Estudo da influência de sais de cálcio em materiais híbridos quitosana – vidro bioativo preparados pelo método sol-gel

Abstract

In this work, organic-inorganic hybrid materials based on chitosan and bioactive glass were prepared by the sol-gel method and calcium salts (chloride, sulfate and phosphate) were incorporated in order to obtain biomaterials that can be applied in replacement, restoration or repair of bone tissue. This work aimed to study the influence of calcium salts on the properties of these materials. Bioactive glasses and class I and II hybrids were produced using chitosan, tetraethylorthosilicate and (3-glycidyloxypropyl) trimethoxysilane (as a coupling agent) with the addition of calcium salts. The nanostructure was evaluated by Fourier Transform Infrared Spectroscopy Absorption (FTIR) and X-Ray Diffraction (XRD) and the results suggested, respectively, the formation of the hybrid with calcium ions incorporated in the silica lattices and the calcium chloride presented a better dispersion in the hybrid matrix, while calcium sulfate and phosphate did not completely solubilize, partially remaining in the crystalline form on materials. Scanning Electron Microscopy (SEM) analysis showed the heterogeneity of the surface of the samples. The mapping performed by Energy Dispersive Spectroscopy (EDS) showed a homogeneous distribution of silicon, oxygen, carbon and calcium on the surface of all hybrids, mainly for class II hybrids and those with chloride. Atomic Force Microscopy (AFM) studies showed irregular surfaces, with roughness suitable for osteoblastic cells. Bioactivity studies suggested apatite formation after 28 days of incubation in simulated body fluid (SBF). The biodegradability of the materials was confirmed by enzymatic degradation tests, with a more controlled degradation for the hybrids containing calcium phosphate.