چكيده به لاتين
Fabrication of appropriate scaffolds for soft tissue repair is very challenging due to the complex three-dimensional structure and variable mechanical properties of these tissues. 3D scaffolds provide mechanical properties more consistent with soft tissue and can mimic complex and heterogeneous structures similar to soft tissue. Injectable biomaterials are beneficial because they can be used in minimally invasive surgical procedures and fill the defect area in a coordinated and complete manner, as well as carrying various therapeutic agents such as drugs, growth factors, and cells. All of these cases lead to a reduction in the risk of infection, pain and length of treatment after surgery. Since natural polymers have biocompatibility, biodegradability and extracellular matrix similar to natural body tissues, they show better compatibility with host tissues and cells and are the best option for making injectable hydrogels for soft tissue repair. Among the natural polymers, silk fibroin with more than 16 amino acids has been widely used in the field of body tissue regeneration due to its excellent biological and mechanical properties. According to the cases mentioned in this research, silk/tyraminated alginate composite injectable hydrogels containing polydopamine nanoparticles were made. In the first stage, pure tyraminated alginate solution 1% by weight containing polydopamine nanoparticles and pure silk fibroin solution 4% by weight with volume percentages of 75.25, 50.50 and 25.75 were mixed with each other and then with the combination of HRP and 𝐻2𝑂2sol to gel conversion process was done. Also, the formation of hydrogel network was confirmed by FTIR test. Using the MTT test, the cytotoxicity of the scaffolds was checked, and the cell viability above 85% was obtained for all groups and all time points. The percentage of porosities in the substitution test varied from 55% to 87.5%, their water absorption varied from 682% to 3228%, and their degradability varied from 21% to 95%. Morphological evaluation, measurement of the size of pores and adhesion of fibroblast cells on the surface of the scaffolds was done by scanning electron microscope (FESEM) and according to the observations of the structure of the scaffolds, they are completely porous with the size of the pores between 20 to 80 micrometers, having a good potential for cell adhesion, proliferation and penetration. Mechanical analyses showed also that the young modulus of theses hydrogels is about 0.06 to 0.15 Kpa that is suitable for soft tissues. Regarding to achieved results, it can be said this injectable hydrogel is a good choice to be used in the field of tissue engineering
