Desenvolvimento de biomateriais híbridos a base de celulose e apatita de estrôncio voltados à reconstrução óssea

Abstract

Bone problems, such as congenital malformations, accidents, tumors and osteoporosis, are becoming very common. Replacing compromised limbs with implants is a widely used form of treatment. Materials commonly used in this area are easily susceptible to immunological rejection and additional complications because they are metals or metal alloys. To mimic the structure of bone tissue and, consequently, overcome this problem, hybrid biomaterials, composed of an organic and an inorganic part, present themselves as strong competitors to replace traditional implants. What is expected of these materials is that they present characteristics such as: biocompatibility; bioactivity, stimulating the cells that are part of this tissue to produce new tissue; and biodegradability, not requiring additional procedures to remove implanted material. In this context, the present work proposes to obtain new hybrid biomaterials composed of porous membranes of cellulose acetate (CA), bacterial cellulose (BC) and oxidized bacterial cellulose (OBC) incorporated with strontium apatite (SrAp) through the biomimetic method. This method consists of using a simulated body fluid (SBF) solution modified with strontium ions (Sr2+). The incorporation of SrAp into membranes was chemically evaluated by Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS). The Sr2+ incorporated in the membranes was quantified by atomic absorption spectrometry (AAS), where it is possible to observe that the concentration of Sr2+ adsorbed by the membranes studied does not present significant differences over the days. Scanning electron microscopy (SEM) demonstrates a deformation in the membrane structure after modification with SrAp. X-ray diffraction (XRD) shows that membranes modified with SrAp showed a decrease in their crystallinity. The samples were also evaluated for their degree of swelling, showing high hydrophilicity of CA, BC and OBC membranes. Cell viability was studied with mouse osteoblast cells (MC3T3-E1 Subclone 14) and mouse fibroblast cells (L-929), demonstrating that the membrane biomineralization with SrAp favored the cell viability of these materials. From these results, it can be identified that oxidized bacterial cellulose biomineralized with SrAp by the biomimetic method proved to be the most promising material to be used in the regeneration of bone tissue.