title: Bienzymatic glucose biosensor based on direct electrochemistry of cytochrome c on gold nanoparticles/polyaniline nanospheres composite.
abstract: Gold nanoparticles (GNPs) assembled polyaniline nanospheres (PANS) composite were prepared by noncovalent strategy. Cytochrome c (Cyt c) was electrostatically adsorbed on the GNPs/PANS modified electrode. The direct electron transfer (DET) between Cyt c and GNPs/PANS modified electrode was investigated. Cyt c shows a couple of quasi-reversible and well-defined cyclic voltammetry (CV) peaks with a formal potential (E(0')) of -0.27 V (versus Ag/AgCl) in pH 7.0 phosphate buffer solution (PBS). The Cyt c/GNPs/PANS modified electrode gives an improved electrocatalytic activity toward the reduction of hydrogen peroxide (H2O2). The catalysis currents increase linearly to the H2O2 concentration in a wide range of 0.01-2.4 mM with a correlation coefficient 0.998. After immobilized glucose oxidase (GOD) on the Cyt c/GNPs/PANS modified electrode by Nafion polymer, a bienzymatic glucose biosensor was further prepared for sensitive detection of glucose. The amperometric detection of glucose was assayed by potentiostating the bienzymatic electrode at -0.2 V versus Ag/AgCl to reduce the enzymatically produced H2O2 with minimal interference from the coexisting electroactive compounds. The proposed glucose biosensor exhibits good response performance to glucose with a wide linear range from 0.01 to 3.2mM with a correlation coefficient of 0.997. The electrode has high sensitivity of 63.1 μA mM(-1)cm(-2) and a detection limit 0.01 mM at the signal-to-noise ratio of 3. Moreover, the glucose biosensor possesses good stability and reproducibility.
authors.affiliation: Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin 541004, PR China.
authors.forename: Cuili
authors.initials: C
authors.lastname: Xiang
authors.forename: Yongjin
authors.initials: Y
authors.lastname: Zou
authors.forename: Shujun
authors.initials: S
authors.lastname: Qiu
authors.forename: Lixian
authors.initials: L
authors.lastname: Sun
authors.forename: Fen
authors.initials: F
authors.lastname: Xu
authors.forename: Huaiying
authors.initials: H
authors.lastname: Zhou
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D000818:Animals; D015374:Biosensing Techniques; D045304:Cytochromes c / Q000378:metabolism*; D055664:Electrochemical Techniques / Q000379:methods*; D005947:Glucose / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D006736:Horses; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission
chemical_list: D000814:Aniline Compounds; C416807:polyaniline; D006046:Gold; D045304:Cytochromes c; D005947:Glucose