Binding of hydroxylated single-walled carbon nanotubes to two hemoproteins, hemoglobin and myoglobin

• This paper attests that HO-SWCNTs exhibited significant bindings to Hb and Mb.
• Multi-noncovalent interactions stabled the HO-SWCNTs–Hb/Mb complex.
• The secondary structures of Hb and Mb were destroyed by HO-SWCNTs.
• Molecular calculation showed that there were the preferable binding sites of HO-SWCNTs on Hb and Mb.

Herein, we studied the binding interactions between hydroxylated single-walled carbon nanotubes and hemoglobin and myoglobin by the use of multi-spectral techniques and molecular modeling. The ultraviolet–vis absorbance and circular dichroism spectral results indicated that the binding interactions existed between hydroxylated single-walled carbon nanotubes and hemoglobin/myoglobin. These binding interactions partially affected the soret/heme bands of hemoglobin and myoglobin. The secondary structures of hemoproteins were partially destroyed by hydroxylated single-walled carbon nanotubes. Fluorescence studies suggested that the complexes formed between hydroxylated single-walled carbon nanotubes and hemoglobin/myoglobin by hydrogen bonding, hydrophobic, and π–π stacking interactions. In addition, molecular modeling analysis well supported the experimental results.

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