Tesis: "Poly(2-oxazoline)"

1

Barnes, Suzanne R. "Size Exclusion Chromatography of Poly(2-ethyl-2-oxazoline) Homopolymers and Poly(ethylene oxide)-b-Poly(2-ethyl-2-oxazoline) Copolymers". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/24907.

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Size exclusion chromatography is the method of choice for characterizing molecular weights and molecular weight distributions of polymers. An important advancement in SEC is multidetection SEC which includes multi-angle laser light scattering, viscometry, refractive index and UV spectroscopy to analyze block and graft copolymers as well as polymers with oligomeric molecular weights. Oligomeric molecular weights present special challenges since the light scattering and viscosity detectors are more sensitive to higher molecular weights and both detectors have low molecular weight threshold values. The molecular weights and distributions of poly(2-ethyl-2-oxazoline) oligomers and block copolymers as well as poly(2-ethyl-2-oxazoline) were investigated by SEC using multiple detectors. Both a universal calibration method and light scattering were used to determine molecular weights and molecular weight distributions. The solvent was N-methylpyrrolidone that contained 0.05M LiBr used to minimize interactions among the polymers and solvent. SEC was used to establish that the diblock copolymers had heterogeneous compositional distributions. The low molecular weights of the diblock and homopolymer made it necessary to use the universal calibration method with combined refractive index and viscometry detectors to determine absolute molecular weights.
Master of Science

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2

Jordan, Rainer y Dan Gieseler. "Poly(2-oxazoline) molecular brushes by grafting through of poly(2-oxazoline)methacrylates with aqueous ATRP". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-188802.

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Molecular brushes of poly(2-oxazoline)s (POx) are an intriguing class of polymers as they combine a unique architecture with the properties of POx as a biomaterial. Here, the synthesis of several POx macromonomers with methacrylate end groups and consecutive grafting through polymerization by aqueous atom transfer radical polymerization (ATRP) at room temperature is reported. 1H-NMR spectroscopy and size exclusion chromatography (SEC) confirmed the synthesis of POx molecular brushes with maximum side chain grafting densities, narrow molar mass distributions (Đ ≤ 1.16) and final molar masses corresponding to the initial macromonomer : initiator ratio. Chain extension experiments show high end group fidelity and formation of block copolymer molecular brushes, and kinetic studies revealed a polymerization behavior of oligo(2-methyl-2-oxazoline) methacrylate very similar to the frequently used oligo(ethylene glycol) methacrylate (OEGMA475). Aqueous solutions of POx molecular brushes with poly(2-ethyl- and 2-isopropyl-2-oxazoline) side chains exhibit the typically defined thermoresponsive behavior with a tunable, very narrow and reversible phase transition

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3

Liu, Qin. "Poly(2-alkyl-2-oxazoline) containing multiphase systems". Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/37884.

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This research is focused on the polymerization of 2-alkyl-2-oxazoline homopolymers and 2-alkyl-2-oxazoline containing copolymers with well-defined structures. In addition, the potential of selected materials as polymer blend compatibilizers was briefly evaluated. The polymerization of 2-alkyl-2-oxazoline was investigated with regard to the effects of initiator structures on molecular weight control and molecular weight distribution, living characteristics, and mechanisms and kinetics. The structure of initiators was shown to greatly affect the molecular weight control and molecular weight distribution of poly (2-ethyl-2-oxazoline). The living nature of poly (2-ethyl-2-oxazoline) in chlorobenzene initiated by benzyl iodide, benzyl chloride/NaI, or chloroethyl ethyl ether/NaI has been established by Mn-conversion plots and sequential monomer addition experiments. However, the molecular weight distributions of these polymers were not as narrow as Poisson distributions, Mechanistic and kinetic studies of 2-ethyl-2-oxazoline polymerizations suggested that, at very early stages of polymerization, the active species is covalent. After that very early Stage of polymerization, ionic species are present and the overall propagation rates increases. The rate determining step was found to be the initial propagation step(s) using benzyl iodide as the initiator, and initiation and/or the initial propagation step(s) in the case of iodobutane as an initiator. A kinetic study of 2-methyl-2-oxazoline polymerization in CD₃CN also indicated slower initiation than propagation rates using both butyl mesylate and butyl iodide as initiators. Based on the knowledge of 2-alkyl-2-oxazoline homopolymerizations, poly(2-alkyl-2-oxazoline) containing copolymers were prepared using macroinitiator methods, with poly(2-alkyl-2-oxazoline) being either the macroinitiator or the second component synthesized. Narrow distribution poly(dimethylsiloxane) oligomers terminated with benzyl chloride endgroups were prepared by living anionic ring-opening polymerization of hexamethylcyclotrisiloxane followed by termination with a benzyl chloride containing chlorosilane reagent. Cationic ring-opening polymerization of 2-ethyl-2-oxazoline using these macroinitiators in combination with NaI generated a series of well defined block copolymers. Poly(butyl vinyl ether) and poly(methyl vinyl ether) oligomers with Poisson distributions and precisely terminated on one end with a chloroethyl ether functional group were prepared by living cationic polymerization of alkyl vinyl ethers using a chloroethyl vinyl ether/HI initiating system with ZnI₂ as catalyst and terminated by lithium borohydride. The chloroethyl ether functional groups were used in conjunction with sodium iodide to polymerize 2-ethyl-2-oxazoline blocks. In order to insure effective initiation and to narrow the copolymer molecular weight and composition distributions, the chloride to iodide conversion was made prior to the addition of monomer. A series of these diblock materials was prepared wherein the molecular weight distributions ranged from 1.3 to 1.4. The bulk, solution and surface properties of these copolymers were investigated by NMR, DSC, XPS and surface tension measurements. Both types of materials described above are currently being utilized for studying the parameters important for steric stabilization of inorganic particles in polar media. A less defined series of materials was also prepared. Using poly(butyl vinyl ether-co-chloroethyl vinyl ether) random copolymers as: macroinitiators, 2-methyl-2-oxazoline was polymerized, resulting in poly(butyl vinyl ether-2-methyl-2- oxazoline) graft copolymers. Poly(2-methyl-2-oxazoline-ε-caprolactone) block copolymers were prepared using hydroxyterminated poly(2-methyl-2-oxazoline) as miacroinitiators. Poly(butyl vinyl ether-g-2-methyl-2-oxazoline) (PBVE-g-PMOX) or poly(2-methyl-2-oxazoline-b-ε-caprolactone) (PMOX-b-PCL) were screened as potential blend compatibilizers for poly(ε-caprolactam) (Nylon 6) and isotactic poly(propylene). Analysis of these blends by SEM indicated that PBVE-g-PMOX might function as a blend compatibilizer for Nylon 6/poly(propylene) blend while PMOX-b-PCL would not.
Ph. D.

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4

Bernard, Ayanna Malene. "Molecular modeling of poly(2-ethyl-2-oxazoline)". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24793.

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Thesis (Ph.D.)--Chemical Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Peter Ludovice; Committee Member: Amyn Teja; Committee Member: Arthur Ragauskas; Committee Member: William Koros; Committee Member: Yulin Deng.

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5

Park, Jongryul. "Poly(2-oxazoline) architectures for drug delivery systems". Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/211439/1/Jongryul_Park_Thesis.pdf.

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The overall aim of my PhD research was to develop biocompatible materials, namely poly(2-oxazoline)s, in terms of chemical structures and chemical and physical properties for drug delivery systems. This thesis demonstrated novel strategies and unique approaches towards sophisticated drug delivery formulations. A combination of crosslinking chemistry, thermoresponsive properties, and drug conjugation was introduced to overcome common issues in typical drug delivery devices such as burst drug release and low drug efficiency. Ultimately, this thesis aimed to promote poly(2-oxazoline)s as the most promising emerging polymers in the future.

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6

Cesana, Sonia. "Functionalization of poly(2-oxazoline)s with cyclic RGD peptides". [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974209643.

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7

Greß, Anja. "Funktionalisierte Poly(2-oxazoline) : kontrollierte Synthese, bioinspirierte Strukturbildung und Anwendungen". Phd thesis, Universität Potsdam, 2008. http://opus.kobv.de/ubp/volltexte/2008/1864/.

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Funktionalisierte Poly(2-oxazoline) als neue Materialien stellen sowohl unter strukturellen Gesichtspunkten als auch im Hinblick auf potentielle Anwendungen eine interessante Polymerklasse dar. Die Ausbildung von hierarchischen Strukturen mit Poly(2-oxazolinen) über intermolekulare Wasserstoffbrückenbindungen ist hierbei ein bisher nicht beachteter Aspekt. Über einen bioinspirierten Ansatz sollten gezielt funktionelle Gruppen, die für einen hierarchischen Aufbau, z.B. in Proteinen, verantwortlich sind, in vereinfachter Weise auf die synthetische Substanzklasse der Poly(2-oxazoline) übertragen werden. Die vorliegende Arbeit beschäftigt sich mit der modularen Synthese neuer, funktionalisierter Poly(2-oxazolin) Homo- und Copolymere. Ausgehend von der Synthese von 2-(3-Butenyl)-2-oxazolin wurden definierte Präpolymere in einer kationischen Isomerisierungspolymerisation unter kontrolliert/„lebenden“ Bedingungen hergestellt. In einer anschließenden „Thio-Click“ (Thiol-En-Reaktion) Modifizierungsreaktion wurden die gewünschten funktionellen Gruppen quantitativ eingeführt. Hydroxylierte Poly(2-oxazoline) wurden hinsichtlich ihres Aggregationsverhaltens in Wasser untersucht. Bereits die jeweiligen Homopolymere bildeten aufgrund von intermolekularen Wasserstoffbrückenbindungen supramolekulare tubuläre Nanofasern aus. Durch Einsatz verschiedener analytischer Methoden konnte die innere Struktur der Nanoröhren beschrieben und ein entsprechendes Modell aufgestellt werden. Die dargestellten funktionellen Poly(2-oxazoline) wurden hinsichtlich ihrer Anwendung als potentielle, synthetische „antifreeze additives“ untersucht. Alle Polymere besitzen eine ausgeprägte Tendenz zur Nukleierung von Wasser und führen daher zu signifikanten Änderungen der Eismorphologie. Des weiteren wurde ein carboxyliertes Derivat zur biomimetischen Mineralisation von Kalziumcarbonat eingesetzt und nach phänomenologischen Gesichtspunkten untersucht.
Functionalized poly(2-oxazoline)s are a promising class of materials concerning their self-assembly behavior as well as for future applications. Hierarchical structure formation based on hydrogen bonding interactions has not been investigated yet. Applying a bioinspired approach, functional groups promoting hierarchical structure formation are introduced to poly(2-oxazoline)s. This work is focused on the modular synthesis of new functionalized poly(2-oxazoline) homo and copolymers. Starting from the synthesis of the new monomer 2-(3-butenyl)-2-oxazolin, well-defined precursor materials were prepared via cationic isomerization polymerization. Next, the polymers were quantitatively modified with the aimed functional groups using a “thio-click” (thiol-ene) reaction. The aggregation behaviour of hydroxylated poly(2-oxazolines) in water was investigated. Homo- as well as block copolymers can form supramolecular hollow nanofibers via intermolecular hydrogen bonding. Using a variety of different analytical methods, the structure of the nanotubes was determined and a formation model was proposed. Furthermore, the functionalized poly(2-oxazoline)s were investigated as synthetic mimics of natural anti-freeze additives. It was found, that these polymers show the tendency to nucleate water, thus influencing the morphology of ice. Finally, a carboxylated derivative was applied as an additive for the mineralization of calcium carbonate.

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8

Merckx, R., Thomas Swift, R. Rees, Guyse J. F. R. Van, E. Schoolaert, Clerck K. De, H. Thienpont y V. V. Jerca. "Förster resonance energy transfer in fluorophore labeled poly(2-ethyl-2-oxazoline)s†". Royal Society of Chemistry, 2020. http://hdl.handle.net/10454/18374.

