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Materials 2014, 7(2), 1069-1083; doi:10.3390/ma7021069
Article

Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase Immobilized in a DNA/Chitosan-Fe3O4 Magnetic Nanoparticle Bio-Complex Film

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Received: 30 November 2013; in revised form: 25 December 2013 / Accepted: 27 January 2014 / Published: 11 February 2014
(This article belongs to the Special Issue Functional Materials and Proteins for Bio-Sensing Applications)
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Abstract: A DNA/chitosan-Fe3O4 magnetic nanoparticle bio-complex film was constructed for the immobilization of horseradish peroxidase (HRP) on a glassy carbon electrode. HRP was simply mixed with DNA, chitosan and Fe3O4 nanoparticles, and then applied to the electrode surface to form an enzyme-incorporated polyion complex film. Scanning electron microscopy (SEM) was used to study the surface features of DNA/chitosan/Fe3O4/HRP layer. The results of electrochemical impedance spectroscopy (EIS) show that Fe3O4 and enzyme were successfully immobilized on the electrode surface by the DNA/chitosan bio-polyion complex membrane. Direct electron transfer (DET) and bioelectrocatalysis of HRP in the DNA/chitosan/Fe3O4 film were investigated by cyclic voltammetry (CV) and constant potential amperometry. The HRP-immobilized electrode was found to undergo DET and exhibited a fast electron transfer rate constant of 3.7 s−1. The CV results showed that the modified electrode gave rise to well-defined peaks in phosphate buffer, corresponding to the electrochemical redox reaction between HRP(Fe(III)) and HRP(Fe(II)). The obtained electrode also displayed an electrocatalytic reduction behavior towards H2O2. The resulting DNA/chitosan/Fe3O4/HRP/glassy carbon electrode (GCE) shows a high sensitivity (20.8 A·cm−2·M−1) toward H2O2. A linear response to H2O2 measurement was obtained over the range from 2 µM to 100 µM (R2 = 0.99) and an amperometric detection limit of 1 µM (S/N = 3). The apparent Michaelis-Menten constant of HRP immobilized on the electrode was 0.28 mM. Furthermore, the electrode exhibits both good operational stability and storage stability.
Keywords: horseradish peroxidase; direct electron transfer; DNA/chitosan polyion complex film; Fe3O4 magnetic nanoparticles; H2O2 biosensors horseradish peroxidase; direct electron transfer; DNA/chitosan polyion complex film; Fe3O4 magnetic nanoparticles; H2O2 biosensors
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Gu, T.; Wang, J.; Xia, H.; Wang, S.; Yu, X. Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase Immobilized in a DNA/Chitosan-Fe3O4 Magnetic Nanoparticle Bio-Complex Film. Materials 2014, 7, 1069-1083.

AMA Style

Gu T, Wang J, Xia H, Wang S, Yu X. Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase Immobilized in a DNA/Chitosan-Fe3O4 Magnetic Nanoparticle Bio-Complex Film. Materials. 2014; 7(2):1069-1083.

Chicago/Turabian Style

Gu, Tingting; Wang, Jianli; Xia, Hongqi; Wang, Si; Yu, Xiaoting. 2014. "Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase Immobilized in a DNA/Chitosan-Fe3O4 Magnetic Nanoparticle Bio-Complex Film." Materials 7, no. 2: 1069-1083.


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