Preparation and biocompatibility evaluation of polyurethane filled with multiwalled carbon nanotubes

Biocompatibility has been one of the most crucial performances that determine the clinical application potentials of biomaterials and implants. As carbon is one inner substance and possesses clinical accepted blood compatibility, carbon nanotubes may bring improved hemocompatibility of polymeric materials when used as fillers. In this work, a kind of composite composed of polyurethane and multiwalled carbon nanotubes has been developed using a customized sol-gel technique. The cytotoxicity of the composite was evaluated by examining viability of the endothelium cells seeded on the composite or cultured with composite extraction using MTS assay and Environmental Scanning Electronic Microscope. Tissue compatibility was evaluated by subcutaneous implantation of the composite film in the paraspinal skin incision of rat. Dynamic clotting test of the composite were conducted to evaluate blood compatibility. Experiments results revealed that multiwalled carbon nanotubes were well dispersed into the polyurethane matrix. More functional endothelial cell grew on the composite than polyurethane. When implanted subcutaneously, the composite did not induce long-term inflammation in the implanted sites and exhibited good tissue compatibility. The dynamic clotting test showed that the composite had longer clotting time than PU, indicating that anti-coagulant property of the composite was improved.