Browsing by Author "Sahin, Fikrettin"

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Citation Count: 0
ALGINATE-BASED CELL ENCAPSULATION USING DIFFERENT CROSSLINKER ELEMENTS
(World Scientific Publ Co Pte Ltd, 2024) Acar, Özge; Tuncer, A. Alperen; Sahin, Fikrettin; Kose, Gamze Torun; Aysan, Erhan; Genetik ve Biyomühendislik / Genetic and Bio-Engineering
Alginate microcapsules are the most frequently used materials for cell transplantation. Different crosslinkers affect crosslinking affinity, which has a significant influence on microcapsule properties. The objective was to prepare in vitro microcapsules using calcium, barium, iron, manganese, nickel, and strontium as divalent cations to observe their potential for use in cell transplantation. Sodium alginate was added dropwise to the individually prepared crosslinkers to observe diffusion-based gelling. Alginate microcapsules were investigated regarding capsule stability, physiological properties, and cell viability. After 30 days of incubation, cell viability was greater than 90% for the cell-encapsulated microcapsules when crosslinked with CaCl2 and NiCl2. Viability decreased in the following order: CaCl2 > NiCl2 > BaCl2 > SrCl2 > MnCl2 > FeCl2. A compression test was performed to investigate the required force to deform 30% of microcapsules, and only MnCl2, FeCl2 (180mM), and NiCl2 (50mM) demonstrated higher resistance to the applied force than CaCl2. Except for the FeCl2 group, all cell-encapsulated microcapsules remained intact for 45 days. Potential sensitivities to CaCl2 during cell transplantation may compel alternative crosslinker usage, and our study revealed that NiCl2 and BaCl2 can be used as alternative crosslinkers to CaCl2 due to their high cell viability and consistent stability.
Citation Count: 1
Combined approaches for detecting polypropylene microplastics in crop plants
(Academic Press Ltd- Elsevier Science Ltd, 2023) Acar, Özge; Unek, Ceren; Sut, Pinar Akkus; Acar, Ozge Karabiyik; Yurtsever, Meral; Sahin, Fikrettin; Genetik ve Biyomühendislik / Genetic and Bio-Engineering
Microplastics (MPs) pollution in the terrestrial environment causes accumulation in crop plants. Consumption of these plants may have negative effects on human health. Therefore, it is crucial to analyze MPs accumulation in the plants. The aim of this study is to determine polypropylene (PP) particles in plants exposed to label-free PP for 75 days. In order to extract PP from organic matter, a two-step alkaline and wet peroxide oxidation chemical digestion method was applied to the roots, stems, and leaves of maize and wheat. The PP particles in the digested solutions were detected by the Nile red staining method, which has not been used previously in the detection of MPs in plants. Nile red stained PP particles mostly accumulated in the roots of wheat and the stems of maize plants. Statistical analysis revealed that the maize deposited more and larger PP particles regardless of the location. Moreover, the presence of PP particles in the digestion solutions was proved by the heating method. The PP particles on the glass slides were transformed into different shapes due to melting.
Citation Count: 17
Effect of a novel bioceramic root canal sealer on the angiogenesis-enhancing potential of assorted human odontogenic stem cells compared with principal tricalcium silicate-based cements
(Univ Sao Paulo Fac Odontologia Bauru, 2020) Olcay, Keziban; Çiftçioğlu, Elif; Yalçın Ülker, Gül Merve; Ulker, Gul Merve Yalcin; Ogut, Emine Esen; Ciftcioglu, Elif; Sahin, Fikrettin; Endodonti / Endodontics; Ağız,Diş ve Çene Cerrahisi / Oral, Dental and Maxillofacial Surgery
Objective: This study evaluated the angiogenesis-enhancing potential of a tricalcium silicate-based mineral trioxide aggregate (ProRoot MTA), Biodentine, and a novel bioceramic root canal sealer (Well-Root ST) in human dental pulp stem cells (hDPSCs), human periodontal ligament stem cells (hPLSCs), and human tooth germ stem cells (hTGSCs). Methodology: Dulbecco's modified Eagle's medium was conditioned for 24 h by exposure to ProRoot MTA, Biodentine, or Well-Root ST specimens (prepared according to the manufacturers' instructions). The cells were cultured in these conditioned media and their viability was assessed with 3-(4,5-dimethyl-thiazol-2-yl)-5-(3-carboxy-methoxy-phenyl)-2-(4-sulfo-phenyl)-2H tetrazolium (MTS) on days 1, 3, 7, 10, and 14. Angiogenic growth factors [platelet-derived growth factor (PDGF), basic fibroblast growth factor (FGF-2), and vascular endothelial growth factor (VEGF)] were assayed by sandwich enzyme-linked immunosorbent assay (ELISA) on days 1, 7, and 14. Human umbilical vein endothelial cell (HUVEC) migration assays were used to evaluate the vascular effects of the tested materials at 6-8 h. Statistical analyses included Kruskal-Wallis, Mann-Whitney U, and Friedman and Wilcoxon signed rank tests. Results: None of tricalcium silicate-based materials were cytotoxic and all induced a similar release of angiogenic growth factors (PDGF, FGF-2, and VEGF) (p>0.05). The best cell viability was observed for hDPSCs (p<0.05) with all tricalcium silicate-based materials at day 14. Tube formation by HUVECs showed a significant increase with all tested materials (p<0.05). Conclusion: The tricalcium silicate-based materials showed potential for angiogenic stimulation of all stem cell types and significantly enhanced tube formation by HUVECs.
