Preparation And Osteogenic Properties Of Biomimetic Fluorine-Doped Hydroxyapatite Coatings

As an important type of biomedical material,bone repair materials can effectively treat bone defects,such as osteoporosis fracture.Based on the composition of bone tissue and the bone absorption surface with micro/nano topography formed in the process of bone reconstruction,the design and preparation of biomimetic bone repair materials attract wide attention in the field of bone tissue engineering.However,single-component bone repair materials are commonly difficult to meet the needs in the rapid development of bone tissue engineering.Therefore,design and preparation of bone repair composite materials with biomimetic topography and composition for excellent biodegradable,biocompatibility and osteogenic performances become one of the research hotspots.In this thesis,two kinds of nanoneedle-typed biomimetic coatings were prepared on AZ31 magnesium alloys through microwave aqueous method,i.e.,FHA coatings and APS/FHA composite coatings.The main research contents are as follows.(1)FHA nanoneedle coatings with different micro/nano topographies were prepared on alkali-treated Mg alloy substrates by adjusting the pH value of calcium,phosphorus and fluorine precursor solution;the diameter of FHA nanoneedle on surface and bottom layers and surface roughness of coating could be controlled within a certain range.The formation mechanism of the biomimetic micro/nano topographical structure of FHA coating was basically explained from the perspective of crystal nucleation and growth.In vivo and in vitro osteogenic performance results showed that the FHA coating with pH value of 6.0 for precursor solution showed the best osteogenic performance,which might be ascribed to that the topography of coating is more similar to the unique topography of bone absorption surface,so that it can exert a stronger biophysical stimulation to promote osteogenic differentiation of BMSC and new bone regeneration.(2)One type of APS with high thermal stability was screened.A series of APS/FHA composite coatings were prepared with the addition of APS into the precursor solution.By adjusting APS doping amount,the diameter of nanoneedle and surface roughness of APS/FHA composite coating can be controlled within a certain range.The formation mechanism of biomimetic micro/nano topographical structure of APS/FHA composite coating was basically explained.Moreover,cell viability of APS/FHA composite coatings were tested and analyzed.In this thesis,the two kinds of nanoneedle-typed biomimetic coatings prepared have biomimetic micro/nano topographical structure and composition,which provides some theoretical guidance for the research and clinical application of ion-doped HA/natural bioactive polysaccharide biomimetic coatings in bone tissue engineering field.