Surface functionalization of poly(ε-caprolactone) and poly(3-hydroxybutyrate) with VEGF

In this study, surface modifications for the biodegradable polymers poly(ε-caprolactone) (PCL) and poly(3-hydroxybutyrate) [P(3HB)] were developed in order to improve their suitability as scaffold material for bioartificial vessel prostheses. The challenge of wet-chemical surface modifications is to avoid bulk adjustments resulting in undesired changes in mechanical properties of these polymers. Nevertheless subsequent immobilization and controlled release of potent angiogenic biomolecules like vascular endothelial growth factor (VEGF) from the polymer surface is required. In order to improve the biocompatibility of PCL and P(3HB), terminal hydroxyl groups on the surface of these polymers were generated via oxygen (O2) and carbon dioxide (CO2) plasma. Then, the immobilization of VEGF was achieved through hydrolysable ester bonds using the crosslinker N,N′-disuccinimidyl carbonate (DSC). Our studies demonstrated that the plasma surface activations have no negative influence on the viability of L929 mouse fibroblasts and hemocompatibility. The immobilization of VEGF on the modified polymers via DSC is improved compared to the untreated reference. For the CO2plasma-chemical activated surfaces we observed the highest VEGF surface immobilization. Our release studies also reveal the highest cumulative release using CO2plasma-chemical activated samples.