Caracterizacao de hidrogeis a base de galactomanana oxidada e carboxietilquitosana para engenharia de tecidos

Abstract

The growing demand for organ and tissue and the desire to reduce traditional surgeries, in addition to the inability to meet the full demand, have led to the rapid development of tissue engineering. Among the biomaterials used in tissue engineering are porous supports (scaffolds) which are porous matrices that mimic the extracellular matrix, aiding in cell differentiation, proliferation and biosynthesis for the development of new tissues. The use of natural polymers in biological processes has some advantages such as: biodegradability, biocompatibility, low toxicity of by-products generated in degradation. This work aims to develop de hydrogels from galactomannan extracted from the Cassia fistula plant, oxidized with sodium periodate and interconnected with chitosan modified with acrylic acid (CEQ). The galactomannan from Cassia fistula (GCF) was oxidized, obtaining oxidation degrees 10, 20, 50 and 80%. Hydrogels were prepared from the interaction of oxidized polysaccharide with modified chitosan. The rheological analysis showed that the CEQB/CF50 hydrogels had higher values of modulus of elasticity (G') (2.3 kPa), while the CEQA/CF10 hydrogel had only 2.1 Pa, which demonstrates that the increase in degree of oxidation and the decrease in the degree of modification of the chitosan increase the elastic character of the hydrogel. The gelling time obtained by the tube, magnetic bar and rheometer inversion techniques were very close to each other, varying on average between 192±26 and 29±5 s, for the more crosslinked and less crosslinked hydrogels, respectively. Scanning electron microscopy (SEM) analyzes of lyophilized hydrogels (porous supports) showed high porosity and heterogeneous pores. It was observed that the average pore size is proportional to the degree of oxidation of GCF. Mechanical tests showed that the scaffolds showed elastic behavior with compression modulus values ranging from 5.5 to 8.3 kPa. Cytotoxicity assays demonstrated that the scaffolds resulted in the conditions made in this work and do not present toxicity. CEQA/CF20 and CEQB/CF20 scaffolds have good bactericidal capacity against gram-positive bacteria Staphylococcus epidermidis and Staphylococcus aureus. The results obtained make these scaffolds good candidates to be used in tissue engineering.