Reagentless biosensor based on layer-by-layer assembly of functional multiwall carbon nanotubes and enzyme-mediator biocomposite |
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| Authors: | Zhou Xing-Hua Xi Feng-Na Zhang Yi-Ming Lin Xian-Fu |
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| Institution: | (1) Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi, India, 221005 |
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| Abstract: | A simple and controllable layer-by-layer (LBL) assembly method was proposed for the construction of reagentless biosensors
based on electrostatic interaction between functional multiwall carbon nanotubes (MWNTs) and enzyme-mediator biocomposites.
The carboxylated MWNTs were wrapped with polycations poly(allylamine hydrochloride) (PAH) and the resulting PAH-MWNTs were
well dispersed and positively charged. As a water-soluble dye methylene blue (MB) could mix well with horseradish peroxidase
(HRP) to form a biocompatible and negativelycharged HRP-MB biocomposite. A (PAH-MWNTs/HRP-MB)
n
bionanomultilayer was then prepared by electrostatic LBL assembly of PAH-MWNTs and HRP-MB on a polyelectrolyte precursor
film-modified Au electrode. Due to the excellent biocompatibility of HRP-MB biocomposite and the uniform LBL assembly, the
immobilized HRP could retain its natural bioactivity and MB could efficiently shuttle electrons between HRP and the electrode.
The incorporation of MWNTs in the bionanomultilayer enhanced the surface coverage concentration of the electroactive enzyme
and increased the catalytic current response of the electrode. The proposed biosensor displayed a fast response (2 s) to hydrogen
peroxide with a low detection limit of 2.0×10−7 mol/L (S/N=3). This work provided a versatile platform in the further development of reagentless biosensors. |
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| Keywords: | Reagentless biosensor Layer-by-layer assembly Horseradish peroxidase-methylene blue (HRP-MB) biocomposite Functional multiwall carbon nanotubes Hydrogen peroxide |
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