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Cell transplantation methods in cardiology
Kukhta, Dziyana ; Hežová,, Reneta (oponent) ; Skopalík, Josef (vedoucí práce)
This master’s thesis is devoted to tissue engineering, notably to creation homogeneous, isotropic and planar cardiac muscle cell layer using two technologies scaffold-based and scaffold-free. Firstly it describes the histology of heart wall, cardiac muscle cells, and cells cultures. This is followed by a description of tissue engineering, which includes cell sheet technology and scaffold-based tissue engineering. And at the end of the theoretical part application of tissue engineering and cell visualisation assay are described. The practical part is dedicated to the creation of a planar cell layer from cardiomyocytes and fibroblasts, using information from the theoretical part.
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Poly(3-hydroxybutyrate) based materials for 3D printing in medical applications
Krobot, Štěpán ; Vojtová, Lucy (oponent) ; Přikryl, Radek (vedoucí práce)
This master's thesis deals with the preparation and testing of 3D printed scaffolds for bone tissue engineering. The aim of the thesis is laboratory preparation of polymer blends on the basis of poly(3-hydroxybutyrate), poly(lactic acid) and polycaprolactone and their processing into the form of 3D printing filaments. Three polymeric blends were prepared and processed into the form of 3D printing filaments. Differential scanning calorimetry was conducted to evaluate the thermal properties, followed by temperature tower test and warping test to determine the processing conditions for 3D printing. The lowest warping coefficient was 1.26 for a blend of poly(3-hydroxybutyrate) with polycaprolactone and plasticizer. Tensile test, three-point flexural test and compression test were used to study the mechanical properties of materials. Scaffolds with different surfaces for bone tissue engineering were 3D printed from prepared filaments to determine the most optimal surface for cell proliferation. To determine the surface properties and their influence on cell adhesion, optical contact angle measurement with the use of OWRK method to calculate surface energy was conducted. 3D printed surfaces were also subjected to roughness analysis by confocal microscopy to determine their roughness and its effect on contact angle with water and cell growth. Finally, in the last part, in vitro tests on scaffolds were conducted in collaboration with the Institute of Experimental Medicine (Czech Academy of Sciences) to find out whether the prepared materials are non-cytotoxic and how the surface of scaffold affects the cell growth and proliferation. In the end, two out of three materials were proven to be non-cytotoxic (both blends of poly(3-hydroxybutyrate) with polycaprolactone) and that their mechanical properties were comparable with human trabecular bone. The most optimal surface for cell growth is probably grid diameter 50 m with roughness along the perimeter 1.9 m, which corresponds with water contact angle 74.1°.
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Modification of Biodegradable Polyurethanes by Biologically Active Substances
Kupka, Vojtěch ; Khunová, Viera (oponent) ; Pekař, Miloslav (oponent) ; Vojtová, Lucy (vedoucí práce)
Presented dissertation thesis is focused on novel preparation of biodegradable polyurethanes (PUs) and their modification by biologically active cellulose nanocrystals. Literary review deals with current state of bioresorbable PUs used in tissue engineering. Examples of prepared PU elastomers, scaffolds and injectable PUs, together with biodegradation pathways to non-toxic products are summarized. The last part of the literary review is targeting on nanocellulose, which has gained much attention for the use as biomedical material due to its remarkable physical (high specific surface area, mechanical reinforcement) and biological (biocompatibility, biodegradability and low toxicity) properties. Experimental part presents characterization of biodegradable amphiphilic polyurethane films (bio-PUs) synthesized by solvent free polyaddition reaction of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(e-caprolactone) (PCL) as macrodiols with hexamethylene diisocyanate. Prepared bio-PUs were characterized on one hand by means of different PEG/PCL ratio and on the other hand by changing the isocyanate ratio between NCO/OH groups. Abrupt enhancement of mechanical properties was observed when PEG/PCL weight ratio was equal to or less than 20/80 and was ascribed to the PCL ability to form crystalline domains. The increasing amount of PEG promoted the ability of bio-PUs to absorb water and enhance the rate of hydrolytic degradation. Whereas, reducing the ability of bio-PUs to absorb water and prolonged time of hydrolytic degradation was achieved with increasing the crosslink density by enhancing the isocyanate ratio. The last part deals with novel solvent free preparation of nanocomposite utilizing bio-PU as a matrix and cellulose nanocrystals either neat or surface grafted by PEG. Structural analysis demonstrated that the presence of rod-like nanoparticles causes the immobilization of the PU chains in matrix resulting in increased stiffness and rigidity of bio-PU/cellulose nanocomposite. By adjusting the PEG/PCL ratio, the amount of isocyanate or the presence of nanofiller, the novel bio-PU material with desirable mechanical (toughness, flexibility) and physical (swelling, degradation) properties can be obtained. Prepared solvent free bio-PUs may advantageously be used in regenerative medicine for soft tissue regeneration (e.g. as vascular grafts).
