Synthesis and characterization of biocomposites with different hydroxyapatite-collagen ratios.

Hydroxyapatite (HA)-type I collagen (Col) composite is a tissue-engineered bone graft which can act as a carrier or a template structure for cells or any other agents. In this paper, the effect of Col ratio on the scaffold structure and composition was analyzed. Scaffolds composed by HA/Col with different weight ratios (80:20; 50:50; 20:80, and 10:90) were produced by the precipitation method at pH 8-9, 37 degrees C and 6 h of ripening. Using X-ray diffraction data, the Rietveld structure refinement showed that the size of HA crystals along the c-axis direction (002) decreases significantly in the presence of Col. Thus, the HA crystal shape turned from needle-like in pure HA, into spherical, in the 10:90 composite due to Col fibrillogenesis. The homogeneity of the composite was significantly dependent on the amount of Col in it. HA/Col 20/80 composite presented HA particles in a more homogenous way. Such a biocomposite was successfully produced in a rapid way and it is potentially useful for both small tissue repairs and engineering.