Preparação de scaffolds de poliuretano a partir de técnicas de lixiviação e CO2 supercrítico

Abstract

Tissue engineering has adopted different strategies that can increasingly mimic tissue regeneration in ex vivo conditions. One of the main trends is the development of three-dimensional porous structures (scaffolds), that serve as support for cell attachment, allowing their adhesion, proliferation and extracellular matrix production, which leads to the formation of new tissue. This work aimed to synthesize biopolyurethane (PU) from a polycarbonate diol (PC) and 4,4-dicyclohexylmethylene diisocyanate (H12MDI), and to evaluate its use in the preparation of scaffolds using leaching techniques (PU_L) and phase inversion in supercritical CO2 medium (PU_S) (scCO2). The synthesized PU is amorphous and presented weight average molar mass of 200000 g/mol, numerical average molar mass of115000 g/mol and polydispersity index of 1.9. The scaffolds prepared by both techniques has hydrophilic character, surfaces with roughness and porosity and internally interconnected pores. For PU_L the pore size distribution was of 19 - 200 μm with a heterogeneous and random dispersion, while for PU_S the pore size dispersion was between 9 - 150 μm presenting two distinct pore size regions (one with size between 9 - 48 μm and one with size between 101 - 151 μm). Both scaffolds under different conditions (dry and wet) showed typical mechanical behavior of an elastomeric material. The scaffoldd showed no cytotoxicity in vitro assay with fibroblastic cells and, the cells presented mitochondrial activity greater than 70%. The results of in vitro assays combined with mechanical properties suggest that scaffolding has potential for tissue engineering applications in preferably ex vivo situations as temporary cell support.