Functionalization and Toxicity Effect of Multi-walled Carbon Nanotubes with Urea Derivatives via Microwave Irradiation

Abstract

Nanotubes were used in medical sciences especially in drug delivery system and cancer therapy. In this study, we have reported a highly efficient approach to functionalization of carboxylated multi-walled carbon nanotubes (MWNT-COOH) by 4,4'-oxydianiline or 4,4'-oxybis(2-nitroaniline) and the latter modification with phenylisocyanate for producing urea derivatives under microwave irradiation. Reducing the reaction time to the order of minutes and the number of steps in the reaction procedure is the major advantage of this procedure respect to conventional functionalization methods. These reactions were carried out in 25 min under microwave conditions, and the results were similar to what was achieved in 4 days using conventional methods. The interesting point is that modified MWNTs can be homogeneously dispersed in DMF without sonication, and the dispersed MWNTs does not sediment in 3 month. All products were characterized by Fourier transform infrared and Raman spectroscopy, scanning electron microscope, elemental analysis, TGA, DTG and cellular investigations. Toxicity assays with Stem cells and MTT test for measurement of viable cell numbers were also performed. Cellular results showed high toxicity of MWNT-Amide samples especially with NO₂ groups.

Keywords:

• MWNT-COOH
• functionalization
• phenylisocyanate
• toxicity investigation

Acknowledgments

The financial and encouragement support provided by Research vice Presidency of Ayatollah Amoli branch, Islamic Azad University and Iranian Nanotechnology Initiative (Government of Iran).