Various strategies for functionalization are employed and mainly involve two approaches, the first strategy involves additional reactions for attachment of organic moieties on the sidewalls and tips and the second approach includes oxidation along with carboxyl couplings. The first strategy involves blending of pristine carbon nanoparticles and aniline and the pressure applied during mixing facilitates liber­ation of the bundled outer nanoparticles, which react with the reagent to initiate the process of functionalization. This leads to covalent functionalization of the individual nanoparticle, which prevents it from bundling with other particles and increases surface area for attachment of molecules along with improving the solu­bility. This strategy is a simple procedure, which generates soluble nanoparticles and facilitates their industrial application [17]. However, this method has a major limi­tation of preventing many essential changes in the nanoparticle. The second method used for functionalization involves oxidation and couplings that are carboxyl group based. This procedure involves creation of cap openings and holes along the side walls through oxidation, which uses concentrated acids. Furthermore, carboxylic groups are also introduced, which increase the solubility of nanoparticles in aqueous medium [18]. Carboxylic group forms amide and ester linked covalent bonds with several biologically active molecules such as peptides [19, 20], nucleic acids [21, 22], proteins [23] and anti-tumor drugs [24, 25]. Appropriate bonding enhances solubility of nanoparticles in both aqueous [26] as well as organic solvents [27]. Carboxylic functional groups decrease interactions driven by Van der Waals forces between the nanoparticles, facilitating separation of bundles [28].