Research Of An Injectable Nanoscale Bone Restoration Material

Hydroxyapatite has the similar structure with the inorganic component of human bones which leads to its good biology compatibility, bone conductivity and inductivity. So it's often reported to be used as bone restoring materials. But hydroxyaptite has low mechanical properties and it's hard to be molded, which handicaps its development a lot. Now it's a promising way to use other materials to improve the mechanical properties of hydroxyapatite, and there have been many achievements reported. But there have been few researches reported about using medical calcium sulfate to improve the mechanical properties of nanometer hydroxyapatite and doing research about its restoration effects in thighbone defect of rabbits. And that's what my experiments all about.In my experiment, nanometer hydroxyapatite is synthesized which has the similar shapes and size with the hydroxyapatite in human bones. Then it is modified with medical calcium sulfate, and prepare an injectable nanometer scale bone substitute , whose hardening time and compressive strength are studied. Furthermore, it is soaked in the simulated body fluid (SBF) to study its absorption to learn something about its absorption in human body by analogy. After proving it is harmless for cells through celluar toxicity experiment MTT, it's finally used to cure the thighbones defect of rabbits'. And the effect is been assessed by X-rays, histology observation and electrical microscope every 2 weeks.Conclusions:(1) The synthesized nanoscale hydroxyapatite crystals is like rod, which has about 65nm length and 10-20nm width.(2) The compressive strength of the mulriple material is between that of spongy bones and os integumentales of human body.(3) It releases Calcium and Phosphorus continually when soaked in SBF, which supplies a lot of Calcium and Phosphorus to help bone growth. And it has larger velocity than pure Calcium sulfate material and pure hydroxyapatite.(4) Its celluar toxicity grade is 0 or 1 grade, and it won't result in dropsy, fester , fibres and putrescence in rabbits' muscles, which proves its good biological compatibility.(5) 6 weeks after the surgery , the thighbone defects using the material has been cured while those which didn't use it just had obvious bone growth, which means its good effect to cure the bone defects.