Hidrogéis híbridos poliméricos de quitosana funcionalizada e gelatina fotoreticulados como matrizes porosas tridimensionais para potencial reparo de tecido epitelial

Abstract

Hydrogels have been proven effective in aiding tissue regeneration processes of soft organs, such as skin. Chitosan and gelatin are natural, highly available, non-toxic, bioactive and biodegradable materials. The addition of methacrylic anhydride (AM) to chitosan chains gives rise to the side group methacrylamide, which increases the solubility of the raw material and contains vinyl groups which serve as sites for photophoreticulation of the chains in the presence of a photoinitiator (FI). In this work, hydrogels based on chitosan methacrylamide and gelatin were produced. The chemical crosslinking of the hydrogels was led by photoreticulation under UV irradiation in the presence of 2-Hydroxy-4 '- (2-hydroxyethoxy) -2-methylpropiophenone (Irgacure 2959) FI and, after the reaction, the system was stabilized by the addition of Ascorbic acid(AA). The raw material was characterized by Infrared Spectroscopy by Fourier transform (FTIR) before and after the functionalization with methacrylic anhydride. Analysis of the curing process was based on UV-Visible Spectroscopy (UV-Vis) and FTIR. Hydrogels morphology was evaluated by Scanning Electron Microscopy (SEM) and Computed Tomography (-CT). Physical-chemical characteristics, such as swellingability, and biological, such as toxicity / cellular viability, were analyzed by 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The results of FTIR and UV-Vis proved the functionalization of chitosan by the reaction with AM. The formation of the photochemical crosslinking of the hydrogels was confirmed and its mechanism was suggested based on the results obtained by FTIR. Analysis of the degree of swelling of the hydrogels indicated a swelling capacity ranging from 500% to 2000%, depending on the composition of the hydrogels. MEV associated with -CT Xray imaging of the hydrogels showed a uniform porous 3D structure with interconnectivity between pores and whose architecture features are influenced by the photoreticulation extent. The system presented biocompatibility, with cellular viability above 90%. These new hydrogels, with properties projected by means of their relative composition and photoreticulation extension, have potential to be used as wound dressings and in tissue repair applications