Desenvolvimento de suportes porosos de poliuretano/poli(ácido láctico) produzidos por fluido supercrítico para aplicação em engenharia de tecidos

Abstract

The development of biomaterials with specific features to aid in tissue recovery damaged by accident or disease is one of the challenges in the scientific field that involves the areas of medicine and engineering. These biomaterials can be applied in tissue engineering as scaffolds that resemble the extracellular matrix functioning as a temporary structure for cell proliferation and reconstruction of new organs and tissues. To evaluate the potential use of scaffolds as biomaterial, this work proposes the development and characterization of polyurethane (PU), poly(lactic acid) (PDLLA) and polyurethane/poly(lactic acid) (PU/PDLLA) scaffolds produced by gas foaming technique. The pure polymers and the mixture were characterized, in films form, by gel permeation chromatography (GPC), rheological analysis, thermogravimetric (TG), differential scanning calorimetry (DSC) and field emission gun scanning electron microscopy (FEG-SEM). After expansion, in scaffolds shape, the samples were characterized by FEG- SEM, pore size, density, mechanical properties and in vitro cytotoxicity and cell adhesion with 1, 4 and 6 days of exposure. For films characterization, the sample PU/PDLLA presented intermediate characteristics to the pure polymers, showing the behavior of the two polymers in the sample without phase separation in the micrograph FEG-SEM and bimodal molar mass distribution by GPC. The scaffolds showed interconnectivity and pore size of 141 μm ± 108 μm for the PU and 52 μm ± 32 μm for PDLLA. The sample PU/PDLLA had a bimodal structure in which the PU in the mixture presented pores of 75 μm ± 57 μm, while for the PDLLA, the pore size was 19 μm ± 12 μm. In vitro tests confirmed the adhesion of L929 cells in Pusp, PDLLAsp and PU/PDLLAsp scaffolds, showing no cytotoxic effect. Finally, it can be concluded that it is possible to produce PU, PDLLA and PU/PDLLA scaffolds by supercritical fluid, which may be applied as biomaterials.