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A Simple Layer‐by‐Layer Assembly Strategy for a Reagentless Biosensor Based on a Nanocomposite of Methylene Blue‐Multiwalled Carbon Nanotubes
Author(s) -
Zhang Yiming,
Liu Lijun,
Xi Fengna,
Wu Tianxing,
Lin Xianfu
Publication year - 2010
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200900307
Subject(s) - nanocomposite , biosensor , cyclic voltammetry , dielectric spectroscopy , materials science , carbon nanotube , horseradish peroxidase , detection limit , methylene blue , electrode , chemical engineering , layer by layer , nuclear chemistry , analytical chemistry (journal) , electrochemistry , layer (electronics) , chemistry , nanotechnology , chromatography , catalysis , organic chemistry , enzyme , photocatalysis , engineering
A simple layer‐by‐layer (LBL) assembly strategy was established for constructing a novel reagentless biosensor based on a nanocomposite of methylene blue multiwalled carbon nanotubes (MB‐MWNTs). A nanocomposite of MB‐MWNTs was obtained by direct premixing and possessed good dispersion in barbital‐HCl buffer. Through electrostatic interactions, the nanocomposite of MB‐MWNTs could alternately be assembled with horseradish peroxidase (HRP) on the Au electrode modified with precursor films. UV/Vis spectra and scanning electron microscopy (SEM) were applied to reveal the formation of the nanocomposite of MB‐MWNTs. The LBL assembly process was also verified by electrochemical impedance spectroscopy (EIS). The MB is a well‐established mediator and efficiently facilitated the electron shuttle between the HRP and the electrode, as demonstrated by the cyclic voltammetry (CV) measurements. The as‐prepared reagentless biosensor exhibited a fast response for the determination of hydrogen peroxide (H 2 O 2 ) and reached 95% of the steady‐state current within 3 s. It was found that the linear response range of the reagentless biosensor for H 2 O 2 was from 4.0 μM to 3.78 mM with a detection limit of 1.0 μM and a sensitivity of 22.5 μA mM −1 . The biosensor exhibited a high reproducibility and stability.