title: Direct electrochemistry and electrocatalytic properties of hemoglobin immobilized on a carbon ionic liquid electrode modified with mesoporous molecular sieve MCM-41.
abstract: The direct electron transfer and electrocatalysis of hemoglobin (Hb) entrapped in the MCM-41 modified carbon ionic liquid electrode (CILE) were investigated by using cyclic voltammetry in 0.10 M pH 7.0 phosphate buffer solution (PBS). Due to its uniform pore structure, high surface areas and good biocompatibility, the mesoporous silica sieve MCM-41 provided a suitable matrix for immobilization of biomolecule. The MCM-41 modified CILE showed significant promotion to the direct electron transfer of Hb, which exhibited a pair of well defined and quasi-reversible peaks for heme Fe(III)/Fe(II) with a formal potential of -0.284 V (vs. Ag/AgCl). Additionally, the Hb immobilized on the MCM-41 modified carbon ionic liquid electrode showed excellent electrocatalytic activity toward H(2)O(2). The electrocatalytic current values were linear with increasing concentration of H(2)O(2) in a wide range of 5-310 microM and the corresponding detection limit was calculated to be 5 x 10(-8)M (S/N=3). The surface coverage of Hb immobilized on the MCM-41 modified carbon ionic liquid electrode was about 2.54 x 10(-9) molcm(-2). The Michaelis-Menten constant K(m)(app) of 214 microM indicated that the Hb immobilized on the modified electrode showed high affinity to H(2)O(2). The proposed electrode had high stability and good reproducibility due to the protection effect of MCM-41 and ionic liquid, and it would have wide potential applications in direct electrochemistry, biosensors and biocatalysis.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Hunan, Changsha 410082, PR China.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Li
authors.forename: Xiandong
authors.initials: X
authors.lastname: Zeng
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Liu
authors.forename: Xinsheng
authors.initials: X
authors.lastname: Liu
authors.forename: Wanzhi
authors.initials: W
authors.lastname: Wei
authors.forename: Shenglian
authors.initials: S
authors.lastname: Luo
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004579:Electron Transport; D006454:Hemoglobins / Q000737:chemistry* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D052578:Ionic Liquids / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D052578:Ionic Liquids; C509968:MCM-41; D002244:Carbon; D012822:Silicon Dioxide; D006861:Hydrogen Peroxide