HUVEC biocompatibility and platelet activation of segmented polyurethanes prepared with either glutathione or its amino acids as chain extenders

Abstract

Novel biodegradable segmented polyurethanes (SPUs) were synthesized with polycaprolactone diol, 4,4′-methylen bis (cyclohexyl isocyanate) (HMDI), and either L-glutathione or its constituent amino acids (L-glutamic acid, L-cysteine and glycine) as chain extenders. Fourier transform infrared spectroscopy analysis revealed the feasibility of obtaining polyurethanes through the presence of NH (Amide II), C–N, C–O, and C=O bands and the absence of NCO band. Differential scanning calorimetry and X-ray diffraction revealed that a semicrystalline polymer (T _m = 42–52 °C; 2θ = 21.3° and 23°) was obtained in all cases, while dynamic mechanical analysis (DMA) revealed an amorphous phase (T _g = −30 to −36 ^oC). These properties, in addition to their high molecular weight, led to high moduli and higher extensibilities when glycine and glutamic acid were used as chain extenders. Clotting times (Lee–White test) and activated partial thromboplastin time determined on these polyurethanes were longer than with glass. In addition, all synthesized SPU exhibited platelet activation indexes below the collagen type I positive control. Human umbilical vein endothelial cells viability was higher in SPUs containing either glycine or cysteine. The obtained results indicate that SPUs that use cysteine as chain extender are promising candidates for cardiovascular applications.

Keywords:

• segmented polyurethane
• chain extender
• amino acids
• endothelial cell viability
• hemocompatibility

Acknowledgments

This work was supported by CONACYT (México) grants 79371, 123913 and FOMIX 108160. DMH was supported by the NSF Stem Cell Biomanufacturing IGERT (NSF DGE 0965945). We also thank D.H. Aguilar for technical support.