ABSTRACT

Carbon nanotubes (CNTs) are believed to be important classical nanomaterials although they have been found for no more than 20 years (Iijima 1991) because of their wide use in various fi elds (Chen et al. 2010; Yang et al. 2010; Bao et al. 2010). Recently their application in neuroscience has also attracted increasing attention of people (Malarkey and Parpura 2010). Structurally, carbon nanotubes (CNT) are composed of sheets of graphene that form into a cylinder, either with a single wall, single-walled carbon nanotube (SWCNT), or multiple wall, multi-walled carbon nanotubes (MWCNT). Another kind of CNT, double-walled CNTs (DWCNT) composed of two concentric graphene cylinders, represents an

intermediate structure between MWCNTs and SWCNTs. The diameter of CNTs ranges typically from 0.4 to 2 nm for SWCNT and 2 to 100 nm for MWCNT while the lengths of these nano carbon structures can get to several hundred micrometers. The arrangement of the carbon atoms in the wall of CNTs can take several conformations, including armchair, chiral or zigzag ones. These conformations determine the physical and chemical properties of these carbon nanostructures; all armchair CNTs are conductive (metallic), while the zigzag and chiral CNTs can be either metallic or semiconducting. There are a variety of ways for the synthesis of CNT, including chemical vapor deposition, electric arc discharge and laser ablation. After manufacture, CNTs can be modifi ed to enable them to perform new functions and improve their biocompatibility by attaching various chemical groups to them. Some functional groups, such as lipids, DNA and various peptides, can often be simply adsorbed to the wall of CNTs. If a more fi rm and durable attachment is desired and needed, compounds may be covalently linked to CNTs. This is most often done without too much diffi culty by incubating CNTs with strong oxidizing agents, which add carboxyl groups to the ends of the tubes and any defect sites. Then, other groups can be added, usually converting the carboxyl group to acyl chloride, which can then be reacted with the compound of interest. For more information on the modifi cations of CNT structures see previous chapters (Bekyarova et al. 2005). Although CNTs have shown promise in many fi elds of biomedicine, here we discuss the use of CNTs in neuroscience, focusing mainly on recent developments with regard to their use as drug carriers in the treatment of some diseases in the central nervous systems, with a brief coverage of earlier studies. For more information on the earlier applications of CNTs in neurobiology see Malarkey and Parpura’s article (2007).