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Compatibility of piezoelectric semicrystalline polymerand osteoblastic cells
Havlíková, Tereza
For the improvement of tissue regeneration,functional polymer scaffolds that can mimic the extracellularmatrix of human tissue are extremely desirable. Depending on thetissue that the scaffolds are intended to resemble, these scaffoldsmust satisfy highly precise requirements such as non-toxicity orfibrous structure. High piezoelectricity and hydrophilicity alsoproved to have convenient effects. Due to their innate capability tocreate surface charges under mechanical stress, piezoelectricmaterials such as polyvinylidene fluoride (PVDF) become excellentcandidates for creating functional scaffolds. It is desired for PVDFto also have hydrophilic properties. Otherwise, it could preventadequate cell adhesion and growth necessary for the constructionof biomimetic scaffolds. For this study, electrospinned PVDFnanofibers covered by human or mouse osteoblasts were subjectedto Raman spectroscopy, measurement of the contact angle of theliquid wettability on the sample surface to observe hydrophobicityand hydrophilicity, and scanning electron microscopy (SEM) toassess properties of the material in relation to oxygen plasmatreatment.
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Bone regeneration and its analysis
Tesařová, Adéla ; Hovořáková, Mária (advisor) ; Zahradníček, Oldřich (referee)
Bone regeneration can take place throughout life as a natural process (remodeling) or because of trauma when fractures heal in which the damaged or missing part is replaced by new tissue. The aim of my bachelor thesis was to create a literature search on the issue of bone regeneration. The introductory part deals with the bone as such - its structure and the process of new formation (ossification) and remodeling. The following section describes some of the methods used to support bone regeneration in therapy - selected types of carriers and molecules that play an important role in regeneration and are part of the carriers or therapies used. At the end of the thesis, the basic methods used to analyze bone regeneration are described and provide us with an insight into the success of the tested therapeutic approaches, how well the bone heals and how effective the methods used are. The bachelor thesis was processed in the form of a literary search.
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Optimization of poly(3-hydroxybutyrate) based biocomposite with respect to its printability and mechanical properties
Chaloupková, Kateřina ; Obruča, Stanislav (referee) ; Přikryl, Radek (advisor)
The presented theses deals with preparation and optimalization of biocompatible material based on poly(3-hydroxybutyrate). Other components of prepared samples are polylactid acid, hydroxyapatite and commercially available plasticizer Syncroflex3114. These components were chosen based on their biocompatibility and properties that can be possibly used in tissue engineering. Theoretical part of this theses contains general overview of bone tissue and review of materials used in bone tissue regeneration. Part of this thesis also deals with the problematics of scaffolds. Aim of the experimental part is a planned experiment, which is used to optimize the mixture with respect to printability and mechanical properties. The first step is the preparation of samples based on the proposed conditions and their subsequent processing into a filament with an exact diameter of 1,75 mm for 3D printing using the fused deposition modeling method. From the prepared filaments, test specimens were printed for the following experiments: temperature tower, warping coefficient measurement, bending and pressure test. Data from these experiments were processed using a mathematical model in the form of graphs and equations which show the effect of material components on the measured quantity. It was found that the amount of plasticizer in the sample affects the properties the most. This effect is negative in all cases and worsens the properties of the material. The result of the planned experiment is also a mixture optimized for the best possible printability and mechanical properties (bending modulus 3,3 GPa and pressure modulus 2,3 GPa). With regard to the potential application of the material in bone tissue engineering, the first accelerated biodegradation screening tests were performed for selected samples. The results of accelerated degradation tests are ambiguous and further optimization is needed. Simultaneously with the diploma thesis, biological testing of scaffolds printed on a 3D printer from prepared samples took place. All tested samples were found to be biocompatible.
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Kompozitní pěnové nosiče pro tkáňové inženýrství kostí
Kuntová, Henrieta ; Rampichová, Michala (advisor) ; Krulová, Magdaléna (referee)
The goal of my work was to introduce the fast pacing field of tissue engineering with focus on bone regeneration. Tissue engineering could be a future alternative to the currently used conventional approaches that suffer from healing failures. Due to increasing demand for bone tissue replacement damaged by degenerative diseases or injuries, many laboratories have attempted to come up with solutions in a form of artificial constructs. In the present light of interest are composite scaffolds usually made of polymer and ceramic combinations. Their main advantage is that they combine elasticity and tensile strength of a polymer with bioactivity and mechanical hardness of a ceramic, while removing drawbacks of each material. Powered by TCPDF (www.tcpdf.org)
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Scaffold hopping-based exploration of chemical space
Mikeš, Marek ; Hoksza, David (advisor) ; Krivák, Radoslav (referee)
This work is based on the Molpher SW project, which is client-server application aiding exploration of chemical space between two input molecules. Aim of master thesis was modify the current version of program to manage scaffold hopping technique. This technique represents molecule in a simplified way. The simpler molecule is called scaffold. First of all there was need to define seve- ral levels of granularity and for each level define morphing operators. Server was modified with respect for parallelization. Experimental exploration of chemical space with and without the new feature is part of this work too. Powered by TCPDF (www.tcpdf.org)
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Biomechanical response of scaffold on mechanical loading
Anděrová, Jana ; Jelen, Karel (advisor) ; Amler, Evžen (referee)
The purpose of this work is to identify the parameters of scaffold's mechanical properties by observing/monitoring their response to defined external mechanical strain. The first part of the work is summarizing the knowledge about the required properties of scaffolds, their production and the factors influencing production. The practical part of the work concerns itself with measurement, analysis and evaluation of data based on proprietary methodology. Based on the results at this stage of the research, we can confirm, that scaffolds have viscoelastic, or viscoplastic character and its response depends on the magnitude of deformation, state of hydration, ratio of solutions and period of networking. Keywords: scaffod, tensile test, rheologic model
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Analysis of structural changes of nanofiber scaffolds in relation with their relative extension
Morávek, Martin ; Lopot, František (advisor) ; Hadraba, Daniel (referee)
The goal of this thesis was to find a suitable method for evaluating structural changes of scaffolds as influenced by external mechanical pressure and to verify the validity of hypothesis which assumes a change of directionality of fibers and also thinning of fibers according to the stretching of a scaffold. Assumptions formulated in these three hypothesis were tested on a scaffold with a plasma surface treatment and without any plasma surface treatment. To examine structural changes an electrone microscope was used to observe the surface of scaffolds. Incurred photos were then processed with the help of automatic software picture analysis and observed data were statisticly evaluated. The result of this experiment is a description of used method which can be used in future for larger studies. It was found that by the effect of external mechanical pressure fibers of examinated scaffolds turn in the direction of the pull. It has also been found that the average thickness of fibers didn't change. Results of this work give insight into the evaluation of structural changes of scaffolds when pressured by an external mechanical power and open possibilities for deeper and more exact research in this field. Key words: scaffold, picture analysis, fiber directionality, fiber thickness.
