DLP-printed biomimetic dual-layer scaffold based on SilMA hydrogel with controlled release of chondrocytes for osteochondral defect reconstruction.

The aging population and the increasing prevalence of sports-related injuries have made osteochondral defects a major global health issue. The repair of osteochondral defect is still a challenge due to poor regeneration of both cartilage and bone tissues. To address this issue, this study developed a biomimetic dual-layer scaffold based on SilMA hydrogel using DLP technology. For the upper area of scaffold, PEGDA was used to enhance the mechanical strength of SilMA hydrogel, making it more suitable for the environment of articular cartilage, while cell microspheres were incorporated as 3D carriers for chondrocyte encapsulation and delivery, providing seed cells for regeneration. For the lower area of scaffold, the lower part was loaded with hydroxyapatite to promote bone tissue regeneration. This study systematically investigated the design of 3D printable inks for osteochondral defect repair, exploring the effects of PEGDA and HAp on the printability and physicochemical properties of SilMA bioink through orthogonal experiments. In vitro and in vivo results demonstrated that the biomimetic dual-layer scaffold exhibited good biocompatibility, promoting cell adhesion and proliferation. Thus, these dual-layer scaffolds loaded with chondrocyte microspheres effectively promote the synchronous repair of both articular cartilage and subchondral bone.