Carbon nanotube biogels

There are numerous biomedical devices that rely on efficient electrical communication with living tissue. Advancement of these devices depends on effectively bridging the tissue/electrode interface and is dependent on advances in new materials. We report on the modification of carbon nanotubes with various biomolecules to develop biological based conducting material suitable for bridging this interface. The non-covalent modification of single-wall carbon nanotubes (SWCNT) with three biological molecules (DNA, hyaluronic acid and chitosan) has been achieved. Coherent SWCNT biofilms were produced from the dispersions by drop casting onto glassy carbon electrodes. The SWCNT biofilms underwent hydration upon immersion into electrolyte to form a gel that exhibited considerably lower impedance than the glassy carbon substrate. In addition, incorporation of the neurotrophin NT-3 into these CNT biogels was possible with the controlled release of the NT-3 being influenced by the application of electrical stimulation. Compatibility of the materials prepared with a fibroblast cell line (L-929) was also tested and it was determined that they were non-toxic to the cells under consideration. The soft character of these conducting biogels coupled with their dynamic nature provides an extra dimension in designing interfaces between the hard, digital electronics world and the soft, amorphous world of biological systems.