Preparation Of Fe₃O₄/CaP Core-Shell Magnetic Nanocomposite Particles And Its Biocapability

Magnetic particles have developed quickly in recent years as a new functional carrier material especially in the biomedical field. Calcium phosphate (CaP) has the similar composition to bone minerals and good biocompatibility which provides surgeons with an alternative or an additional material to graft the site and participates in the healing process. In this thesis the two materials were combined to prepare Fe3O4/CaP core-shell magnetic nanocomposite particles which could be used in controlling cell development and bone repair engineering.Firstly, Fe3O4 magnetic nanoparticles were synthesized by co-precipitation method. Effects of factors including the dropping speed of precipitant and the volume ratio of solvent on the crystalline, particle diameter and magnetic properties of the final products were discussed. Then the Fe3O4 nanoparticles were surface modified by sodium citrate. The crystal size and dispersion of Fe3O4 were obtained from transmission electron microscopy (TEM). The phase purity and saturation magnetization (Ms) were confirmed by X-ray powder diffraction (XRD) analysis and vibration sample magnetometer (VSM) respectively.Secondly, Fe3O4/calcium phosphate core-shell magnetic nanocomposite particles were prepared with sol-gel or precipitation methods. With the component, crystalline and morphology of nanocomposite particles being characterized, the differences between the two methods were discussed. By the sol-gel method, Fe3O4/β-TCP nanoparticles were produced. However, the Fe3O4/calcium phosphate particles obtained by soaking the Fe3O4 nanoparticles in 5-timed simulated body fluid exhibited the more controllable morphology and saturation magnetization.Thirdly, cytotoxicity test (MTT test) and osteoblast cells (MG-63) in vitro co-culture experiments had been performed to evaluate the biocompatibility of the above-mentioned Fe3O4/β-TCP nanoparticles. MTT test results indicated that the growth of L-929 in the presence of Fe3O4/β-TCP nanoparticles was comparable to the controls within the 4 days incubation. The results of co-culture in vitro showed that the Fe3O4/β-TCP nanoparticles allowed cells to achieve good adhesion and proliferation.In a summary, this paper takes a prospect on the application of magnetic particles and puts forwards its views on the extension of this subject.