Desenvolvimento de compósitos biodegradáveis a base de PCL/biocerâmica para regeneração óssea.

Abstract

The objective of this work is to obtain porous three-dimensional structures of PCL and β-tricalcium phosphate (β-Ca3(PO4)2), wollastonite (CaSiO3) and bredigite (Ca14Mg2 (SiO4)8) for application in bone regeneration and drug. In order to obtain structures with better properties with respect to reabsorption, morphology and chemical composition similar to the bone mineral phase, characteristic of the phosphates. In addition, provide bioactive characteristics, biodegradation and osteoinduction. The ceramics were obtained by the synthesis of combustion in solution because this is a simple and efficient method to obtain nano-scale materials. The materials used to obtain the ceramics were: calcium nitrate, magnesium nitrate, colloidal silica, dibasic ammonium phosphate, as source of calcium, magnesium and phosphorus, respectively. Nitric acid and nitrate ions were used as oxidants. The urea was used as fuel. It was investigated the effect of the fuel and also the proportion of fuel and oxidant on the combustion reaction, as well as on the chemical composition of the obtained powders. After the synthesis, the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy with field emission (SEM-FEG) and specific surface. In the synthesis of calcium phosphate (TCP) the following phases were obtained: beta- calcium phosphate (β-Ca3(PO4)2) and hydroxyapatite, using three times the amount of fuel. In the synthesis of wollastonite (W) the parawollastonite phase (CaSiO3) was obtained, using twice the amount of fuel. In the synthesis of bredigite (BRE) the bredigite (Ca14Mg2(SiO4)8) and dicalcium silicate (γ-Ca2SiO4) phases were obtained when the amount of fuel was used three times. All samples had submicron structure with low specific surface area. Scaffolds composed of PCL/TCP/W and PCL/TCP/BRE were produced by the solvent evaporation and particle leaching method, using NaCl as a porogenic agent, to obtain interconnected pores in the range of 100 to 500 micrometers. The scaffolds produced were characterized by optical microscopy (OM), scanning electron microscopy (SEM), compressive strength, in vitro bioactivity, cell adhesion, drug release and antimicrobial capacity. The composition with 70% (v / v) of inorganic filler showed better pore uniformity and better compressive strength. These scaffolds presented acceptable compressive strength for materials with high porosity, in addition, they were biodegradable in vitro, good bioactive capacity, and adequate surface for cell adhesion. The scaffolds with the drug vancomycin showed slow and uniform release of the drug for a period of 2 months and good antimicrobial capacity, suggesting the advantageous application of these devices for the regeneration of bone tissues.