Master Degree / Yüksek Lisans Tezleri

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

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Access Right: Open AccessAuthor: search.filters.author.Bulmuş, Volga

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  • Master Thesis
    Cloning of Sericin-Like Proteins for Recombinant Production in Bacteria
    (Izmir Institute of Technology, 2019) Bostan, Fatmanur; Sürmeli Eraltuğ, Nur Başak; Bulmuş, Volga
    Silk consists of two main proteins called fibroin and sericin. While fibroin is used in textile production and various biomaterial applications, sericin is considered as waste material in the textile industry. Sericin is a multi-component protein with an indefinite structure and it has been shown to be biocompatible and has biological activity. Because of the positive effects on keratinocytes and fibroblasts have led to the development of sericin-based biomaterials for the repair of skin tissue. Sericin from silkworm cocoons can be obtained by chemical treatment, enzymatic treatment and boiling in water. Although sericin can be separated from fibroin by chemical, enzymatic and boiling in water treatment methods, all these treatment methods are not enough to obtain recovery of high-quality sericin. Moreover, in these treatment methods, the exposure of sericin protein to high temperature causes even sericin protein obtained by the same method to indicate different characteristics. The fact that the obtained sericin demonstrate such major changes in the structure according to treatment methods bring inconsistencies in the quality of sericin produced as a biomaterial. The aim of the study is to produce native sequence of sericin that forms a tetramer contain each containing 38 amino acids with recombinant production in E.coli and to characterize structural properties Thus, obtaining sericin protein from the bacteria with recombinant methods will solve these problems in question The results indicate that for the first time, the conformational properties of recombinant sericin were obtained similar to the native sericin structure.
  • Master Thesis
    Modification of Graphene Surfaces for Detection of Biomicroparticles
    (Izmir Institute of Technology, 2019) Yeşiltaş, Gözde; Bulmuş, Volga
    Pathogens present in the food we consume and the water we drink pose a major threat to human health. Another major health concern is the metastasis of cancer in which cancer cells spread to new areas of the body, often by way of the lymph system or bloodstream. To minimize the burden on health and economy, the detection of biomicroparticles such as pathogens or circulating cancer cells in a highly sensitive and practical manner is higly desirable. This thesis aims to develop a method to create graphene-based biosensor substrate for detection of biomicroparticles such as bacteria, viruses or mammalian cells. For this aim, graphene surface was first functionalized using a linker molecule. The effect of solvent type on functionalization was investigated via Raman spectroscopy and X-Ray spectroscopy (XPS). AntiCD2 antibodies (Ab), as a model antibody, were then conjugated to the functionalized graphene via NHS/EDC chemistry. The Ab conjugation was verified by Raman spectroscopy and XPS analyses. Finally, Jurkat cells, as model biomicroparticles, were recognized and captured by Abconjugated graphene surface, as evidenced by optical microscopy. The temperature, medium, and method for interaction of cells with graphene surfaces as well as the specificity of the Ab- functionalized graphene surface were investigated. The results overall showed the specific and efficient recognition of model cell line by Abconjugated graphene surfaces.
  • Master Thesis
    Fabrication of Microfluidic Devices Via 3d Printer
    (Izmir Institute of Technology, 2019) Keçili, Seren; Tekin, Hüseyin Cumhur; Bulmuş, Volga
    The purpose of this thesis is to provide easy and rapid prototyping of microfluidic devices using 3D printing technology that overcomes disadvantages of traditional fabrication techniques and also enhanced optical transparency of 3D-printed microfluidic devices fabricated using new bonding strategies. For performance analysis of 3D printer, microfluidic channels and molds having different shape and dimensions were designed and fabricated. After the fabrication process, designed and fabricated channel dimensions were compared. Structures having at least having 50 μm feature were printed successfully. For enhancing transparency of fabricated 3D structures, two different fabrication techniques were developed. In these techniques, 3D structures were bonded on glass substrates with poly (dimethylsiloxane) (PDMS) and Formlabs Clear Resin interlayers. After 3D-printed structures were put on interlayers coated glass slides, they were either remained on coated slides or transferred on new slides. Bonding between 3D structures and glass slides were provided with UV exposure for resin and with elevated temperature for PDMS interlayers. Bonding strength of fabricated channels was investigated for different thicknesses of PDMS and resin interlayers. The bright-field and fluorescence imaging properties of these channels were also analyzed. Proposed fabrication technique showed 2-fold improved bonding strength and comparable bright-field and fluorescence imaging capability with respect to traditional plasma activated PDMS-glass bonding. Furthermore, protein modified glass substrates can be integrated in 3D-printed channels using the presented fabrication technique without disturbing protein functionality. Finally, in order to design a 3D-printed micropump having membranes that can be activated with compressed air, membrane deformation was characterized with different dimension.
  • Master Thesis
    Development of a Fluidic Platform for Automated Analysis of Heavy Metals
    (Izmir Institute of Technology, 2019) Gülmez, Yekta; Tekin, Hüseyin Cumhur; Bulmuş, Volga
    Heavy metals are part of Earth’s crust and the significant problem is accumulation of them in the ground waters. They have harmful results to body even they are at low concentration. Arsenic is one of the heavy metals which cause serious health problems such as; cancer, diabetes etc. Most of the developing countries are lack of detecting arsenic amount into drinking water. Therefore, especially in Bangladesh 1 out of 100 people die due to arsenic related cancer. According to World Health Organization, the maximum arsenic concentration in the drinking water must be 10 μg/L but the concentration amount reaches 50 μg/L or more at the developing countries. However, existing methods cannot detect arsenic at this range or the ones that can detect arsenic at the standard have so high prices that developing countries cannot afford. Therefore, the aim of this project is to develop a device for arsenic detection. In this thesis, a microfluidic chip was developed, and gold nanoparticles was used to detect arsenic in samples using absorbance spectroscopy. The detection principle was designed based absorption of arsenic and then gold on thiol-modified surfaces. The different concentration of arsenic samples was injected into microfluidic chip and 1.3 mg/L arsenic concentration could be detected. Then, syringe pump was added to the system and flow applied. As a result, the developed microfluidic chip is able to detect arsenic at 2.2 μg/L.