Biomedical Engineering Reference
In-Depth Information
Glucose
-gluconolactone
Gluconic acid
Hydrolysis
O
2
H
2
O
2
(GOD)
Graphene
Coated metal
wire
Figure 1.1
Schematic illustration of the glucose sensing setup using a working electrode
comprised of graphene nanosheets (GSs) coated with GOx, along with the possible
electrochemical reaction near the electrode. (Reprinted with permission from [10];
Copyright © 2012
Journal of Biosensors and Bioelectronics
).
where direct electron transfer of GOx was achieved with a high hetero-
geneous electron transfer rate constant of (0.67 ± 0.06) s
−1
. h e prepared
reagentless mediator-free third-generation biosensor displayed good sen-
sitivity (97 nA mM
-1
), wide linear range (1-15 mM), low LOD (0.04 mM),
and fast response for the detection of glucose. h e prickly ZnO/Cu nano-
composite proved to be a promising matrix for direct electrochemistry of
proteins and biosensors.
A composite i lm based on the dispersion of nanosized l ower-like ZnO
in a chitosan solution was applied as matrix for HRP immobilization for
electro-biosensing [42]. Using hydroquinone as the mediator, this ampero-
metric H
2
O
2
biosensor showed a fast response of less than 5 s with the lin-
ear range of 1.0×10
5
to 1.8×10
3
M and a LOD of 2.0 μM. h e biosensor
exhibited satisfactory reproducibility and stability and retained about 78%
of its original response at er 40 days storage.
A nanostructured inorganic-organic hybrid material based on porous
nanosheet-based ZnO microspheres (Figure 1.2) combined with Nai on
(ZnO−Nai on composite) has been used for the construction of direct
amperometric biosensors [19]. h is ZnO-based composite demonstrated
to be a biocompatible immobilization matrix for enzymes with good enzy-
matic stability and bioactivity, facilitating direct electron transfer of the
