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Study of aggregation process and physical stability of polymeric micelle by fluorescence probe method
Chovancová, Romana ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
Amphiphilic block copolymer poly(ethylene glycol)-b-poly(–caprolactone) (PEG–PCL) was synthesized from poly(ethylene glycol) (PEG) and poly(–caprolactone) (PCL) by using ring-opening polymerization. The structure and composition of this copolymer was determined by IR spectroscopy. Polymeric micelles were prepared by membrane dialysis method and direct dissolution of copolymer in water. The process of aggregation and physical stability in water solution was studied by fluorescence spectroscopy using pyrene and perylene as fluorescent probes.The results of steady-state and time resolved fluorescence measurements indicate that system of PEG–PCL forms both unimolecular and multimolecular micelles, which depends on copolymer concentration. The critical micelle concentration (CMC) was around 0,002 g/L. Measurement of micelles size by dynamic light scattering method suggested that systems with higher concentration form bigger aggregates. In addition, copolymer behavior was explored under physiological conditions. The results show that CMC of copolymer increased in 0,15 mol/L sal solution at temperature 37°C to 0,02 g/L when compared to copolymer in water.
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Effect of steric constraint and surface interactions on the behavior of block copolymers (Computer study)
Blovský, Tomáš ; Limpouchová, Zuzana (advisor) ; Lísal, Martin (referee)
In this thesis, the influence of spatial confinement and interactions with solid surfaces on the conformational behavior of symmetric diblock amphiphilic copolymers A5B5 is stud- ied using dissipative particle dynamics (DPD). In the first two chapters, the motivation for studying such systems and the description of the simulation method are given. In the remaining chapters, the effect of spatial confinement on the association behavior of diblock copolymers is studied, as well as the effect of interactions between the solvophobic block B and the solid wall. The results are compared with simulations without spatial confinement. DPD simulations showed that the attractive interaction between block B and the wall significantly changes the association behavior of block copolymers in a se- lective solvent, whereas the purely steric effect is negligible in spatially confined systems with a non-interacting wall. Keywords: block copolymers, surface interactions, steric constraint, computer simula- tion, complex solution, dissipative particle dynamics
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Synthesis of triblock terpolymers as a tool for preparation of smart drug delivery nanosystems
Orságh, Martin ; Uchman, Mariusz Marcin (advisor) ; Fernandez Alvarez, Roberto (referee)
In this thesis, we describe the synthesis and self-assembly of new photo-responsive triblock terpolymers by RAFT polymerization. These triblock terpolymers were characterized by GPC, NMR and IR spectroscopy. The resulting nanoparticles were characterized by DLS, SAXS and Cryo-EM. To avoid problems with RAFT polymerization of the photo-responsive monomer o- nitrobenzyl acrylate, we used naphthacyl methacrylate, a new RAFT-polymerizable photo- responsive monomer. In addition, we used phenylboronic acid moieties to conjugate model drugs with our triblock terpolymers via dynamic covalent bonding and studied stimuli-triggered release of a model drug-like compound, Alizarin Red S. Our results showed that naphthacyl methacrylate is indeed polymerizable by RAFT and that such polymers retain photo-responsive properties. We were also able to bind Alizarin Red S to the polymer via boronate ester linkage and trigger its release by dopamine or fructose addition, both of which are biologically relevant compounds. Therefore, our photo- and diol-responsive nanoparticles open up opportunities for developing new drug-delivery systems.
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Study of self-assembly and degree of ionization of block copolymers using transmission electron microscopy and molecular simulations
Illés, Peter ; Nová, Lucie (advisor) ; Štěpánek, Miroslav (referee)
Responsive systems, such as block copolymers with solvent-affine blocks, can undergo self-assembly into structures like micelles or vesicles. These assem- blies are highly sensitive to slight changes in external conditions, like pH or temperature, leading to the formation or dissolution of micelles. When one of the polymer blocks is a weak polyelectrolyte, its degree of ionization depends not only on the external conditions but also on the association state. This study focuses on investigating the size and degree of ionization of micellar struc- tures formed by polymer chains containing thermoresponsive and pH-responsive blocks. The investigation combines high-resolution transmission electron mi- croscopy and Hamiltonian Monte Carlo simulations to provide a comprehensive understanding of these micellar structures. 1
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Self-assemblies based on hydrophilic polymers in aqueous media
Fanova, Anastasiia ; Štěpánek, Miroslav (advisor) ; Pánek, Jiří (referee) ; Angelov, Borislav (referee)
This doctoral thesis is devoted to investigation of self-assemblies based on hydrophilic polymers (both homopolymers and block copolymers) in aqueous media. Specifically, we focused on two classes of systems: (i) hydrophilic polymers whose self-assembly in aqueous solutions is driven by association of terminal hydrophobic groups and (ii) double hydrophilic block polyelectrolytes whose self-assembly occurs via electrostatic complexation of polyelectrolyte blocks. For characterization of formed assemblies, we mostly used different scattering techniques (light scattering, small-angle X-ray scattering) in a combination with a number of supplementary methods including microscopy, fluorometry and calorimetry. Keywords: hydrophilic polymers, block copolymers, association, self-assembly, micelles, scattering
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Post-polymerization modification of block copolymers as a tool for preparation of new drug delivery nanosystems
Marková, Pavlína ; Uchman, Mariusz Marcin (advisor) ; Košovan, Peter (referee)
Amphiphilic block copolymers self-assemble into clinically efficacious nanostructures, whose size, stability, and surface chemistry can be easily adjusted for each purpose. This versatility has prompted the vast scope of their biomedical applications, especially in the field of drug delivery. In particular, polyester-based nanoparticles have been used in gene, nucleic acid, therapeutic protein and drug delivery for their in vivo biocompatibility and biodegradability. However, most studies have only focused on amphiphilic copolymers with either short hydrophobic segments, no modification or a single preparation pathway. This diploma thesis focuses on the synthesis of poly(ethylene oxide)-b-poly(caprolactone) copolymers containing propargyl groups using two parallel approaches, namely a copolymerization with a modified monomer and a post-polymerization modification. A subsequent thiol-yne click reaction with 1-thioglycerol yielded copolymers with vicinal diols, which can reversibly bind to benzoxaborole- and boronic acid-derived compounds. Both synthetic pathways were evaluated based on macromolecular characteristics afforded by nuclear magnetic resonance spectroscopy and by size exclusion chromatography. Furthermore, we characterized the self-assembled nanoparticles by static and dynamic light...
