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3D Printing of Ceramic Bone Grafts with Different Internal Architecture
Novotná, Lenka ; Sekora, Jiří (referee) ; Provazník, Ivo (advisor)
Bioceramics in the form of scaffolds hold great promise in bone tissue regeneration. While the scaffold composition is important for biocompatibility, the internal architecture plays a key role in allowing proper cell penetration, nutrient diffusion, bone ingrowth, vascularization as well as mechanical properties. A solid freeform fabrication is a promising processing technique, allowing to study structural parameters independently. This bachelor thesis is focused on ceramic bone replacements with different internal structure. The thesis is divided into 8 chapters. The first four chapters briefly summarize the current state of the art in the following fields: bone structure, requirements for synthetic bone replacements, scaffold architecture, and fabrication methods with an emphasis on 3D printing. The next chapters deal with experimental part. The image analysis of mouse skeleton was performed. On the basis of the measured pore size (50 200 m) and according to the literature search, 16 structures with various shape, curvature and pore size were designed. The CAD models were printed by a stereolithography from a tricalcium phosphate dispersion. Sintered ceramic scaffolds exhibited an ideal structure for application in bone tissue engineering. Scaffolds contained both interconnected macro- and micropores of optimal sizes up to 500 m and about 3 m, respectively. The results confirm that stereolithography is suitable, and compared to others, precise method for preparing scaffolds having different internal structures. The individual structural characteristics influencing the scaffold behaviour will be possible to study independently to each other. And thus improve the scientific knowledge in the field of treatment of large segmental bone defects.
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Effect of bioceramic additives on morphology, physical and biological properties of collagen scaffolds for bone tissue engineering
Klieštiková, Nikola ; Poláček, Petr (referee) ; Brtníková, Jana (advisor)
Diplomová práce se zabývá přípravou trojrozměrných porézních kolagenových kompozitních nosičů pro tkáňové inženýrství kostí a studiem vlivu přídavku biokeramických částic na morfologické, biomechanické a biologické vlastnosti. Teoretická část popisuje biomateriály a biokeramické částice používané pro nosiče v tkáňové inženýrství kostí a jejich metody výroby. Pokud jde o experimentální část, byly vzorky připraveny metodou lyofilizace. Testovaným materiálem byl kolagen typu I z prasečího a hovězího zdroje, který byl kombinován s hydroxyapatitem a směsí -fosforečnanu vápenatého s -fosforečnanem vápenatým v poměrech 1 : 1, 1 : 2 a 2 : 1. Byl hodnocen vliv rozpustnosti a velikosti částic na morfologii, mechaniku a biokompatibilitu nosičů. Přidání biokeramických částic změnilo morfologii vzorků. Velikost pórů se snížila, zatímco pórovitost byla ve všech testovaných vzorcích téměř stejná. Biokeramické částice také způsobily, že kolagenová matrice nosičů byla méně hydrofilní, a navíc dokázaly stabilizovat nosiče proti působení enzymatické degradace. Biomechanické vlastnosti vzorků byly testovány v suchém i mokrém stavu. V suchém stavu dosáhl nejvyšší pevnosti v tlaku čistý bovinní kolagenový nosič, naopak v hydratovaném stavu, dosáhly nejvyšší hodnoty vzorky obsahující biokeramické částice. Žádný ze vzorků nebyl cytotoxický a nejvhodnější prostředí pro buněčnou adhezi a proliferaci bylo v čistém bovinním kolagenovém nosiči a také v kolagenovém kompozitním nosiči s poměrem HAp : -TCP : 1 : 1.
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The effect of salts on the hydrolytic stability of biopolymer carriers with antibacterial substances
Tertinská, Martina ; Brtníková, Jana (referee) ; Vojtová, Lucy (advisor)
Táto diplomová práca sa zaoberá vplyvom soli na stabilitu biopolymérnych nosičov z proteínu a polysacharidu. Teoretická časť sa zaoberá biomateriálmi a materiálmi na prípravu vzoriek a taktiež sa zaoberá momentálnou situáciou liečby infikovaných rán rôznymi materiálmi. V experimentálnej časti boli pripravené nosiče v dvoch rôznych pufroch, s rôznymi koncentráciami chloridu sodného v snahe stabilizovať bioaktívne proteíny, peptidy alebo enzýmy, všeobecne používané a vkladané do nosičov. Boli sledované vlastnosti ako hydrolytická stabilita, botnanie a vplyv rôznych koncentrácii soli na stabilitu vzorku. Keď bola stanovená vhodná koncentrácia soli, do vzoriek bol pridaný antibakteriálny enzým a bolo sledované jeho uvoľňovanie. Zatiaľ čo pri nesieťovaných vzorkách boli sledované významné rozdiely v hydrolytickej stabilite a uvoľňovaní pre vzorky so soľou a bez nej, pri sieťovaných vzorkách boli tieto rozdiely zanedbateľné. Vo všetkých prípadoch sa však enzým uvoľnený zo vzoriek uvoľňoval podľa kinetiky prvého rádu, ktorá závisí na koncentrácii. Na základe výsledkov z difúznych testov robených na rôznych kmeňoch Zlatého stafylokoka bola pre túto prácu vybraná koncentrácia lyzostafínu 325 mg/ml. Pripravené nosiče s antibakteriálnymi enzýmami by mohli byť používané ako kryty rán s krátkodobým alebo dlhodobým uvoľňovaním na rany infikované Zlatým stafylokokom alebo methycilín rezistentným Zlatým stafylokokom (MRSA).
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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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