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Yes
Dye-functionalized polymers have been extensively studied to understand polymer chain dynamics, intra or inter-molecular association and conformational changes as well as in practical applications such as signal amplification in diagnostic tests and light-harvesting antennas. In this work, the Förster resonance energy transfer (FRET) of dye-functionalized poly(2-ethyl-2-oxazoline) (PEtOx) was studied to evaluate the effect of dye positioning and polymer chain length on the FRET efficiency. Therefore, both α (initiating terminus)- or ω (terminal chain end)-fluorophore single labeled and dual α,ω-fluorescent dye labeled PEtOx were prepared via cationic ring opening polymerization (CROP) using 1-(bromomethyl)pyrene as the initiator and/or 1-pyrenebutyric acid or coumarin 343 as the terminating agent, yielding well-defined PEtOx with high labeling efficiency (over 91%). Fluorescence studies revealed that intramolecular FRET is most efficient for heterotelechelic PEtOx containing both pyrene and coumarin 343 fluorophores as chain ends, as expected. A strong dependence of the energy transfer on the chain length was found for these dual labeled polymers. The polymers were tested in both dilute organic (chloroform) and aqueous media revealing a higher FRET efficiency in water due to the enhanced emissive properties of pyrene. The application of dual labeled polymers as fluorescent probes for temperature sensing was demonstrated based on the lower critical solution temperature behavior of the PEtOx. Furthermore, these polymers could be successfully processed into fibers and thin films. Importantly, the fluorescence properties were retained in the solid state without decreasing the FRET efficiency, thus opening future possibilities for application of these materials in solar cells and/or sensors.
The full-text of this article will be released for public view at the end of the publisher embargo on 8 Sep 2021.

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9

Celebi, Oguzhan. "Synthesis and Characterization of Poly(2-Ethyl-2-Oxazoline) Functional Prepolymers and Block Copolymers". Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/24908.

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This dissertation focuses on the synthesis and characterization of functional poly(2-ethyl-2-oxazoline) (PEtOx) containing homo- and block copolymers that are potential materials for membrane-based water purification and gas separation, drug delivery, magnetic resonance imaging and tissue engineering applications. The polymerization of 2-ethyl-2-oxazoline (EtOx) was investigated with regard to the effects of initiator structures and reaction parameters such as polymerization time and temperature on molecular weight control and molecular weight distribution, endgroup functionality, living characteristics, and mechanism and kinetics. The structure of initiators was shown to significantly affect the molecular weight control and molecular weight distribution of PEtOx oligomers. Methyl triflate initiated polymerizations were found to result in oligomers with low polydispersity (PDI) values around 1.10-1.15 and symmetrical chromatograms were obtained via size exclusion chromatography (SEC) studies with the use of refractive index, light scattering and viscosity detectors. However, EtOx polymerizations initiated by halide containing initiators such as benzyl chloride, dibromo- and diiodo-p-xylene, and vinylsilylpropyl iodides yielded PEtOx oligomers with higher PDI values ~ 1.30-1.40. Higher molecular weight distributions can be attributed to the presence of covalent species during polymerization and slower initiation rate as evidenced by kinetic studies when compared to PEtOx prepared from methyl triflate initiators. In all cases, termination reactions with aliphatic cyclic amines were quantitative. Mono- and diamine functional PEtOx oligomers with controlled molecular weight and excellent end-group functionality may be used as prepolymers for incorporation into multiblock and graft copolymer and crosslinked structures for a variety of applications such as membranes and hydrogels for tissue engineering matrices. Poly(2-ethyl-2-oxazoline) containing block copolymers were prepared using the macroinitiator method. First, amphiphilic triblock copolymers with hydrophobic poly(arylene ether sulfone) (PSF) central block and hydrophilic PEtOx side blocks were synthesized via polymerization of EtOx sequences from tosylate functional telechelic PSF macroinitiators. PSFs are well-known engineering thermoplastics with excellent resistance to hydrolysis and oxidation, as well as displaying good mechanical properties, thermal stability and toughness. Phenol functional PSFs were prepared via step-growth polymerization of dichlorodiphenylsulfone and bisphenol-A (slight excess) monomers. Phenolic chain ends were then converted to aliphatic hydroxyethyl endgroups by reaction with ethylene carbonate. Upon treatment with p-toluenesulfonyl chloride, tosylate functional PSF macroinitiators were prepared. PEtOx-b-PSF-b-PEtOx triblock copolymers (pendent acyl groups of PEtOx side blocks) were partially hydrolyzed in an acidic medium to introduce random charged poly(ethylene imine) units to prepare ionomer structures that may show good salt rejection, water flux and antibacterial properties for membrane-based water purification applications. Phosphonic acid modified poly(ethylene oxide)-b-poly(2-ethyl-2-oxazoline) (PEO-b-PEtOx) diblock copolymers were prepared via cationic ring opening polymerization of EtOx monomers from tosylate functional PEO macroinitiators and subsequent functionalization reactions on the polyoxazoline block. Post-modification reactions included controlled partial pendent acyl group hydrolysis under an acidic medium to form the random block copolymers of PEtOx and poly(ethyleneimine) (PEI), Michael addition of diethylvinyl phosphonate groups to PEI units and hydrolysis of the ethyl groups on the phosphonates to yield pendent phosphonic acid groups on the polyoxazoline block. After each step of functionalization reactions, structures and compositions were confirmed utilizing 1H NMR and the degree of phosphorylation was found to be > 95%. Both PEO and PEtOx are biocompatible polymers and the anionic quality of the phosphonic acid has the potential to be pH controllable and provide an environment where cationic drugs and contrast agents can be attached. Thus, these polymers have potential as drug carriers and contrast enhancement agents for magnetic resonance imaging applications.
Ph. D.

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10

Fisher, Adam. "Some novel biological applications of polymers based on poly(2-oxazoline)s". Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/380885/.

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Poly(2-oxazoline)s have attracted much attention in recent times due to their potential advantages over other similar polymers. They are easy to synthesise while maintaining control over length, polydispersity and functionality1, 2. Furthermore the 2-methyl and 2-ethyl poly(2-oxazoline)s have both been shown to be ‘stealth’ biopolymers similar to that of poly(ethyleneglycol), (PEG)3 suitable for biological applications. Poly(2-isopropy-2-oxazoline), poly(2-n-propyl-2-oxazoline) and poly(2-ethyl-2-oxazoline) have all been found to show thermoresponsive behaviour and are therefore potential alternatives to poly(N-isopropylacrylamide) (PNiPAAm)4, 5. We are interested in exploiting these properties of poly(2-oxazoline)s in novel applications particularly in the biological context. We describe the synthesis and characterisation of poly(2-oxazoline) homo and co-polymers with particular attention paid to their cloud point temperature behaviour. We then developed a method to allow poly(2-oxazoline)s to be covalently attached to glass using a ‘grafting-to’ approach. We then successfully demonstrated their potential as cell selective surfaces. Two different classes of thermogelling materials have also been synthesised, one based on a carboxymethylcellulose co-polymer and another poly(2-oxazoline) only co-polymer. Both of these materials have been characterised using rheology and their potential for tissue engineering applications has been demonstrated. Finally the non-fouling properties of poly(2-methyl-2-oxazoline) coated surfaces has been explored. It has been shown that the non-fouling behaviour is dependent on the way in which bacteria are brought in contact with the surfaces.

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11

Legros, Camille. "Engineering of poly (2-oxazoline)s for potential use in biomedical applications". Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0174/document.

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Ce travail décrit d'abord l’élaboration de nanogels hydrophiles stimulables, sensibles à un changement de pH et à un environnement où les propriétés d’oxydo-réduction peuvent varier. Ils ont été synthétisés en milieu dilué, d’une part, et en émulsion inverse, d’autre part; dans les deux cas à partir d’un copolymère statistique composé d’unités 2-éthyl-2-oxazoline et éthylène imine. Ces nanogels n’ont pas montré d’interactions spécifiques avec des protéines telles que la BSA et se sont avérés non-toxiques in vitro. Une plateforme à base d’un copolymère POx statistique porteur de fonctions aldéhydes a par ailleurs permis d’accéder à une librairie de POx, incluant des structures greffées et réticulées. Enfin, l’autoassemblage en solution d’un copolymère à blocs de type poly(2-methyl-oxazoline)-bpoly(2-isopropyl-2-oxazoline) (PMeOx-b-PiPrOx), a été étudié en détail. Des micelles ont été observées à des temps courts au-dessus du point trouble du PiPrOx. Pour des temps plus longs, la formation de fibres et de micelles réticulées physiquement ont été mise en évidence, comportement expliqué par la cristallisation des chainesde PiPrOx stabilisées par les blocs PMeOx hydrophiles
This PhD work is based on the design of poly(2-oxazoline) (POx)hydrogels and nanogels, by chemical or physical cross-linking, aimed to be used for biomedical applications. Nanogels were first prepared in dilute media and in inverse emulsion based on a statistical copolymer made of 2-ethyl-2-oxazoline and ethyleneimine units. These stimuli-responsive nanogels were swelling in acidic media and were cleaved in reductive environment. They proved to be non-cytotoxic and act as protein repellent. Second, a reactive platform based on a statistical POx polymerbearing aldehyde functionalities was engineered, enabling the synthesis of graft and cross-linked POx. Last, a block copolymer made of 2-methyl- and 2-isopropyl-2-oxazoline units, proved to self-assemble into micelles when heated above its LCST,for a short period of time (< 1h30). When annealed for a longer time (> 1h30),crystallization-driven self-assembly led to the formation of different morphologies(fiber rods and cross-linked micelles)

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12

Rayeroux, David. "Polymérisation radicalaire contrôlée par transfert d'iode en mode inverse (RITP) : Synthèse de copolymères amphiphiles". Thesis, Montpellier, Ecole nationale supérieure de chimie, 2012. http://www.theses.fr/2012ENCM0025/document.

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Ce travail de thèse décrit la synthèse de copolymères diblocs amphiphiles par polymérisation radicalaire contrôlée par transfert d'iode en mode inverse (RITP). Dans un premier temps, des homopolymères à base de monomères activés (styrène, acrylate de méthyle, méthacrylate de méthyle), non activés (acétate de vinyle) et fonctionnels (chlorométhylstyrène, acrylate de tert-butyle), ont été synthétisés par RITP. Des aspects tels que le contrôle des masses molaires ainsi que la fonctionnalité en iode du bout de chaîne ont été examinés. Afin de démontrer la compatibilité de la RITP avec d'autres techniques de polymérisation contrôlée/vivante (non radicalaires), le copolymère amphiphile non-ionique poly(styrène)-b-poly(2-méthyl-2-oxazoline) (PS-b-P(MOx)) a été élaboré par la voie toute iode en procédé « one-pot » en combinant de manière consécutive la RITP du styrène avec la polymérisation cationique par ouverture de cycle (CROP) de la 2-méthyl-2-oxazoline. Par ailleurs, des copolymères cationiques poly(styrène)-b-poly(chlorométhylstyrène) quaternisé avec la triéthylamine (PS-b-PCMS+) et anioniques poly(styrène)-b-poly(acide acrylique) (PS-b-PAA-) ont été synthétisés par RITP du styrène suivie de l'ITP du bloc hydrophile. Tous ces copolymères amphiphiles ont été obtenus à partir de polystyrène iodé (PS-I) de faibles masses molaires, allant de 1000 à 3000 g.mol-1, jouant le rôle de macro-amorceurs (CROP) ou de macro-agents de transfert (ITP). L'étude de l'auto-organisation en phase aqueuse de ces copolymères amphiphiles a révélé la formation de micelles pour des concentrations supérieures à la concentration d'agrégation critique (CAC) dont la valeur a été déterminée par diffusion dynamique de la lumière (DDL) et spectroscopie de fluorescence. Enfin, des résultats très prometteurs ont été obtenus dans l'utilisation d'un copolymère cationique amphiphile PS-b-PCMS+ comme agents structurants de matériaux siliciques mésoporeux nanostructurés élaborés par procédé sol-gel en milieu basique. La synthèse de ces copolymères amphiphiles ainsi que leur caractérisation physico-chimique ont mis en exergue que la RITP permet de couvrir la synthèse de différentes catégories de copolymères amphiphiles, tout en étant une technique simple à mettre en œuvre, peu couteuse et robuste
This manuscript describes the synthesis of amphiphilic diblock copolymers by reverse iodine transfer polymerization (RITP). Firstly, homopolymers derived from activated (styrene, methyl acrylate, methyl methacrylate), non-activated (vinyl acetate) and functional monomers (chloromethylstyrene, tert-butyl acrylate) synthesized by RITP, were studied. Aspects including molecular weight control as well as iodine chain-end functionality were investigated. In order to highlight the compatibility of RITP with other living/controlled (non-radical) polymerization techniques, a poly(styrene)-b-poly(2-methyl-2-oxazoline) (PS-b-P(MOx)) non-ionic copolymer was conceived through an ‘all-iodine', ‘one-pot' process by combining successively RITP of styrene with cationic ring-opening polymerization (CROP) of 2-methyl-2-oxazoline. Besides, poly(styrene)-b-poly(chloromethylstyrene) quaternized with triethylamine (PS-b-PCMS+) cationic copolymers and poly(styrene)-b-poly(acrylic acid) (PS-b-PAA-) anionic copolymers were elaborated by RITP of styrene, followed by ITP of the hydrophilic moiety. All these amphiphilic copolymers were obtained from iodine-bearing chain-end poly(styrene) (PS-I) of low molecular weights, in the range of values of 1000 to 3000 g.mol-1, playing the role of macro-initiators (CROP) or macro-transfer agents (ITP). Studies of the self-assembly of these amphiphilic copolymers in aqueous phases revealed the formation of micelles for concentrations superior to the critical aggregation concentration (CAC). The latter value was determined by dynamic light scattering (DLS) and fluorescence spectroscopy. Moreover, highly-promising results were obtained in the use of PS-b-PCMS+ cationic copolymers as structuring agents meant for the elaboration of nanostructured, mesoporous silica-based materials through the sol-gel process in basic medium. Both the synthesis of the amphiphilic copolymers and their physico-chemical characterizations have evidenced that RITP fosters the synthesis of different categories of amphiphilic copolymers, while being a simple, cheap and robust technique

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13

Guillerm, Brieuc. "Synthèse et étude physico-chimique de copolymères amphiphiles à base de poly(2-méthyl-2-oxazoline)". Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20102/document.

