SURFACE MODIFICATION AND NON-COVALENT FUNCTIONALIZATION OF SINGLE-WALLED CARBON NANOTUBES AND THEIR CHARACTERIZATION

Single-walled carbon nanotubes (SWNTs) though emerged as a promising material for delivery of biomolecules into various cells, due to their high cytotoxicity, they are limited in use in many biological systems and also in humans. The present research explores the preparation of functionalized SWNTs of low cytotoxicity and biocompatibility by altering the size and surface functionalization. Noncovalent amine functionalization improves their biocompatibility, solubility and alters their cellular interaction pathways resulting in reduced cytotoxic effects so that the biomolecule will be preferably released from the carbon nanotube when the complex has been taken up by endocytosis into the cells. The noncovalent functionalization of SWNTs was carried out by using polymer 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino (polyethylene glycol) – 2000] (ammonium salt) (DSPE-PEG 2000 amine) which makes the hydrophobic lipid chains of PEG to get strongly anchored onto the nanotube surface, whereas the hydrophilic chain renders SWNTs water soluble and biocompatible which results in the development of NH₂-PEG-SWNTs. The functionalized SWNTs were further characterized by FE-SEM, Raman spectroscopy, FT-IR and UV-VIS-NIR, and zeta potential. So these functionalized SWNTs can be used as effective carbon materials with enhanced solubility properties and has potential biomedical applications in the delivery of biomolecules to disease target sites.