Structure-property relations and cytotoxicity of isosorbide-based biodegradable polyurethane scaffolds for tissue repair and regeneration

Microporous scaffolds with potential applications for tissue engineering were produced from the biodegradable aliphatic isosorbide-based polyurethane using a combined salt leaching-solvent evaporation-coagulation process. Alkaline sodium phosphate heptahydrate crystals were used as a solid porogene, and acetone-water mixture was used as a nonsolvent-coagulant. The scaffolds used in this study had interconnected pores with sizes in the range of 70-120 mu m and a pore-to-volume ratio of 87%. The XPS measurements showed that the residence of the scaffold in an aqueous solution of the alkaline porogene changed its surface atomic composition, that is increased the surface concentration of oxygen and nitrogen and reduced the surface concentration of hydrocarbons relative to the control material. This also enhanced the hydrophilicity of the scaffold's surfaces as assessed from contact angle measurements. The alkaline porogene did not affect the polymer's molecular weight. The MTT cytotoxicity assay showed that the isosorbide-based polyurethane scaffold is noncytotoxic. The amounts of interleukin-6 and interlukin-8 proinflammatory cytokines released from human blood leukocytes exposed to the polyurethane scaffolds in vitro were comparable and/or lower than the amount of the cytokines released by leukocytes exposed to the culture-grade polystyrene control. (C) 2007 Wiley Periodicals, Inc.