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Ce travail de thèse décrit l'élaboration de copolymères amphiphiles obtenus par couplage de deux homopolymères. La synthèse des copolymères s'est effectuée en deux étapes. Dans un premier temps, des homopolymères de type poly(2-méthyl-2-oxazoline) (P(MOx)) et poly(acrylate de tert-butyle) (P(At-Bu)) ont été préparés par polymérisation par ouverture de cycle cationique (CROP) et par polymérisation radicalaire contrôlée de type RAFT ou ATRP, respectivement. Puis les copolymères amphiphiles diblocs ont finalement été obtenus par une réaction de couplage polymère-polymère de type cycloaddition de Huisgen. Une étude physico-chimique de ces copolymères dans l'eau a mis en évidence la présence d'agrégats qui présentent une morphologie sphérique, des tailles inférieures à 100 nm et des concentrations d'agrégation critique de l'ordre de 10-6 mol.L-1.Les connaissances acquises sur la synthèse et l'étude des copolymères à blocs amphiphiles ont également permis le développement de copolymères greffés amphiphiles poly(-caprolactone)-g-poly(2-méthyl-2-oxazoline) (PCL-g-P(MOx)), constitués d'un bloc hydrophobe PCL sur lequel des chaînes hydrophiles P(MOx) ont été greffées. L'étude du comportement de ces copolymères dans l'eau montre la formation d'agrégats avec des caractéristiques proches de celles obtenues pour les copolymères diblocs amphiphiles. Un autre point intéressant est que la P(MOx) permet de solubiliser la PCL dans l'eau.Ces deux études illustrent l'apport de la chimie macromoléculaire pour la préparation de structures amphiphiles parfaitement définies qui s'organisent en phase aqueuse en agrégats. Ces derniers pourraient notamment être utilisés dans le domaine biomédical
This manuscript deals with the synthesis of amphiphilic diblock copolymers obtained by the coupling of both hydrophobic and hydrophilic homopolymers. The copolymers were achieved in two steps. On the one hand, homopolymers poly(2-methyl-2-oxazoline) P(MOx)s and poly(tert-butyl acrylate)s (P(At-Bu) were synthesized by cationic ring opening polymerization (CROP) and by Reversible Addition-Fragmentation Transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP), respectively. Finally, amphiphilic diblock copolymers were achieved by Huisgen's cycloaddition. Physical chemistry studies in water proved the formation of aggregates. The latter had a spherical morphology, sizes below 100 nm and critical aggregation concentration around 10-6 mol.L-1.Knowledge acquired on the synthesis and the study of amphiphilic block copolymers led to the development of poly(-caprolactone)-g-poly(2-methyl-2-oxazoline) (PCL-g-P(MOx)) amphiphilic graft copolymers, made of a hydrophobic PCL grafted with hydrophilic P(MOx) moieties. The study of aqueous solution of such copolymers showed the formation of aggregates with characteristics close from those obtained for the diblock copolymers. Another interesting point is that P(MOx) permitted the solubilization of PCL in water.The reported work illustrated the importance of macromolecular chemistry for the obtaining of amphiphilic copolymers with controlled molecular weight and narrow molar mass distributions which self-assemble in water. Such kind of materials could be used in the biomedical field

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14

McMaster, Rebecca J. "A simple method towards 3D-printing and crosslinking partially hydrolysed poly(2-ethyl-2-oxazoline)". Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/109910/1/Rebecca_McMaster_Thesis.pdf.

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The two projects covered by this thesis represent advancements in the field of biofabrication. The first project was a proof-of-principle study focused on the development of a new polymer ink for 3D-printing. Scaffold structures were printed with a hydrophilic polymer and characterized to determine optimum printing parameters. Crosslinking strategies to create hydrogels with properties similar to human tissue were also explored. The second project was focused towards developing adipose grafts for soft tissue defects. Microfibre scaffolds were designed and 3D-printed with pores suitably sized for seeding with aggregates of human stem cells, and differentiated into fat tissue under in vitro conditions.

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15

Carmichael-Baranauskas, Anita Yvonne. "Synthesis of Amphiphilic Block Copolymers for Use in Biomedical Applications". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31737.

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The research presented in this thesis focuses on the synthesis of three amphiphilic block copolymer systems containing poly(ethylene oxide) (PEO) blocks. The polymer systems were developed for use in biomedical applications. The first of these is a series of poly(ethylene oxide-bÂ¬-oxazoline) (PEO-b-POX) diblock copolymers for use in the progress towards novel non-viral gene transfer vectors. Poly(ethylene oxide-bÂ¬-2-ethyl-2-oxazoline) (PEO-b-PEOX) and poly(ethylene oxide-bÂ¬-2-methyl-2-oxazoline) (PEO-b-PMOX) were investigated. The PEOX block was hydrolyzed with acid to form linear polyethylenimine (L-PEI). The polycation L-PEI is well known for its DNA binding efficiency but the water solubility of the resulting DNA/polymer complex is limited. Addition of a PEO block is directed towards the formation of a water dispersible DNA/copolymer complex. Dynamic light scattering of the PEO-b-PEOX and PEO-b-PEI block copolymers indicated that both systems existed as single chains in aqueous solution at pH 7. PEO copolymers also play a significant role in the formation of magnetic magnetite nanoparticles, which are dispersible in water at biological pH (pH =7). There is significant interest in the design of magnetic nanoparticle fluids for biomedical applications including magnetic field-directed drug delivery, magnetic cell separations, and blood purification. For use in vivo, the magnetite nanoparticles must be coated with biocompatible materials. Such polymers render the nanoparticles dispersible in water. Harris1 et al. synthesized PEO based, polyurethane triblocks with pendant carboxylic acid groups for use in formation of stable aqueous magnetic fluids. Building from this work, two polyurethane and polyurethaneurea systems were synthesized with 1300 g/mol PEOX and 2500 g/mol and PEOX2070 g/mol poly(ethylene oxide-co-propylene oxide) tailblocks, respectively. The PEO/PPO random copolymer contained about 25 weight percent PPO, and this disrupted the capacity of the PEO to crystallize. The PEOX based urethane triblocks were synthesized through reacting the tailblocks with the monomers for the center block whereas the PEO/PPO based polyurethaneurea was synthesized through forming the central urethane block with pendant acid groups first and then terminating the copolymer with the monofunctional copolymer. Terminal amine groups on the PEO/PPO tailblock afforded a triblock linked with two urea groups. The new polyurethanes with the PEOX tailblocks and the new polyurethaneurea with the PEO/PPO tailblocks could be utilized to efficiently stabilize magnetite nanoparticles in water.
Master of Science

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16

Lück, Steffen. "Monodisperse Microgels based on Poly(2-Oxazoline)s for Regenerative Cell Replacement Therapy". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-218782.

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17

Lübtow, Michael M. [Verfasser], Robert [Gutachter] Luxenhofer y Jürgen [Gutachter] Groll. "Structure-property relationships in poly(2-oxazoline)/poly(2-oxazine) based drug formulations / Michael M. Lübtow ; Gutachter: Robert Luxenhofer, Jürgen Groll". Würzburg : Universität Würzburg, 2020. http://d-nb.info/1206097825/34.

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18

Lorson, Thomas [Verfasser], Robert [Gutachter] Luxenhofer y Paul D. [Gutachter] Dalton. "Novel Poly(2-oxazoline) Based Bioinks / Thomas Lorson ; Gutachter: Robert Luxenhofer, Paul D. Dalton". Würzburg : Universität Würzburg, 2019. http://d-nb.info/1186632623/34.

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19

Le, fer Gaëlle. "Nouvelles architectures de polymères à base de poly(2-méthyl-2-oxazoline) pour l'élaboration de nanoparticules destinées à la vectorisation". Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1174.

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Ce sujet s'inscrit dans le domaine de la vectorisation de médicaments et de la nanomédecine, un domaine en pleine expansion. Les nanovecteurs destinés à la santé doivent être stables, non-toxiques et furtifs vis-à-vis du système immunitaire pour pouvoir circuler librement dans le sang. C'est pourquoi il est nécessaire d'élaborer des polymères pouvant former des nanoparticules possédant un caractère furtif. Le poly(acide lactique) (PLA) est un polyester hydrophobe et biodégradable couramment utilisé pour former des nanoparticules (NPs) capables d'encapsuler des composés apolaires. Le poly(2-méthyl-2-oxazoline) (PMeOx) est un polymère hydrophile, biocompatible et non toxique. Il peut être synthétisé par polymérisation cationique par ouverture de cycle (CROP), ce qui permet la préparation de polymères avec un bon contrôle de la masse molaire et une faible polymolécularité. Différentes architectures de copolymères PMeOx-co-PLA (di-,triblocs ou greffés) ont été développées en couplant la CROP et la chimie « clic ». Des NPs sont obtenues par nanoprécipitation de ces copolymères et caractérisées par un large éventail de techniques expérimentales dont, notamment, la diffusion dynamique de la lumière, la cryo-microscopie électronique à transmission, et la diffusion de neutrons aux petits angles. Ces techniques complémentaires ont permis de mettre en évidence l'obtention de NPs possédant des structures internes variées, telles que des polymersomes, des nanoparticules cœur-couronne ou multicouches. L'évaluation de la furtivité a été menée par l'étude de l'adsorption d'une protéine modèle, l'albumine de sérum bovin (BSA), sur la surface des nanoparticules. Enfin l'encapsulation de l'α-tocophérol et de quantum dots a démontré les nombreuses possibilités d'application de ces nouvelles NPs
This subject falls within the fields of drug delivery and nanomedecine, a topic of growing interest over the last years. Nanosystems dedicated to health must be stable, non-toxic and stealthy in the immune system in order to move freely in the blood. For this purpose, the design of elaborate polymers that can form stealthy nanoparticles is required. Poly(lactic acid) (PLA) is a hydrophobic and biodegradable polyester usually used to form nanoparticles able to encapsulate apolar compounds. Poly(2-methyl-2-oxazoline) (PMeOx) is a hydrophilic, biocompatible and non toxic polymer. PMeOx can be synthesized via cationic ring opening polymerization (CROP), which allows the design of polymers with a good control of the molecular weights and a low dispersity. Thus, in this context, we have developed several strategies to design different architectures of amphiphilic PMeOx-co-PLA copolymers such as di-, triblock or graft copolymers. Such strategies relied on the combined use of CROP and « click »chemistry ». Nanoparticles were obtained by nanoprecipitation, and characterized by a wide range of experimental techniques including dynamic light scattering, cryogenic transmission electron microscopy and small angle neutron scattering. These complementary approaches evidenced that nanoparticles could be obtained with a large variety of internal structure, such as polymersomes, core-shell or multilayer nanoparticles. The evaluation of the stealthiness was performed by considering the adsorption behavior of a model protein, bovin serum albumine (BSA), on the surface of the nanoparticles. The encapsulation of α-tocopherol and quantum dots demonstrated the numerous applicative possibilities offered by these new NPs

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20

Atilkan, Nurcan. "Investigation Of Thermal Characteristics Of A Series Polyoxazolines By Direct Pyrolysis Mass Spectrometry". Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613019/index.pdf.

