Master Degree / Yüksek Lisans Tezleri

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Access type: Open accessSubject: search.filters.subject.Block copolymers

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  • Master Thesis
    Synthesis and Characterization of Polycaprolactone-Polyvalerolactone Copolymer and Its Use in Melt Electrowriting Applications
    (01. Izmir Institute of Technology, 2024) Dinçkal, Sanem; Yıldız, Ümit Hakan
    This thesis focuses on the synthesis and characterization of Poly(ε-caprolactone) (PCL) and its block copolymers, Poly(ε-caprolactone)-b-Poly(4-hydroxyvalerate) (PCL-b-P4HV) and Poly(ε-caprolactone)-b-Poly(δ-valerolactone) (PCL-b-PVL). These polymers were synthesized through ring-opening polymerization of various lactones (ε-caprolactone, γ-valerolactone, and δ-valerolactone) using biocatalysts such as citric acid, glycolic acid, salicylic acid, boric acid and acetic acid. Detailed analytical and thermoanalytical characterizations were performed. Differential Scanning Calorimetry (DSC) showed that most homopolymers and copolymers exhibited crystallization (Tc) and melting temperatures (Tm) varying between 5-25°C and 50-65°C respectively, confirming successful polymerization. DSC thermograms of block copolymers revealed that solvent choice for precipitation affected crystallinity and thermal properties, with a small second melting point observed due to different crystalline forms. Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) confirmed the homopolymerization of Poly(ε-caprolactone) using citric, glycolic, and salicylic acids. Mass spectrometry further revealed characteristic peaks corresponding to expected molecular weights and compositions of the copolymers. The presence of these peaks corroborated the formation of block copolymers with distinct blocks of PCL, P4HV, and PVL confirmed the molecular integrity of the synthesized block copolymers. This thesis provides a comprehensive analysis of the synthesis and characterization of block copolymers, offering insights into their structural properties and potential applications. The findings contribute to the understanding of the polymerization process and the properties of the resulting materials, which are significant for industrial and biomedical applications. The resultant copolymers were utilized in Melt Electrowriting process to provide tissue scaffold. Despite their brittleness, all copolymers were electrowritten without issues, indicating their potential interest in tissue engineering applications.
  • Master Thesis
    Development of Polymeric Carriers for Mrna Delivery
    (01. Izmir Institute of Technology, 2023) Savaş, Müge; Bulmuş Zareie, Esma Volga
    Development of efficient delivery systems is a constraint on the delivery of messenger RNA (mRNA). In gene therapy, it is crucial that mRNA molecules are efficiently delivered into cells. The thesis study has focused on the development of a relatively new polymer, P(OEGMA)-b-P(AEAEMA) as a new mRNA delivery system. P(OEGMA)-b-P(AEAEMA) block copolymers with changing block lengths (P(OEGMA)42-b-P(AEAEMA)48 and P(OEGMA)42-b-P(AEAEMA)71) were first synthesized via RAFT polymerization. The synthesized block copolymers efficiently complexed with eGFP encoded mRNA as shown by gel electrophoresis. The hydrodynamic size of polyplexes was less than 150 nm, as determined by dynamic light scattering measurements. Zeta potential measurements showed that the surface charge of the polymer-mRNA complexes was slightly negative. The eGFP-encoding mRNA transfection ability of the copolymers was investigated via fluorescence microscopy and Image J analyses. The block copolymers showed mRNA transfection efficiency on human embryonic kidney (HEK293T) and mouse fibroblast (L929) cell lines higher than the golden standard polymer, branched PEI. P(OEGMA)42-b-P(AEAEMA)48 and P(OEGMA)42-b-P(AEAEMA)71 showed a transfection efficiency of 54 and 64% of the positive control (cells transfected with Lipofectamine-mRNA complexes), respectively, on human embryonic kidney (HEK293T) cell line. On mouse fibroblast (L929) cell line, P(OEGMA)42-b-P(AEAEMA)48 and P(OEGMA)42-b-P(AEAEMA)71 block copolymers showed a transfection efficiency of 61 and 56% of the positive control, respectively. The polymer complexes showed tolerable (>70%) or no cytotoxicity on the cells in the tested range. In summary, P(OEGMA)-b-P(AEAEMA) block copolymers have shown promising mRNA transfection ability on both HEK293T and L929 cell lines.