Stability and mechanical evaluation of bovine pericardium cross-linked with polyurethane prepolymer in aqueous medium

The present study investigates the potential use of non-catalyzed water-soluble blocked polyurethane prepolymer (PUP) as a bifunctional cross-linker for collagenous scaffolds. The effect of concentration (5, 10,15 and 20%), time (4,6,12 and 24 h), medium volume (50, 100, 200 and 300%) and pH (7.4, 8.2, 9 and 10) over stability, microstructure and tensile mechanical behavior of acellular,pericardial matrix was studied. The cross-linking index increased up to 81% while the denaturation temperature increased up to 12 degrees C after PUP crosslinking. PUP-treated scaffold resisted the collagenase degradation (0.167 +/- 0.14 mmol/g of liberated amine groups vs. 598 +/- 60 mmol/g for non-cross-linked matrix). The collagen fiber network was coated with PUP while viscoelastic properties were altered after cross-linking. The treatment of the pericardial scaffold with PUP allows (i) different densities of cross-linking depending of the process parameters and (ii) tensile properties similar to glutaraldehyde method. (C) 2013 Elsevier B.V. All rights reserved.