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Tiskové hlavy pro 3D tisk hydrogelů s nízkou viskozitou
Havlíček, Václav ; Harabiš, Vratislav (oponent) ; Jaroš,, Josef (vedoucí práce)
V této bakalářské práci se věnuji 3D biotisku v tkáňovém inženýrství a rozebírám používané materiály a technologie, které lze pro 3D biotisk využít. V práci je také obsažena diskuze vybavení pro 3D biotisk a současné výzvy 3D biotisku metodou extruze. V praktické části je navrženo řešení extruzivního 3D biotisku nízkoviskózních hydrogelů pomocí hydraulické pumpy, vlastní tiskové hlavy a chladícího okruhu.
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The effect of biologicaly active substances on the structure and properties of collagenous substrates
Muchová, Johana ; Michlovská, Lenka (oponent) ; Vojtová, Lucy (vedoucí práce)
The thesis deals with the preparation of 3D porous collagen scaffolds by freeze-drying and their modification with bioactive compounds. The natural polysaccharides, chitosan, calcium oxidized cellulose and chitin/chitosan-glucan complex for the modification have been used. The mechanical properties of the scaffolds have been enhanced by crosslinking process with carbodiimides. Growth factors have been delivered in the form of platelet lysate. The influence of biologically active additives, crosslinking agents, and enrichment with growth factors on the properties of the prepared scaffold and their bioactivity in tissues of living organisms have been investigated. Specifically, this study includes the morphological properties, structure, porosity, swelling stability, chemical composition, temperature of denaturation and biological properties. Scanning electron microscopy, infrared specktroscopy, differential scanning calorimetry and confocal microscopy have been used to the characterization. Prepared collagen substrates involving bioactive additive and platelet lysate could be used as scaffold for growing cells in systems with low mechanical loading and which has potential application in biomedicine.
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Structure and Properties of Collagen/HAP Nanocomposite Networks
Kopuletá, Ema ; Lehocký,, Marián (oponent) ; Amler,, Evžen (oponent) ; Jančář, Josef (vedoucí práce)
Polymer-based materials are some of the most promising materials for tissue engineering and controlled drug delivery. Collagen, as one of the most abundant proteins to be found in mammals, is especially interesting due to its tunable properties and excellent host reactions. This thesis is focused on the self-assembly and the mechanical properties of collagen in solution, its kinetics and general principles controlling the process. The effect of hydroxyapatite nanoparticles on the collagen self-assembly and mechanical properties is also investigated. Possible mechanisms of collagen/hydroxyapatite interactions are elucidated along with the description of structure evolution and properties at various structural levels. The shear rate dependences and viscoelastic behavior of collagen I and its nanocomposites with hydroxyapatite (HAP) were measured and interpreted molecularly. The structure of collagen I scaffolds was studied and the effect of HAP and cross-linking was determined. Finally, the results were discussed in terms of the applicability of collagen/hydroxyapatite nanocomposites in scaffolds for bone tissue regeneration.
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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 (oponent) ; Brtníková, Jana (vedoucí práce)
The diploma thesis deals with preparation of three-dimensional porous collagen composite scaffolds for bone tissue engineering and study of the effect of addition of bioceramic particles on morphological, biomechanical and biological properties. Theoretical part describes biomaterials and bioceramic particles used for scaffolds in bone tissue engineering and their fabrications method. As for experimental part, samples were prepared by the freeze-drying method. As tested material, type I collagen from porcine and bovine sources was combined with hydroxyapatite and mixture of -tricalcium phosphate and -tricalcium phosphate in ratios 1 : 1, 1 : 2 and 2 : 1. The effect of bioceramics solubility and particle sizes on scaffolds morphology, biomechanics and biocompatibility was evaluated. Addition of bioceramic particles changed the morphology of the samples. The pore size decreased, whereas the porosity was nearly the same in all tested samples. Bioceramic particles also made the collagen matrix of the scaffolds less hydrophilic, moreover they stabilized the scaffolds against the effect of enzymatic degradation. The biomechanical properties of the samples were tested in both dry and hydrated state. In dry state, the pure bovine collagen scaffolds reached the highest compressive strength, contrary in hydrated state, the samples containing bioceramic particles reached the highest value. None of the samples was cytotoxic and the most preferable environment for cell adhesion and proliferation was in the pure bovine collagen scaffolds and also in the composite scaffolds with ratio HAp : -TCP : 1 : 1.
