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Upconverting nanoparticles as contrast agents for biomedicine
Mrázek, Jiří ; Vránová, Jana (advisor) ; Šuta, Daniel (referee) ; Matějka, Roman (referee)
Upconverting nanoparticles (UCNP) represent an interesting class of contrast agents for biomedical applications due to their ability to convert infrared light into the visible or even UV region of the spectrum. The aim of this work was to prepare UCNP with bound hyaluronan (HA), a natural polysaccharide, and to investigate their interaction with cells in vitro. The reproducibility of the synthesis of β-Na(RE)F4 UCNP was demonstrated in a series of 15 consecutive preparations. Particles with different ratios of RE elements (Yb, Gd, Y, Lu, Er, Tm) with emission spectra covering the range from NIR to UV and advanced core/shell type UCNP with different combinations of core/shell material were prepared. The layer-by-layer shell growth method allowed to control the particle size. Hydrophobic UCNP were incorporated into oleyl-HA micelles. The UCNP@oleyl-HA micelles were stable in buffers and in cell culture media, where they effectively limited the quenching of UCNP luminescence. The second method of UCNP modification consisted of sorption of HA-furanyl onto particles followed by photochemical crosslinking. The UCNP@HA-furanyl particles with a hydrodynamic diameter of ~180 nm formed stable colloids in cell culture media. UCNP@oleyl-HA micelles reduced the viability of MDA-MB-231 cancer cells but were...
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Autonomous system for maintaining the biophysical conditions required for culturing biological cultures in vitro
Matějka, Roman ; Rosina, Jozef (advisor) ; Pantoflíček, Tomáš (referee) ; Kvašňák, Eugen (referee)
Cardiovascular disease is one of the leading causes of death worldwide. Surgical techniques, including bridging, replacing, or plasticizing damaged tissue, need suitable grafts for these operations. The ideal source is autologously obtained grafts, which, however, require another invasive approach, and there are not enough of them, or they do not meet the optimal anatomical form. Allogeneic grafts from cadaveric donors are not immediately available for acute interventions. Synthetic replacements show good results in large arteries, but restenosis occurs in small diameter vessels and often require further reoperation. The use of tissue engineering methods to modify these replacements by cell colonization may provide their better patency. Furthermore, decellularized xenogeneic tissues are promising matrices for the development of tissue-engineered cardiovascular grafts. Due decellularization the immunogenic complex is minimized while maintaining a suitable building structure. In combination with recolonization with suitable cells using culture bioreactors, new functional cardiovascular replacements can be created. Endothelialization of the inner lumen is a crucial element in the formation of cardiovascular replacements. The effect of shear stress simulated in the bioreactor has a positive effect on...
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Adhesion and growth of adipose tissue-derived stem cells on fibrin assemblies with attached growth factors for tissue engineering of heart valves
Filová, Elena ; Trávníčková, Martina ; Knitlová, Jarmila ; Matějka, Roman ; Kučerová, Johanka ; Riedelová, Zuzana ; Brynda, Eduard ; Bačáková, Lucie
Currently used xenogeneic biological heart valve prostheses are decellularized and crosslinked with glutaraldehyde. These grafts usually undergo degeneration and calcification. Pericardium-based heart valve prostheses, re-seeded with autologous cells, i.e. Adipose tissue-derived cells (ASCs) and endothelial cells, could have longer durability and biocompatibility. In order to improve the adhesion of cells and their ingrowth into decellularized pericardium, various fibrin (Fb) layers were developed, i.e. Fb, Fb with covalently bound heparin (H), Fb with either vascular endothelial growth factor (VEGF) or fibroblast growth factor 2 (FGF) in various concentrations (1 ng/ml, 10 ng/ml, 100 ng/ml) or with both VEGF and FGF (100 ng/ml). Growth factors were attached onto Fb via heparin or were adsorbed. ASCs were seeded on theses layers in a DMEM medium supplemented with 2 % of fetal bovine serum, TGFβ1 and BMP-4 (both 2.5 ng/ml), and with ascorbic acid. Cell adhesion and growth/viability was assessed by counted cell number/MTS evaluation. ASCs were stained for differentiation markers of smooth muscle cells, such as alpha-actin, calponin, and myosin heavy chain. On day 7, ASCs on Fb-H-VEGF layers produced both calponin and alpha-actin. An increased FGF concentration caused reduced calponin staining of ASCs. Lack of heparin in fibrin assemblies with growth factors inhibited the production of both alpha-actin and calponin in ASCs. The highest ASCs density/viability was found on Fb-H-VEGF-FGF layer. The proper formulation of fibrin coatings could be favorable for ASCs growth and differentiation and could subsequently support endothelialization of cardiovascular prostheses with endothelial cells.
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Private law aspects of consumer protection
Matějka, Roman ; Švestka, Jiří (advisor) ; Salač, Josef (referee)
Charles University in Prague Faculty of Law Department of Civil Law Private law aspects of consumer protection Diploma Thesis Abstract Roman Matějka Supervisor: prof. JUDr. Jiří Švestka, DrSc. Prague, September 2011 Abstract Private law aspects of consumer protection The aim of this thesis is to analyze the issue of consumer protection in private law. The author focused mainly on the latest changes in the applicable legislation dealing with the consumer protection. The thesis also contains critical evaluation of current legislation and a comparison with the draft of the new Civil Code. The thesis should contribute to the discussion of the ongoing recodification of private law. The thesis is divided into ten chapters. The first chapter deals with the definition of the term consumer protection and consumer protection law. It also includes a brief excursion on the topic of consumer protection in public law. The second chapter consists of a list of acts that regulate consumer protection. First, it brings a list of national sources of consumer protection in the Czech legislation. It also contains an overview of the legislation protecting consumers in Community law, both in the primary, and the secondary legislation. The third chapter discusses the key terms of consumer protection - consumer and supplier. There...
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