Development of the layer-by-layer biosensor using graphene films: application for cholesterol determination
The preparation and characterization of graphene films for cholesterol determination are
described. The graphene films were synthesized by thermal chemical vapor deposition (CVD)
method. Methane gas (CH4
) and copper tape were used as carbon source and catalyst in the
graphene growth process, respectively. The intergrated array was fabricated by using
micro-electro-mechanical systems (MEMS) technology in which Fe3O4
-doped polyaniline
(PANi) film was electropolymerized on Pt/Gr electrodes. The properties of the
Pt/Gr/PANi/Fe
3O4
films were investigated by field-emission scanning electron microscopy
(FE-SEM), Raman spectroscopy and electrochemical techniques. Cholesterol oxidase (ChOx)
has been immobilized onto the working electrode with glutaraldehyde agent. The cholesterol
electrochemical biosensor shows high sensitivity (74 µA mM
−1
cm
−2
) and fast response time
(< 5 s). A linear calibration plot was obtained in the wide cholesterol concentration range
from 2 to 20 mM and correlation coefficient square ( R
2
) of 0.9986. This new layer-by-layer
biosensor based on graphene films promises many practical applications.
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