Biomedical Engineering Reference
In-Depth Information
IL-graphene and the enzyme due to its good biocompatibility and excellent
i lm-forming ability for the solubility in slightly acidic solution, attributed
to its protonation and insolubility in solutions with pH above its pKa (6.3).
h e IL-graphene/chitosan-modii ed GCE showed a more stable and low-
potential amperometric detection of NADH when compared with the bare
electrode. h e IL-graphene/chitosan i lm of ered a remarkable decrease in
the overvoltage for the NADH oxidation and eliminated surface fouling
ef ects. Furthermore, the IL-graphene/chitosan-modii ed GCE exhibited
a good linearity, from 0.25 to 2 mM, and a high sensitivity of 37.43 μA
mM
−1
cm
−2
. h e ability of IL-graphene to promote the electron transfer
between NADH and the electrode substrate exhibited a novel and promis-
ing biocompatible platform for the development of dehydrogenase-based
amperometric biosensors. Using ADH as a model enzyme, a rapid and
highly sensitive amperometric biosensor for ethanol, with a low LOD
(5 μM), was constructed by immobilizing ADH on the GCE surface in the
IL-graphene/chitosan coating process through a simple casting method.
h e IL-graphene-based sensor for NADH and dehydrogenase substrates
exhibited very good analytical performance with low cost, convenient
preparation, and sensitive, rapid, and reproducible detection. Moreover,
the proposed biosensor was used to determine ethanol in real samples
with the results in good agreement with those certii ed by the supplier,
thus demonstrating that such IL-functionalized graphene nanocomposite
provided a biocompatible platform for the fabrication of sensitive electro-
chemical biosensors and biomolecular diagnostics with great potential for
practical applications.
h e GSs modii ed GCEs (GSs/GCE) have been presented and applied
for the electrochemical biosensing of NADH and ethanol [50]. Based on
the highly enhanced electrochemical activity of NADH, ADH was immo-
bilized on the graphene modii ed electrode, displaying a more desirable
analytical performance in the amperometric detection of ethanol, com-
pared with the conventional graphite-functionalized and bare GCE-based
bioelectrodes. It also exhibited good performance with faster, highly selec-
tive and sensitive response, and a wide linear range and low LOD for etha-
nol detection. Moreover, the accurate determination of ethanol in real
samples demonstrated the great potential of this proposed biosensor for
practical applications. Above all, GS, with favorable electrochemical activ-
ity, was considered as opening up a new challenge to explore a range of
electrochemical sensing and biosensing applications.
A highly sensitive amperometric biosensor has been developed for
L-lactic acid detection based on the lactate oxidase immobilization on the
surface of ZnO nanotetrapods (Figure 1.5) by electrostatic adsorption [51].
