| Bone lesions and defects, which often arise from trauma, skeletal diseases or tumor resections, can cause pain, significant limitation in quotidian activities and even lead to death. However, the large defect of bone is difficult to heal by the capacity of bone regeneration and self-healing. Traditional treatment of bone defects is frequently accomplished by autologous bone grafting and the use of alloplastic implants. In general, the current standard treatment of bone defect is autografts, which are often not precluded by risks of disease transfer and histo-incompatibilities, but a lack of sufficient autograft tissue. On the other hand, the use of alloplastic implants is associated with risks of pathogen transmission, infection transmission and even implants failure. Tissue engineering has emerged as a potential alternative strategy to regenerate bone. Biomaterial scaffolds play central roles in regenerative medicine and tissue engineering, which promote tissue regeneration by directing cellular behaviors and functions. Accordingly, the essential properties required for an ideal scaffold in bone tissue engineering includes good osteoconductivity even osteoinductivity, mineralization, and proper mechanical properties, highly porous with interconnected structures and composed of biocompatible and degradable biomaterials. Hence, it is desirable to devise a biomimetic bone tissue engineering scaffold for the repair of bone defect.Among various biomaterials, hydroxyapatite (HA), the main inorganic component of bone, has attracted much attention for large bone defects regeneration, due to its good osteoinductivity, osteoconductivity, and osteointegration. Cellulose nanocrystals (CMC), obtained by sulphuric acid hydrolysis of native cellulose, has been studied as a carrier of demineralized bone matrix with encouraging results in vivo. However, the low compressive strength of HA and CNC limited they application to non/low-load bearing bone repairs. To improve the compressive strength of HA and CNC, uniform distribution of HA or CNC particles in the polymer matrix to fabricate functional scaffolds is the traditional fabrication method. Chen et al prepared bioactive biogass/chitosan/CNC composite hydrogel for bone regeneration. The results reported the composite hydrogel had the hemostasis effect and its biodegradation also led to the functional reconstruction of bone defects. Silk fibroin (SF), a natural macromolecular polymer derived from the silkworm Bombyx mori, has superior mechanical strength, excellent biocompatibility, long-term biodegradability and ease of processing. Various strategies have been investigated the possibility of HA/SF scaffold as bone defect repair materials, and the results suggest that HA/SF scaffolds can be an excellent source for bone regenerationoThe purpose of this study was to design and characterize a novel biomimetic scaffold for the repair of criticalsized calvarial defect. In this study, we developed a new hydroxyapatite/carboxymethyl cellulose/silk fibroin (HA/CNC/SF) scaffold by mixing SF solution, HA and CNC nanoparticles. The scaffold was fabricated by freeze-drying. The average pore size and porosity of the HA/CNC/SF scaffolds were 110 μm and 90%, respectively. Furthermore, the thermostability and mechanical properties of the scaffolds was significantly higher than that of either SF, CNC/SF or HA/SF scaffolds. And the composite scaffold exhibited excellent biocompatibility and superior osteoconductive. Hence, we evaluated the efficacy of the HA/CNC/SF scaffold for bone regeneration in the rat calvarial defect model. The results revealed that the calvarial defect of rat was healed with new-formed bone within 12 weeks of implantation and degradation rate of scaffold matched well with the regeneration rate of bone. Therefore, the HA/CNC/SF scaffold is deemed as a strong potential candidate for the repair of bone defects in bone tissue engineering. |
PDF Full Text Request