Comprehensive studies on the nature of interaction between carboxylated multi-walled carbon nanotubes and bovine serum albumin.

Herein, the interaction between carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) and bovine serum albumin has been investigated by using circular dichroism, UV-vis, and fluorescence spectroscopic methods and molecular modeling in order to better understand the basic behavior of carbon nanotubes in biological systems. The spectral results showed that MWCNTs-COOH bound to BSA and induced the relatively large changes in secondary structure of protein by mainly hydrophobic forces and π-π stacking interactions. Thermal denaturation of BSA in the presence of MWCNTs-COOH indicated that carbon nanotubes acted as a structure destabilizer for BSA. In addition, the putative binding site of MWCNTs-COOH on BSA was near to domain II. With regard to human health, the present study could provide a better understanding of the biological properties, cytotocicity of surface modified carbon nanotubes.