Preparación y caracterización de composites de hidroxiapatita deficiente en calcio y quitosana

Abstract

In this work chitosan/calcium - deficient hydroxyapatite (CHI/CDHA) composites were obtained by a
biomimetic method (nucleation of the inorganic phase inside the polymeric matrix) with the objective to obtain a novel
material that combine the biodegradability and flexibility of the chitosan with the bioactivity and osteoconductivity of
the hydroxyapatite with a view to their possible employment as a candidate for bone replacement. For this purpose
systems with the CHI/CDHA ratios 20/80, 50/50 and 80/20 were prepared. The samples were prepared as particles shape
and their morphology was inspected with a magnifying glass. It was seen that the particles with less chitosan content
were less spherical, smaller and irregular. The organic and inorganic phases of the composites obtained were identified
by FTIR spectroscopy, X-ray diffraction and thermal analysis. The FTIR spectra of composites showed the characteristic
absorption bands of both components, the chitosan and the hydroxyapatite. The thermal analysis evidenced the interaction
existence between the chitosan matrix and the inorganic component. It also revealed that there is a correspondence
between the chitosan/inorganic component ratio in the feed mixture and in the resulting composite. On the other hand,
the broadening observed in the diffractogram peaks was indicative of the small size of the hydroxyapatite crystals formed
in situ. The X-ray analysis of the residues after igniting the composites at 1 000 ºC for 15 h indicates that the inorganic
phase of the composites is calcium deficient hydroxyapatite.