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Synthesis of block copolymers by ring-opening polymerization and post polymerization modification with phenylboronic acid
Dudičová, Dorota ; Uchman, Mariusz Marcin (advisor) ; Strachota, Adam (referee)
This thesis deals with the synthesis of propargyl-functionalized amphiphilic diblock copolymers, poly(ε-caprolactone)-b-poly(ethylene oxide), PgCL-PEO via Ring Opening Polymerization (ROP) using monohydroxyl-terminated PEO block as the macroinitiator and its post polymerization modification via Copper-Catalyzed Azide-Alkyne Click reaction (CuAAC) to introduce phenylboronic acid functionality into block copolymers. A reproducible synthetic protocol was developed for preparation of well-defined functional diblock copolymers. The amphiphilic block copolymers were characterized in terms of molecular weight and dispersity by various techniques: Nuclear Magnetic Resonance (NMR) spectroscopy, Gel Permeation Chromatography (GPC) and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI ToF) Mass Spectrometry. Keywords: Amphiphilic block copolymers, CuAAC click, phenylboronic acid, poly-ε- caprolactone, ring-opening polymerization
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Nanoparticles based on complexes of hydrophilic block polyelectrolytes and new gemini ionic surfactants
Šomšáková, Katarína ; Uchman, Mariusz Marcin (advisor) ; Trhlíková, Olga (referee)
This bachelor thesis deals with preparation and study of the aqueous solutions of block polyelectrolyte poly(2-vinylpyridine)-b-poly(ethylen oxide), P2VP-PEO with gemini surfactants 6,6'-(ethan-1,2-diylbis(oxy)) bis(3-dodecylbenzenesulfonate acid), 6,6'- (buthan-1,4-diylbis(oxy)) bis(3- dodecylbenzenesulfonate acid) and 6,6'-(hexane-1,6- diylbis(oxy)) bis(3- dodecylbenzenesulfonate acid) complexes and with P2VP-PEO and sodium dodecylsulfate, SDS, complexes, and compares their physico-chemical properties. Formed particles were characterized by static and dynamic light scattering, zeta potential, isothermal titration calorimetry and transmission cryo-electron microscopy. Even small amount of surfactant leads to coassembly of P2VP-PEO with surfactants, formed by PEO shell and P2VP/surfactant core. The nanoparticles of block polyelectrolyte and gemini surfactants in 0.1M HCl are stable and their size depends on the spacer lenght and the surfactant/polymer ratio.
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Synthesis of block copolymers by ring-opening polymerization and post polymerization modification with phenylboronic acid
Dudičová, Dorota ; Uchman, Mariusz Marcin (advisor) ; Strachota, Adam (referee)
This thesis deals with the synthesis of propargyl-functionalized amphiphilic diblock copolymers, poly(ε-caprolactone)-b-poly(ethylene oxide), PgCL-PEO via Ring Opening Polymerization (ROP) using monohydroxyl-terminated PEO block as the macroinitiator and its post polymerization modification via Copper-Catalyzed Azide-Alkyne Click reaction (CuAAC) to introduce phenylboronic acid functionality into block copolymers. A reproducible synthetic protocol was developed for preparation of well-defined functional diblock copolymers. The amphiphilic block copolymers were characterized in terms of molecular weight and dispersity by various techniques: Nuclear Magnetic Resonance (NMR) spectroscopy, Gel Permeation Chromatography (GPC) and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI ToF) Mass Spectrometry. Keywords: Amphiphilic block copolymers, CuAAC click, phenylboronic acid, poly-ε- caprolactone, ring-opening polymerization
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