Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Characterization and Utilization of Injectable Hydrogels for Tissue Engineering Applications(Izmir Institute of Technology, 2020) Güzelgülgen, Meltem; Arslan Yıldız, AhuTissue engineering combines the knowledge of the engineering aspects with life sciences to improve human health. Recent studies in tissue engineering have focused on investigating biocompatible scaffold materials and design. Quince seed hydrogel(QSH) has been used in traditional and modern medicine for skin wound and burn treatments, synovial lubrication, cough and asthma removal, and oral drug delivery with its antioxidant potential and biocompatible aspects. This thesis focuses on developing QSH and evaluating its potential as an injectable hydrogel in treating bone tissue defects as a totally new tissue scaffold and also as a promising tissue filling material. For this purpose, QSH scaffold optimization was carried out using various concentrations of hydrogel and crosslinkers which were glutaraldehyde(GTA) and 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide(EDC)/N-hydroxysuccinimide(NHS). Morphological and chemical analysis of QSH was done using SEM, FTIR, AFM, and protein adsorption test. Thus, porosity, swelling ratio, degradation rate and surface characteristics were evaluated. NIH-3T3 and SaOS-2 cell lines were utilized for 3D cell culture formation. Afterward, 3D spheroids were analyzed for cell viability and proliferation by using AlamarBlue and LiveDead assays, and also cell imaging technics. Results showed that QSH scaffolds did not show any cytotoxic effect on NIH-3T3 and SaOS-2 cells. The optimum results were achieved with 2mg/mL of QSH and 0.03M GTA concentrations; where 76.59µm average pore size, 56.8 fold water holding capacity and at least 80% cell viability was observed. Therefore, it was concluded that QSH has a high potential to promote tissue engineering applications with its injectable texture as a filling material.Master Thesis Ultra-Porous Interconnected Hydrogel Structures for Tissue Engineering Applications(Izmir Institute of Technology, 2018) Yıldız, Büşra; Yıldız, Ümit Hakan; Arslan Yıldız, AhuTissue engineering aims to repair and regenerate tissue and organs with functional defects. The most significant developments in tissue engineering emerging as modification of the scaffold used to mimic native extracellular matrix (ECM) and support cell proliferation and differentiation. Hydrogel-based biomaterials are one of the most utilized materials as scaffold providing excellent chemical, physical/biophysical properties, high biocompatibility and functionality necessary for the applications in tissue engineering. In this study, Gelatin methacryloyl hydrogel (GelMA) and Gelatin-urethane hydrogels (GelatinK) are successfully synthesized as scaffold material for tissue engineering applications. Gelatin is modified with methacrylic anhydride for GelMA polymer and with 2-isocyanatoethly methacrylate for GelatinK polymer. The hydrogels of these two novel polymer are produced with photopolymerization reactions in aqueous media using Irgacure 2959 as redox initiator. Hydrogels are freeze-dried to remove solvent in the gel matrix and then they immersed in distilled water to reach equilibrium swelling ratio. The swelling capacity of GelMA hydrogels ranges between 1200 and 300% whereas GelatinK hydrogels has swelling capacity in between 1900-380%. Also, morphology of the hydrogels were investigated with Scanning Electron Microscopy (SEM). GelMA hydrogels has pore sizes between 142-14 µm while GelatinK hydrogels has between 160-56 µm pore sizes. The cell viability assay were also conducted using GelMA and GelatinK hydrogels. The results showed that both hydrogels provide high viability as compared to 2D control assay.Master Thesis Polymer Based Extracellular Matrix Mimetics for 3d Cell Culture(Izmir Institute of Technology, 2018) Türker, Esra; Arslan Yıldız, AhuTissue engineering combines engineering principles and knowledge of life sciences to improve biological substituents. Three dimensional (3D) supporting structures, namely scaffolds obtained from biomaterials to mimic extracellular matrix (ECM) that provides suitable microenvironment for cell proliferation, migration and differentiation. In this study, poly (L-lactide-co-ε-caprolactone) (PLLCL) and collagen type I was used to fabricate scaffold by electrospinning method. In literature, collagen was often dissolved in toxic and harmful solvents that creates the major problem for cell culture applications. To overcome this problem “co-spinning” methodology is utilized for the formation of non-toxic collagen-based ECM mimetic scaffold. Collagen mixed with water-soluble carrier materials which is either polyvinylpyrrolidone (PVP) or polyvinyl alcohol (PVA) and co-electrospinning is carried out with PLLCL. Fabricated scaffolds were immersed into water to remove co-spinning agent; PVA or PVP, so only PLLCL/Collagen remained. PLLCL has homogeneous fibers in a diameter of 1.312 ± 0.22μm. The contact angle of PLLCL (136.6° ± 2.6) proved hydrophobic behavior of PLLCL material. The contact angle of the scaffold decreased up to 86.7° ± 0.1 confirming that hydrophobic behavior is decreased with the addition of collagen. Also, collagen-containing scaffolds were saturated at lower amount of protein than PLLCL, PLLCL/PVA and PLLCL/PVP scaffolds. Cytotoxicity analysis of scaffolds showed that PVA containing scaffolds had lower viability than PVP containing scaffolds; so most of the cell studies were carried out with PLLCL/ Collagen scaffolds fabricated by PVP cospinning. Cell proliferation on PLLCL/Collagen scaffolds found to be more favorable than PLLCL and PLLCL/PVP scaffolds.