This study described the bioelectrochemistry of hemoglobin (Hb) at multiwall carbon nanotubes (MWCNTs) noncovalently functionalized with biopolymers of sodium alginate (SA). The characteristics of Hb/SA-MWCNTs composite film were studied by using FT-IR spectroscopy, UV-vis spectroscopy and electrochemical methods. Hb immobilized on SA-MWCNTs composite film retained its native secondary structure, achieved direct electron transfer with the apparent heterogeneous electron transfer rate constant (ks) of (9.54 ± 0.883) s-1 and showed excellent bioelectrocatalytic activity to the reduction of hydrogen peroxide. The amperometric response of the biosensor varied linearly with the H2O2 concentration ranging from 40 to 200 μM, with a detection limit of 16.41 × 10-6 M (S/N = 3) and the good long-term stability. Finally, we applied this proposed method to investigate the concentration of hydrogen peroxide in real samples.
- Direct electron transfer
- Sodium alginate-multiwall carbon nanotubes composite film