Tissue Adhesive Silk Fibron-based Joint Surface Paint For Articular Cartilage Regeneration

Osteoarthritis is a high incidence of osteoarthritis in the elderly population,mainly manifested in the destruction of articular cartilage secondary to intra-articular inflalmation.The early clinical manifestations of osteoarthritis are diffuse,various sizes of cartilage superficial defect.In the early stage,the injury of daily activities or motor joints will result in cartilage tearing,the stripping of cartilage mass,the formation of full-layer injury and small superficial injury or diffuse shallow injury of different depth.It is more difficult to repair cartilage tissue due to its limited self-repair ability,especially the unique structure and physiological and pathological characteristics of superficial cartilage.At the same time,due to the limited treatment of defects can not be well dealt with,and has a great impact on the later stage of the disease,so the research and development of superficial cartilage defects is of great signifcance.In view of the fact that superficial cartilage does not have the ability to repair spontaneously,the aim of this study is to promote the process of cartilage self-repair by repairing defects in situ with biomaterials,and to block the further wear of cartilage and the deterioration of disease.In this study,the natural silk fibroin microspheres were modified by surface modification,and small molecule nb(o-nitrobenzene)was connected to the surlfce of the microspheres.The silk fibroin microspheres were anchored in the cartilage defects by binding to the rich amino groups in the cartilage tissue.The natural silk fibroin with good biocompatibility was used to adsorb the stem progenitor cells and chondrocytes in the articular cavity and around the cartilage defect so as to promote the repair of cartilage at the defect site.The results showed that the modified fibroin microspheres were successfully attached to the cartilage defects by the "bridging" action of small molecule nb,and the modified fibroin microspheres still had good biocompatibility.Cells can be attracted to migrate to the microspheres,and the microspheres in the three-dimensional space of attachment and growth.Finally,the effect of modified silk fibroin microspheres "joint paint" on the repair of articular cartilage tissue was verified on the rabbit knee joint.In this paper,according to the physiological and pathological characteristics of superficial cartilage defects,we prepared a new biomaterial,which can conveniently repair cartilage injury in situ,avoid its deterioration to osteoarthritis,and provide a new method for clinical treatment of osteoarthritis in the future.