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In the latest years, many studies especially on characterization and synthesis of polyoxazolines have been made. During these studies, new polyoxazolines such as poly(2-isopropyl-2-oxazoline) (PIPOX), poly(2-(3-butenyl)-2-oxazoline) (PBOX) and modified PBOX were synthesized. However, there has been no investigation on their thermal characteristics such as thermal stability and thermal degradation products. In this study, thermal degradation characteristics, thermal degradation products and thermal stability of PIPOX, PBOX and modified PBOX polymers PBOX-Perf, PBOX-Thiop, PBOX-Sug, PBOX-SP and PBOX-TP were investigated. In this study mercaptans 1H,1H,2H,2H-perfluoro-octanethiol, 3-mercapto-1,2 propanediol, thio-&beta
-D-glucose derivative and their mixture were used in PBOX modifications. The effect of modification of PBOX with different mercaptans on thermal characteristics was also analyzed. For the PIPOX, formations of protonated monomer and oligomers from dimer to heptamer were observed. However, when the isopropyl group changes with 3-butenyl group, protonated oligomers up to trimer were observed because the crosslinking formed during the polymerization of unsaturated butenyl inhibited the production of oligomers. In addition to this, thermal degradation at lower temperatures was observed. The change in thermal stability and thermal degradation products were observed as a result of modification of PBOX with different mercaptans. Unlike PBOX-Sug thermal degradation started at very low temperatures for PBOX-Thiop and PBOX-Perf. This degradation observed at lower temperatures disappeared for PBOX-SP and PBOX-TP. For PBOX-Perf, PBOX-Sug and PBOX- Thiop, decomposition of side chains at low temperatures and decomposition of the main chain at high temperatures were observed. Although the same thermal degradation behavior for PBOX-TP and PBOX-Thiop was expected, since PBOX-TP was obtained as a result of modification of PBOX with high amounts of mercaptan used in PBOX-Thiop and small amounts of mercaptan used in the PBOX-Perf, the results show that neither PBOX-Thiop nor PBOX-Perf thermal degradation behavior are dominant. This is also valid for PBOX-SP. PBOX-SP has higher thermal stability when compared to PBOX-Sug.

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21

Liebscher, [geb Blöhbaum] Julia [Verfasser] y Jürgen [Gutachter] Groll. "Side chain functional poly(2-oxazoline)s for biomedical applications / Julia Liebscher [geb. Blöhbaum] ; Gutachter: Jürgen Groll". Würzburg : Universität Würzburg, 2020. http://d-nb.info/1210427044/34.

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22

Gil, Alvaradejo Gabriela [Verfasser] y G. [Akademischer Betreuer] Delaittre. "New Functional Poly(2-alkyl-2-oxazoline)s and Alternatives to PEG in Protein Stabilization / Gabriela Gil Alvaradejo ; Betreuer: G. Delaittre". Karlsruhe : KIT-Bibliothek, 2018. http://d-nb.info/1162540826/34.

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23

Haigh, Jodie N. "Melt electrospinning writing as a method to form novel hydrogel architectures and constructs". Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/103849/1/Jodie_Haigh_Thesis.pdf.

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The addition of three-dimensional structure in hydrogels, and the first reported instance of melt electrospinning writing (MEW) of polypropylene, provides a foundation for the production of complex hydrogel systems for a variety of applications. This project provides a novel, facile and universal method to produce porous structures in soft hydrogels, using sacrificial templates produced via MEW. While the optimization of the MEW of polypropylene was completed elucidating methods to enable the production of MEW scaffolds with high melting point polymers.

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24

Chen, Alfred Yuen-Wei. "Synthesis and Functionalization of Poly(ethylene oxide-b-ethyloxazoline) Diblock Copolymers with Phosphonate Ions". Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23930.

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Poly(ethylene oxide) (PEO) and poly(2-ethyl-2-oxazoline) (PEOX) are biocompatible polymers that act as hydrophilic "stealth" drug carriers. As block copolymers, the PEOX group offers a wider variety of functionalization. The goal of this project was to synthesize a poly(ethylene oxide)-b-poly(2-ethyl-2-oxazoline) (PEO-b-PEOX) block copolymer and functionalize pendent groups of PEOX with phosphonic acid. This was achieved through cationic ring opening polymerization (CROP) of 2-ethyl-2-oxazoline monomer onto PEO. These polymerizations used tosylsulfonyl chloride as initiator. Size-exclusion chromatography (SEC) was used to determine the molecular weights of the block copolymers. Two samples of 1:2 and one sample of 1:3 of PEO-to-PEOX block copolymers were made. These samples underwent partial hydrolysis of the PEOX pendent groups to form the random block copolymer, poly(ethylene oxide)-b-poly(2-ethyl-2-oxazoline)-co-poly(ethyleneimine) (PEO-b-PEOX-co-PEI). These reactions showed that there was a degree of control based on the moles of acid. Diethyl vinyl phosphonate was attached to the nitrogen of PEI units via Michael addition where the phosphorylation left <1% of PEI units unattached. The ethyl groups on the phosphonates were further hydrolyzed off phosphonate with HCl acid leaving phosphonic acid. After each step of synthesis, structures and composition were confirmed using 1H NMR. Due to the nature of the phosphonic acid, the polymer can be utilized in the incorporation and release of cationic drugs.
Master of Science

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25

Hartlieb, Matthias Verfasser], Ulrich Sigmar [Akademischer Betreuer] [Schubert, Felix H. [Akademischer Betreuer] Schacher y Lorenz [Akademischer Betreuer] Meinel. "Poly(2-oxazoline)-based materials for biomedical applications / Matthias Hartlieb. Gutachter: Ulrich Sigmar Schubert ; Felix H. Schacher ; Lorenz Meinel". Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2015. http://d-nb.info/1077478194/34.

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26

Hartlieb, Matthias [Verfasser], Ulrich Sigmar [Akademischer Betreuer] Schubert, Felix H. [Akademischer Betreuer] Schacher y Lorenz [Akademischer Betreuer] Meinel. "Poly(2-oxazoline)-based materials for biomedical applications / Matthias Hartlieb. Gutachter: Ulrich Sigmar Schubert ; Felix H. Schacher ; Lorenz Meinel". Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2015. http://d-nb.info/1077478194/34.

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27

Petri, Christian [Verfasser]. "Synthesis and characterization of novel photocrosslinkable poly(2-oxazoline)-based hydrogel systems for the application as biosensor matrix / Christian Petri". Siegen : Universitätsbibliothek der Universität Siegen, 2018. http://d-nb.info/115709452X/34.

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28

Lück, Steffen [Verfasser], Rainer [Akademischer Betreuer] Jordan y Carsten [Gutachter] Werner. "Monodisperse Microgels based on Poly(2-Oxazoline)s for Regenerative Cell Replacement Therapy / Steffen Lück ; Gutachter: Carsten Werner ; Betreuer: Rainer Jordan". Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://d-nb.info/1125851015/34.

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29

Englert, Christoph [Verfasser], Ulrich Sigmar [Gutachter] Schubert, Thomas [Gutachter] Heinze y Stefan [Gutachter] Spange. "Cationic polymers made from poly(2-oxazoline)s for biomedical applications / Christoph Englert ; Gutachter: Ulrich Sigmar Schubert, Thomas Heinze, Stefan Spange". Jena : Friedrich-Schiller-Universität Jena, 2018. http://d-nb.info/1170398960/34.

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30

Huettner, Nick. "Developing hydrogel systems for Biofabrication". Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/126397/1/Nick_Huettner_Thesis.pdf.

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The two research projects cover the versatile applications of hydrogels in biofabrication. Hydrogels find application as synthetic matrices in bioprinting, can be easily modified with bioactive motifs and processed by robotic systems, enabling high-throughput screening (HTS) approaches. The first project targeted cellular response to cell adhesion peptides in poly(ethylene glycol)-based hydrogels. An upscalable platform using a robotic system was developed, enabling HTS of the peptide-modified hydrogel matrices, tailorable to different cell types. The second project aimed to develop a tailorable physical hydrogel for bioprinting, based on different architectures of a poly(2-oxazoline)-b-poly(2-oxazine) copolymer. Hydrogel properties were evaluated by rheology.

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31

Leiske, Meike Nicole [Verfasser], Ulrich Sigmar [Gutachter] Schubert, Felix H. [Gutachter] Schacher y Stefan [Gutachter] Spange. "Poly(2-oxazoline)s – synthesis, self-assembly and biomedical applications / Meike Nicole Leiske ; Gutachter: Ulrich Sigmar Schubert, Felix H. Schacher, Stefan Spange". Jena : Friedrich-Schiller-Universität Jena, 2018. http://d-nb.info/1170587305/34.

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32

Plet, Laëtitia. "Synthèse de nouveaux vecteurs cationiques à architecture en étoile pour le transfert de gènes". Electronic Thesis or Diss., Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2019SORUS297.pdf.

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Certaines maladies rares d’origine génétique, peuvent être traitées par une thérapie nommée « thérapie génique » qui consiste à introduire un polynucléotide (ADN ou ARN) à l’intérieur des cellules pour moduler leur activité dans un but thérapeutique. L’emploi d’un vecteur capable de protéger le polynucléotide et de le véhiculer jusqu’au noyau des cellules cibles est nécessaire. La polyéthylèneimine (PEI) est actuellement le polymère cationique de référence dans ce domaine. Cependant, en raison de sa toxicité importante, de nombreuses études visant à modifier la PEI sont toujours en cours pour améliorer ses propriétés. Entre autre, il a été montré que des architectures compactes conféraient de meilleures propriétés aux polymères. Dans ce contexte, des PEI en étoile ont été synthétisées pour la première fois. A cette fin, des précurseurs de poly(2-oxazoline)s en étoile ont été préparés et leur architecture a été confirmée par des analyses par chromatographie d’exclusion stérique et des études cinétiques. Des PEI de masse molaire (8, 16 et 25 K) et d’architecture (linéaire, à 3 et 4 branches) variables ont ensuite été obtenues par adaptation du protocole d’hydrolyse utilisé pour les polymères linéaires. La transfection de cellules CFBE et HepG2 par des polyplexes à base d’ADNp et de ces polymères a été évaluée. L’influence de la masse molaire et de l’architecture a été étudiée. Pour finir, la modification de ces PEI par des résidus histidine connus pour améliorer l’efficacité de transfection des lPEI a été réalisée avec succès. La synergie espérée entre les modifications chimique et architecturale n’a pas été observée pour la transfection des cellules HepG2 in vitro
Some rare diseases of genetic origin can be treated by a therapy called "gene therapy" which consists in introducing a polynucleotide (DNA or RNA) into the cells to modulate their activity for therapeutic purposes. The use of a vector able to protect the polynucleotide and to transport it to the nucleus of the target cells is necessary. Polyethyleneimine (PEI) is currently the cationic polymer gold standard in this field. However, due to its high toxicity, many studies aiming to modify PEI are still underway to improve its properties. Among other things, it has been shown that compact architectures give better properties to polymers. In this context, star PEI were synthesized for the first time. To this end, star poly(2-oxazoline)s precursors were prepared and their architecture was confirmed by steric exclusion chromatography analyses and kinetic studies. PEI of variable molar mass (8, 16 and 25 K) and architecture (linear, 3 and 4 arms star) were then obtained by adapting the hydrolysis protocol used for linear polymers. The transfection of CFBE and HepG2 cells with polyplexes based on pDNA and these polymers was evaluated. The influence of molar mass and architecture was studied. Finally, the modification of these PEI with histidine moieties known to increase lPEI transfection efficiency was successfully achieved, however, the expected synergy between the chemical and architectural modifications was not observed for the in vitro transfection of HepG2 cells

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33

Tauhardt, Lutz Verfasser], Ulrich Sigmar [Akademischer Betreuer] [Schubert y Dagmar [Akademischer Betreuer] Fischer. "Poly(2-oxazoline)s and their derivatives : a versatile polymer class with manifold application possibilities / Lutz Tauhardt. Gutachter: Ulrich Sigmar Schubert ; Dagmar Fischer". Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2015. http://d-nb.info/1067098801/34.

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34

Tauhardt, Lutz [Verfasser], Ulrich Sigmar [Akademischer Betreuer] Schubert y Dagmar [Akademischer Betreuer] Fischer. "Poly(2-oxazoline)s and their derivatives : a versatile polymer class with manifold application possibilities / Lutz Tauhardt. Gutachter: Ulrich Sigmar Schubert ; Dagmar Fischer". Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2015. http://d-nb.info/1067098801/34.

