![]() ![]() ![]() “Cancer nanotechnology” is the novel emerging field which used nanocarriers like liposome, polymeric nanoparticles, dendrimers, quantum dots, polymersomes, carbon nanotubes, and so forth, for delivering drugs to the target site and thus holds tremendous potential to overcome several problems associated with the conventional therapies. Besides precise tumor targeting and toxicity concerns, drug resistance remains a major obstacle for the treatment of advanced cancerous tumor. This nonspecificity of the drug limits the therapeutic dose within cancer cells while providing excessive toxicities to normal cells, tissues, and organs and thereby causing several adverse effects. The main problem incurred with various chemotherapies for treating cancer is lack of selectivity of the anticancer drug towards cancerous cells. Therefore, significant amounts of research have been carried out to overcome these problems. One of the aims of cancer therapy is to prevent the metastatic process as early as possible. Many patients who succumb to death due to cancer do not die as a result of the primary tumor, but because of the systematic effects of metastases on the other regions away from the original site. Though the current treatments of cancer by surgery, radiation, and chemotherapy are successful in several cases however, these curative methods are likely to kill healthy cells and cause toxicity to the patient. With more than 10 million new cases every year, cancer is one of the most devastating diseases. Owing to the sp 2 hybridization in MWCNTs, a delocalized electron cloud along the wall is generated which is responsible for the π- π interactions between adjacent cylindrical layers in MWCNTs resulting in a less flexible and more structural defects. Electric arc and chemical vapor deposition (CVD) are the main techniques for their production. The outer diameter of MWCNTs ranges from 2 to 100 nm, while the inner diameter is in the range of 1–3 nm, and their length is 1 to several μm. MWCNTs consist of several coaxial cylinders, each made of a single graphene sheet surrounding a hollow core. Ĭarbon nanotube: (a) single walled carbon nanotube and (b) multiwalled carbon nanotube. SWCNTs are produced by the electric arc, laser ablation, chemical vapor deposition (CVD), and gas-phase catalytic processes (HiPco or high-pressure CO conversion). SWCNTs are made up of single graphene layer wrapped into a hexagonal close-packed cylindrical structure whose diameter varies from 0.4 to 3.0 nm and length ranges from 20 to 1000 nm and are held together by Vander Waals forces, which makes them easily twistable and more pliable. Depending on the number of sheets rolled into concentric cylinders, there are two broad categories of CNTs, namely, single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) ( Figure 1). CNTs are graphene sheets rolled into a seamless cylinder that can be open ended or capped, having a high aspect ratio with diameters as small as 1nm and a length of several micrometers. After the discovery of the third allotropic form of carbon fullerene in 1991, Sumio Iijima identified a new structural form of this allotrope, the cylindrical fullerene and named them as carbon nanotubes (CNTs). ![]()
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