Date

2006

Author

Güven, Sinan

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Tissue engineering has the potential to create new tissue and organs from cultured cells for transplantation. Biodegradable and biocompatible scaffolds play a vital role in the transfer of the cultured cells to a new tissue. Various scaffolds for soft tissue engineering have been developed, however there is not any structure totally mimicking the natural extracellular matrix (ECM), ready to use. In this study biodegradable and biocompatible scaffolds were developed from natural polymers by tissue engineering approach and tested in vitro. Scaffolds (SCAF) were prepared with freeze drying and composed of chitosan, gelatin and dermatan sulfate. Polymer solutions were treated with different stirring rates (500 rpm and 2000 rpm), freezing temperatures (-20 °C and -80 °C) and molding (cylindrical mold and petri dish) to achieve porous structure in order to provide sufficient space for cell growth and extracellular matrix production. Among the prepared scaffolds at different conditions, the scaffolds prepared at 500 rpm and frozen at -80 °C, (SCAF-1), was chosen for further studies. These scaffolds achieved 0.512 MPa tensile strength, with 9.165 MPa tension modulus and 3.428 MPa compression modulus. Besides in lysozyme containing degradation medium they conserved their integrity and lost about 30 % of their initial weight in 30 days period. Mechanical and enzymatic degradation tests showed that scaffolds have physical integrity for the tissue engineering applications. To mimic the natural tissue and enhance cell growth, biologically active arginine glycine - aspartic acid - serine (RGDS) peptides and platelet derived growth factor-BB (PDGF-BB) were immobilized on the SCAF-1. Fibroblast cells were seeded on the scaffolds containing RGDS, (SCAF-1-RGDS), and PDGF-BB, (SCAF-1-RGDS-PDGF), and incubated in media either free of serum or containing serum. Scaffolds immobilized with RGDS and PDGF-BB had the highest attached cell number by the day 15. Florescence microscopy studies also indicated that RGDS and RGDS-PDGF modified scaffolds were more suitable than controls, (SCAF-1), for cell growth and proliferation. According to scanning electron microscopy (SEM) results, modified scaffolds demonstrated better cell morphology and attachment of cells. Based on the obtained results, it can be concluded that RGDS-PDGF immobilized chitosan-gelatin-dermatan sulfate systems have a great potential to be used as a scaffold for soft tissue engineering applications.

Subject Keywords

Bioengineering.

URI

http://etd.lib.metu.edu.tr/upload/3/12607436/index.pdf
https://hdl.handle.net/11511/16271

Collections

Graduate School of Natural and Applied Sciences, Thesis