DNA-hemoglobin-multiwalls carbon nanotube hybrid material with sandwich structure: Preparation, characterization, and application in bioelectrochemistry

A novel multiwall carbon nanotubes (MWNTs)-based hybrid material with sandwich structure (DNA-Hb-MWNTs) was fabricated by alternative electrostatic assembly of hemoglobin (Hb) and DNA on MWNTs. TEM showed that such a nanocomposite behaved as an obvious core-shell structure. SEM proved the well-preserved 3-D structure of DNA-Hb-MWNTs assembled on an electrode. UV-vis and FTIR spectroscopy were used to monitor the assembly procession and also demonstrated that Hb had been sandwiched into DNA and MWNTs without denaturation. A pair of stable and well-defined redox peaks of Hb with a formal potential of about -0.298 V (vs Ag/AgCl) in a pH 6.0 phosphate buffer solution (PBS) were obtained at the DNA-Hb-MWNTs nanocomposite film-modified glassy carbon (GC) electrode (DNA-Hb-MWNT/GC electrode). Compared with the Hb-MWNTs/GC electrode, the DNA-Hb-MWNTs/GC electrode exhibited enhanced faradic current response, and the portion of the electroactive proteins had been greatly improved. Furthermore, the modified electrode also displayed good sensitivity, wide linear range, and long-term stability to the detection of hydrogen peroxide. Such an organized multicomponent biosensor platform may find wide potential applications in biosensors, biocatalysis, biomedical devices, and bioelectronics.