Preparation and Characterization of Disulfide Functionalized Multi-Walled Carbon Nanotubes for Biomedical Applications

To interact with different biologic systems for biomedical applications, chemical modification of carbon nanotubes is always a key step. Disulfide is sensitive to the reductive intracellular environment, and such stimulus-responsive covalent bonds were used to modify carbon nanotubes. After deprotection of N-tert-butoxycarbonyl (Boc) groups of the N-(tert-butyloxycarbonyl) cystamine modified multi-walled carbon nanotubes (MWNTs), positively charged ammonium (NH3) functionalized MWNTs (MWNTs-S-S-NH3) with disulfide linkages were obtained. Their surface functional groups and changes of morphologies were characterized by infrared (IR) spectroscope and transmission electron microscope (TEM), respectively. The weight percentage of the immobilized disulfide was estimated by thermogravimetric analysis (TGA). And their cytotoxicity in vitro on cultured human nasopharyngeal SUNE1 cells was evaluated. The biocompatibility of MWNTs was improved compared to that of MWNTs without functional groups.