title: Direct electrochemistry and electrocatalysis of hemoglobin entrapped in semi-interpenetrating polymer network hydrogel based on polyacrylamide and chitosan.
abstract: Semi-interpenetrating polymer network (semi-IPN) hydrogel based on polyacrylamide (PAM) and chitosan was prepared to immobilize redox protein hemoglobin (Hb). The Hb-PAM-chitosan hydrogel film obtained has been investigated by scanning electron microscopy (SEM) and UV-VIS spectroscopy. UV-VIS spectroscopy showed that Hb kept its secondary structure similar to its native state in the Hb-PAM-chitosan hydrogel film. Cyclic voltammogram of Hb-PAM-chitosan film-modified glass carbon (GC) electrode showed a pair of well-defined and quasi-reversible redox peaks for Hb Fe(III)/Fe(II), indicating that direct electron transfer between Hb and GC electrode occurred. The electron-transfer rate constant was about 5.51 s(-1) in pH 7.0 buffers, and the formal potential (E degrees ') was -0.324 V (vs. SCE). The dependence of E degrees ' on solution pH indicated that one-proton transfer was coupled to each electron transfer in the direct electron-transfer reaction. Additionally, Hb in the semi-IPN hydrogel film retained its bioactivity and 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 5-420 microM. The unique semi-IPN hydrogel would have wide potential applications in direct electrochemistry, biosensors and biocatalysis.
authors.affiliation: State Key Laboratory of Chemo/Biosensoring and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Hunan, Changsha 410082, P. R. China.
authors.forename: Xiandong
authors.initials: X
authors.lastname: Zeng
authors.forename: Wanzhi
authors.initials: W
authors.lastname: Wei
authors.forename: Xuefang
authors.initials: X
authors.lastname: Li
authors.forename: Jinxiang
authors.initials: J
authors.lastname: Zeng
authors.forename: Ling
authors.initials: L
authors.lastname: Wu
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D002384:Catalysis; D048271:Chitosan / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D006454:Hemoglobins / Q000737:chemistry* / Q000378:metabolism; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008027:Light; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D013057:Spectrum Analysis; D014466:Ultraviolet Rays; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D048271:Chitosan; D006454:Hemoglobins; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D006861:Hydrogen Peroxide; D000099166:Polyacrylamides