Síntese e caracterização de hidroxiapatita nucleada a partir de polissacarídeo sulfatado para enxertia óssea

Abstract

Hydroxyapatite (HA) is the main mineral that makes up the bones and teeth of vertebrates. However, despite its good characteristics of biocompatibility and bioactivity compared to bones, this material has a small amount of pores, hindering the development of bone cells. In order to improve the porosity of the material to be grafted, HA will be combined with a sulfated polysaccharide, more specifically microcrystalline cellulose. The sulfation of cellulose, in this case, will be done as a way of creating negative charges in the molecular structure, which will nucleate the synthesis of hydroxyapatite. With the quantification of the degree of substitution, using ultraviolent spectroscopy, it was possible to observe a resulte qual to 1, meaning that each unit of glucose occurs a modification of a hydroxyl by a sulfate group. When this combined material was sintered, the polysaccharide was eliminated, confirmed by infrared spectroscopy. Mercury intrusion porosimetry and scanning electron microscopy were performed for the characterization of the material, identifying the morphology of this new HA and the diameters of the pores in the structure. A greater homogeneity was observed in the pores, indicating a smaller size distribution after the expulsion of the sulfated polysaccharide. Therefore, it is concluded that the methodology used presented excellent results regarding the degree of sulphation in the structure of the polysaccharide, in addition to obtaining a material with more regular pores, although with a size even smaller than the desired one for it is biomedical application.