CONICET | Buscador de Institutos y Recursos Humanos

The development of elastomeric biodegradable and biocompatible segmented polyurethanes (SPU) for use in tissue engineering applications has been a subject of considerable interest in recent years. In this work, a series of poly(e-caprolactone)-based SPU with different hard segment chemistry were synthesized using aliphatic diisocyanates, 1,6-hexamethylene diisocianate (HDI) and L-lysine methyl ester diisocyanate (LDI), and novel chain extenders containing urea or aromatic aminoacid derivatives. Non-porous films were prepared by casting of SPU solutions in N,N-dimethylacetamide onto siliconized Petri dishes. Sub-micro fibrous scaffolds were obtained by electrospinning technique. SPU solutions were prepared in 1,1,1,3,3,3-hexafluoro-2-propanol (20% w/v) and delivered at a 0.5-3 ml/h flow rate. Electrospinning was carried out by applying a positive voltage of 15 kV. Electrospun fibers were deposited on a grounded flat aluminum plate, with a needle-plate distance of 15 cm. All the samples were dried under vacuum at room temperature, and stored in a desiccator. Thermal properties were determined by differential scanning calorimetry (DSC). Swelling and in vitro hydrolytic behaviors were both tested in phosphate-buffered solution (PBS) at 37ºC for specific periods of time, while accelerated degradation was studied in H2O2/CoCl2 solution at 37ºC and PBS solution at 70ºC. The effect of the hard segment composition and polyurethane sample (non-porous film and non-woven mesh) on the measured properties were analysed. Thermal transitions were affected by the processing conditions. Film samples displayed low swelling (less than 3 wt%), the values being higher in the case of LDI-based SPU. This particular series also exhibited the less hydrolytic stability in all tested media.

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