title: Hydrogen peroxide biosensor based on direct electrochemistry of soybean peroxidase immobilized on single-walled carbon nanohorn modified electrode.
abstract: Single-walled carbon nanohorns (SWCNHs) were used as a novel and biocompatible matrix for fabricating biosensing devices. The direct immobilization of acid-stable and thermostable soybean peroxidase (SBP) on SWCNH modified electrode surface can realize the direct electrochemistry of enzyme. Cyclic voltammogram of the adsorbed SBP displays a pair of redox peaks with a formal potential of -0.24 V in pH 5 phosphate buffer solution. The formal potential has a linear relationship with pH from 3 to 9 with a slope of -48.7 mV/pH, close to the value of -55.7 mV/pH expected at 18 degrees C for the reversible transfer of one proton and one electron. Bioactivity of SBP remains good in SWCNH microenvironment, along with effective catalysis of the reduction of H(2)O(2). In the absence of a mediator, this H(2)O(2) biosensor exhibited a high sensitivity (16.625 microAL/mmol), a linear range from 0.02 to 1.2 mmolL(-1), and a detection limit of 5.0 x 10(-7) mmolL(-1), as well as acceptable preparation reproducibility and excellent stability.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, Jilin 130022, China.
authors.forename: Lihong
authors.initials: L
authors.lastname: Shi
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Liu
authors.forename: Wenxin
authors.initials: W
authors.lastname: Niu
authors.forename: Haijuan
authors.initials: H
authors.lastname: Li
authors.forename: Shuang
authors.initials: S
authors.lastname: Han
authors.forename: Jiuan
authors.initials: J
authors.lastname: Chen
authors.forename: Guobao
authors.initials: G
authors.lastname: Xu
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006861:Hydrogen Peroxide / Q000032:analysis*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010544:Peroxidases / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013025:Glycine max / Q000201:enzymology*
chemical_list: D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D006861:Hydrogen Peroxide; D010544:Peroxidases