title: Direct electrochemistry and electrocatalysis of heme proteins immobilised in carbon-coated nickel magnetic nanoparticle-chitosan-dimethylformamide composite films in room-temperature ionic liquids.
abstract: The direct electrochemistry and electrocatalysis of heme proteins entrapped in carbon-coated nickel magnetic nanoparticle-chitosan-dimethylformamide (CNN-CS-DMF) composite films were investigated in the hydrophilic ionic liquid [bmim][BF4]. The surface morphologies of a representative set of films were characterised via scanning electron microscopy. The proteins immobilised in the composite films were shown to retain their native secondary structure using UV-vis spectroscopy. The electrochemical performance of the heme proteins-CNN-CS-DMF films was evaluated via cyclic voltammetry and chronoamperometry. A pair of stable and well-defined redox peaks was observed for the heme protein films at formal potentials of -0.151 V (HRP), -0.167 V (Hb), -0.155 V (Mb) and -0.193 V (Cyt c) in [bmim][BF4]. Moreover, several electrochemical parameters of the heme proteins were calculated by nonlinear regression analysis of the square-wave voltammetry. The addition of CNN significantly enhanced not only the electron transfer of the heme proteins but also their electrocatalytic activity toward the reduction of H2O2. Low apparent Michaelis-Menten constants were obtained for the heme protein-CNN-CS-DMF films, demonstrating that the biosensors have a high affinity for H2O2. In addition, the resulting electrodes displayed a low detection limit and improved sensitivity for detecting H2O2, which indicates that the biocomposite film can serve as a platform for constructing new non-aqueous biosensors for real detection.
authors: Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and the College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, PR China.
authors: Ting
authors: T
authors: Wang
authors: Lu
authors: L
authors: Wang
authors: Jiaojiao
authors: J
authors: Tu
authors: Huayu
authors: H
authors: Xiong
authors: Shengfu
authors: S
authors: Wang
mesh_terms: D015374:Biosensing Techniques; D002384:Catalysis; D048271:Chitosan / Q000737:chemistry; D004126:Dimethylformamide / Q000737:chemistry; D004563:Electrochemistry; D006420:Hemeproteins / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000302:isolation & purification*; D055767:Immobilized Proteins / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry
chemical_list: D006420:Hemeproteins; D055767:Immobilized Proteins; D052578:Ionic Liquids; D009532:Nickel; D004126:Dimethylformamide; D048271:Chitosan; D006861:Hydrogen Peroxide
keywords: Carbon-coated nickel magnetic nanoparticles; Electrocatalysis; Heme proteins; Hydrogen peroxide; Room-temperature ionic liquid