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35

Adam, Stefan. "Entwicklung von neuartigen thermoresponsiven Oberflächenbeschichtungen auf der Basis von Poly-2-oxazolinen". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-211563.

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Im Rahmen dieser Arbeit wurden für die Herstellung neuartiger funktioneller Oberflächenbeschichtungen Polymerbürstensysteme basierend auf linearen, thermoresponsiven Poly-2-oxazolinen (POX) entwickelt und ausführlich charakterisiert. Als Grundbaustein für die Herstellung von POX-Bürsten wurden drei endfunktionalisierte thermoresponsive POX mittels kationisch ringöffnender Polymerisation synthetisiert, wobei jeweils 2-Cyclopropyl-2-oxazolin (cPrOX) als thermoresponsive Wiederholungseinheit und 2-Methyl-2-oxazolin (MeOX) als hydrophiles Comonomer zu verschiedenen Anteilen verwendet wurden. Mittels VIS-spektroskopischen Trübungsmessungen wurde für alle POX in Wasser ein LCST-Entmischungsverhalten mit einem reversiblen und scharfen Phasenübergang nachgewiesen, wobei die Trübungstemperaturen stark von der Polymerhydrophilie sowie der Molmasse und der Polymerkonzentration in Lösung abhingen. Die Herstellung der POX-Polymerbürsten auf der Basis der synthetisierten POX erfolgte über einen „grafting to“-Ansatz, bei welchem die Polymere in einem thermisch initiierten Prozess über ein funktionalisiertes Kettenende kovalent an ein Substrat angebunden wurden. Als Hauptmethode zur Charakterisierung der physikochemischen Eigenschaften der hergestellten Schichten, insbesondere deren temperaturabhängiges Schaltverhalten in Wasser, wurde spektroskopische Ellipsometrie verwendet. Zusätzlich kamen Rasterkraftmikroskopie, Kontaktwinkel und Quarzkristallmikrowaage mit Dissipationsaufzeichnung zum Einsatz. Im Gegensatz zum sehr scharfen, diskontinuierlichen Phasenübergang der POX in Lösung konnte für alle POX-Bürsten ein kontinuierlicher Übergang von einem gestreckten Bürstenzustand bei niedrigen Temperaturen in einen kollabierten Zustand bei hohen Temperaturen bestimmt werden, wobei das Quellvermögen und die temperaturabhängigen Quellkurvenverläufe durch die Polymereigenschaften und die Bürstenparameter beeinflussbar waren. Durch die Kombination eines POX mit Polyacrylsäure (PAA) als zweite Komponente konnten zudem neuartige binäre Polymerbürstensysteme hergestellt werden, welche ein komplexes pH- und temperaturabhängiges Schaltverhalten sowie ein steuerbares Proteinadsorptionsvermögen in Abhängigkeit von der Bürstenpräparationsmethodik, der POX-PAA-Zusammensetzung sowie der Temperatur und dem pH-Wert der umgebenden Pufferlösung aufwiesen. Zur ausführlichen Charakterisierung der Schichteigenschaften wurde neben den bereits benannten Methoden der spektroskopischen Ellipsometrie, Rasterkraftmikroskopie und der Kontaktwinkelmessung auch Röntgenphotoelektronenspektroskopie genutzt. Abschließende Zelladhäsionsexperimente mit humanen mesenchymalen Stammzellen auf den bürstenmodifizierte Oberflächen unter physiologischen Bedingungen offenbarten deutliche Unterschiede in der Affinität der Zellen zur Adhäsion auf POX-Homopolymerbürsten in Abhängigkeit der Bürstenhydrophilie. Darüber hinaus konnte die Zelladhäsion auch auf POX-PAA-Mischbürstensystemen gesteuert werden.

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36

Delecourt, Gwendoline. "Synthèse de nanoparticules monoplasmidiques pour le transfert de gènes". Electronic Thesis or Diss., Sorbonne université, 2021. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2021SORUS002.pdf.

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Depuis le XXème siècle, la thérapie génique ouvre la voie au traitement de maladies d’origine génétique et de maladies acquises. L’introduction d’un polynucléotide dans les cellules présentant une mutation génétique permet de moduler leur fonctionnement. Afin de passer les différentes barrières biologiques et de rejoindre le noyau des cellules ciblées, l’ADN doit être protégé par un vecteur. Divers vecteurs ont été développés tels que les vecteurs polymériques à base de PEI. Malgré leur efficacité, ces vecteurs montrent des réactions immunogènes. Des fonctionnalisations sont développées pour réduire cette toxicité notamment par la formation de vecteurs furtifs. La stratégie standard de PEGylation montre, cependant, des limites nécessitant l’utilisation de nouveaux polymères hydrophiles. Dans ce contexte, la POxylation a été étudiée comme alternative à la PEGylation pour le design de nouveaux polyplexes. Une nouvelle méthode de synthèse de copolymères PEI-b-POx par hydrolyse sélective de copolymères à blocs poly(2-R1-2-oxazoline-b-2-R2-2-oxazoline) a été mise au point ainsi que la fonctionnalisation par des résidus histidine pour améliorer l’efficacité de transfection et diminuer la toxicité du vecteur polymère. Un ligand galactose a été greffé en fin de chaîne hydrophile pour induire un ciblage cellulaire. Les polymères synthétisés ont été utilisés pour former des polyplexes avec l’ADN via une méthode de formulation « par extrusion » avant de réaliser des tests de transfection in vitro et in vivo. Une réduction de la cytotoxicité a été observée lors de l’utilisation des copolymères PEI-b-POx en comparaison aux PEI tout en conservant une efficacité de transfection
Since 20th century, breakthrough in gene therapy paves the way for new therapeutic strategies against genetic disorders, cancers and neurodegenerative diseases. Cells with genetic mutation may have their cellular machinery modulated via the introduction of polynucleotides in their nucleus. Nevertheless, DNA needs to be protected by a vector to cross biological barriers and to reach targeted cell nucleus. Various types of vectors have been developed like PEI-based vectors. However, those efficient polymeric vectors exhibit a toxicity which can be lowered by PEG functionalization. Nevertheless, the well-known PEGylation approach shows limits requiring news hydrophilic polymers. In this context, POxylation was studied as PEG alternatives in the design of new pDNA containing nanovectors. A new synthetic strategy was developed with a selective hydrolysis of block poly(2-R1-2-oxazoline-b-2-R2-2-oxazoline) copolymers. The functionalization of the synthetized PEI-b-POx copolymers with histidine moieties was achieved, along with galactose grafting to induce cellular targeting or histidine grafting to improve endosomal escape. These polymers were used to form polyplexes with DNA via extrusion method and further biological testing via in vitro and in vivo transfection essays were performed. An efficient transfection was obtained with a reduction of the cytotoxicity for PEI-b-POx copolymers compared to PEI

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37

Lorson, Thomas. "Novel Poly(2-oxazoline) Based Bioinks". Doctoral thesis, 2019. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-180514.

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Motivated by the great potential which is offered by the combination of additive manufacturing and tissue engineering, a novel polymeric bioink platform based on poly(2 oxazoline)s was developed which might help to further advance the young and upcoming field of biofabrication. In the present thesis, the synthesis as well as the characteristics of several diblock copolymers consisting of POx and POzi have been investigated with a special focus on their suitability as bioinks. In general, the copolymerization of 2-oxazolines and 2-oxazines bearing different alkyl side chains was demonstrated to yield polymers in good agreement with the degree of polymerization aimed for and moderate to low dispersities. For every diblock copolymer synthesized during the present study, a more or less pronounced dependency of the dynamic viscosity on temperature could be demonstrated. Diblock copolymers comprising a hydrophilic PMeOx block and a thermoresponsive PnPrOzi block showed temperature induced gelation above a degree of polymerization of 50 and a polymer concentration of 20 wt%. Such a behavior has never been described before for copolymers solely consisting of poly(cyclic imino ether)s. Physically cross linked hydrogels based on POx b POzi copolymers exhibit reverse thermal gelation properties like described for solutions of PNiPAAm and Pluronic F127. However, by applying SANS, DLS, and SLS it could be demonstrated that the underlying gel formation mechanism is different for POx b POzi based hydrogels. It appears that polymersomes with low polydispersity are formed already at very low polymer concentrations of 6 mg/L. Increasing the polymer concentration resulted in the formation of a bicontinuous sponge like structure which might be formed due to the merger of several vesicles. For longer polymer chains a phase transition into a gyroid structure was postulated and corresponds well with the observed rheological data. Stable hydrogels with an unusually high mechanical strength (G’ ~ 4 kPa) have been formed above TGel which could be adjusted over a range of 20 °C by changing the degree of polymerization if maintaining the symmetric polymer architecture. Variations of the chain ends revealed only a minor influence on TGel whereas the influence of the solvent should not be neglected as shown by a comparison of cell culture medium and MilliQ water. Rotationally as well as oscillatory rheological measurements revealed a high suitability for printing as POx b POzi based hydrogels exhibit strong shear thinning behavior in combination with outstanding recovery properties after high shear stress. Cell viability assays (WST-1) of PMeOx b PnPrOzi copolymers against NIH 3T3 fibroblasts and HaCat cells indicated that the polymers were well tolerated by the cells as no dose-dependent cytotoxicity could be observed after 24 h at non-gelling concentrations up to 100 g/L. In summary, copolymers consisting of POx and POzi significantly increased the accessible range of properties of POx based materials. In particular thermogelation of aqueous solutions of diblock copolymers comprising PMeOx and PnPrOzi was never described before for any copolymer consisting solely of POx or POzi. In combination with other characteristics, e.g. very good cytocompatibility at high polymer concentrations and comparably high mechanical strength, the formed hydrogels could be successfully used for 3D bioprinting. Although the results appear promising and the developed hydrogel is a serious bioink candidate, competition is tough and it remains an open question which system or systems will be used in the future
Motiviert durch das große Potential, das die Kombination aus additiver Fertigung und künstlicher Geweberegeneration bietet, wurde eine neuartige polymerbasierte Biotintenplattform auf Basis von Poly(2 oxazolin)en entwickelt. Diese soll zukünftig dazu beitragen das noch junge, aber aufstrebende Forschungsfeld der Biofabrikation weiterzuentwickeln. In der vorliegenden Arbeit wurden die Synthese sowie die Eigenschaften von mehreren Diblock Copolymeren, bestehend aus POx und POzi, untersucht, wobei der Hauptfokus auf deren Eignung als Biotinte lag. Grundsätzlich konnte gezeigt werden, dass Copolymere, bestehend aus 2 Oxazolinen und 2 Oxazinen, die unterschiedliche Alkylseitenketten besitzen, synthetisiert werden können. Dabei lagen die ermittelten Polymerisationsgrade nahe am zuvor errechneten Wert. Die Polymere wiesen mittlere bis niedrigere Dispersitäten auf. Für jedes der im Rahmen der vorliegenden Arbeit synthetisierten Diblock Copolymere konnte eine mehr oder weniger starke Abhängigkeit der dynamischen Viskosität von der Temperatur gezeigt werden. Allerdings ist es nicht möglich, aus den thermischen Eigenschaften des Bulkmaterials Rückschlüsse auf das temperaturabhängige Verhalten in Lösung zu ziehen. Diblock Copolymere mit einem hydrophilen PMeOx Block und einem thermoresponsiven PnPrOzi Block bildeten oberhalb einer Kettenlänge von 50 Einheiten und einer Polymerkonzentration von 20 Gew% ein physikalisches Gel. Solch ein Verhalten wurde bisher noch nicht für Copolymere, die ausschließlich auf POx oder seinen höheren Homologen basieren, beschrieben. Physikalische Hydrogele, basierend auf POx b POzi Copolymeren, weisen eine umgekehrte thermische Gelierung wie auch wässrige Lösungen von PNiPAAm und Pluronic F127 auf. Allerdings konnte durch die komplementäre Verwendung von SANS, DLS und SLS gezeigt werden, dass sich der zugrundeliegende Gelbildungsmechanismus für POx b POzi basierte Hydrogele deutlich von den beiden zuvor genannten unterscheidet. Es wird davon ausgegangen, dass sich zunächst bei einer sehr geringen Polymerkonzentration von 6 mg/L Vesikel mit geringer Polydispersität ausbilden. Eine Erhöhung der Konzentration resultiert in der Ausbildung eines bikontinuierlichen Netzwerks mit schwammartiger Struktur. Dieses bildet sich vermutlich durch die Fusion mehrerer Vesikel. Des Weiteren wird für höhere Polymerisationsgrade ein Phasenübergang zu einer gyroidalen Struktur postuliert der sich sehr gut mit den gewonnenen rheologischen Daten deckt. Stabile Hydrogele mit außergewöhnlich hoher mechanischer Stärke (G‘ ≈ 4kPa) bildeten sich oberhalb der Tgel, die über eine Temperaturspanne von 20 °C durch Änderung des Polymerisationsgrades eingestellt werden konnte. Veränderung der Kettenenden zeigten nur einen geringen Einfluss auf die TGel, wobei der Einfluss des verwendeten Lösemittels nicht unterschätzt werden sollte. Dies konnte durch den direkten Vergleich von MilliQ Wasser und Zellkulturmedium gezeigt werden. Rheologische Untersuchungen, die sowohl im rotierenden als auch im oszillierenden Modus durchgeführt wurden, zeigten eine gute Eignung der POx b POzi basierten Hydrogele für Extrusion basierte Druckverfahren. Insbesondere aufgrund des stark ausgeprägten scherverdünnenden Verhaltens und der ausgezeichneten Strukturerholung nach hoher Scherbelastung sollten gute Druckergebnisse erzielbar sein. Zellviabilität-Assays (WST-1) von PMeOx b PnPrOzi Copolymeren an NIH 3T3 Fibroblasten und HaCat-Zellen zeigten, dass die Polymere bei Konzentrationen von bis zu 100 g/L und Inkubationszeiten von 24 h keine dosisabhängige Zytotoxizität besitzen. Zusammenfassend kann festgehalten werden, dass die Copolymerisation von POx und POzi den verfügbaren Eigenschaftsbereich von POx basierten Materialien deutlich vergrößert hat. Insbesondere die temperaturinduzierte Gelierung von wässrigen Polymerlösungen wurde noch nie zuvor für ein anderes Copolymer auf Basis von POx und POzi beschrieben. Aufgrund ihrer herausragenden Eigenschaften, wozu unter anderem eine sehr gute Zytokompatibilität bei hohen Polymerkonzentrationen und eine vergleichsweise hohe mechanische Festigkeit zählen, konnten die entwickelten Hydrogele erfolgreich für den 3D Biodruck verwendet werden. Obwohl die beschriebenen Ergebnisse sehr vielversprechend sind und die entwickelte Hydrogelplattform folglich als ernstzunehmender Biotintenkandidat angesehen werden sollte, ist die Konkurrenz sehr groß und es bleibt abzuwarten, welche Tinte bzw. Tinten in Zukunft zum Einsatz kommen

