Filmes reticulados de quitosana para aplicação como biomaterial.

Abstract

Among biodegradable polymers, chitosan has been the focus of an extensive research in the recent years. Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). Chemical modifications of chitosan through crosslinking can produce materials with a wide variety of physical, mechanical and biological properties. The aim of the present work was to obtain and characterize ionic crosslinked chitosan films for biomedical applications such as for wound healing. The chitosan films were prepared by the solvent evaporation technique and crosslinking was introduced by reaction with sulfuric acid. Five different crosslinked films were obtained by using different reaction times. The crosslinked films were characterized by Fourier Transformed Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy and Contact Angle (CA) measurements. Cytotoxicity tests were carried out using NIH 3T3 cells in culture to evaluate the cytotoxicity potencial of ionic crosslinked chitosan films, by evaluating the metabolic activity (through the resazurin reduction assay) of cells subjected to several dilutions of extracts of the films. Cell adhesion studies were performed by direct cell culture over the films surface. Using NIH 3T3 and HFF 1 cell lines. According to FTIR results, an effective reaction between the sulfate ions and chitosan films was achieved with visible changes in the spectra. A decrease in the crystalline profile of chitosan films, characteristic of crosslinked materials, could be seen by XRD analysis. Any morphological changes were detected in the crosslinked films after SEM visualization of the samples. The contact angle measurements showed an increase in the hidrophilicity of the samples compared with pure chitosan films. The biological assays revealed that the films were promising for biomedical applications.