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Boron cluster conjugates as building blocks for the preparation of polymeric nanostructures
Steiner, Filip ; Matějíček, Pavel (advisor) ; Ďorďovič, Vladimír (referee)
Charles University in Prague Faculty of Science Department of Physical and Macromolecular Chemistry Author: Bc. Filip Steiner Supervisor: prof. RNDr. Pavel Matějíček, Ph.D. Advisor: Ing. Mariusz Uchman, Ph.D. Title: Boron Cluster Conjugates as Building Blocks for the Preparation of Polymeric Nanostructures Abstract This diploma thesis investigates the synthesis and supramolecular behaviour of amphiphilic conjugates of closo-dodecaborate dianion, [B12H12]2- , with polycationic diblock copolymer poly(ethylene oxide)-block-poly(2-(N, N, N', N'-tetramethyl guanidium ethyl acrylate), PEOn-b-PGEAm. The boron cluster dumbbells were synthesised by the exoskeletal, electrophile-induced nucleophilic substitution (EINS) and by subsequently ring-opening reaction with various aliphatic diols, resulting in a hybrid dumbbell molecule. These molecules were used for preparation of nanoparticles by co- assembly with polycationic diblock copolymer in water. Resulted nanostructures were characterised by static and dynamic light scattering and NMR spectroscopy. Keywords: boron cluster compounds, polymeric nanoparticles, co-assembly, NMR, light scattering
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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...
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Self-assembled polymer systems responsive to external stimuli for biomedicine
Sincari, Vladimir ; Štěpánek, Petr (advisor) ; Matějíček, Pavel (referee) ; Sedláková, Zdeňka (referee)
The first work in my doctoral thesis described a novel rapid and eco-friendly reversible addition-fragmentation chain transfer (RAFT) polymerization reaction of the N-(2- hydroxypropyl) methacrylamide (HPMA) monomer under microwave irradiation (MWI). Optimal conditions for the polymerization such as reaction time, solvents, monomer stoichiometry and RAFT agents was determined. The polymerization kinetics demonstrated the linear increase in the number-average molecular weight (Mn) with monomer conversion. Good agreement between the theoretical and experimental Mn values was verified with pseudo-first- order kinetic plots, with low dispersities (Đ ≤ 1.04). Furthermore, this publication demonstrated the ability of MWI to facilitate copolymer formation by the preparation of relevant copolymers, such as poly(HPMA-b-bocAPMA), poly(HPMA-b-MABH) and poly(HPMA-b-PDPA) which were used as a base for the following work in the thesis. The second and third study are devoted to delivery of therapeutic molecules by using cargo-delivery self-assemblies in the form of polymersomes (PS). Such drug delivery systems (DDS) potentially minimize the premature degradation of drug, fast clearance from bloodstream and dosing frequency which leads to lower toxicity. The main advantage of DDS is the controlled manner of drug...
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Nanomaterials based on nano-ion hydrophylic polymer interactions
Mesíková, Soňa ; Matějíček, Pavel (advisor) ; Strachota, Adam (referee)
The Thesis deals with the co-assembly of triblock copolymers poly(2-(N, N, N′, N′-tetramethyl guanidinium)ethyl acrylate)-b-poly(ethylene oxide)-b-poly(2-(N, N, N′, N′-tetramethyl guanidinium)ethyl acrylate), PGEA-PEO-PGEA, and poly(N-isopropylacrylamide)-b- poly(acrylic acid)-b-poly(N-isopropylacrylamide), PNIPAM-PAA-PNIPAM, with anionic boron cluster compounds closo-dodecaborate anion, [B12H12]2- , and [cobalt(3+) bis(1,2- dicarbollide)] anion, COSAN, in aqueous solutions, respectively. Synthesis of PNIPAM-PAA- PNIPAM triblock copolymers was performed. The formation of gels based on electrostatic interactions of cationic blocks of PGEA-PEO-PGEA copolymer with closo-dodecaborate anion and on dihydrogen bonding of neutral PNIPAM blocks of PNIPAM-PEO-PNIPAM with COSAN was investigated. The inner structure of the gels was investigated by scattering techniques and fluorescent spectroscopy. Their mechanical properties were studied by diverse rheology measurements. Influence of lithium and sodium salts on PEO/COSAN complex formation and stability in aqueous solution was also studied.
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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...
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Interaction of metallacarboranes with biocompatible polymers in solutions
Ďorďovič, Vladimír ; Matějíček, Pavel (advisor) ; Cígler, Petr (referee)
The bachelor thesis deals with the behavior of aqueous solutions of polystyrene- block-poly(ethylene oxide), PS-PEO, and poly(ethylene oxide)-block-poly(2-ethyl oxazoline), PEO-PEOX, and their interaction with sodium 3-cobalt bis(1,2-dicarbollide), NaCoD. The prepared nanoparticles were characterized by static and dynamic light scattering, AFM and cryo-TEM. While PEO-PEOX is molecularly soluble in water, PS- PEO forms micelles with PS core and PEO shell. We determined by dialysis that CoD¯ interacts with both PEO and PEOX segments depending on the salt concentration. Even small amount of NaCoD results in destabilization of PS-PEO micelles. On the other hand, PEO-PEOX mixtures with NaCoD in salted aqueous solutions contain vesicles with radii 69 nm.
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Comicellization of polystyrene-block-poly(acrylic acid) with low-molar-mass surfactants
Paloncýová, Markéta ; Štěpánek, Miroslav (advisor) ; Matějíček, Pavel (referee)
This B.Sc. thesis deals with the study of the effect of low-molar-mass ionic surfactants sodium dodecyl sulfate (SDS) and hexydecyltrimethylammonium bromide (HTAB) on association behavior of the block copolymer polystyrene-b-polyacrylic acid (PS-b-PAA) in alkaline aqueous solutions. Prepared polymeric nanoparticles were characterized by static and dynamic light scattering, transmission electron microscopy and 1 H NMR spectroscopy. It was found that both surfactants interact only with PAA blocks and their presence in the system leads to worsening of the copolymer solubility which manifests itself in the formation of large micellar aggregates and in precipitation of the copolymer-surfactant complexes.
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