Person: TUNCABOYLU, DENIZ CEYLAN
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Publication Metadata only In situ formation of biocompatible and ductile protein-based hydrogels via Michael addition reaction and visible light crosslinking(2023-05-22) Tutar R.; Koken S. Y.; TUNCABOYLU D. C.; Çelebi-Saltik B.; ÖZEROĞLU C.; TUNCABOYLU, DENIZ CEYLANKeratin, a biological polymer with high sulfur content, is the main component of hair, feathers and wool. Human hair is the cheapest natural source of keratin. In this study, an optimized and very effective reduction reaction method was used to obtain keratin from human hair. During this process, the disulfide bridge of keratin was reduced in the presence of sodium sulfide to form free sulfhydryl (thiols) that would act as a strong nucleophile. The results of FTIR spectroscopy, Tricine-SDS-PAGE and MALDI-TOF/MS verified the successful extraction of the reduced human hair keratin. A well-interconnected structure with three-dimensional (3D) scaffolds was prepared using keratin and methacrylated gelatin (GelMA), KeratinGel, for tissue engineering and other biomedical applications. KeratinGel hydrogels were in situ prepared via Michael addition reaction and visible light crosslinking. Two complementary crosslinking reactions were combined to enhance the network structure and provide ductility. With the targeted two-step method, the reactivity of vinyl groups of GelMA to photocrosslinking and thiol groups in keratin to the Michael addition reaction was exploited. Rheological monitoring of the Michael addition reaction was performed for KeratinGel hydrogels in a basic reaction environment at pH 7.4 with a constant concentration of GelMA (10% w/v) and different amounts of reduced human hair keratin (5, 7.5 and 10% w/v) at room temperature. The physical properties, swelling and degradation rates of KeratinGel hydrogels were determined to understand their suitability for tissue regeneration. We finalize that KeratinGel hydrogels would be better in minimally invasive surgeries, soft tissue engineering, especially with in situ gelling features, and favourable for the preparation of complex shapes and applications.Publication Open Access G-POSS connected double network starch gels for protein release(2023-12-01) Cosgun, Seyma Nur Kirmic; Tuncaboylu, Deniz Ceylan; Alemdar, Mahinur; TUNCABOYLU, DENIZ CEYLANStarch is one of the most frequently preferred natural polymers in hydrogel synthesis. Herein, we combined two strategies of associating brittle and ductile networks in a structure and incorporating inorganic particles into the polymeric gel to design mechanically enhanced nanocomposite double network (DN) starch gels. For the first time in the literature, nanocomposite starch gels (s-NC) were designed by cross-linking starch chains with 8-armed glycidyl-polyhedral oligomeric silsesquioxane (g-POSS) units. Fourier Transform Infrared Spectroscopy and Energy Dispersive X-Ray Spectroscopy analyses have proven that g-POSS is included in the gel structure and is homogeneously distributed throughout the network. More stable d-NC-DMA and d-NC-VP gels were obtained by incorporating N,N-dimethylacrylamide (DMA), or 1-vinyl-2-pyrrolidinone (VP) units, respectively, into g-POSS-linked starch gels, and the reaction kinetics were followed in situ. In SEM images, it was observed that d-NC-DMA had smaller pores and thicker pore walls compared to s-NC and d-NC-VP starch gels, and its mechanical strength was shown to be much superior by rheological tests, compression, and tensile analyses. In addition to increasing the mechanical strength of the gels, the potential of starch in protein release applications using amylase sensitivity has been demonstrated in vitro experiments using the model protein BSA.