| Bone tissue engineering is an important research field of tissue engineering, providing a feasible treatment for bone damage caused by a variety of reasons. Bone tissue engineering scaffolds have been widely used in bone regeneration as an vital component of bone tissue engineering. Bone tissue engineering scaffolds composed of diverse materials including metals, inorganic materials, polymer materials and so on. Each mentioned material has its own advantages and disadvantages, they can not fully meet the requirements of bone regeneration. Hence, finding an ideal scaffold is an important task in tissue engineering.Hydroxyapatite is the main inorganic component of bone, which has good biocompatibility, bioactivity and good osteoconductive as bone implant materials. But poor mechanical properties hinder its application when used as scaffold. Chitosan is a excellent material that has good biocompatible, biodegradable, antibacterial property. But, it can not carry bone implants because of low strength when used alone. Using chitosan to modify hydroxyapatite, the resulting material has the advantage of the two materials and the synergistic effect between the two phases gives excellent performance. However, its osteoconductive and osteoinductive need to be improved. Magnetic therapy is widely regarded as one of the effective methods for the bone-related disease treatments. The magnetic field can promote bone healing, improve bone density and the integration between bone and scaffold. Therefore, the scaffold can be further magnetic modified. The study includes the following three aspects:(1) Chitosan modified hydroxyapatite nanopowders were prepared by titrated co-precipitation method. The results show that:the prepared chitosan modified hydroxyapatite powders were nanoscale, nanoneedles HAP oriented along with c-axisation, the average length of nanopowders was 50nm-100nm, width was 5nm-7nm. CS was irregular distributed of HAP surface. With the increase of CS amount, CS functional groups has interaction with HAP. Cell toxicity results showed that the chitosan modified hydroxyapatite nanopowders was 0-1 grade of toxicity.(2) Chitosan modified hydroxyapatite scaffolds were prepared using pore-forming and molding method. The optimal preparation of the material was determined by orthogonal experiment. The results show that:the obtained scaffolds had porosity of 65.78%, compressive strength of 0.82Mpa, pore size of 100-500μm. The porous structure not only has non-uniform interconnected shape but also having a microporous structure. Degradation results show that needle-like calcium phosphate salts were generated in porous scaffolds during the degradation in simulated body fluid, the degradation rate reached 27.96% after 15 weeks. The biological activity of scaffolds showing 0-1 toxicity which meet the performance requirements of bone regeneration.(3) The magnetic modified chitosan/hydroxyapatite porous scaffolds were prepared by adding iron oxide nanoparticles. The results show that:the mechanical strength of the magnetic-modified scaffolds was increased to 0.86Mpa, porosity of 65%. A large change in hole shape and the structure did not occur. The pore size was 100-500μm, having a microporous structure. The addition of inorganic iron oxide phase component was determined by XRD and EDS analysis. The magnetic scaffolds had paramagnetic saturation magnetization with 1.476emu/g. Cell totoxicity results showed that magnetic scaffolds was 0-1 toxicity, did not represent a toxic reaction.
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