Master Degree / Yüksek Lisans Tezleri

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

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Language: search.filters.language.enSubject: search.filters.subject.Sericin

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  • Master Thesis
    Cloning of Novel Sericin Like Proteins and Optimization of Their Expression
    (Izmir Institute of Technology, 2022) Gürerk, Gamze; Şanlı Mohamed, Gülşah; Şanlı Mohamed, Gülşah
    Sericin is a protein that helps fibroin fibers link together to create the cocoon, and it forms silk with fibroin. Fibroin is used in textile production as well as in biomaterial applications. Sericin has essential biocompatibility, biodegradability, cryoprotection, antioxidant properties, and a multi-component structure. Thanks to these properties, its use in biomaterial and biomedical fields is expanding and also used in cosmetic research and wound healing, and drug delivery thanks to its high fiber structure. Sericin can be obtained from silkworm cocoons by degumming method but changes the structure of the obtained protein since the protein is exposed to high temperatures. Sericin produced in different batches is obtained in different quantities and these create inconsistencies in the quality of the biomaterials obtained from the sericin, limiting the use of the sericin as a biomaterial. Besides, obtaining protein by recombinant production provides the advantage that the repetitive chain length can adjust as desired and the protein can be standardized. In this thesis, recombinantly generated and optimized a novel sericin-like protein (Ser-12mer) with the native sericin sequence encoding twelve repeats of recombinantly conserved 38 amino acid motifs in Escherichia coli and characterized its structural properties. In addition, the effects of induction cell density and cell culture media on the expression of the previously produced sericin-like protein (Ser-4mer) was investigated and its expression and concentration were increased by optimization. Recombinant production of a sericin-like protein will provide an understanding of the sequence-structure relationships and significantly expand their applications as biomaterials.
  • 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
    Sericin-Polymer Conjugates: Preparation and Physicochemical Characterization
    (Izmir Institute of Technology, 2017) Gül, Abdulkadir; Bulmuş Zareie, Esma Volga
    Sericin is a protein derived from silkworm, Bombyx mori, and has several useful properties as a natural biomaterial such as antioxidant character, moisturizing ability, hydrogel forming property and most importantly immunogenic inertness. The aim of this thesis is to prepare and physicochemically characterize sericin-polymer conjugates as potential natural-synthetic hybrid biomaterials with enhanced properties for drug delivery and tissue engineering applications. For this purpose, three polymers having the same degree of polymerization (n~42) and varying chemical nature, i.e. poly(oligoethylene glycol methacrylate), P(OEGMA) hydrophilic and neutral, poly(hydroxyethylmethacrylate) P(HEMA) less hydrophilic and neutral, and poly(dimethylaminoethyl methacrylate) P(DMAEMA) hydrophilic and cationic after quaternization, were first synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization. Each polymer was characterized via nuclear magnetic resonance (1H-NMR) and gel permeation chromatography (GPC). Separately, molecular weight and isoelectric point of sericin were characterized using various techniques including Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and High-Resolution Two-Dimensional Polyacrylamide Gel Electrophoresis (2D-PAGE). Polymers were then covalently conjugated to sericin using NHS/EDC chemistry. The conjugates were characterized using SDS-PAGE, GPC and DLS (Dynamic Light Scattering). The SDS-PAGE and GPC results showed the successful preparation of the conjugates. DLS revealed that the hydrodynamic size of P(OEGMA) and P(DMAEMA) polymers and their conjugates were between 1 and 10 nm as they are soluble in PBS and do not form aggregates. Unlike the other two polymers, although the size of P(HEMA) polymer was observed to be 3.24 ± 0.62 nm, the DLS measurements of P(HEMA) conjugates indicated the presence of self-organization and aggregation of Sericin-P(HEMA) conjugates in aqeuous solution. Consequently, the size of sericin-P(HEMA) conjugates were found to be 530 ± 60.83 and 223.3 ± 25.2, respectively.