Construction Of Tissue-engineered Scaffolds In Vitro By Using Medical Gelatin Sponge And Sodium Alginate Hydrogel

Normal human articular cartilage has excellent biomechanical properties and can play a buffering role between joints.The integrity of cartilage plays an important role in promoting body movement.Therefore,the integrity of articular cartilage is very important.However,articular cartilage injury is a common type of injury in orthopedics.Due to the lack of blood vessels and blood supply of articular cartilage,it is very difficult to self repair.The injury of articular cartilage is usually accompanied by the injury of the infraarticular bone,which can further develop into osteoarthritis,which has a huge impact on the life of patients.At present,the clinical treatment of cartilage injury,such as cartilage drilling,periosteum and perichondrium transplantation,subchondral bone drilling,artificial joint replacement and so on,is not ideal.In recent years,the rapid development of tissue engineering provides a new way and method for the repair of cartilage and subchondral bone.As one of the core contents of tissue engineering,scaffold plays an important role.The traditional cartilage tissue engineering is to implant chondrocytes on the scaffold,on the one hand,the implantation rate of cells is relatively low;on the other hand,from the perspective of repair,cartilage damage is usually accompanied by the injury of subchondral bone,and the repair efficiency of subchondral bone is limited simply by using chondrocytes to repair cartilage and ignoring the repair of subchondral bone.Therefore,we consider whether we can construct a composite scaffold,and implant chondrocytes in the upper part of the scaffold and osteoblasts in the lower part of the scaffold.The difficulty of composite support lies in how to choose the right material.Therefore,based on the in-depth understanding of articular cartilage and articular subchondral bone,we choose medical gelatin sponge and sodium alginate hydrogel to build composite scaffolds.Previous studies have shown that the biocompatibility,pore size ratio and mechanical properties of medical gelatin sponge and sodium alginate can support their use as scaffold materials for cartilage tissue engineering.The feasibility of gelatin sponge alginate hydrogel composite scaffolds in cartilage tissue engineering is elucidated,which provides theoretical basis and technical support for the regeneration and repair of articular cartilage defects with new ideas.Method:1.to construct the underlying scaffold containing osteoblastsThe osteoblasts MC3T3-E1 were expanded and planted on the gelatin sponge.The osteoblasts were cultured in vitro to induce the differentiation of osteoblasts.The adherence,proliferation and differentiation of osteoblasts on the scaffold surface were monitored.2.Preparation and culture of composite scaffolds containing cellsSodium alginate solution containing chondrocytes was crosslinked onto CaCl?gelatin solution to form sodium alginate hydrogel on the gelatin sponge scaffold.The scaffold was cultured and the attachment,proliferation and differentiation of osteoblasts on the scaffold surface and the proliferation of chondrocytes in the hydrogel were detected.3.Detection of composite scaffolds containing cellsThe expression of alkaline phosphatase and glycosaminoglycan in the composite scaffolds was determined.Result:MC3T3-E1 grew well on the gelatin sponge scaffold,and the number of living cells on the scaffold increased with time.2.sodium alginate hydrogel and gelatin sponge scaffold joined well.Pig knee cartilage cells and MC3T3-E1 grew well on alginate hydrogel and gelfoam sponge respectively.Stained by dead cells showed that the number of two living cells on scaffolds increased over time.3.the expression of alkaline phosphatase and glycosaminoglycan increased in cells on composite scaffolds compared with those in pure gelatin sponge and sodium alginatehydrogel alone.Conclusion: the scaffold constructed by sodium alginate solution can be successfully cross-linked with CaCl solution.The gelatin sponge alginate hydrogel composite scaffold can promote the proliferation and differentiation of MC3T3-E1 cells and pig knee chondrocytes better than simple gelatin sponge scaffolds and simple alginate scaffolds.The application of gelatin sponge sodium alginate hydrogel composite scaffold in articular cartilage tissue engineering has a good application prospect.