Abstract
The repair of large segmental bone defects remains a big challenge due to limited self-healing capacity of bone. Digging into the structure and composition of natural long bone let us realize that the periosteum cambium on the surface of diaphysis plays a crucial role in bone repair. In this study, we explored the feasibility of using a tissue-engineered periosteum-diaphysis substitute to repair the large segmental bone defects. To create an artificial periosteum cambium, bone marrow mesenchymal stem cells (BMSCs) and endothelial progenitor cells (EPCs) were co-cultured on electrospun silk fibroin (SF) fibrous membranes for mimicking the cellular composition and microstructure of cambium layer of the native periosteum. These SF membranes supported the adhesion and proliferation of both BMSCs and EPCs. In addition, we found that a 1:1 ratio of BMSCs and EPCs supported osteogenesis and angiogenesis optimally. This biomimetic periosteum layer was integrated with artificial diaphysis made of tubular SF scaffolds to construct a biomimetic periosteum-diaphysis substitute. Animal studies confirmed that the biomimetic periosteum-diaphysis substitutes promoted the repair of critical-size bone defects of rabbit radius. Furthermore, the transplanted biomimetic periosteum-diaphysis substitute could prevent the growth of fibrous tissues in the bone defect, and thus reduce the occurrence of nonunion. This study described a promising tissue engineering strategy for the repair of large segmental bone defects.
| Original language | English |
|---|---|
| Article number | 110505 |
| Journal | Composites Part B: Engineering |
| Volume | 252 |
| Early online date | 7 Jan 2023 |
| DOIs | |
| Publication status | Published - 1 Mar 2023 |
Funding
The repair of large segmental bone defects remains a big challenge due to limited self-healing capacity of bone. Digging into the structure and composition of natural long bone let us realize that the periosteum cambium on the surface of diaphysis plays a crucial role in bone repair. In this study, we explored the feasibility of using a tissue-engineered periosteum-diaphysis substitute to repair the large segmental bone defects. To create an artificial periosteum cambium, bone marrow mesenchymal stem cells (BMSCs) and endothelial progenitor cells (EPCs) were co-cultured on electrospun silk fibroin (SF) fibrous membranes for mimicking the cellular composition and microstructure of cambium layer of the native periosteum. These SF membranes supported the adhesion and proliferation of both BMSCs and EPCs. In addition, we found that a 1:1 ratio of BMSCs and EPCs supported osteogenesis and angiogenesis optimally. This biomimetic periosteum layer was integrated with artificial diaphysis made of tubular SF scaffolds to construct a biomimetic periosteum-diaphysis substitute. Animal studies confirmed that the biomimetic periosteum-diaphysis substitutes promoted the repair of critical-size bone defects of rabbit radius. Furthermore, the transplanted biomimetic periosteum-diaphysis substitute could prevent the growth of fibrous tissues in the bone defect, and thus reduce the occurrence of nonunion. This study described a promising tissue engineering strategy for the repair of large segmental bone defects.To support the artificial periosteum and promote bone regeneration, an SF tubular scaffold with directionally connected pores was utilized as biomimetic diaphysis (Fig. 1F). The pores of these tubular scaffolds were oriented with pore diameters ranging from 20 to 100 μm and a porosity of approximately 60%. It was reported that the minimum pore size necessary for significant bone growth was 75–100 μm [28], while the micropores could facilitate the exchange of nutrients, oxygen, and the transport of waste. Subsequently, electrospun SF membranes were wrapped on the surface of SF tubular scaffolds to form combined periosteum-bone substitute. Obtained SEM images clearly showed the membrane layer and the hollow scaffold structure. Photographs of the scaffold further illustrated the tubular structure (Fig. 1G). In vitro degradation assays showed that 40% of SF was partially degraded within 2 months (Fig. 1H).To evaluate the effect of electrospun SF membranes on the proliferation of co-cultured cells, BMSCs and EPCs were seeded on the membranes for 1, 3 and 5 days at different ratios (1:0, 0:1, 2:1, 1:1 and 1:2). Cell proliferation assays were performed using cell tracking (Fig. 2A) and the CCK-8 cell proliferation assay (Fig. 2C). The results showed that both BMSCs (green) and EPCs (red) grew well on the membranes. The number of both cells increased significantly, and there was no significant difference between the proliferation of the two different cell populations (Fig. 2A, C). The morphology of cells on the SF membranes was also determined by SEM. As shown in Fig. 2B, cells spread well on the nanofibers at 3 days. These results indicated the excellent biocompatibility of electrospun SF membranes that were able to support the proliferation of co-cultured cells.The authors are grateful for the funding provided for this study by the National Key Research and Development Program of China (2020YFC1107401), the National Natural Science Foundation of China (81925027, 82111530157, 31872748), the Royal Society (IEC\NSFC\201166), Jiangsu Provincial Special Program of Medical Science (BL2012004), Science and Technology Innovation Project of Foshan City (1920001000025) and the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions. The authors are grateful for the funding provided for this study by the National Key Research and Development Program of China ( 2020YFC1107401 ), the National Natural Science Foundation of China ( 81925027 , 82111530157 , 31872748 ), the Royal Society ( IEC\NSFC\201166 ), Jiangsu Provincial Special Program of Medical Science ( BL2012004 ), Science and Technology Innovation Project of Foshan City ( 1920001000025 ) and the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions .
Keywords
- Bone repair
- Diaphysis
- Electrospun membrane
- Periosteum cambium
- Silk fibroin