title: Electrochemically deposited chitosan hydrogel for horseradish peroxidase immobilization through gold nanoparticles self-assembly.
abstract: A new strategy for immobilization of horseradish peroxidase (HRP) has been presented by self-assembling gold nanoparticles on chitosan hydrogel modified Au electrode. From a mildly acidic chitosan solution, a chitosan film is electrochemically deposited on Au electrode surface via a negative voltage bias. This process is accompanied by the hydrogen evolution reaction, and the released hydrogen gas made the deposited chitosan film with porous structure, which facilitates the assembly of gold nanoparticles and HRP. The resulting substrates were characterized by atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The immobilized HRP displayed an excellent catalytic property to the reduction of H2O2 in the presence of methylene blue mediator. The resulting biosensor (HRP-modified electrode) showed a wide dynamic range of 8.0 microM-15 mM H2O2, and the linear ranges were 8.0 microM-0.12 mM and 0.50-12 mM, with a detection limit of 2.4 microM estimated at a signal-to-noise ratio of 3. Moreover, the biosensor remained about 85% of its original sensitivity after four weeks' storage.
authors.affiliation: The Key Lab of Analytical Chemistry for Life Science, Institute of Analytical Science, Department of Chemistry, Nanjing University, 22 Hankou Road, Nanjing 210093, P.R. China.
authors.forename: Xi-Liang
authors.initials: XL
authors.lastname: Luo
authors.forename: Jing-Juan
authors.initials: JJ
authors.lastname: Xu
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: Gong-Jun
authors.initials: GJ
authors.lastname: Yang
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Chen
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation; D003386:Brachyura; D048271:Chitosan; D004563:Electrochemistry; D004566:Electrodes; D004800:Enzymes, Immobilized; D006046:Gold; D006735:Horseradish Peroxidase / Q000648:ultrastructure; D020100:Hydrogels; D018625:Microscopy, Atomic Force; D049329:Nanostructures / Q000648:ultrastructure
chemical_list: D004800:Enzymes, Immobilized; D020100:Hydrogels; D006046:Gold; D048271:Chitosan; D006735:Horseradish Peroxidase