Fluorescence Spectroscopic Investigation of Interaction of Single-Walled Carbon Nanotubes with Bovine Hemoglobin

Single-walled carbon nanotubes (SWCNTs) can combine with proteins in organisms, creating potential biosafety risks. In this paper, SWCNTs and two separated single-chiral single-walled carbon nanotubes ((6,5)-SWCNTs, (8,3)-SWCNTs) were combined with bovine hemoglobin (BHb), respectively, and interaction between SWCNTs and BHb was analyzed by fluorescence spectroscopy. The results showed that the fluorescence quenching of BHb by SWCNTs was stemmed from the combination of dynamic quenching and static quenching. The fluorescence quenching of BHb by single chiral (6,5)-SWCNTs and (8,3)-SWCNTs was static quenching. At 298 K, the order of the binding constants of BHb with different SWCNTs were as follows: SWCNTs > (6,5)-SWCNTs > (8,3)-SWCNTs. Van der Waals force, hydrogen bond and hydrophobic interaction were the main forces in the interaction.