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38

Lübtow, Michael M. "Structure-property relationships in poly(2-oxazoline)/poly(2-oxazine) based drug formulations". Doctoral thesis, 2020. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-193387.

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According to estimates, more than 40% of all new chemical entities developed in pharmaceutical industry are practically insoluble in water. Naturally, the demand for excipients which increase the water solubility and thus, the bioavailability of such hydrophobic drugs is enormous. Poly(2-oxazoline)s (POx) are currently intensively discussed as highly versatile class of biomaterials. Although selected POx based micellar drug formulations exhibit extraordinarily high drug loadings > 50 wt.% enabling high anti-tumor efficacies in vivo, the formulation of other hydrophobic compounds has failed. This casts doubt on the general understanding in which a hydrophobic active pharmaceutical ingredient is dissolved rather unspecifically in the hydrophobic core of the micelles following the fundamental concept of “like dissolves like”. Therefore, a closer look at the interactions between all components within a formulation becomes increasingly important. To do so, a large vehicle platform was synthesized, loaded with various hydrophobic drugs of different structure, and the formulations subsequently characterized with conventional and less conventional techniques. The obtained in-depth insights helped to develop a more thorough understanding about the interaction of polymer and incorporated API finally revealing morphologies deviating from a classical core/shell structure. During these studies, the scarcely investigated polymer class of poly(2-oxazine)s (POzi) was found as promising drug-delivery vehicle for hydrophobic drugs. Apart from this fundamental research, the anti-tumor efficacy of the two APIs curcumin and atorvastatin has been studied in more detail. To increase the scope of POx and POzi based formulations designed for intravenous administration, a curcumin loaded hydrogel was developed as injectable drug-depot
Schätzungen zufolge sind mehr als 40% aller „new chemical entities“, welche in der pharmazeutischen Industrie entwickelt werden, wasserunlöslich. Aus diesem Grund ist der Bedarf an Zusatzstoffen, welche die Wasserlöslichkeit und dadurch die Bioverfügbarkeit erhöhen, enorm. Poly(2-oxazolin)e (POx) werden derzeitig intensiv als vielseitig einsetzbare Biomaterialien untersucht. Obwohl bestimmte POx basierte, mizellare Wirkstoffformulierungen außergewöhnlich hohe Beladungskapazitäten > 50 Gew.% aufwiesen und dadurch ausgeprägte anti-Tumor Effektivität in vivo ermöglichten, schlug die Formulierung anderer hydrophober Stoffe fehl. Dies lässt Zweifel an dem altbewährten Konzept aufkommen, in welchem hydrophobe Arzneistoffe mehr oder weniger unspezifisch im hydrophoben Kern einer Mizelle gelöst werden. Aus diesem Grund ist ein genauerer Blick auf die Interaktionen zwischen allen Bestandteilen einer Formulierung vonnöten. Deshalb wurde eine große Polymerplattform synthetisiert, mit verschiedenen hydrophoben Wirkstoffen unterschiedlicher Struktur beladen und die Formulierungen im Anschluss mit herkömmlichen und weniger herkömmlichen Methoden charakterisiert. Die daraus erhaltenen Einblicke ermöglichten es ein umfassenderes Verständnis über die Interaktionen von Polymer und Wirkstoff zu entwickeln. Innerhalb dieser Studien wurden Aggregate charakterisiert, welche von einer klassischen Kern/Schale Morphologie abwichen. Des Weiteren konnte die kaum erforschte Polymerklasse der Poly(2-oxazin)e (POzi) als vielversprechende Wirkstoffträgerplattform für hydrophobe Wirkstoffe charakterisiert werden. Von dieser Grundlagenforschung abgesehen, wurde die anti-Tumor Effektivität von Curcumin und Atorvastatin Nanoformulierungen untersucht. Um den Anwendungsbereich der POx und POzi basierten Wirkstoffformulierungen, welche für intravenöse Verabreichung entwickelt wurden, zu erweitern, wurde ein Curcumin beladenes Hydrogel als injizierbares Wirkstoffdepot entwickelt

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39

Fan, Kuo-Rung y 范國榮. "Enzymatic Degradation Behaviour of Poly(2-ethyl-2-oxazoline)/Poly(L-lactide) Triblock Copolymers". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/35357691860129696331.

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碩士
國立清華大學
化學工程學系
91
In this study, ABA triblock copolymers consisting of poly(L-lactide) (PLLA) A block and poly(2-ethyl-2-oxazoline) (PEOz) B block are synthesized. By controlling inlet ratio of L-lactide and 2-ethyl-2-oxazoline, triblock copolymers with various amphiphilicity can be obtained. Afterward, casting polymer films are degraded in the presence of proteinase K. During degradation, the composition and properties of films and degradation residues are analyzed in detail, respectively. The purpose is to investigate the degradation behavior of these polymers thoroughly. In addition, by virtue of unique microphase separation of triblock copolymer and the distinct amphiphilicity between PEOz and PLLA, we expect one of the blocks can be removed quickly by enzymatic degradation, and left the highly-ordered nanostructure. Therefore, on one hand the weight and water absorption change of films are weighed. The rate of weight loss is proportioned to water absorption. The molecular weight and molecular weight distribution are determined by gel permeation chromatography, and it shows degradation prefer lower molecular weight polymers in the beginning. Furthermore, according to 1H nuclear magnetic resonance analysis, the weight loss in early stage is mainly attributed to PEOz, and then PEOz and PLLA are washed away at fixed proportion. And the surface and cross section morphology are observed by scanning electronic microscope. The result shows there are different morphology changes between the film surface that contacts air and that contacts Teflon mold. The air side of films is more degradable than Teflon side, and it would generate lots of porous microspheres on the surface. Last, the increase of crystallinity and recrystallization phenomena that reduce degradation rate are observed by differential scanning calorimetry. On the other hand, the analysis of degradation residues shows it consists of particles dispersed in solution that comprise PEOz and poly(ethyleneimine) (PEI) copolymers and PLLA oligomers and monomers dissolved in solution. Based on the results, a mechanism of enzymatic degradation is proposed that the degradation behavior of PLLA-PEOz-PLLA triblock copolymer displays as two stages. In the first stage, the loss of PEOz-dominant segments forms particles dispersed in solution, and results in porous films. And in the second stage, enzyme permeates films via these pores makes the loss of a large number PLLA of which oligomers and monomers dissolved in solution, and makes films with uniform pores. Therefore, we provide a point of view which takes degradation residues into consideration to evaluate the properties in application and to solve the encountered problems of this biodegradable polymer. Besides, the highly-ordered erosion film may provide a economic and convenient way to produce scaffold in tissue engineering and photonic crystal in drug delivery or other applications.

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Zhang, Ning [Verfasser]. "Molecular brushes of poly(2-oxazoline)s / Ning Zhang". 2010. http://d-nb.info/1008986496/34.

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Liebscher, [geb Blöhbaum] Julia. "Side chain functional poly(2-oxazoline)s for biomedical applications". Doctoral thesis, 2020. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-203960.

