3D-printed regenerative polycaprolactone/silk fibroin osteogenic and chondrogenic implant for treatment of hip dysplasia

Hip dysplasia is a developmental disorder that resulted in insufficient acetabular coverage. Current surgical treatments are technically demanding, complex, invasive, and often lead to associated complications. Therefore, the development of regenerative implants that fit to the bone and induce osteogenesis and chondrogenesis is in high demand. In this study, an implant was developed in which the osteogenic part was 3D printed using polycaprolactone (PCL), crosslinked with dopamine, and subjected to surface mineralization; while the chondrogenic part was prepared using silk fibroin (SF) and bone morphogenetic protein 2. Physical and chemical characterization of the implant was conducted using energy dispersive spectrometry (EDS) and scanning electron microscopy (SEM). The viability of rabbit adipose-derived mesenchymal stem cell (ADSCs) was evaluated by LIVE/DEAD staining and alamarBlue. SEM showed crosslinked polydopamine and crystals produced by mineralization on the surface of the implant, while EDS revealed the deposition of calcium and phosphorus on its surface. LIVE/DEAD staining and alamarBlue assay demonstrated that both the PCL and SF parts exhibit good biocompatibility. An in vivo hip dysplasia model was established in rabbits using a bone rongeur to make acetabular defects. Macroscopic observation, histological analysis, postoperative imaging, and biomechanical analysis of this model demonstrated the osteogenic and chondrogenic effects of the implant, and revealed that it provided good coverage of the femoral head, restoring the anatomical morphology of the acetabulum. Thus, this novel regenerative and cytocompatible implant provides a potentially viable strategy for the treatment of hip dysplasia.