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

• Binding interaction of MWCNTs-COOH with BSA was investigated.
• hydrophobic force and π-π stacking were involved in the binding process.
• MWCNTs-COOH acted as a structure destabilizer for BSA.
• The pseudo-second-order model describe the adsorption of BSA on MWCNTs-COOH.

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.

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