|
|
Self-Assembled Polymer Systems Based on Poly[(N-2,2-difluoroethyl)acrylamide] as Diagnostic and Theranostic Tracers for 19F Magnetic Resonance Imaging
Kolouchová, Kristýna ; Hrubý, Martin (advisor) ; Matějíček, Pavel (referee) ; Poučková, Pavla (referee)
In this doctoral thesis we describe a series of stimuli-responsive polymers which could be used as diagnostic tools or as smart drug delivery systems with simultaneous diagnosis (theranostics). All hereby mentioned polymers are thermoresponsive copolymers of (N-2,2-difluoroethyl)acrylamide exhibiting lower critical solution temperature in aqueous milieu. This means that they are water-soluble at low temperature while when heated above a certain temperature, they self-assemble into nano- or macro- sized assemblies. Because of the high concentration of fluorine atoms, all these polymers could be used as 19 F MRI tracers. We designed multiple different thermoresponsive, thermo- and pH-responsive, thermo-and reactive-oxygen-species-responsive polymers that could find numerous discussed applications in human medicine. We investigated their physico-chemical properties with 1 H and 19 F nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), elemental analysis, dynamic light scattering (DLS), static light scattering (SLS), small angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), and turbidimetry. After the physicochemical optimization of the parameters for the selected applications, their biocompatibility was tested in vitro. Several promising polymers were tested in vivo...
|
|
|
Preparation of hybrid nanoparticles based on interaction of block polyelectrolytes with atypical ions
Mesíková, Soňa ; Matějíček, Pavel (advisor) ; Štěpánek, Miroslav (referee)
The Thesis deals with the co-assembly behaviour of cationic diblock copolymers poly(2- vinyl pyridine)-b-poly(ethylene oxide), P2VP-b-PEO, and poly(ethylene oxide)-b-poly(2- (N, N, N′, N′-tetramethyl guanidinium) ethyl acrylate), PEO-b-PGEA, with closo- dodecaborate anion, [B12H12]2- , in aqueous solutions. Formation of stable PEO-b- PGEA/[B12H12] nanoparticles was investigated by static and dynamic light scattering and 1 H NMR spectroscopy, and they were visualized as spherical nanoparticles by cryo- TEM imaging. According to the NMR results, both studied diblock copolymers form core- corona micelles with dodecaborate. The micellar molar mass and the aggregation number of PEO-b-PGEA/[B12H12] micelles were obtained in water and 0.156 M NaCl solution by standard Zimm method. For this, refractive index increment was evaluated by refractometer. The studied nanoparticles are promising for the boron delivery in medicine.
|
|
|
Preparation of uniform superparamagnetic particles with polymer coating for biomedical applications
Patsula, Vitalii ; Horák, Daniel (advisor) ; Sysel, Petr (referee) ; Matějíček, Pavel (referee)
Aim of this thesis was to design and prepare polymer-coated monodisperse Fe3O4 nanoparticles as a safe and non-toxic contrast agent for magnetic resonance imaging (MRI) and heat mediator for hyperthermia. Uniform superparamagnetic Fe3O4 nanoparticles were synthesized by thermal decomposition of Fe(III) oleate, mandelate, or glucuronate in high- boiling solvents at temperature >285 řC. Size of the particles was controlled in the range of 8- 27 nm by changing reaction parameters, i.e., temperature, type of iron precursor, and concentration of stabilizer (oleic acid and/or oleylamine), while preserving uniformity of the nanoparticles. Because particles contained hydrophobic stabilizer on the surface, they were dispersible only in organic solvents. To ensure water dispersibility, oleic acid on the particle surface was replaced by hydrophilic and biocompatible methoxy-poly(ethylene glycol) (PEG) and poly(3-O-methacryloyl-α-D-glucopyranose) by ligand exchange. Polymers were previously terminated with anchoring-end groups (hydroxamic or phosphonic) to provide firm bonding to iron atoms on the particle surface. Fe3O4 nanoparticles were also hydrophilized by encapsulation into a silica shell by reverse microemulsion method. Tetramethyl orthosilicate was used to prepare Fe3O4@SiO2 nanoparticles, which were...
|
|
| |
|
|
Smart hybrid gels
Strachota, Beata Katarzyna ; Matějka, Libor (advisor) ; Matějíček, Pavel (referee) ; Krakovský, Ivan (referee)
This Thesis is dedicated to the development of mechanically reinforced thermoresponsive hydrogels, able of fast and extensive temperature-induced volume transition. Poly(N-isopropylacrylamide)- (PNIPA-) based hydrogels crosslinked with Laponite clay nano-platelets, which are known for their extraordinary mechanical properties, were synthesized by free radical polymerization of the NIPA monomer in the presence of exfoliated clay nanoplatelets. In this work, the crucial role of the employed redox initiators in the formation of the physical PNIPA/clay network was established, and the particular processes taking place during the polymerization and network structure formation were described. The correlation of the time-dependent NIPA monomer conversion and of the observed structure-formation stages made possible to propose a general mechanism of the PNIPA/clay hybrid gel formation. Generally, a considerable attention was paid to the investigation of the formation-structure-property relationships. This knowledge makes it possible to control the structure evolution and hence the final material properties of the gels. An important part of this work is dedicated to the study of mechanical properties of the PNIPA/clay nanocomposite hydrogels and of the parameters which control them. The gained knowledge of...