Citation Count: 1
In vitro tooth-shaped scaffold construction by mimicking late bell stage
(Tubitak Scientific & Technological Research Council Turkey, 2020) Yalçın Ülker, Gül Merve; Yalcin Ulker, Gul Merve; Cumbul, Alev; Uslu, Unal; Yilmaz, Sahin; Bozkurt, Batuhan Turhan; Sahin, Fikrettin; Ağız,Diş ve Çene Cerrahisi / Oral, Dental and Maxillofacial Surgery
Neogenesis of osseous and ligamentous interfacial structures is essential for the regeneration of large oral or craniofacial defects. However, current treatment strategies are inadequate in renewing supporting tissues of teeth after trauma, chronic infections or surgical resection. Combined use of 3D scaffolds with stem cells became a promising treatment option for these injuries. Matching different scaffolding materials with different tissues can induce the correct cytokines and the differentiation of cells corresponding to that particular tissue. In this study, a hydroxyapatite (HA) based scaffold was used together with human adipose stem cells (hASCs), human bone marrow stem cells (hBMSCs) and gingival epithelial cells to mimic human tooth dentin-pulp-enamel tissue complexes and model an immature tooth at the late bell stage in vitro. Characteristics of the scaffold were determined via SEM, FTIR, pore size and density measurements. Changes in gene expression, protein secretions and tissue histology resulting from cross-interactions of different dental tissues grown in the system were shown. Classical tooth tissues such as cementum, pulp and bone like tissues were formed within the scaffold. Our study suggests that a HA-based scaffold with different cell lineages can successfully mimic early stages of tooth development and can be a valuable tool for hard tissue engineering.
Citation Count: 2
Production of parathyroid-like cells from thyroid stem cells in co-culture environment
(Lippincott Williams & Wilkins, 2022) Acar, Özge; Nozhatzadeh, Gulcin Delal; Tuncer, Alperen; Kose, Gamze Torun; Hacihasanoglu, Ezgi; Sahin, Fikrettin; Aysan, Erhan; Genetik ve Biyomühendislik / Genetic and Bio-Engineering
Background:Parathyroid-like cells were aimed to be developed using cells isolated from thyroid since their embryological origins are the same. Method:Activin A and sonic hedgehog (Shh) are the proteins used in differentiation (dif) medium. Parathyroid and thyroid cells were cultured in a 3-dimensional environment and divided into five groups: thyroid standard (st) medium, thyroid dif medium, parathyroid st medium, thyroid-parathyroid co-culture st medium, and thyroid-parathyroid co-culture dif medium. Throughout 28 days of incubation, groups were investigated by carrying out the live dead assay, confocal microscopy, real-time PCR, immunohistochemistry and biochemical assays. Results:Thyroid-parathyroid co-culture cells grown in dif medium exhibited upregulated expressions of parathormone (PTH) (5.1-fold), PTH1R (3.6-fold), calcium sensing receptor (CaSR) (8.8-fold), and loss of thyroid-specific thyroid transcription factor 1 (TTF1) expression when compared to the thyroid st medium group. PTH secretion decreased by 35% in the parathyroid st medium group and 99.9% in the thyroid-parathyroid co-culture st medium group but decreased only 3.5% in the thyroid-parathyroid co-culture dif medium group on day 28. Conclusion:Using Activin A and Shh proteins, thyroid stem/progenitor cells were differentiated to parathyroid-like cells successfully in a co-culture environment. A potentially effective novel method for cell differenatiation is co-culture of cells having the same embryological origin.