Carbon Nanotubes

Carbon nanotubes (CNTs) are one-dimensional systems made ofone-atom-thick sheet of graphite (called graphene) rolled up into a seamless cylinder with diameter in the order of a nanometer. Although the diameter of a nanotube is just a few nanometers (approximately

  • 50.000 times smaller than the width of a human hair) in size, these constructs can be up to several millimeters in length. The length to diameter ratio of these nanosystems exceeds
  • 10.000 times rendering CNTs with novel properties. CNTs have a wide variety of applications including biomedical imaging, electronics, optics, and other fields of materials science. These nanotubes exhibit extraordinary strength and electrical and optical properties and are efficient heat conductors. The optical properties of CNTs include effective absorption, fluorescence, and Raman spectroscopy.

CNTs are generally prepared by simple chemical vapor deposition method [13]. Other techniques include arc discharge, laser ablation, and high-pressure carbon monoxide disproportionation. In the chemical vapor deposition process, hydrocarbon polymer vapors are passed through a catalyst reactor at high temperature [13]. Nanotubes grow on the catalyst and are subsequently cooled and collected [14]. The unique physicochemical properties of carbon nanoparticles enable delivery of a variety of hydrophilic and hydrophobic drugs and even codelivery oftwo different drug molecules for combinatorial therapy. Functionalization of CNT has expanded the applications as a delivery platform for diverse molecules such as peptides, proteins, plasmid DNA, and synthetic oligodeox- ynucleotides [15]. In fact these tubes can be even functionalized for targeted drug delivery in hard-to-reach tumor cells. CNTs are widely studied as potential theranostic agents and they can deliver both diagnostic/contrast and therapeutic agents [3,16].

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