Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7755
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Article Citation - WoS: 40Citation - Scopus: 47Gelatin-Based 3d Conduits for Transdifferentiation of Mesenchymal Stem Cells Into Schwann Cell-Like Phenotypes(Elsevier Ltd., 2017) Uz, Metin; Büyüköz, Melda; Sharma, Anup D.; Sakaguchi, Donald S.; Alsoy Altınkaya, Sacide; Mallapragada, Surya K.In this study, gelatin-based 3D conduits with three different microstructures (nanofibrous, macroporous and ladder-like) were fabricated for the first time via combined molding and thermally induced phase separation (TIPS) technique for peripheral nerve regeneration. The effects of conduit microstructure and mechanical properties on the transdifferentiation of bone marrow-derived mesenchymal stem cells (MSCs) into Schwann cell (SC) like phenotypes were examined to help facilitate neuroregeneration and understand material-cell interfaces. Results indicated that 3D macroporous and ladder-like structures enhanced MSC attachment, proliferation and spreading, creating interconnected cellular networks with large numbers of viable cells compared to nanofibrous and 2D-tissue culture plate counterparts. 3D-ladder-like conduit structure with complex modulus of ∼0.4 × 106 Pa and pore size of ∼150 μm provided the most favorable microenvironment for MSC transdifferentiation leading to ∼85% immunolabeling of all SC markers. On the other hand, the macroporous conduits with complex modulus of ∼4 × 106 Pa and pore size of ∼100 μm showed slightly lower (∼65% for p75, ∼75% for S100 and ∼85% for S100β markers) immunolabeling. Transdifferentiated MSCs within 3D-ladder-like conduits secreted significant amounts (∼2.5 pg/mL NGF and ∼0.7 pg/mL GDNF per cell) of neurotrophic factors, while MSCs in macroporous conduits released slightly lower (∼1.5 pg/mL NGF and 0.7 pg/mL GDNF per cell) levels. PC12 cells displayed enhanced neurite outgrowth in media conditioned by conduits with transdifferentiated MSCs. Overall, conduits with macroporous and ladder-like 3D structures are promising platforms in transdifferentiation of MSCs for neuroregeneration and should be further tested in vivo. Statement of Significance This manuscript focuses on the effect of microstructure and mechanical properties of gelatin-based 3D conduits on the transdifferentiation of mesenchymal stem cells to Schwann cell-like phenotypes. This work builds on our recently accepted manuscript in Acta Biomaterialia focused on multifunctional 2D films, and focuses on 3D microstructured conduits designed to overcome limitations of current strategies to facilitate peripheral nerve regeneration. The comparison between conduits fabricated with nanofibrous, macroporous and ladder-like microstructures showed that the ladder-like conduits showed the most favorable environment for MSC transdifferentiation to Schwann-cell like phenotypes, as seen by both immunolabeling as well as secretion of neurotrophic factors. This work demonstrates the importance of controlling the 3D microstructure to facilitate tissue engineering strategies involving stem cells that can serve as promising approaches for peripheral nerve regeneration.Doctoral Thesis Preparation and Characterization of Polymeric Scaffolds for Nerve Tissue Engineering Applications(Izmir Institute of Technology, 2014) Büyüköz, Melda; Alsoy Altınkaya, Sacide; Erdal, Şerife EsraThe major goal in tissue engineering is to develop three-dimensional biomimetic scaffolds which can provide an optimal environment for cell adhesion, proliferation, differentiation and guide new tissue formation. In this study macroporous, nanofibrous gelatin scaffolds in the form of a disc and channeled conduit were prepared for nerve tissue engineering applications. Alginate microspheres have been integrated into the scaffolds to deliver nerve growth factor (NGF) to differentiate PC12 cells. Methods combining thermally induced phase separation technique with porogen leaching and injection molding were used to manifacture disc shaped and channeled nanofibrous scaffolds, respectively. Microcarriers loaded with NGF were fabricated by water-in-oil emulsification technique and attached in the scaffold by chemical crosslinking with carbodiimide reaction. The relationship among processing parameter, porosity, pore size, interpore connectivity and the mechanical properties were investigated. In addition release kinetics of NGF from the particles were determined and viability, proliferation and differentiation of PC12 cells in the scaffolds were evaluated. The fiber sizes of nanofibrous scaffolds were found similar to the size of natural collagen fiber bundles. In nanofibrous scaffolds, the dimensional stability and in vitro degredation rates improved when compared to solid walled scaffolds. The release rate of NGF from the particles was controlled by the alginate concentration and poly(L-lysine) coating. Integrating NGF into the nanofibrous gelatin scaffold in encapsulated form reduced amount of NGF and time required for the differentiation of PC12 compared to free NGF directly added to the cells.