l-Leucine-Based Poly(ester urea)s for Vascular Tissue Engineering

Poly(ester urea)s (PEUs) derived from α-amino acids are promising for vascular tissue engineering applications. The objective of this work was to synthesize and characterize l-leucine-based PEUs and evaluate their suitability for vascular tissue engineering. Four different PEUs were prepared from di-p-toluenesulfonic acid salts of bis-l-leucine esters and triphosgene using interfacial condensation polymerizations. Mechanical testing indicated that the elastic moduli of the respective polymers were strongly dependent on the chain length of diols in the monomers. Three of the resulting PEUs showed elastic moduli that fall within the range of native blood vessels (0.16 to 12 MPa). The in vitro degradation assays over 6 months indicated that the polymers are surface eroding and no significant pH drop was observed during the degradation process. Human umbilical vein endothelial cells (HUVECs) and A-10 smooth muscle cells (A-10 SMCs) were cultured on PEU thin films. Protein adsorption studies showed the PEUs did not led to significant platelet adsorption in platelet rich plasma (PRP) after pretreatment with fibrinogen. Taken together, our data suggest that the l-leucine-based PEUs are viable candidate materials for use in vascular tissue engineering applications.