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, two different poly( ε-caprolactone)-based SPU were synthesized using 1,6-hexamethylene diisocyanate (HDI) and novel chain extenders containing urea groups or an aromatic aminoacid derivative. Non-porous films were prepared by casting of SPU solutions in N,N-dimethylacetamide onto siliconized Petri dishes. Micro/nanofibrous scaffolds were obtained by electrospinning technique. Thermal properties, as determined by differential scanning calorimetry, were influenced both by the different chemical structure of the hard segments and the processing conditions. Mechanical properties, as examined by uniaxial stress-strain behavior, showed lower values of elastic moludus, and ultimate strain and tensile stress for the scaffolds. Swelling and in vitro hydrolytic behaviors were tested in phosphate-buffered solution (PBS) at 37 ºC for specific periods of time, while accelerated degradation was studied in PBS solution at 70 ºC. Film samples displayed low swelling (less than 2 wt %), the values being much higher for the scaffolds. The introduction of the aminoacid derivative chain extender with hydrolyzable ester bonds contributed to a higher degradation of this SPU. Fibrous scaffolds exhibited higher hydrolytic stability than films at shorter times of assay, due to their more crystalline structures and higher degrees of association by hydrogen bonding, but also higher mass loss values in the accelerated medium, suggesting that degradation rate is not constant but depends on the degradation time and the type of sample.