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Pěnové keramické bioaktivní materiály – výrobní postupy, zkoušení vlastností a aplikace
Motyka, Jan ; Hadraba, Hynek (oponent) ; Řehořek, Lukáš (vedoucí práce)
Porézní materiály pro tkáňové inženýrství jsou novou skupinou materiálů, ktré poskytují některé unikátní vlastnosti, zejména bioaktivitu, biodegradabilitu a osteokonduktivitu. Keramické porézní struktury pro náhrady kostí se zdají mít značný potenciál pro aplikace v medicínské praxi. Bioaktivní prekurzory vykazují velice slibné výsledky při napomáhání hojení kostí, jako výplně kostí a taky jako jejich náhrady. Nejsou zatím však dost mechanicky kompetentní, aby mohly přenášet zatížení, takže jsou využívány pouze pro nízkozátěžové aplikace. Všecny tyto - a jistě mnohé další - důvody, způsobují značný rozvoj v této oblasti materiálů, zvláště v posledních letech. Existuje celá škála výrobních procesů, produkujících pěny s různou strukturou a vlastnostmi. Stručně jsou zde popsány nejběžnější techniky přípravy pěnových struktur a vyjmenovány některé další používané. Dále je zde pojednáno o mechanických vlastnostech, jejich predikci a zkoušení.
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Materiály v lékařství
Dvořáková, Tereza ; Čikl, Josef (oponent) ; Molliková, Eva (vedoucí práce)
Tato bakalářská práce je zaměřena na rešeršní studii kovových, keramických i polymerních materiálů pro medicínské aplikace. V první části práce je sepsána historie těchto materiálů, jejich vlastnosti a požadavky na ně kladené. Dále jsou představeny nejčastější oblasti použití fixačních prostředků a umělých náhrad měkkých i tvrdých tkání. Práce je zakončena představením perspektivního vědního oboru, jímž je tkáňové inženýrství.
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The effect of organic and inorganic additives on the chemico-physical properties of biopolymer substrates for tissue engineering
Kohoutek, Martin ; Muchová, Johana (oponent) ; Brtníková, Jana (vedoucí práce)
This bachelor’s thesis deals with the preparation and characterization of composite collagenous scaffolds for possible applications in both bone and skin tissue engineering with an emphasis on their chemico-physical properties. In the theoretical part, the selected components for fabrication of the scaffolds are described and later were used to fabricate 3D porous composite scaffolds in the experimental part. Altogether, four different composite collagenous scaffold types and a reference pure collagen scaffold type were prepared using the freeze-drying fabrication technique. Two scaffold types were made by combining collagen with either oxidised cellulose (OC) or carboxymethyl cellulose (CMC). The other two types of scaffolds had the same biopolymeric origin enhanced with the addition of bioceramics based on the hydroxyapatite and tricalcium phosphates. The microstructure, porosity and pore size were assessed by the scanning electron microscopy. The highest porosity and pore size were achieved by the reference purely collagenous scaffolds, followed by the collagen composites with OC and CMC. Scaffolds with the content of bioceramics had the lowest porosity and pore size, especially those containing CMC. Swelling behaviour analysis and enzymatic degradation in vitro showed, that the hydrophilicity and mass loss in the degradation process correlate with each other. The scaffolds without bioceramics were more hydrophilic and achieved greater mass loss than the scaffolds containing bioceramics. The pure collagen was in the between the two groups. Scaffolds containing CMC achieved greater mass loss and hydrophilicity than their OC counterparts. In terms of mechanical properties, scaffolds with bioceramics achieved higher compressive strength in the wet state than the other three scaffold types. The mechanical properties were generally better for scaffolds with lower porosity and lower hydrophilicity.
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