A literature study was conducted to review peptide adhesion to carbon nanotubes and they were found to be important in the drug designing industries. To attain target specificity CNTs (functionalized with DNA, peptides etc.) have been used as potential vector system. Prior studies show that single walled nanotubes (SWNTs) when functionalized with peptides have been proven to be better delivery systems than the previous vector delivery systems. Functionalized SWNTs can deliver the peptides to the specific target organs in the right concentration without having prominent toxic effect. Toxicity studies show that since the SWNTs have shorter half life periods most of them get washed away after they deliver the ligands to the target organs. It has been shown that SWNTs that are toxic to the body are so solely due to manufacturing defects. Pure SWNTs are not toxic to the body. Recently functionalized CNTs are also used for cancer therapy. A docking study was carried out on interaction of hydrogen and nitrogen functionalized SWNTs with peptides where vasopressin is the model peptide. In order to study the effect of dimensions of SWNTs and functionalized group attached to the SWNTs on the strength of a bond, binding free energies were calculated from the docking models. Hydrogen functionalized, nitrogen functionalized and non-functionalized SWNTs binding energies were compared with each other. Results show that functionalized SWNTs tend to bind with more peptide molecules than nonfunctionalized SWNTs. The interactions on the inner walls of SWNTs are more unstable than the outer wall interactions
