Exploring Amphiphilic PEGMA-Based Architectures as Nanoparticles for Drug Delivery
| Autor: | Porsch, Christian |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Druh dokumentu: | Doctoral Thesis<br />Text |
| Popis: | Within the last decades, the stated potential of polymer constructs as drug delivery systems have challenged researchers to develop sophisticated polymers with tunable properties. The versatility of polymers makes them highly attractive to tailor nanoparticles (NPs) which fulfill the demands of effective drug delivery systems (DDS). The aim of this work was to design and synthesize amphiphilic ethylene glycol methacrylate-based (EGMA) macromolecules, and explore their potential as NPs for drug delivery. Initially, a study of the controlled synthesis and solution properties of linear EGMA polymers, as well as the potential to transfer their behavior to amphiphilic comb copolymers, was conducted. Well-controlled polymers with interesting tunable thermo-responsive properties were accomplished by altering the monomer feed ratio. Furthermore, the comb copolymers formed self-assembled core-shell type structures in aqueous solution. A library of amphiphilic fluorinated polymers was successfully established to explore the potential of EGMA-based polymers in a dual-functional theranostic delivery system. The non-toxic polymers self-assembled into small “stealthy” NPs, and the combination of fluorinated segments with EGMA segments allowed for detection by 19F-MRI with good imaging properties. The hydrophobic core of the NPs was capable to encapsulate and release an anti-cancer therapeutic, and effectively reduced the viability of three different cancer cell lines. The diffusion-controlled release kinetics of the drug from the NPs interestingly depended on the nature of the core moiety. To reduce issues with instability of self-assembling NP systems the possibility to synthesize amphiphilic hyperbranched dendritic-linear polymers (HBDLPs) was investigated. Their three-dimensional structure was hypothesized to facilitate stabilization as unimolecular micelles. The architecture, hydrophilic/hydrophobic ratio, and high molecular weight showed to be crucial to avoid polymer association and stabilize the HBDLPs individually. In addition, the hyperbranched core of the HBDLPs was readily functionalized with disulfide bonds, either in the backbone or in the pendant groups. Under reductive conditions, selective cleavage of the disulfides thereby enabled either significant molecular weight reduction, or allowed for triggered release of a covalently bound dye, mimicking a drug. Potentially, such HBDLPs could be stable during circulation, while allowing for selective degradation and/or therapeutic release upon delivery to a cancer tissue. QC 20150909 |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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