The mechanics and biocompatibility characteristics of carbon nanotubes-polyurethane composite membranes:a preliminary study

Objective: To discuss the mechanics and biocompatibility characteristics of carbon nanotubes-polyurethane composite membranes. Methods: The mechanics property of carbon nanotubes-polyurethane composite membranes with different carbon nanotubes contents were tested by universal material testing machine. The surface of the membranes was observed by electron microscope when the stent was bent 90 degree. And its cytotoxicity was tested by cultivating study with 7721 cell. The metallic stent that was covered with carbon nanotubes-polyurethane composite membrane by using dip-coating method was inserted in rabbit esophagus in order to evaluate its biocompatibility in vivo. Results: Composite membranes tensile strength (MPa) and elongation at break (%) were 4.62/900, 6.05/730, 8.26/704 and 5.7/450 when the carbon nanotubes contents were 0%, 0.1%, 0.3% and 0.5%, respectively. If the stent was bent at 90 degree, its surface was still smooth without any fractures when it was scanned by electron microscope.Composite membranes had critical cytotoxicity when its carbon nanotubes content was up to 0.5% and 1.0%. No fissure nor degradation of composite membranes occurred at 30 days after composite membrane covered metallic stent was inserted in rabbit esophagus. Conclusion: When moderate carbon nanotubes are added into polyurethane composite membrane, the mechanics and biocompatibility characteristics of the polyurethane composite membrane can be much improved. (authors)