Cardiovascular implants including bypass grafts, heart valves and stents are prone to thrombogenicity and mechanical incompatibility thus leading to limited graft patencies. Thus to overcome these issues, a nanocomposite polymer based on polyhedral oligomeric silsesquioxane (POSS) nanoparticles and poly(carbonate urea)urethane (PCU) has been developed and patented. A solvent exchange coagulation technique has been used in the fabrication of a compliant, POSS PCU graft. In addition, we present details of bonding of bioactive peptides to attract progenitor stem cells from peripheral circulating blood onto the implants and the endothelialisation potential on the lumen. Peptides are designed to enhance interactions with cell receptor integrins whilst and in-vitro and in-vivo tests are performed to determine both endothelial and platelet as well as whole blood interactions. In conclusion these results, together with its ease of manufacture and low cost, suggest that POSS-PCU nanocomposite could be an attractive material of choice for the development of cardiovascular implants.