Optimization of 3D Alginate Scaffold Properties with Interconnected Porosity Using Freeze-drying Method for Cartilage Tissue Engineering Application

Alginate scaffolds are extensively used in bone and cartilage tissue engineering because of their chemical similarity to the extracellular matrix. However, for the successful replacement of hard tissue, the properties of alginate scaffolds should be tailored. In this study, for the first time, we optimized the porosity, degradation rate, mechanical, and osteogenic properties of alginate scaffolds by the freeze-drying method. The freeze-drying method was used to prepare different concentrations of alginate scaffolds (4, 8, and 16% (w/v)). Their porosity, mechanical properties, surface-wetting behavior, and osteogenic properties were characterized. The results showed that the 8% (w/v) alginate scaffold had an interconnected porosity of about 80%, a hydrophilic surface with a contact angle of water on the surface of 39 degrees +/- 0.56, and compressive strength of 2.7 MPa. This concentration of alginate also showed the degradation rate of 70% in Dulbecco's Modified Eagle's Medium (DMEM) with fetal bovine serum. The periodontal ligament stem cells culture results confirmed that the 8% alginate scaffold had good biocompatibility and cell differentiation ability and it could enhance cell ingrowth and attachment. These results showed that the modified 8% (w/v) alginate scaffold is a good candidate in cartilage and bone tissue replacement.