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The aim of the thesis was to develop water soluble poly(2-oxazoline) (POx) copolymers with new side group functionalities, which can be used for the formation of hydrogels in biomedical applications and for the development of peptide-polymer conjugates. First, random copolymers of the monomer MeOx or EtOx with ButEnOx and EtOx with DecEnOx were synthesized and characterized. The vinyl functionality brought into the copolymer by the monomers ButEnOx and DecEnOx would later serve for post-polymerization functionalization. The synthesized copolymers were further functionalized with thiols via post-polymerization functionalization using a newly developed synthesis protocol or with a protected catechol molecule for hydrogel formation. For the formation of peptide-polymer conjugates, a cyclic thioester, namely thiolactone acrylamide and an azlactone precursor, whose synthesis was newly developed, were attached to the side chain of P(EtOx-co-ButEnOx) copolymers. The application of the functionalized thiol copolymers as hydrogels using thiol-ene chemistry for cross-linking was demonstrated. The swelling behavior and mechanical properties were characterized. The hydrophilicity of the network as well as the cross-linking density strongly influenced the swelling behavior and the mechanical strength of the hydrogels. All hydrogels showed good cell viability results. The hydrogel networks based on MeOx and EtOx were loaded with two dyes, fluorescein and methylene blue. It was observed that the uptake of the more hydrophilic dye fluorescein depended more on the ability of the hydrogel to swell. In contrast, the uptake of the more hydrophobic dye methylene blue was less dependent on the swelling degree, but much more on the hydrophilicity of the network. For the potential application as cartilage glue, (biohybrid) hydrogels were synthesized based on the catechol-functionalized copolymers, with and without additional fibrinogen, using sodium periodate as the oxidizing agent. The system allowed for degradation due to the incorporated ester linkages at the cross-linking points. The swelling behavior as well as the mechanical properties were characterized. As expected, hydrogels with higher degrees of cross-linking showed less swelling and higher elastic modulus. The addition of fibrinogen however increased the elasticity of the network, which can be favorable for the intended application as a cartilage glue. Biological evaluation clearly demonstrated the advantage of degradable ester links in the hydrogel network, where chondrocytes were able to bridge the artificial gap in contrast to hydrogels without any ester motifs. Lastly, different ways to form peptide-polymer conjugates were presented. Peptides were attached with the thiol of the terminal cysteine group to the vinyl side chain of P(EtOx-co-ButEnOx) copolymers by radical thiol-ene chemistry. Another approach was to use a cyclic thioester, thiolactone, or an azlactone functionality to bind a model peptide via native chemical ligation. The two latter named strategies to bind peptides to POx side chains are especially interesting as one and in the case of thiolactone two free thiols are still present at the binding site after the reaction, which can, for example, be used for further thiol-ene cross-linking to form POx hydrogels. In summary, side functional poly(oxazoline) copolymers show great potential for numerous biomedical applications. The various side chain functionalities can be introduced by an appropriate monomer or by post-polymerization functionalization, as demonstrated. By their multi-functionality, hydrogel characteristics, such as cross-linking degree and mechanical strength, can be fine-tuned and adjusted depending on the application in the human body. In addition, the presented chemoselective and orthogonal reaction strategies can be used in the future to synthesize polymer conjugates, which can, for example, be used in drug delivery or in tissue regeneration
Das Ziel der Arbeit war es, wasserlösliche Poly(2-oxazolin) (POx) Copolymere mit neuen Seitenkettenfunktionalitäten zu entwickeln, welche zur Synthese von Hydrogelen für biomedizinische Anwendungen und zur Entwicklung von Peptid-Polymer Konjugaten genutzt werden können. Zunächst wurden Copolymere aus den Monomeren MeOx oder EtOx mit ButEnOx und EtOx mit DecEnOx synthetisiert und anschließend charakterisiert. Die Monomere wurden statistisch miteinander copolymerisiert, indem sie zusammen zum Start der Reaktion in das Reaktionsgefäß gegeben wurden. Die Vinyl Funktionalität, die durch die Monomere ButEnOx und DecEnOx eingebracht wurde, kann später zur nachträglichen Funktionalisierung am Polymer verwendet werden. Die synthetisierten Copolymere wurden weiterhin mit Thiolen oder mit funktionellen Catecholgruppen ausgestattet, um Hydrogele herzustellen. Um Peptid-Polymer Konjugate zu bilden, wurden zyklische Thioester, genauer Thiolacton acrylamid und ein Azlacton Präkursor, dessen Synthese neu entwickelt wurde, an die Seitenkette von P(EtOx-co-ButEnOx) Copolymere angebunden. Im Folgenden wurde die Anwendung der thiol funktionalisierten Copolymere als Hydrogele, welche mittels radikalischer Thiol-ene Chemie vernetzt wurden, präsentiert. Das Quellverhalten und die mechanischen Eigenschaften wurden analysiert. Sowohl die Hydrophilie des Netzwerkes als auch die Vernetzungsdichte beeinflusste das Quellverhalten und die mechanische Festigkeit stark. Alle Hydrogele zeigten gute Zellverträglichkeit. Die Hydrogele basierend auf MeOx und EtOx wurden außerdem mit den Farbstoffen Fluorescein und Methylenblau beladen. Es wurde beobachtet, dass von den beiden Farbstoffen die Aufnahme des hydrophileren Farbstoffs Fluorescein stärker vom Quellungsgrad des Hydrogels abhing. Hingegen war die Aufnahme des hydrophoberen Farbstoffs Methylenblau weniger davon abhängig wie sehr das Hydrogel quellen konnte, sondern stärker von der Hydrophilie des Hydrogel-Netzwerkes. Um die potenzielle Anwendung als Knorpelkleber zu testen, wurden (biohybrid) Hydrogele basierend auf Catechol-funktionalisiertem Copolymeren mit und ohne zusätzliches Fibrinogen und dem Oxidationsmittel Natriumperiodat hergestellt. Das System war durch die eingebauten Ester Vernetzungspunkte abbaubar. Das Quellverhalten und die mechanischen Eigenschaften wurden charakterisiert. Wie zu erwarten, zeigten Hydrogele mit stärkerer Vernetzung eine geringe Quellung und einen höheren elastischen Modulus. Die Zugabe von Fibrinogen jedoch erhöhte die Elastizität des Netzwerkes, welches förderlich für die avisierte Anwendung als Knorpelkleber sein kann. Die biologische Auswertung zeigte, dass die Ester-haltigen, abbaubaren Vernetzungspunkte von großem Vorteil sind. Die Chondrozyten konnten ohne Probleme den Defektspalt überbrücken, was nicht möglich war, sobald keine Ester Funktionalitäten im Hydrogel eingebunden waren. Zuletzt wurden verschiedene Möglichkeiten Peptid-Polymer Konjugate zu synthetisieren präsentiert. Zum einen wurden Peptide mit der Thiolgruppe des endständigen Cysteins an die Vinyl Seitenkette der P(EtOx-co-ButEnOx) Copolymere mittels radikalischer Thiol-en Chemie angebunden. Des Weiteren wurde ein zyklischer Thioester, das Thiolacton, und eine Azlacton Funktionalität verwendet, um ein Modell Peptid mittels nativer chemischer Ligation zu binden. Die zwei zuletzt genannten Strategien, um Peptide an Polymere zu binden, sind besonders interessant, da hier ein beziehungsweise im Fall der Thiolacton Funktionalität zwei freie Thiole an der Bindungsstelle nach der Reaktion entstehen. Diese könnten genutzt werden, um zum Beispiel über Thiol-en Chemie Peptid-haltige Hydrogele herzustellen. Zusammenfassend zeigen seitenkettenfunktionale Poly(oxazolin) Copolymere ein großes Potenzial für biomedizinische Anwendungen. Die vielen verschiedenen Seitenkettenfunktionalitäten können durch das passende Monomer oder durch Post-Polymerisationsfunktionalisierung eingebracht werden, wie in dieser Arbeit gezeigt. Durch ihre Multifunktionalität können Hydrogel Charakteristika, wie der Vernetzungsgrad und die mechanische Festigkeit, fein eingestellt und angepasst werden, je nach Anwendungsbereich im menschlichen Körper. Die entwickelten chemoselektiven und orthogonalen Reaktionswege können in der Zukunft genutzt werden, um Polymer Konjugate zu synthetisieren, welche zum Beispiel für das Drug Delivery oder im Bereich der Geweberegneration zum Einsatz kommen

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42

Aljeban, Norah. "Synthesis and Characterization of Novel Amphiphilic Diblock Copolymers Poly (2-Ethyl-2-Oxazoline)-b-Poly (Vinylidene Fluoride)". Thesis, 2021. http://hdl.handle.net/10754/669889.

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Poly (2-ethyl-2-oxazoline)-based amphiphilic diblock copolymer has the potential to form promising membrane materials for water purification due to the thermal stability and good solubility in aqueous solution and also for gas separation because of the presence of polar amide group along the polymer backbone. Moreover, their self-assembly into micelles renders them candidate materials as nanocarriers for drug delivery applications. In this study, a novel well-defined linear PEtOx-based amphiphilic diblock copolymer with a hydrophobic fluoropolymer, i.e., PVDF, have been successfully synthesized by implementing a synthesis methodology that involves the following four steps. In the first step, poly (2-ethyl-2-oxazoline) (PEtOx) was synthesized via living cationic ring-opening polymerization (LCROP) of 2-ethyl-2-oxazoline (EtOx) monomer. The “living” nature of LCROP allows the desirable termination to occur by using the proper termination agent, namely, water, to achieve the polymer with a terminal hydroxyl group, i.e., PEtOx-OH. The hydroxyl end group in PEtOx-OH was converted to PEtOx-Br using 2-bromopropionyl bromide via an esterification reaction. In the third step, the PEtOx-Br macro-CTA was subsequently reacted with potassium ethyl xanthate to insert the necessary RAFT agent via nucleophilic substitution reaction to obtain PEtOx-Xanthate. It s worth mentioning that this step is vital for the sequential addition of the second block via the RAFT polymerization reaction of fluorinated monomer, i.e., VDF, to finally obtain the well-defined amphiphilic diblock copolymer with variable controlled chain lengths. Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR) and Fourier Transform Infrared Spectroscopy (FT-IR) confirmed the structure of the macroinitiator and final copolymer, respectively. Size Exclusion Chromatography (SEC) determined the number-average molecular weight (Mn) and the polydispersity index (PDI) of the obtained copolymer. Furthermore, the polymorphism of the diblock copolymer characterized by X-Ray Diffraction (XRD) indicated that the copolymer displays the electroactive α-phase. The resultant amphiphilic diblock copolymer exhibits spherical micelles morphology, as confirmed by Dynamic Light Scattering (DLS) and Atomic Force Microscopy (AFM). Moreover, Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) investigated the thermal decomposition behavior of the copolymer and determined the glass transition temperature (Tg ≈ 70 °C), melting temperature (Tm ≈ 160-170 °C), and crystallization temperature (Tc ≈ 135-143 °C) of the diblock copolymer, respectively.

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43

張唯聖. "Use of Branched-Poly(ethylenimine) & Poly(2-ethyl-2-oxazoline)-Poly(methacrylic acid)/siRNA Ternary Polyion Complex for Gene Silencing". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/11963855088104069591.

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44

Wei-ChihCheng y 鄭偉志. "Poly(acrylic acid)-Poly(2-ethyl-2-oxazoline) Interpolymer Complexes:Interaction with Sodium Dodecyl Sulfate and Application in Drug Carrier". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/96360577505091005675.

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碩士
國立成功大學
化學工程學系
103
In this study, polymer concentration and the pH of polymer solution was shown to have significant effect on the interaction between poly(acrylic acid) (PAA) and poly(2-ethyl-2-ozazoline) (PEtOz) and also on the structure of the interpolymer complexes (IPCs). In addition, Sodium dodecyl sulfate (SDS) was introduced into PAA/PEtOz solution so as to mimic the the microstructure change of interpolymer complexes caused by amphipiles in biological system. The competitive behavior between IPCs and SDS were studied in terms of pyrene solubilization and transparency. The microstructure of PAA-PEtOz IPCs was found to be varied with the amount of SDS added. Futhermore, doxorubicin (DOX) was added to PAA/PEtOz solution in order to examine the drug-loading capacity of PAA-PEtOz IPCs. It was found that the hydrophobicity of PAA-PEtOz IPCs dominated the loading efficiency of DOX before IPCs forming precipitate due to the growth of size by the solubiliztion of DOX. Moreover, the release rate of DOX from PAA-PEtOz IPCs was also found to be depended on the hydrophobicity of IPCs.

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45

Cesana, Sonia [Verfasser]. "Functionalization of poly(2-oxazoline)s with cyclic RGD peptides / Sonia Cesana". 2004. http://d-nb.info/974209643/34.

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46

Lafon, Adeline. "La poly(2-isopropyl-2-oxazoline) et ses dérivés en solution aqueuse et aux interfaces". Thèse, 2016. http://hdl.handle.net/1866/18436.

