| Silk fibroin and chitosan are both natural polymer material with good mechanical properties and biocompatibility. They have been increasingly studied for their tissue engineering application. The core of tissue engineering is to create propertied three-dimensional scaffold for cells survival and tissue formation. Some silk-based scaffold and chitosan-based scaffold have been studied. However, pure chitosan scaffold degradation rate is fast and lack of sufficient flexibility; while pure silk fibroin scaffold is fragile. For their further application in tissue engineering materials, modification of silk fibroin and chitosan is needed. Blending both components is a good idea, but there are certain difficulties in practice, e.g. chitosan is usually dissolved in acetic acid solution, while the silk fibroin very sensitive to acid at room temperature as it is prone to conformational change denaturation to be gel or phase separation.In the present work, we tried hard to employ a simple method to prepare the silk fibroin/chitosan three-dimensional scaffold, i.e., mixing the two materials in the weak acidic aqueous solution as co-solvent at room temperature, pouring the mixture into the appropriate mold and freezing and then, adding ethanol in low temperature to change conformation of silk fibroin and fix the shape of scaffold. We adjusted the proportion of the two components and other conditions of preparation to control the pore size of three-dimensional porous material, check the structure and morphology of the porous scaffold by SEM. We checked the influence of these factors on various properties of the regenerated silk fibroin/chitosan scaffold, such as the size of pores, water absorption and mechanical properties.Our results showed that, the porous structure of the materials obtained by this method was quite regular. We could adjust the internal pore size of the scaffold by change the concentration of regenerated silk fibroin. When the concentration of regenerated silk fibroin aqueous solution was reduced from16wt%to4wt%, the pore size of the scaffold was increased from60±20μm (16wt%RSF/1wt%CS) to100±6μm (4wt%RSF/1wt%CS). We could also adjust the internal pore size of the scaffolds by optimizing the freezing conditions as the pore size of the scaffold (4wt%RSF/1wt%CS) was increased from100±16μm to about176±29μm in such a case. The water absorbability of the RSF/CS scaffold we made was significantly superior to the pure RSF scaffold, so the blend scaffold is more suitable for the cells to adhesion and proliferation on it. Generally, the RSF/CS blend scaffold had better compression performance than that of pure RSF scaffold, and increased the proportion of chitosan in blends materials could enhance the elastic modulus of the blend scaffold. We also did the tests about the biocompatibility of the RSF/CS scaffold based on the culturing of L929mouse fibroblast cell. The results indicated that the RSF/CS scaffold could well support the growth of L929.Thus, the regenerated silk fibroin/chitosan blended scaffold showed better properties than those of pure silk protein or pure chitosan scaffold, while the internal pore size, water absorption and mechanical properties of the scaffold could be adjusted to meet different application needs, and it may become a promising tissue engineering materials. |
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