Spectroscopic Analysis of the Redox Processes of the Ensemble between Chiral Single-Walled Carbon Nanotubes and Bovine Hemoglobin Complex

In this paper, unseparated single-walled carbon nanotubes (SWCNTs) and two types of single-chiral SWCNTs, namely (6,5)-SWCNTs and (8,3)-SWCNTs, were used to associate with bovine hemoglobin (BHb), respectively. The interaction between SWCNTs and BHb, and the spectral responses corresponding to the redox process of SWCNTs/BHb composites, were analyzed. The results indicated that the binding with SWCNTs led to changes in the secondary structure of BHb, with the largest structural alteration observed for unseparated SWCNTs, resulting in fluorescence quenching and ɑ-helix loss in BHb. During the oxidation process, the fluorescence intensity of both BHb and SWCNTs at their maximum emission wavelengths increased; Whereas, during the reduction process, the fluorescence intensity of BHb and SWCNTs gradually recovered to the original state. The findings of this study provide insight into monitoring the redox process of hemoglobin.