Studies On Like-bone Composite Biomaterial Of Biomimetic Synthesis Silk Fibroin/hydroxyapatite

Multiplicity mineralized composite procedures in Nature provide a rich foundation for biomineralization and novel materials designs. i.e. sea hells, bone and other hard tissue. The procedure is the Natural inorganic mineral formatted by the organic template regulation. The formation of Natural inorganic-organic composites is a complex process, including the assembly of the organic template (i.e. protein, polysaccharides, nucleinic acid, biological membrane and liposome) subsequent inorganic mineral deposition, nucleation and growth on the organic template surface by the the organic template regulation.The major of thesis focused on the study of the like-bone Silk fibroin (SF)/ hydroxyapatite(HA) biocomposite. First prepare the SF organic template, secondly under controlled PH and temperature calcium and phosphorus begin deposition and nucleation and growth on the organic template surface by the the organic template precise regulation and form like-bone silk fibroin /hydroxyapatite biocomposite. at the same time, research the effect of temperature on the hydroxyapatite crystal direction on the silk fibroin template surface.Firstly the preparation of like-bone Silk fibroin (SF)/ hydroxyapatite (HA) biocomposite by biomineralization. Ca(OH)₂, H₃PO₄ and SF were used as starting materials, and their composites were synthesized by a biomineralization. The starting materials were prepared for the composition of the SF/HA composite to be 30/70 in weight ratio. add SF template into the H3PO4 solution with vigorous stirring until uniform mixing, the prepare of the composite was conducted by adding the H₃PO₄ solution with the SF slowly into the Ca(OH)₂ solution with vigorous stirring and adjust PH to 9～10 With NaOH at grade temperature (25℃,37℃,50℃,60℃,70℃). Checking the biomaterial prepared at grade temperature, chose the better reparation condition. The results from the tests of FTIR,XRD show that the hydroxyapatite is low crystallinity nano-carbonated apatite [CO₃-substituted Ca₁₀(PO₄)₆(OH)₂].it is consistent with the hydroxyapatite crystals in bone. the size of hydroxyapatite crystals is 15.6～22.8nm showed by XRD, and the crystals size of composite is 0.229⁰.409um.they indicate that the crystals size increase with the rising of temperature. The results from the tests of SEM,TEM and electron diffraction show that the needle-like hydroxyapatite crystal grows along the c-axes of hydroxyapatite crystal and The crystallographic c-axes of hydroxyapatite were aligned along the long axes of the fibers, consistent with observations of collagen fibrils and hydroxyapatite crystals in bone at the 60℃,70℃.the like-bone structure is better at the aqueous bath of 70℃than 60℃.Secondly, in vitro experiments were designed and carried out to evaluate the biological reaction of the biomaterial prepared as described in the first part. Compress the SF/HA powder into disk shape with 1.2mm diameter by tablet machine. and MG63, which is human osteoblast cell phenotypes was adopted to valuate the biological reaction. controlled by HA. Morphology observation ,SEM and MTT results show that the like-bone SF/HA is better benefit to MG63 that HA, it is benefit to MG63 adhesion differentiation and proliferation. At the same time the results of ALP, Ca²⁺ concentration and OC indicate that The SF/HA can promote the ALP express, hasten the delivery of cell matrix Ca²⁺ and induce the OC perspire controlled with HA. So the like-bone SF/HA biomaterial is a better biomaterial.Based on the evidences from the experiments. calcium and phosphorus begin deposition , nucleation and growth on the organic template surface by the organic template precise regulation and form like-bone silk fibroin/hydroxyapatite biocomposite. The hydroxyapatite is low crystallinity nano-carbonated apatite [CO₃-substituted Ca₁₀(PO₄)₆(OH)₂]. It is consistent with the hydroxyapatite crystals in bone. and the needle-like hydroxyapatite crystal grows along the c-axes of hydroxyapatite crystal and The crystallographic c-axes of hydroxyapatite were aligned along the long axes of the fibers, consistent with observations of collagen fibrils and hydroxyapatite crystals in bone. At the same time, evaluate the biological reaction, the like-bone SF/HA can promote MG63 adhesion differentiation and proliferation and ossify activity.