title: Reagentless biosensor for hydrogen peroxide based on self-assembled films of horseradish peroxidase/laponite/chitosan and the primary investigation on the inhibitory effect by sulfide.
abstract: Horseradish peroxidase (HRP) was successfully incorporated into the laponite/chitosan (Chit)-modified glassy carbon electrode (GCE) using step-by-step self-assembly. The self-assembly processes were monitored by X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectra (EIS). Direct electrochemistry and electrocatalysis of the self-assembled HRP were investigated. Cyclic voltammetry of HRP/laponite/Chit/GCE, in anaerobic phosphate buffer solution (0.025 M PBS, pH 7.0), displayed a pair of stable and quasi-reversible peaks at potentials Epa=0.024 V and Epc=-0.132 V vs. SCE, attributed to the HRP-Fe(III)/HRP-Fe(II) redox couple. The electrochemical reaction of the HRP/laponite/Chit/GCE exhibited a surface-controlled electrode process. The electron transfer rate constant was estimated to be 1.82 s(-1). The self-assembled HRP maintained its biological activity and exhibited an excellent electrocatalytic performance for the reduction of H2O2 with fast amperometric response (10 s), broad linear range (2.9×10(-5) to 1.4×10(-3) M), good sensitivity (19.7±0.5 mA M(-1) cm(-2)) and low detection limit (5×10(-6) M) at a signal-to-noise ratio of 3. Moreover, the inhibitory of sulfide to the self-assembled HRP was also investigated.
authors.affiliation: Key Laboratory of Environmental Material & Environmental Engineering of Jiangsu Province, School of Chemistry & Chemical Engineering, Yangzhou University, Si Wangting Road 180, Yangzhou, Jiangsu 225002, China. danshan@yzu.edu.cn
authors.forename: Dan
authors.initials: D
authors.lastname: Shan
authors.forename: Qing-Bo
authors.initials: QB
authors.lastname: Li
authors.forename: Shou-Nian
authors.initials: SN
authors.lastname: Ding
authors.forename: Jia-Qi
authors.initials: JQ
authors.lastname: Xu
authors.forename: Serge
authors.initials: S
authors.lastname: Cosnier
authors.forename: Huai-Guo
authors.initials: HG
authors.lastname: Xue
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D048271:Chitosan / Q000737:chemistry*; D003217:Conductometry / Q000295:instrumentation*; D004791:Enzyme Inhibitors / Q000737:chemistry; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000032:analysis* / Q000737:chemistry; D007202:Indicators and Reagents; D017640:Silicates / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*
chemical_list: D004791:Enzyme Inhibitors; D004800:Enzymes, Immobilized; D007202:Indicators and Reagents; D017640:Silicates; D013440:Sulfides; D048271:Chitosan; D006861:Hydrogen Peroxide; C524813:laponite; D006735:Horseradish Peroxidase