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Characterization of hydrogels based on photocross-linked derivative of hyaluronan
Hekrlová, Veronika ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
This bachelor thesis focuses on characterization of hydrogels based on photocross-linked Tyramine-modified hyaluronan (HA-Tyr). In the first part of the work, swelling of gels in saline and porcine plasma was examined, in which the hydrogels swell significantly less. The second part of the thesis is focused on rheology. First, dependence of the apparent viscosity of precursor solutions on shear rate was tested. The apparent viscosity increases with the concentration of derivative and Mw. This trend can also be observed when measuring viscoelastic properties (the elastic modulus) in oscillation mode (strain sweep test). The elastic modulus can also be affected by using a higher concentration of the photoinitiator riboflavin (RF), higher radiation intensity or by longer exposure times, although the material can be degraded. The work also includes an ATP bioluminescence method cytotoxicity test, which proved that the methods used are safe for in situ application.
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Characterization of hydrogels based on photocross-linked derivative of hyaluronan
Hekrlová, Veronika ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
This bachelor thesis focuses on characterization of hydrogels based on photocross-linked Tyramine-modified hyaluronan (HA-Tyr). In the first part of the work, swelling of gels in saline and porcine plasma was examined, in which the hydrogels swell significantly less. The second part of the thesis is focused on rheology. First, dependence of the apparent viscosity of precursor solutions on shear rate was tested. The apparent viscosity increases with the concentration of derivative and Mw. This trend can also be observed when measuring viscoelastic properties (the elastic modulus) in oscillation mode (strain sweep test). The elastic modulus can also be affected by using a higher concentration of the photoinitiator riboflavin (RF), higher radiation intensity or by longer exposure times, although the material can be degraded. The work also includes an ATP bioluminescence method cytotoxicity test, which proved that the methods used are safe for in situ application.
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Co-operativity of cytochrome P450 system and its impact on drug and carcinogen metabolism
Holý, Petr ; Hodek, Petr (advisor) ; Chmelík, Josef (referee)
The system of mixed-function oxidases (MFO system) has a significant role in metabolism of many endogenous compounds, as well as xenobiotics (for ex. karcinogens, drugs). Membrane-bound haemoproteins called cytochromes P450 are a vital part of that system. Reactions catalyzed by cytochromes P450 are influenced by another protein of the MFO system, cytochrome b5. The mechanism of this cyt b5 agency has not yet been fully described. One of methods used for study of this protein-protein interaction is covalent cross- linking. By replacing one of three methionines in the cyt b5 structure by a photo-reactive analogue (photo-methionine), an analogue of cyt b5 (photo-cyt b5) can be obtained. When activated by UV radiation, the protein covalently bonds cytochrome P450 in a membrane environment. This paper focuses on expression and isolation of a recombinant cyt b5 analogue with only one methionine position (96) in the protein structure and substitution by photo-methionine. Protein was purified in a yiedl of 6 mg from 1 liter of baterial suspension. Analysis by mass spectrometry (MALDI-TOF/TOF) showed methionine to have been substituted by the photo-reactive analogue in approx. 30 %. Photo-cyt b5 was used to fixate transient protein-protein interactions with cytochrome P450 2B4 (CYP2B4). Photo-cyt b5 was...
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