Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Publisher: search.filters.publisher.01. Izmir Institute of TechnologySubject: search.filters.subject.Tissue engineering

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Now showing 1 - 5 of 5
  • Master Thesis
    Development and Characterization of Surface-Modified Emulsion Templated Scaffolds for Tissue Engineering Applications
    (01. Izmir Institute of Technology, 2024) Kocagöz, Mehmet; Dikici, Betül Aldemir; Zareıe, Esma Volga Bulmuş
    Emülsiyon şablonlama, yüksek ve açık gözeneklilik sağlayan avantajlı bir iskele üretim yöntemidir. Bu yöntemde hidrofobik polimerlerin su ile karıştırılmasıyla yağ içerisinde su (w/o) emülsiyonları elde edilir. İç faz hacmi %74'ün üzerinde olan polimerize emülsiyonlar, yüksek iç fazlı emülsiyonlar (PolyHIPE'ler) olarak adlandırılır. Polikaprolakton, doku mühendisliğinde yaygın olarak kullanılan sentetik, biyolojik olarak bozunabilen ve biyouyumlu bir polimerdir, ancak malzemenin hidrofobik karakteri hücre-materyal etkileşimlerini sınırlamaktadır. Bu nedenle, bu çalışma kapsamında, emülsiyon şablonlama yöntemi ile üretilmiş, polikaprolakton tetrametakrilat (4PCLMA) esaslı iskelelerin biyolojik performanslarını artırmak için iskelelerin alkali muamelesi ve elde edilen iskelelerin karakterize edilmesi amaçlanmıştır. İlk olarak halka açma polimerizasyonu ile 4PCLMA pre-polimeri sentezlenmiş ve metakrilat grupları ile fonksiyon kazandırılmıştır. 4PCLMA ~%97 metakrilasyon derecesi ile başarıyla sentezlenmiş, 4PCLMA esaslı PolyHIPE'ler emülsiyon şablonlama yöntemi ile üretilmiş, üç farklı konsantrasyonda ve inkübasyon süresinde sodyum hidroksit (NaOH) ile muamele edilmiştir. NaOH işleminin iskelelerin morfolojileri, kütle kaybı, su tutma kapasitesi, mekanik özellikleri, yüzey alanı, hidrofilisitesi ve biyolojik performansı üzerindeki etkileri araştırılmıştır. NaOH uygulamasının iskelelerin ağırlığını ve mekanik mukavemetini azalttığı ancak aynı zamanda iskelelerin su tutma kapasitesini, hidrofilisitesini, yüzey alanını ve protein adsorpsiyon kapasitesini artırdığı görülmüştür. NaOH işleminden sonra PolyHIPE'lerdeki kimyasal değişiklikler spektroskopi ile doğrulanmıştır. In vitro sonuçlar, NaOH uygulamasının L929 hücreleri üzerinde sitotoksisiteye neden olmadığını ve Saos-2 hücrelerinin tutunma ve çoğalma davranışını olumlu yönde etkilediğini göstermiştir. Bu çalışma sonucunda NaOH muamelesinin, emülsiyon şablonlama ile üretilmiş doku iskelelerinin hidrofilisitesini ve biyolojik performansını artırmak adına alternatif bir yüzey modifikasyon yöntemi olarak kullanılabileceği gösterilmiştir.
  • Master Thesis
    Development of a Natural Tubular Scaffold From Decellularized Parsley Stems To Be Used in Vascular Tissue Engineering Applications
    (01. Izmir Institute of Technology, 2024) Çevik, Merve; Dikici, Serkan; Özçivici, Engin
    Cardiovascular diseases (CVD) are usually associated with narrowing or blockage of blood vessels and are the leading cause of death globally. By 2030, the annual incidence of CVD-related deaths is estimated to increase 23.3 million. Considering the advancements in endovascular surgery, the use of vascular grafts in cardiovascular surgery is becoming increasingly common. Autografts are the gold standard but have limitations, including limited tissue availability and complications from vessel isolation. Recently, synthetic grafts have emerged as alternatives, though they often fail due to thrombosis, atherosclerosis, intimal hyperplasia, or infection. Thrombosis, the main cause of post-implantation failure, is associated with damage or absence of the endothelial cell lining on the luminal surface of the vascular graft. To overcome the limitations mentioned so far, tissue-engineered vascular grafts (TEVG) have come into prominence. The use of decellularized plant tissues in tissue engineering applications has recently gained great importance. Accordingly, in this study, we fabricated tubular scaffolds from decellularized parsley stems and evaluated them in vitro as potential TEVGs. Our results demonstrated that native plant DNA was successfully removed, and biocompatible tubular biomaterials were successfully fabricated via chemical decellularization of parsley stems. The decellularized parsley stems showed suitable mechanical and biological properties for use as TEVG material. Finally, they were found to provide a convenient environment to form a pseudo-endothelium by recellularization with human endothelial cells prior to implantation. This study is the pioneer in the literature that reports on the potential of parsley stems to be used as a potential TEVG biomaterial.
