Sterilizing Properties of Carbon Nanotube Composites

ABSTRACTHydrogen-free carbon nanotube composites have been created that possess unusual free radical generation properties. These films have the ability to nonspecifically kill bacterial cells and can be used to sterilize a surface. These composites have been formed by simultaneous pulsed laser ablation of carbon and bombardment of nitrogen ions generated by a Kaufman ion source at high temperatures (600- 700°C). The results suggest the creation of a new form of carbon that is predominantly trigonally-coordinated, with small fractions of carbon-nitrogen bonds. TEM studies allow us to conclude that the material consists of sp2-bonded ribbons wrapped approximately +/-15° normal to the surface. Plan-view high resolution TEM specimens demonstrate layers with curvature similar to that seen in multiwalled nanotube structures. In addition, the interlayer order extends to approximately 15–30 nm. These novel structures result from the use of energetic ions, which create nonequilibrium conditions that alter the growth mode of graphitic planes. In vitro testing revealed significant antimicrobial activity against Staphylococcus aureus bacteria. Possible applications include use on the functional surfaces of dialysis equipment, scalpels, and other sterile equipment.