An Overview on Carbon Nanotubes

Abstract

Carbon nanotubes (CNTs) are third allotropic form of carbon–fullerenes which consist of graphite sheet rolled up into a cylindrical tube to form either single–wall (SWCNTs) or multi–wall (MWCNTs). Methods such as: Electrical arc discharge, Laser ablation and Chemical vapor deposition are used to synthesize CNTs. CNTs can be considered as the nano–pharmaceuticals of choice depending on their vast application in drug delivery, drug targeting and in various other fields such as diagnostic, tissue regeneration. To be integrated into the biological systems, CNTs can be chemically modified or functionalised with therapeutically active molecules by forming stable covalent bonds or supra–molecular assemblies based on non–covalent interactions. Owing to their high carrying capacity, biocompatibility, and specificity to cells, various cancer as well diseased cells have been explored with CNTs for evaluation of pharmacokinetic parameters, cell viability, cytotoxicty, and drug delivery in cells. CNTs can also be modified with positively charged bio–molecules such as ammonium group and cationic amino acid lysine, which lead to easy complex formation with genes of interest. CNT–based contrast agent may enhance molecular imaging by improving detection sensitivity and selectivity. The semi–conducting SWCNTs exhibits photoluminescence in the near–infrared (NIR) region. The emission ranges of 800–2000 nm cover the biological tissue transparency window, which is therefore suitable for the imaging of biological systems through the luminescence created by semi–conducting SWCNTs