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Effect of 3D printing technology on the properties of model femur segment
Nečas, Aleš ; Svatík, Juraj (referee) ; Jančář, Josef (advisor)
This bachelor thesis deals with the development of a biodegradable 3D anatomical model of the femur segment and the influence of 3D printing technology on tensile strength and tensile modulus of elasticity of 3D standardized tensile test bodies (ASTM_D_638_IV) made from PLA, nylon, acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), polymethyl methacrylate (PMMA), polyethylene terephthalate glycol (PETG), and resin. For each material, bodies with body thickness of 1 mm, 2 mm, and 3 mm were 3D printed. Next, a PLA simplified femur segment model was created to determine the most suitable layer thickness for body printing in terms of its compressive strength and compressive modulus of elasticity. The thickness of the printed layer of 0.1 mm was chosen as the mechanically most suitable and was subsequently used in the production of a PLA anatomical model of the femur segment which was 3D printed in 3 variants differing in the density of the filling of the internal structures in the area of compact and cancellous bone tissue of real bone. Then, the compressive strength of these models was determined and compared. The PLA anatomical model of the femur segment was developed according to CT images of real bone with the purpose of its potential use in medicine as a bone tissue replacement in large femoral defects. However, before it can be used in medicine, further research is needed.
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Use of biological materials for tissue substitution in plastic surgery
Měšťák, Ondřej ; Sukop, Andrej (advisor) ; Brychta, Pavel (referee) ; Dražan, Luboš (referee)
Užití biologických materiálů k náhradě tkání v plastické chirurgii ! Abstrakt v angličtině Background: Biological meshes are biomaterials consisted of extracellular matrix and used in surgery particularly for hernia treatment or thoracic wall reconstruction. They are capable of vascularization, that decreases risk of infection, expecially when used in contaminated fields. This study compared the strength of incorporation and biocompatibility of two porcine-derived grafts (cross-linked and non-cross-linked) in a rat hernia model. In addition, we hypothesized that combination of extracellular matrices with autologous mesenchymal stem cells used for hernia repair would result in increased vascularization and increased strength of incorporation. Methods: Standardized 2 x 4 cm fascial defect was created in 42 Wistar rats and repaired with a cross-linked or a non-cross-linked graft either enriched or non-enriched with stem cells. The rats were sacrificed 3, 6 and 12 months later. The strength of incorporation, vascularization, cellular invasion, foreign body reaction and capsule formation were evaluated. Results: Comparison of stem cell enriched and non-enriched groups showed no significant differences in the capsule thickness, foreign body reaction, cellularization or vascularization. In the non-cross-linked...
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Multipotent mesenchymal stromal cells in orthopedic: Potentiation of bone healing
Stehlík, David ; Trč, Tomáš (advisor) ; Janíček, Pavel (referee) ; Sedmera, David (referee)
The aim of the thesis was development of an innovative treatment of bone defects. Human multipotent mesenchymal stromal cells (MSC) play a crucial role in bone healing. Clinical applications of MSC require large amount of cells, which could be obtained by autologous expansion of MSC harvested from bone marrow. As a first step, the standard protocol of MSC expansion based on αMEM medium and fetal bovine serum (FBS) was used. Experiments replacing FBS by pooled human serum (HS) in the culture medium concluded in patenting of a new MSC cultivation protocol (EU 1999250, CR 301141). This one-step cultivation protocol and xenogeneic protein-free cultivation medium is based on CellGro® for Hematopoietic Cells' Medium, HS, human recombinant growth factors, dexamethasone, insulin and ascorbic acid. The preclinical in vitro and in vivo experiments with MSC from both expansion protocols were carried out. Fibrillar polylactic scaffolds were seeded with MSC, cultured, differentiated and implanted in immunodeficient mice (NOD/LtSz-Rag1-). Bone-like mineralized tissue containing vessels was observed. The MSC cultured according to patented method were classified as Advanced-therapy Medicinal Product and has to fulfil the European Medicines Agency regulations to enter the clinical trials. Nevertheless the use of MSC seems...
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