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Stimulation of mesenchymal stem cells osteogenic differentiation using perfusion bioreactor
Šljivnjak, Erna ; Rampichová, Michala (advisor) ; Rösel, Daniel (referee)
Bone cells in vivo reside in a dynamic environment exposed to constant chemical and mechanical stimuli caused by the interstitial fluid flow. It is hypothesized that perfusion of the medium through the scaffold increases the mass transport and creates at the same time shear stress, thereby in vitro simulating the interstitial fluid effects and bone tissue formation conditions. This work examined the effects of perfusion flow rates on cell viability, proliferation, migration and osteogenic differentiation of human mesenchymal stem cells within cell-seeded 3D poly-ε-caprolactone scaffolds. Scaffolds were perfused for 21 days at flow rates 1, 3 and 5 mL/min and were compared to the scaffolds from static culture. Cells were most viable, had upregulated expression of osteogenic markers collagen type I and highest alkaline phosphatase activity under flow rate 1 mL/min when compared to their static counterparts. Cells proliferated the most under flow rate 3 mL/min when compared to their static counterparts. Flow rate 5 mL/min did not significantly differ from the static culture in any of the examined parameters. Cell migration into the scaffold was not improved upon exposure to perfusion. This data confirms that medium perfusion may benefit cell proliferation and osteogenic differentiation by enhancing...
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Impact of protein transmembrane domains on membrane organisation
Šljivnjak, Erna ; Cebecauer, Marek (advisor) ; Novotný, Marian (referee)
Plasma membrane is not a static, but rather a dynamic structure that constantly changes its form and local properties. Interactions between building blocks of plasma membrane and external factors are responsible for those changes. In this thesis, I summarize the literature which describes interactions between transmembrane proteins and lipid membranes as well as its consequences. I discuss membrane thickness, respectively thinning, protein sorting and clustering shown to be dependent on the properties of transmembrane domains. Furthermore, the role of proteins in various model of the plasma membrane organization are indicated. Finally, I report on currently discovered impact of the surface roughness of TMDs on local mobility and organization of lipids. All these data indicate importance of detailed understanding of TMDs, their properties and relation to surrounding lipid membranes. Key words: membrane, protein, transmembrane domain, hydrophobic mismatch, protein sorting, models of the plasma membrane
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