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La poly(2-isopropyl-2-oxazoline) (PIPOZ) est un polymère thermosensible qui possède une température de solution critique inférieure (LCST) autour de 40 °C en solution aqueuse. Les travaux présentés s’intéressent aux propriétés en solution aqueuse et aux interfaces, de l’homopolymère PIPOZ, d’une PIPOZ fonctionnalisée avec un groupement lipidique (lipo-PIPOZ) et de copolymères à blocs à base de poly(éthylène glycol) et de PIPOZ. Si elle est régulièrement comparée à son isomère structurel le poly(N-isopropylacrylamide) (PNIPAM), les études sur les propriétés en solution de la PIPOZ sont cependant moins complètes que celles sur le PNIPAM. Le premier objectif des travaux présentés ici est de parfaire la connaissance du comportement en solution de la PIPOZ en présence d’additifs. Les effets de sels et de solvants hydromiscibles sur la solubilité de la PIPOZ ont été investigués par turbidimétrie et microcalorimétrie sur trois homopolymères de masses moléculaires différentes. Contrairement aux solutions de PNIPAM, l’ajout de méthanol à la solution de PIPOZ ne conduit pas au phénomène de cononsolvency où la solubilité du polymère diminue pour une certaine gamme de fractions volumiques de cosolvant. L’effet a néanmoins été observé dans le cas de système PIPOZ/Eau/THF. L’effet de sels sur la solubilité de la PIPOZ suit la série Hofmeister. La présence de sels chaotropes (NaI et NaSCN) en solution ont révélé un effet bien plus important sur la solubilité de la PIPOZ que pour son isomère. Les valeurs de point troubles de la solution de PIPOZ augmentent de plus de 30 °C pour une concentration en sel supérieure à 1 M. L’autre objectif de cette thèse est de synthétiser un système à base de PIPOZ capable de s’auto-assembler à l’interface air-eau afin de former des films interfaciaux par la technique Langmuir-Blodgett. A cette fin, un amorceur contenant un groupement lipidique (2 chaînes alkyles et un groupement phosphate) a été synthétisé et utilisé pour la polymérisation cationique par ouverture de cycle (CROP) du monomère 2-isopropyl-2-oxazoline conduisant à l’obtention d’un lipo-PIPOZ (Mn = 10 kg.mol-1). L’effet de deux sels (NaSCN et NaCl) sur les films interfaciaux a été étudié. Malgré leur effet opposé sur la solubilité de la PIPOZ en solution, ils conduisent tous les deux à l’expansion de la monocouche de lipo-PIPOZ. Transférés sur des substrats de mica, ces films ont été visualisés par microscopie à force atomique (AFM). La iv présence de sels dans la sous-phase lors de la formation de monocouches conduit à la formation d’agrégats d’épaisseur ~ 10 nm dont le diamètre augmente avec la concentration en sel. Enfin, le dernier objectif est de caractériser les propriétés en solutions de copolymères à blocs PIPOZ-b-PEG-b-PIPOZ. La polymérisation par CROP de la 2-isopropyl-2-oxazoline a été amorcée à partir d’un PEG (Mn = 2 kg.mol-1) bifonctionnel, Le polymère synthétisé (TrOH, Mn = 11 kg.mol-1) a ensuite subit une fonctionnalisation des extrémités de chaînes par des groupements octadécyles conduisant à l’obtention d’un copolymère à blocs téléchélique amphiphile et thermosensible (TrC18). Les propriétés des copolymères en solution aqueuse ont été étudiées par turbidimétrie, diffusion dynamique de la lumière (DLS), microcalorimétrie (DSC), microscopie électronique à transmission et spectroscopie à sonde fluorescente, FT-IR et AFM. Les deux copolymères sont thermosensibles et présentent des valeurs de points troubles de ~ 48 °C pour le copolymère TrOH et de ~ 38 °C pour le copolymère amphiphile. Ce dernier s’auto-assemble à température ambiante et forme, en solution aqueuse, des micelles de type fleurs de rayon hydrodynamique RH ~ 8 nm. L’effet prolongé de la température sur la cristallisation des blocs de PIPOZ a aussi été examinée. Les deux polymères cristallisent en solution aqueuse conduisant à la formation de fibres insolubles dans l’eau. Mots-
Poly(2-isopropyl-2-oxazoline) (PIPOZ) is a thermosensitive polymer whose lower critical solution temperature (LCST) in water is ~ 40 °C. This thesis focuses on the properties in aqueous solution and on interfaces of new poly(2-isopropyl-2-oxazoline) systems. PIPOZ is often compared to its structural isomer, the renowned poly(N-isopropylacrylamide) (PNIPAM). If PNIPAM has been the center of thermosensitive polymer research for the last three decades, it is PIPOZ which has recently been gaining interest. The first aim of the thesis is to improve on the knowledge on PIPOZ properties in aqueous solution in the presence of water-soluble additives. Effect of salts and cosolvents were investigated by turbidimetry and microcalorimetry (DSC) on PIPOZ homopolymers of different molecular weights. Effect of salts on PIPOZ solubility follows the Hofmeister series. Chaotropic anions (SCN-, I-) induce a large increase (up to 30 °C) of the cloud point temperature of PIPOZ solution which is 10 times larger than for PNIPAM. Adding methanol into PNIPAM aqueous solution leads to a decrease in solubility of the polymer. This phenomena is called cononsolvency. Unlike PNIPAM solutions, the addition of methanol in PIPOZ solution does not lead to a cononsolvency effect. Nevertheless, cononsolvency has been observed in the case of THF addition into PIPOZ aqueous solutions. The second aim of this work was to design and synthesize an amphiphilic PIPOZ able to anchor itself at the air-water interface and to form stable monolayer via the Langmuir-Blodgett technique. For that purpose, a lipidic initiator containing two alkyl chains and a phosphate group, was synthesized and used to initiate the cationic ring opening polymerization (CROP) of 2-isopropyl-2-oxazoline. The obtained amphiphilic (lipo-PIPOZ, Mn = 10 kg.mol-1) forms stable monolayers at the air-water interface. The presence of salt (NaCl or NaSCN) in the sub-phase during the compression of the films leads to expansion of the monolayer even if the salts have opposite effect on PIPOZ solubility in solution. The interfacial films were then transferred onto mica substrates and captured by atomic force microscopy (AFM). The salts induced the formation of aggregates (height ~ 10 nm) whose diameter depends on the salt and its concentration. At last, a block copolymer, TrOH, containing a central poly(ethylene glycol) (PEG) (Mn = 2 kg.mol-1) and two PIPOZ blocks was obtained by CROP of 2-isopropyl-2-oxazoline initiated vi by a bi-functionnal PEG. The total molecular weight was Mn ~ 11 kg.mol-1. Hydrophobic chain ends modification has been performed onto TrOH to bring amphiphilicity and to get a telechelic octadecyl-end capped block copolymer TrC18. The properties of these two block copolymers in water were characterized by dynamic light scattering (DLS), microcalorimetry (DSC), electronic transmission microscopy (TEM) and fluorescence spectroscopy, FT-IR and AFM. Cloud point temperature of copolymer solutions was found to be around 48 °C for TrOH and around 38°C for the amphiphilic analogue TrC18. The latter self-assembles at room temperature into flower micelles whose hydrodynamic radius is RH ~ 8 nm. Extended heating of both copolymer solutions leads to crystallization of PIPOZ block and insoluble fibers form in solution.

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47

宋岳哲. "A ternary polyion complex vector system for gene transfer based on Branched-Poly(ethylenimine) & Poly(2-ethyl-2-oxazoline)- Poly(methacrylic acid)". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/63828542746580571167.

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碩士
國立清華大學
化學工程學系
96
The purpose of this study was to prepare polymeric gene carriers based on PEOz-b-PMAA, (poly(2-ethyl-oxazoline)- block-poly -methacrylic acid) and Branched-Poly (ethylenimine), (B-PEI). PMAA were partially dissociation under neuteral pH and were with negative charge, so that they could attach to the positive charge surface of B-PEI/DNA polyplex. The newly formed polyplex were biocompatible by the hydrophilic segment, PEOz and could enhance the stability of the polyplex in vivo. We prepared B-PEI/DNA polyplex by varying weight ratio of B-PEI/DNA, till the polyplex were provide with stable particle size and highly positive charge. And the B-PEI/DNA polyplex were then formed a bilayer structure polyplex with PEOz-b-PMAA. The experiment results showed that the particle size of B-PEI/DNA polyplex were about 150 nm, and the bilayer polyplex were about 200~250nm. While B-PEI/DNA polyplex carried posive surface charge with zeta potential of 30mV, the PEOz-b-PMAA could covered up the positive charge of B-PEI when bilayer structure polyplex were prepared. Data of material cytotoxicity showed that B-PEI revealed extremely toxicity to Hela cells under 100μg/ml concentration, and the cells viability approached 0, and PEOz-b-PMAA showed 80% viability under the same conceration. Then We compared the viability of B-PEI/DNA and PEOz-b-PMAA /B-PEI/DNA, and the later kept higher viability then the former . TEM observation showed that PEOz-PMAA/B-PEI/DNA polyplex formed core-shell structure, and the polyplex in pH 5 would collapse and release plasmid.The results of transfection effects indicated that the bilayer structure reduce the efficiency slightly, and RLU/unit weight of the bilayer gene carrier were about 1/10~1/100 of B-PEI/DNA polyplex. By CLSM observation, we observed celluptake of B-PEI/DNA polyplex and bilayer structure polyplex, the result revealed that the bilayer structure polyplex started to accumulate after 3hrs incubation and accumulated a significant amount after 6hrs. In conclusion, the polyplex formed with PEOz-PMAA covered on B-PEI/DNA could improved the cytotoxicity of B-PEI/DNA. The newly ternary polyplex presented a well transfection efficiency and cell uptake efficiency, so the ternary polyplex constitute a useful approach for further design of gene carriers.

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48

Greß, Anja [Verfasser]. "Funktionalisierte Poly(2-oxazoline) : kontrollierte Synthese, bioinspirierte Strukturbildung und Anwendungen / von Anja Greß". 2008. http://d-nb.info/989454290/34.

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49

Lück, Steffen. "Monodisperse Microgels based on Poly(2-Oxazoline)s for Regenerative Cell Replacement Therapy". Doctoral thesis, 2016. https://tud.qucosa.de/id/qucosa%3A30152.

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50

林哲平. "Gene Delivery System and Gene Therapy based on Poly(2-ethyl-2-oxazoline) and it's Copolymers". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/40733602421792558166.

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博士
國立清華大學
化學工程學系
100
The research synthesized the non-viral gene vectors based on poly(2-ethyl-2-oxazo-line) and it’s copolymer. Part 1: This study synthesized the non-viral and pH-sensitive gene carrier, poly((2-ethyl-2-oxazoline)-co-ethylenimine)-block-poly(2- ethyl-2-oxazoline) (P(EOz/EI)-b-PEOz). The gene carrier contains both cationic poly((2-ethyl-2-oxazoline)-co-ethylenimine) (P(EOz/EI)) segments and charge-neutral poly(2-ethyl-2-oxazoline) (PEOz) segments. In this study, PEOz was used as biocompatibility shell and as the core source. A technique using methanesulfonyl poly((2-ethyl-2-oxazoline)-co-ethylenimine, (P(EOz/EI)-OMs) as a macroinitiator to modify the outer shell PEOz segment provided an amino group at the chain terminus. P(EOz/EI)-b-PEOz were coordinated with plasmid DNA, and the resulting complexes were characterized by gel permeation chromatography and 1H NMR spectra. The P(EOz/EI)-b-PEOz polyplexes showed suitable mean particle size, low cytotoxicity, and acceptable transfection because of shielding of PEI by PEOz outer shell. TEM morphology showed that the stable core-shell structure of ternary polyplexes at pH 7.4 collapsed and released plasmid at pH 5. Observations of cell uptake of the B-PEI/DNA polyplex and P(EOz/EI)-b-PEOz/DNA polyplexes by CLSM revealed that P(EOz/EI)-b-PEOz polyplexes started to accumulate after 6 h incubation and accumulated significantly after 12 h. The results indicated that the hydrophilic, charge-neutral PEOz shell stabilized polyplex formation, and enhanced polyplex cell viability. Polyplex transfection efficiencies were as high as those of commercially available transfection reagents. Our results suggest that this novel gene carrier, based on the diblock copolymer P(EOz/EI)-b-PEOz, has potential for in non-viral gene therapy applications. Part 2: This investigation demonstrates new ternary gene delivery systems, based on the pH-responsive diblock copolymer poly(2-ethyl-oxazoline)-block-poly(methacrylic acid) (PEOz-b-PMAA), and the branched-poly (ethylenimine) (B-PEI). The plasmid DNA is complexed with B-PEI and further with PEOz-b-PMAA to obtain ternary polyplexes (DNA/B-PEI/PEOz-b-PMAA). PMAA was partially dissociated at neutral pH with a negative charge, to attach to the positively charged surface of the B-PEI/DNA polyplex. The ternary polyplexes also desorb and return to the original pre-poly complex to help gene release after cell uptake due to PMMA becomes neutral charge under an acid environment in endosome. The ternary polyplexes show suitable mean particle size, low cytotoxicity, and acceptable transfection at pH 7.4 because of shielding of B-PEI by PEOz-b-PMAA. A transmission electron microscopy morphological examination shows that the stable core-shell structure of ternary polyplexes at pH 7.4 collapsed and released plasmid at pH 5. Observations of the cell uptake of the B-PEI/DNA polyplex and ternary polyplexes by confocal laser-scanning microscope revealed that ternary polyplexes started to accumulate after 3 h of incubation and accumulated significantly after 6 h. In conclusion, the ternary polyplex improves the cytotoxicity of the single B-PEI/DNA polyplex, and presents a pH-responsive behavior to enhance gene escape from the polyplex. The ternary polyplex constitutes a useful approach for gene carrier design. Part 3: The primary objective of this study is to explore the feasibility of inhibiting tumor growth via the delivery of endostatin-angiostatin (hEA) fusion gene by above non-viral gene carrer. We first compared above two gene carriers in particles size, zeta potential, cell toxicity and gene transfection efficiency. The results indicated that the gene carrier P(EOz/EI)-b-PEOz from first part had better quality for gene delievery, so we chose P(EOz/EI)-b-PEOz for further research. The results indicated that gene carrier P(EOz/EI)-b-PEOz with hEA led to a higher degree of tumor growth inhibition, and can be easily accumulated in tumor and metabolized. In conclusion, the P(EOz/EI)-b-PEOz constitutes a useful approach for gene carrier design.

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