title: Direct electrochemistry of hemoglobin immobilized on a functionalized multi-walled carbon nanotubes and gold nanoparticles nanocomplex-modified glassy carbon electrode.
abstract: Direct electron transfer of hemoglobin (Hb) was realized by immobilizing Hb on a carboxyl functionalized multi-walled carbon nanotubes (FMWCNTs) and gold nanoparticles (AuNPs) nanocomplex-modified glassy carbon electrode. The ultraviolet-visible absorption spectrometry (UV-Vis), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) methods were utilized for additional characterization of the AuNPs and FMWCNTs. The cyclic voltammogram of the modified electrode has a pair of well-defined quasi-reversible redox peaks with a formal potential of -0.270 ± 0.002 V (vs. Ag/AgCl) at a scan rate of 0.05 V/s. The heterogeneous electron transfer constant (ks) was evaluated to be 4.0 ± 0.2 s(-1). The average surface concentration of electro-active Hb on the surface of the modified glassy carbon electrode was calculated to be 6.8 ± 0.3 × 10(-10) mol cm(-2). The cathodic peak current of the modified electrode increased linearly with increasing concentration of hydrogen peroxide (from 0.05 nM to 1 nM) with a detection limit of 0.05 ± 0.01 nM. The apparent Michaelis-Menten constant (K(m)(app)) was calculated to be 0.85 ± 0.1 nM. Thus, the modified electrode could be applied as a third generation biosensor with high sensitivity, long-term stability and low detection limit.
authors.affiliation: School of Life Sciences, Henan University, Kaifeng 475000, China. hongjun@henu.edu.cn
authors.forename: Jun
authors.initials: J
authors.lastname: Hong
authors.forename: Ying-Xue
authors.initials: YX
authors.lastname: Zhao
authors.forename: Bao-Lin
authors.initials: BL
authors.lastname: Xiao
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Moosavi-Movahedi
authors.forename: Hedayatollah
authors.initials: H
authors.lastname: Ghourchian
authors.forename: Nader
authors.initials: N
authors.lastname: Sheibani
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002417:Cattle; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D005898:Glass / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000032:analysis / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D055767:Immobilized Proteins / Q000737:chemistry* / Q000378:metabolism; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D037742:Nanotubes, Carbon / Q000737:chemistry*
chemical_list: D006454:Hemoglobins; D055767:Immobilized Proteins; D037742:Nanotubes, Carbon; D006046:Gold; D006861:Hydrogen Peroxide