Natural hydroxyapatite/chitosan composite for bone substitute materials

We developed the natural hydroxyapatite/chitosan composite that could be molded into any desired shape. The powder component consists of natural hydroxyapatite, which is epurated from bone of pigs. The liquid component consists of malic acid and chitosan. To study the possibility of the composite on repairing bone defects, 15 white rabbits were each operated on left tibias to create two square bone defects. One of the defects was reconstructed with the composite; the other was not repaired as a blank control. 3 of the animals were killed at the end of 2 weeks, 4 weeks, 8 weeks, 12 weeks and 16 weeks respectively to be evaluated with anatomy and histology. No apparent reject reaction was found, except for a mild inflammatory infiltrate found at postoperative 2 weeks. Fibrous tissue became thinner at postoperative 2-8 weeks and bony connection was partly shown at postoperative 12 weeks. The new bone was the same as the recipient bone at postoperative 16 weeks. The hydroxyapatite/chitosan composite has good biocompatibility and osteoconduction. It is a potential repairing material for clinical application