Journal
BIOSENSORS & BIOELECTRONICS
Volume 45, Issue -, Pages 13-18Publisher
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2013.01.043
Keywords
Maghemite nanoparticles; gamma-Fe2O3; Nanomaterial electrocatalysis; Superparamagnetic nanoparticles; Hydrogen peroxide detection; Glucose biosensor
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Funding
- Progetti di Ateneo [A.0ED00. 0487PRAT08]
- University of Padua
- Operational Program Research and Development for Innovations-European Social Fund [CZ.1.05/2.1.00/03.0058]
- Academy of Sciences of the Czech Republic [KAN115600801]
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A simple carbon paste (CP) electrode, modified with novel maghemite (gamma-Fe2O3) nanoparticles, called SAMNs (suface active maghemite nanoparticles) and characterized by a mean diameter of about 10 nm, has been developed. The electrode catalyzes the electro-reduction of hydrogen peroxide at low applied potentials (-0.1 V vs SCE). In order to improve the electrocatalytic properties of the modified electrode an ionic liquid, namely 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6), was introduced. At -0.1 V, the sensitivity of the SAMN-BMIM-PF6-CP electrode was 206.51 nA mu M-1 cm(-2), with a detection limit (S/N=3) of 0.8 mu M, in the 0-1.5 mM H2O2 concentration range. Furthermore, glucose oxidase was immobilized on the surface of maghemite nanoparticles as a monomolecular layer, by a bridge constituted of rhodamine B isothiocyanate, leading to a fluorescent, magnetic drivable nanocatalyst, containing 10 +/- 2 enzyme molecules per nanoparticle. The resulting enzyme electrode presents a linear calibration curve toward glucose in solution in the concentration range of 0-1.5 mM glucose, characterized by a sensitivity of 45.85 nA mu M-1 cm(-2) and a detection limit (S/N=3) of 0.9 mu M. The storage stability of the system was evaluated and a half-life of 2 months was calculated, if the electrode is stored at 4 degrees C in buffer. The present work demonstrates the feasibility of these surface active maghemite nanoparticles as efficient hydrogen peroxide electro-catalyst, which can be easily coupled to hydrogen peroxide producing enzymes in order to develop oxidase based reagentless biosensor devices. (C) 2013 Elsevier B.V. All rights reserved.
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