Nanophase Hydroxyapatite / Silk Fibroin Bio-composite Materials Preparation And Structural Characteristics Of The Study

Hydroxyapatite, which is the primary mineral component in the organism bones. The chemistry expression of the hydroxyapatite is Ca₁₀(OH)₂(PO₄)₆. Hydroxyapatite is named HA for short. HA can form the basic functional cell in nano-dimension. Its physic value is already proved by many specialists. HA is recognized a sort of organism bones substitute, which has broad application foreground and profundity exploitation potential.The crystal configuration, crystal size of HA and whether or not compound with other material, which are all the influence factor to the mechanics capability and biology capability. The silk fibrin named SF for short was used to compound whit HA for the sake of improving the mechanics capability of the final molding bone in this research. The nano-hydroxyapatite/silk fibroin biology compound material, which is named HA/SF for short, was prepared by auto- design "one-step" method in this study. By the series research, the appropriate compound technics of HA/SF is: The silk fibrin is dissolved at 75±5℃and by 0.5h in the solvent which is CaCl₂ -C₂H₅OH - H₂O (mol ratio 1: 2: 8); The solution of ammonium dibasic phosphate is equably joined in to silk protein solution in 3h and keeping on reaction for 1 h; 30℃in the former 2h and 60℃in the latter 2h. pH is adjusted at 10.5 by ammonia.In the research, the crystal configuration,crystal lattice diffraction,function cell,heating capability and the change of the concentration of silk protein solution in the whole preparation process were observed and tested by TEM,XRD,FTIR,TG-DSC and UVS; The ratio of calcium to phosphorus in HA/SF was tested by chemistry method; The pillar molding material of HA/SF was simply shaped by oil pressure machine and auto- design model tube. And also the compressive strength of HA/SF pillar molding material was tested.HA/SF exhibits compound uniformity and presents network structure. Its crystal particle is speculate or pole configuration and the size is less than 300nm by observing the TEM picture of each product; HA/SF belongs to hexahedron crystal system and its crystal particle grows along the c axes direction when silk protein is joined. That were educed by using auto- design YW method to analyzing the XRD chart of each product; There are the function cells of both HA and SF in HA/SF. The space structure of silk protein primarily presents unformed andα- helix in HA/SF. That is resulted from analyzing the FTIR chart of each product; By adopting the hypothesis-modeling-validation mathematic method to analyzing TG-DSC data of each product, the heating decomposability of both HA and SF would influence each other when the concentration of silk protein solution reaches to 25% in the heated process of HA/SF but there is no distinct influence when the concentration of silk protein solution was under 25%; In the 4h compound process, there is no silk protein in the solution in the former 2h and HA/SF crystal particle grows up to completeness in the latter 2h. The silk protein can be deposited with new producing HA at the same pace to produce compound material when the concentration of silk protein solution is 20%; The ratio of calcium to phosphorus in HA/SF is 1.6692, which is the same as the ratio in standard HA; The compressive strength of HA/SF pillar molding material is 62MPa.