Chemistry / Kimya

Permanent URI for this collectionhttps://hdl.handle.net/11147/4072

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Department: search.filters.department.İzmir Institute of Technology. BioengineeringPublisher: search.filters.publisher.John Wiley and Sons Inc.

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Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 27
    Citation - Scopus: 28
    Biocomposite Scaffolds for 3d Cell Culture: Propolis Enriched Polyvinyl Alcohol Nanofibers Favoring Cell Adhesion
    (John Wiley and Sons Inc., 2021) Bilginer, Rumeysa; Özkendir İnanç, Dilce; Arslan Yıldız, Ahu; Arslan Yıldız, Ahu; Yıldız, Ümit Hakan; 04.01. Department of Chemistry; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
    The objective of this work is generation of propolis/polyvinyl alcohol (PVA) scaffold by electrospinning for 3D cell culture. Here, PVA used as co-spinning agent since propolis alone cannot be easily processed by electrospinning methodology. Propolis takes charge in maximizing biological aspect of scaffold to facilitate cell attachment and proliferation. Morphological analysis showed size of the electrospun nanofibers varied between 172-523 nm and 345-687 nm in diameter, for non-crosslinked and crosslinked scaffolds, respectively. Incorporation of propolis resulted in desired surface properties of hybrid matrix, where hybrid scaffolds highly favored protein adsorption. To examine cell compatibility, NIH-3T3 and HeLa cells were seeded on propolis/PVA hybrid scaffold. Results confirmed that integration of propolis supported cell adhesion and cell proliferation. Also, results indicated electrospun propolis/PVA hybrid scaffold provide suitable microenvironment for cell culturing. Therefore, developed hybrid scaffold could be considered as potential candidate for 3D cell culture and tissue engineering.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Transition-Metal Direct C-H Arylation of Thiophene in Aqueous Media Via Potassium Peroxymonosulfate
    (John Wiley and Sons Inc., 2019) Özenler, Sezer; Özenler, Sezer; Kaya, Hakan; Yıldız, Ümit Hakan; Elmacı, Nuran; Elmacı Irmak, Nuran; Yıldız, Ümit Hakan; 04.01. Department of Chemistry; 01. Izmir Institute of Technology; 04. Faculty of Science
    This study covers the use of potassium peroxymonosulfate (PPS) which, is a mild and inexpensive catalyst, for direct coupling of C-H/C-H for water soluble thiophene. The 3-(4-methyl-3 '- thienyloxy)propyltriethylammonium bromide (M1) has been selected as model monomer that reacted PPS in 2.0, 0.20 and 0.020 monomer to PPS ratio. The reaction has been monitored via NMR spectroscopy revealing the monomer consumption and formation of dimers to tetramers as well as completion of reaction within 15 minutes. Resultant product is easily collected without tedious work up steps. The computational calculation has optimized the regularity of the coupling as head to tail, tail to tail, head to tail (HT-TT-HT) for tetramer. The regularity of tetramer which is further satisfied via NMR analysis showing emergence of new peaks at 3.56 and 4.48. The shifts in the UV maximum of reactive species have been monitored by absorbance spectroscopy showing time dependent red shift corresponds to growing from monomer to tetramers. The reaction has self-stopped due to low solubility of moderate condensates (higher than trimer), however further experiments have performed in water-organic mixtures showed great promises to obtain higher condensates.
  • Article
    Citation - WoS: 15
    Citation - Scopus: 17
    Improved Activity of Alpha-L From Geobacillus Vulcani Gs90 by Directed Evolution: Investigation on Thermal and Alkaline Stability
    (John Wiley and Sons Inc., 2019) Sürmeli, Yusuf; İlgü, Hüseyin; Şanlı Mohamed, Gülşah; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    alpha-L-Arabinofuranosidase (Abf) is a potential enzyme because of its synergistic effect with other hemicellulases in agro-industrial field. In this study, directed evolution was applied to Abf from Geobacillus vulcani GS90 (GvAbf) using one round error-prone PCR and constructed a library of 73 enzyme variants of GvAbf. The activity screening of the enzyme variants was performed on soluble protein extracts using p-nitrophenyl alpha-L-arabinofuranoside as substrate. Two high activity displaying variants (GvAbf L307S and GvAbf Q90H/L307S) were selected, purified, partially characterized, and structurally analyzed. The specific activities of both variants were almost 2.5-fold more than that of GvAbf. Both GvAbf variants also exhibited higher thermal stability but lower alkaline stability in reference to GvAbf. The structural analysis of GvAbf model indicated that two mutation sites Q90H and L307S in both GvAbf variants are located in TIM barrel domain, responsible for catalytic action in many Glycoside Hydrolase Families including GH51. The structure of GvAbf model displayed that the position of L307S mutation is closer to the catalytic residues of GvAbf compared with Q90H mutation and also L307S mutation is conserved in both variants of GvAbf. Therefore, it was hypothesized that L307S amino acid substitution may play a critical role in catalytic activity of GvAbf. (C) 2018 International Union of Biochemistry and Molecular Biology, Inc.