  • Master Thesis
    Development and Characterization of Biomimetic Peptide-Based Bioink for Dental Tissue Engineering
    (01. Izmir Institute of Technology, 2023) Altan, Zeynep; Arslan Yıldız, Ahu
    Recently, the role of molecular control in the tooth mineralization process has received much attention. Biomimetic scaffolds have been started to use in dental tissue engineering and regeneration due to their high applicability, biocompatibility, biodegradability, and mineralization capability. In this thesis, a hybrid biomimetic bio-ink; P11-4 peptide-based Quince Seed Hydrogel (QSH)/Gelatin (Gel) is used in 3D cell culture studies for dental tissue engineering applications. Pristine QSH, QSH/Gel, and P11-4/QSH/Gel bio-inks were characterized by FTIR and viscosity analysis, and their 3D bioprinting parameters were optimized. Hydrogels were crosslinked via 1-Ethyl-3-(3-dimethylaminopropyl) Carbodiimide (EDC)/N-Hydroxysuccinimide (NHS) coupling reaction and various hydrogel concentrations were investigated for scaffold fabrication. Characterization of produced scaffolds was performed by SEM imaging, mechanical testing, protein adsorption, and swelling analyses. As a result, the mechanical strength, viscosity, swelling properties, and surface characteristics of the biomaterial were evaluated. SaOS-2 human osteosarcoma cell line was used for 3D bioprinting studies. Cell viability analyses were performed via Live/Dead and MTT assays. Mineralization was investigated and assay was carried out with Alizarin Red Staining. According to obtained results, P11-4/QSH/Gel scaffolds provide high cell viability and proliferation rate compared to pristine QSH and QSH/Gel control groups. Also, with the addition of P11-4 to QSH/Gel, a certain amount of increase in mineralization was observed after day 7 on long-term cultured scaffolds. As a result of this study, it was concluded that P11-4-based QSH/Gel has a high potential to be used as a bio-ink in the production of 3D scaffolds for dental tissue engineering applications.
  • Master Thesis
    Development and Characterization of Magnesium Alginate Hydrogels for 3d Cell Culture Formation
    (01. Izmir Institute of Technology, 2021) Çoban, Başak; Arslan Yıldız, Ahu
    Cell culture is an important tool for biological research. Two-dimensional (2D) cell culture is still used but growing cells on plastic surfaces offering unnatural growth kinetics and cell attachment. Three-dimensional (3D) cell culture allows cells to growth in their 3D physical shape and interact with their surroundings which represent the natural microenvironment. Hydrogels are crosslinked networks, have become increasingly used biomaterial for 3D cell culture with their ability to simulate the nature of most soft tissues. In this thesis, a new methodology based on bio-patterning was developed to fabricate (3D) cellular structures by using Mg-alginate hydrogel and fabricated 3D cellular structures was utilized for drug screening studies. Mg-alginate hydrogel has a specific gelation/de-gelation characteristics compared to other types of hydrogels due to its weak polymer-ion interaction. In this study slow gelation and de-gelation property of Mg-alginate hydrogel was used for biopatterning of 3D cellular structures. Plackett-Burman and Box-Behnken design models were used to optimize parameters of Mg alginate-based biopatterning method while using HeLa cells as a model cell line. Then, the applicability of newly developed methodology was successfully demonstrated by using SaOS-2 and SH-SY5Y cells to fabricate 3D cellular structures. Cell proliferation and migration profiles were observed during long-term culturing with time-dependent light microscopy images. Also cell proliferation and viability of long-term cultured tumor models were analyzed by using Alamar Blue and Live/Dead assays. Moreover, F-actin, Collagen I, and DAPI staining/immunostaining was done to investigate cellular and extracellular components of 3D cellular structures for short and long-term culture times. Finally, the dose-response of fabricated 3D structures was evaluated and compared with standard 2D cell culture by applying doxorubicin (DOX). The IC50 values were calculated for 3D cellular structure of HeLa, SaOS-2 and SH-SY5Y cells as 8.2, 7.8, and 2.1 µM respectively while IC50 values of 2D controls obtained as 3.2, 4.4, and 0.2 µM respectively. These results were also statistically analyzed and dose responses were found significantly different according to t-test, which means 3D cellular structures were more resistant to drug exposure compared to 2D cell culture.
  • Master Thesis
    Cell Patterning With Magnetic Manipulation
    (01. Izmir Institute of Technology, 2020) Çağan, Melike; Özçivici, Engin
    Tissue engineering is a biomedical engineering field that provides solutions to restore, maintain, improve or replace tissues or whole organs. The main goal tissue engineering is to overcome the restrictions of existing treatments that are based on organ transplantation. Cells and biomaterials can be used to form functional tissues and organs. Actually, the goal is to produce structures that resemble and mimic the real tissues. One of the useful mimicking technique is cell patterning. Cell patterning is a technique that provides cell clusters are located at a proper position for function of tissues. Some of the patterning techniques uses cell adhesion ligands, optical tweezers, acoustic tweezers, dielectrophoresis and magnetic force. In addition to the advantages of all these techniques, there are also disadvantages. However, Magnetic force-based cell patterning techniques provide excellent advantages such as low adverse effects to cell. Magnetophoresis is one of the magnetic force-based cell patterning technique that forms cell patterns without labeling cells in a short time using the principle of movement of the cells to lower magnetic field region in a paramagnetic medium. In this study, a cell patterning system was used to form cell patterns via magnetophoresis. Results showed that cell patterns were formed in different shapes in a short time and they maintained integrity even if magnetic force was removed.