity concept of concentration addition, which can be accurately predicted using the latest mathematical models. Oestrogenic activity and oestrogenic EDs have been detected in many matrices across the globe in biologically relevant concentrations; therefore, they are considered a high risk. The presence of synthetic steroids in the aquatic environment in units of ng/l can disrupt the hormonal pathways of individuals and subsequently cause fatal changes in whole populations. However, if the exposure is terminated, the ecosystem will recover in a few years. Wastewater treatment plants (WWTPs) are able to remove a large number of chemicals, including synthetic and natural oestrogenically active compounds; nevertheless, their occurrence in WWTP effluents and in sewage sludges is frequent. Therefore, WWTPs are considered significant sources of agricultural and water ecosystem pollution. This dissertation thesis focuses on the mixture toxicity of oestrogenic EDs and their occurrence in...
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Biocomposite material for 3D print in the field of regenerative medicine
Chaloupková, Kateřina ; Obruča, Stanislav (referee) ; Přikryl, Radek (advisor)
The presented thesis deals with preparation of material for use in regenerative medicine based on poly(3-hydroxybutyrate) and its characterization. In addition to poly (3-hydroxybutyrate), there were used other materials lactic acid (PLA), tricalcium phosphate (TCP) and two types of plasticizers Citroflex®B-6 (CB6) and Syncroflex3114 (S3114). These materials were selected based on their biocompatibility and, in the case of TCP, also bioactivity. TCP allows new bone to grow on the surface of the scaffold. PLA was used to improve the mechanical properties of the material. Both plasticizers have been used to improve the processability of the material. Theoretical part of this work contains a literature review describing basic information about used materials. Aim of the experimental part is to prepare the material, characterization of properties and determination of printability on a 3D printer. The material is examined for thermal properties by thermogravimetric analysis and differential scanning calorimetry. This work also deals with the matter of 3D printing, especially FDM technology. It has been found that materials containing the syncroflex plasticizer are better processed and therefore printed on a 3D printer. The printability tests performed are temperature towers and filling studies. Printed samples were subjected to mechanical tests of tensile and bending tests. Experiments of cytotoxicity and biocompatibility of the material were also performed. Within the work, TCP particles were characterized using a particle size analyzer. The average TCP particle size is 10,76 µm. Using SEM-EDX, the distribution of TCP in sample filaments was subsequently observed, where it was found that by mixing TCP particles with the remaining components of materials, TCP particles agglomerate into formations up to 20 µm in size. Roughness of materials was determined by confocal microscopy. Cytotoxicity was also tested in the extracts of samples on mouse fibroblasts. Cytotoxicity was determined by metabolic activity assay and light microscopy. The metabolic activity test proved the biocompatibility of the observed materials; therefore, it was possible to perform cell proliferation and biocompatibility tests directly on the samples. Assays were performed using human mesenchymal stem cells. DNA quantification was used to determine cell proliferation. Shape of cells was subsequently observed by confocal microscopy. Tests confirmed growth of cells and their appropriate shape. Stem cell differentiation into bone was performed by measuring alkaline phosphatase activity.
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Hydroxyapatite based ceramic composites
Vojtíšek, Jan ; Ptáček, Petr (referee) ; Bartoníčková, Eva (advisor)
This work was focused on the study of hydroxyapatite based bioceramic materials. These materials are generally very important for medical purposes, especially in the reconstruction and replacement of bone material. For medical applications, inert, bioactive or bioresorbable materials can be used. One of the common "bioactive" materials is hydroxyapatite, which forms a large part of human bone. Hydroxyapatite can be prepared by a wide variety of procedures, one of the most common methods is the precipitation reaction used in this work. To improve the biocompatibility of the bone replacement, porous structures with adequate mechanical stability are used. For the initial study of simulation of the behavior of biomaterials in the human body, called in vitro tests are used in solutions based on synthetic body fluids or cell media. The experimental part deals with the synthesis of hydroxyapatite powder and CA phase composite compounds. The reactions between the individual components were studied by thermal analysis and heat microscopy. The resulting products were analyzed for phase composition by X-ray diffraction. The prepared powders were further processed on foam structures by in situ foaming and sintering at a suitable temperature. In vitro tests, following the behavior of the prepared porous products in the synthetic body fluid, were performed for 7, 14 and 28 days. The monitored composites were then studied for biocompatibility by scanning electron microscopy. At the same time, the change in the concentration of Ca2+ and PO43- ions in the body fluids tested was monitored.
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Evaluation of effectiveness of entomopathogenic fungi Beauveria bassiana using a standard laboratory bioassay
PAULIČ, Radim
In laboratory bioassays, the efficacy of the entomopathogenic fungus Beauveria bassiana against the yellow mealworm (Tenebrio molitor) was tested under various temperature conditions. Six different strains of fungus B. bassiana was investigated. The evaluation was based on vitality bioassays including germination and growth index assessment and the bioassay of virulence based on target organism T. molitor was also assessed growth and yield of conidia different strains of fungus B. bassiana on natural substrates and artificial nutrient substrates.
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