Electrospinning and biocompatibility evaluation of biodegradable polyurethanes based on L-lysine diisocyanate and L-lysine chain extender

A series of biodegradable polyurethanes (PUs) were synthesized using poly(e-caprolactone) diol (PCL) to react with L-lysine ethyl ester diisocyanate (LDI) chain extend with L-lysine ethyl ester (LEE) in solution of DMF. The structure was characterized by gel permeation chromatography, H-1-NMR, Fourier transform infrared, and DSC analyses. Mechanical property testing showed that their tensile strength rose with increasing the hard segment content with a maximum tensile strength of 34.43 +/- 1.73 MPa. The average mass loss for the hydrolytic degradation was only about 13% in 56 days while this value for the enzymatic degradation was around 95% in 30 days. The morphological and bio-mechanical characters of the tubular scaffolds electrospun from the as-prepared PUs were also examined. As the solution concentration was varied from 10 to 18% (w/v), the fiber diameter was progressively increased, and the scaffold tensile strength was enhanced from 2.82 +/- 0.16 MPa to 7.07 +/- 0.44 MPa, the suture retention strength from 2.48 +/- 0.33 to 8.38 +/- 0.35 N, and the burst pressure strength from 72 +/- 2 to 172 +/- 2 kPa, all higher than those of native blood vessels. At the same time, the L-929 mouse fibroblasts (L-929) and human umbilical vein endothelial cells were used in cytotoxicity and cell-adhesion evaluations toward the electrospun scaffolds. The level of toxicity is less than level 1, and cells were found to attach well to and remain viable on the scaffolds. (C) 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 96A: 705-714, 2011.