Auburn University (Auburn, AL) scientists disclose new nanocomposite materials in U.S. Patent Application 20100028960. The materials are comprised of multiple layers of biomolecules bound to aligned carbon nanotubes. The thickness of each of the layers may be precisely controlled using a layer-by-layer (LBL) assembly technique say inventors Chemical Engineering Proessor Virginia A Davis, Aleksandr L. Simonian, Dhriti Nepal and Shankar Balasubramanian.
The Auburn team developed nanocomposites with desirable anti-microbial activity with respect to bacteria. Furthermore, nanocomposites with decontaminating activity were also developed, for example with respect to organophosphorus chemicals. In addition, nanocomposites of CNTs and biomolecules have suitable hardness, Young's modulus, and controlled morphology (e.g., with respect to thickness).
Applications of the carbon nanotube composite materials include biologically-compatible coatings for objects and devices that are inserted or implanted into living organisms, as well as chemical, physical, and electronic sensors, and fiber material for clothing or other structures.
The Auburn researchers have developed a unique multifunctional biomimetic material comprised of SWNT, DNA and lysozyme (LSZ) using LBL assembly. Precise control of both layer thickness and SWNT alignment within each layer was achieved, and the final coatings had robust mechanical properties. Coatings ending in an exposed LSZ-SWNT layer exhibit excellent long-term antimicrobial activity. This has several distinct advantages over coatings which release antimicrobials over time; controlled release coatings lose their antimicrobial efficiency once the concentration of the antimicrobial agent drops below the minimum inhibitory concentration (MIC).
On the other hand, Auburn’s non-leaching coatings exhibit robust mechanical properties and long term protection against bacterial colonization. Furthermore, the spectrum of disinfection of LSZ-SWNT layers can be extended to gram-negative bacteria by simply including chelators such as EDTA. The results of this research demonstrate the significant possibilities for the molecular design of hybrid structural materials from SWNTs and natural biopolymers. Such robust, antimicrobial materials have significant promise in applications including medicine, aerospace engineering, public transportation, home appliances and sporting goods.