A review of ligand tethered surface engineered carbon nanotubes

Carbon nanotubes (CNTs) have emerged as fascinating materials, exhibiting promising potential in receptor based targeting owing to their unique physicochemical properties (cell membrane penetration, high surface area and drug payload, biocompatibility, easy surface modification, photoluminescence property, and non-immunogenicity etc). The hydrophilicity, a major constrain associated with the first generation of CNTs i.e. pristine CNTs, could be overcome using functionalization techniques. In the last two decades variety of functionalized CNTs (f-CNTs) i.e. oxidized, amidated, acylated, surfactant and biopolymer-assisted, and biomolecules modified have been developed and utilized as effective, safe, nano sized, and smart systems to deliver a wide range of bioactives in the biological system. The purpose of this review is to examine the various aspects of conjugation and associated conjugation chemistry of various targeting ligands to CNTs for their respective biomedical applications. The various biomolecules have been easily tethered to CNTs surfaces including proteins and amino acid, enzymes, nucleic acid (DNA and siRNA), aptamers, vitamins, monoclonal antibodies, peptides (NGR, RGD and Aniopep-2) and so on, for targeting purposes.