title: Horseradish peroxidase-catalyzed polymerization of L-DOPA for mono-/bi-enzyme immobilization and amperometric biosensing of H2O2 and uric acid.
abstract: Horseradish peroxidase (HRP)-catalyzed polymerization of L-DOPA (vs. dopamine) in the presence of H2O2 (and uricase (UOx)) was exploited to immobilize mono-/bi-enzymes for hydroquinone-mediated amperometric biosensing of H2O2 and uric acid (UA). The relevant polymeric biocomposites (PBCs) were prepared in phosphate buffer solution containing HRP and L-DOPA (or plus UOx) after adding H2O2. The mono-/bi-enzyme amperometric biosensors were prepared simply by casting some of the PBCs on Au-plated Au (Au(plate)/Au) electrodes, followed by coating with an outer-layer chitosan (CS) film for each. UV-vis spectrophotometry, scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy were used for film characterization and/or process monitoring. The HRP immobilized by enzyme catalysis well preserved its bioactivity, as confirmed by UV-vis spectrophotometry. Under optimized conditions, the monoenzyme CS/HRP-poly(L-DOPA) (PD)/Au(plate)/Au electrode potentiostated at -0.1V responded linearly to H2O2 concentration from 0.001 to 1.25mM with a sensitivity of 700μA mM(-1)cm(-2) and a limit of detection (LOD) of 0.1μM, and the bienzyme CS/UOx-HRP-PD/Au(plate)/Au electrode at -0.1V responded linearly to UA concentration from 0.001 to 0.4mM with a sensitivity of 349μA mM(-1)cm(-2) and a LOD of 0.1μM. The mono-/bi-enzyme biosensors based on biosynthesized PD performed better than many reported analogues and those based on similarly biosynthesized polydopamine.
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Mengzhen
authors.initials: M
authors.lastname: Dai
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Ting
authors.initials: T
authors.lastname: Huang
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Long
authors.initials: L
authors.lastname: Chao
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China. Electronic address: xieqj@hunnu.edu.cn.
authors.forename: Qingji
authors.initials: Q
authors.lastname: Xie
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Yueming
authors.initials: Y
authors.lastname: Tan
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Chen
authors.affiliation: Hunan Normal University Hospital, Changsha 410081, PR China.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Meng
mesh_terms: D015374:Biosensing Techniques; D002384:Catalysis; D048271:Chitosan / Q000737:chemistry; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis* / Q000097:blood; D007980:Levodopa / Q000737:chemistry*; D058105:Polymerization; D014503:Urate Oxidase / Q000737:chemistry*; D014527:Uric Acid / Q000032:analysis* / Q000097:blood
chemical_list: D004800:Enzymes, Immobilized; D014527:Uric Acid; D007980:Levodopa; D006046:Gold; D048271:Chitosan; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; D014503:Urate Oxidase
keywords: H(2)O(2); Horseradish peroxidase-catalyzed polymerization of l-DOPA; Immobilization of uricase; Mono-/bi-enzyme amperometric biosensing; Uric acid