Reconstruction of tracheal window-shape defect by 3D printed polycaprolatone scaffold coated with Silk Fibroin Methacryloyl

Tracheal resection and end-to-end anastomosis has been the standard clinical approach for the treatment of most airway diseases, especially invading the lower trachea or carina. However, when long-length (exceeding 2 cm in children or 5 cm in adults) tracheal circular resection is performed, tracheal replacement therapy is often required. In this study, we aimed to utilize autologous tracheal epithelia and bone marrow mesenchymal stem cells (BMSCs) as the seeding cells, utilize polycaprolactone (PCL) coated with Silk Fibroin Methacryloyl (SilMA) as the scaffold to carry the cells and Kartogenin (KGN). Firstly, SilMA with the concentration of 10%, 15% and 20% was made, and the experiment of swelling and degradation was performed. With the increase of the concentration, the swelling ratio decreased, the degradation progress slowed down. Upon the result of CCK-8 test and HE staining of 3D co-culture, the 20% SilMA was selected. Next, SilMA and the cells attached to SilMA were characterized by scanning electron microscopy (SEM). Furthermore, in vitro cytotoxicity test shows that 20% SilMA has good cytocompatibility. The hybrid scaffold was then made by PCL coated with 20% SilMA. The mechanical test shows this hybrid scaffold has better biomechanical properties. In vivo tracheal defect repair assays were done to evaluate the effect of the hybrid substitution. H&E staining, immunohistochemical (IHC) and immunofluorescence (IF) staining showed that this hybrid substitution ensured the viability, proliferation and migration of epithelium. This study is expected to provide new strategies for the fields of tracheal replacement therapy needing mechanical properties and epithelization.