Desenvolvimento de scaffolds de quitosana para aplicação na engenharia de tecidos.

Abstract

The design and production of scaffolds for tissue engineering is still unable to completely reproduce the native tissue properties. A key challenge is to reproduce the degree of complexity needed to mimic the extracellular matrix (ECM) of the human body natural tissue. Preferably, scaffolds would be made of biodegradable polymers whose properties are more similar to the ECM. Chitosan is biodegradable, non-toxic and possesses antibacterial properties and the possibility of being processed in many forms, shapes and size as well. It is an excellent material due to its versatile properties and it´s scaffolds are one of the widely studied materials for tissue engineering application. The aim of the present work was to produce and characterize chitosan scaffolds through two different methodologies: scaffolds produced by freeze drying and particles aggregation method. The chitosan scaffolds were characterized by Fourier Transformed Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), Porosity (%P), Termogravimetric analysis (TG), Differential Scanning Calorimetry (DSC), Compression Tests, Swelling Degree and Cytotoxicity. The results for freeze-dried scaffolds showed the sulfuric acid caused no significant toxic effects on the cells. However, the results in terms of microstructure were not satisfactory, because the process followed to obtain the scaffolds (solution, freezing, lyophilization, neutralization, washing, halftone, freezing and lyophilization) damaged the internal structure. Through FTIR results, was observed ionic interactions between the negatively charged phosphate groups’ chains of the TPP and the protonated amino groups of chitosan chains. The SEM results showed a three-dimensional structure, with higher porosity and interconnectivity between pores. The TG/DTG and DSC results showed a stable thermal behavior of scaffolds. The Swelling Degree revealed that the scaffolds possess a higher hydrophilicity, even with the presence of the crosslinking. The cytotoxicity results proved that the produced scaffolds did not display toxicity effects and cell viability values were enclose in the range of 70 and 90%.