|
|
|
Fluorometric detection of sacharides based on phenylboronic acids
Pechrová, Zdislava ; Matějíček, Pavel (advisor) ; Strachota, Adam (referee)
This paper deals with influence of fructose, glucuronic acid, glucose and mannose on the fluorescence characteristics of probe Click fluor using stationary and time resolved fluorescence spectroscopy. The spectra were measured for a wide range of concentrations (up to 3M), and the change in fluorescence intensity after the addition of carbohydrate was used to calculate the binding constants of the Click fluor/saccharide complex. Also time resolved fluorescence was measured for glucose and fructose, The last topic was the linking of Click- fluor to poly(ethylene glycol), PEG, with glucose at the end of the chain, glc-PEG-glc. The measurements show that the affinity of the Click-fluor for fructose is the greatest, on the other hand formation of the ester with glucose is very weak. Three strips were observed in the emission spectrum. One corresponds to the unbound probe, the second unstable ester form with sugar, and the third stable cyclic form of the sugar ester. In the time-resolved fluorescence of Click-fluor, changes in the wavelengths corresponding to the carbohydrate ester were seen, but not too pronounced. From the emission spectra of complex Click- fluor/glc-PEG-glc polymer and even lifetime fluorescence values, suggests that there is relatively strong binding of the probe to the...
|
|
|
Self-assembly of boron cluster compounds and their coassembly with polymers
Ďorďovič, Vladimír ; Matějíček, Pavel (advisor) ; Adamczyk-Wozniak, Agnieszka (referee) ; Nunez Aguilera, Maria Rosario (referee)
This thesis focuses on the self-assembly of the boron cluster compounds and the coassembly of metallacaborane cobalt bis(dicarbollide), COSAN, with hydrophilic polymers. The research was motivated by the discovery of HIV inhibition by COSAN and its conjugates. Therefore, we decided to study in detail the behavior of boron cluster compounds in water. We demonstrated the amphiphilic character of several boranes and carboranes by the study of surface tension and self-assembly despite the absence of classical amphiphilic topology. The behavior of COSAN showed similarities with classical surfactants, such as SDS, whereas the behavior of smaller clusters with high charge density reminded of hydrotropes or chaotropes. Furthermore, we searched for the most suitable carriers of COSAN for drug delivery. Based on the earlier findings that COSAN interacts with both poly(ethylene oxide), PEO, and poly(2-oxazoline), POX, we prepared nanoparticles by mixing COSAN with block copolymers of various types of POX. Comparing linear and star-like block copolymers, we showed that the polymer architecture has a crucial role in the morphology of nanoparticles. In addition, we proved different selectivity of alkaline cations towards PEO and POX, resulting in the different structures of nanoparticles depending on the present...
|
|
|
Self-assembling hybrid nanomaterials
Rodzeń, Krzysztof ; Strachota, Adam (advisor) ; Svoboda, Jan (referee) ; Matějíček, Pavel (referee)
Organic-inorganic polymer hybrids containing butyl stannoxane dodecamer cages (Sn_POSS) as nano-building blocks were prepared and investigated. Sn_POSS was employed as a linear, crosslinking or non-bonding molecularly blended unit. For this purpose, it was synthesized with two acrylamido, primary- or secondary amino, or with two additional non- functional groups, which were attached via ionic-bonded sulfonate substituents. The nano- building block was then incorporated in matrices such as PS, PAOS, PETA, PEMA, PHEMA and PPO-based epoxies (the latter with different mesh sizes). Sn_POSS reinforces the studied matrixes by filler-filler interactions (self-assembly to nano-domains). Specific interactions of the ionic bonds of Sn_POSS with suitable pendant groups of the matrixes also can generate reinforcement and suppress filler aggregation. Moreover, the Sn_POSS can undergo several types of chemical reactions like heat-induced oligomerization, dissociation of the ionic substituents, acidolysis of the Sn-butyl bonds, as well as radical reactions of the latter. The influence of ionically bonded cages on the hybrids' morphology, as well as their ability of dissociation and short-distance migration in the polymer network at elevated temperature, was evaluated by TEM, IR and NMR analyses. The mechanical...
|
|
|
Liability for defects in business transactions
Matějíček, Pavel ; Eichlerová, Kateřina (advisor) ; Čech, Petr (referee)
The topic of this thesis is liability for defects in business transactions, or using the terminology of the effective Civil Code, obligations from non-performance. Rights from non- performance are one of the most important legal instruments regarding liability, together with liability for damage and liability for delay, all arising from pecuniary contracts, mainly from purchase contracts and contracts for work. With respect to the elapsed recodification of civil law, obligations arising from non- performance are no longer subject to two codes (in Act No. 40/1964 Coll., Civil Code and in Act No. 513/1991 Coll., Commercial Code), they are now governed only by Act No. 89/2012 Coll., the effective Civil Code. Civil code and its provisions are therefore the main part of this thesis. Moreover, some parts of the thesis contain comparison of the effective Civil Code to the preceding legislation, i.e. the Commercial Code, and to some international treaties as well. The first chapter, which follows right after the preface, contains sources of this thesis. The second chapter deals with the concept of obligations arising from non-performance, compares them to other areas of civil law dealing with liability, and later deals with the concept of commercial obligation. The third chapter talks about the provisions...
|
|
| |
guest ::
RSS feed.