Biomedical Engineering Reference
In-Depth Information
CHIT-
g
-PVAL matrix
Spin coating
GOD
ZnO/CHIT-
g
-PVAL/ITO
core-shell nanocomposite
electrode
ZnO
nano particles
GOD/ZnO/CHIT-
g
-PVAL/ITO
core-shell nanocomposite
bioelectrode
(
a
)
(
b
)
Figure 1.7
Schematic illustration of (a) fabrication of a ZnO/CHIT-g-PVAL core-shell
nanocomposite electrode, and (b) immobilization of GOx on the electrode. (Reprinted
with permission from [31]; Copyright © 2012 Elsevier).
higher than 0.04 V μM
-1
and a response time of 3 s. h e results made two
inferences: (i) ZnO nanoparticles enhance the sensitivity of the bioelec-
trode, (ii) pH responsive, high swelling behavior of the core-shell nano-
composite i lm provides small surface reaction zone and good impulse
propagating materials for glucose biosensing. h e proposed biosensor sys-
tem could be explored for the determination of cholesterol, triglycerides,
etc., in micro/nanomolar concentrations.
A potentiometric and miniaturized cholesterol biosensor based on
physical adsorption of ChOx onto exfoliated GSs onto a thin copper wire
has been described by Israr
et al.
[36]. h e presented potentiometric bio-
sensor revealed excellent stability, reusability, selectivity and sensitivity
(~82 mV decade
-1
) for the detection of cholesterol biomolecules in the
1×10
-6
M to 1×10
-3
M logarithmic range, and a quick output response
within ~4 s. Additionally, this biosensor demonstrated good shelf life when
stored in appropriate environmental conditions, providing i rm ground for
its potential in practical applications.
A simply fabricated and sensitive potentiometric UA sensor based on
well-aligned ZnONWs (80-150 nm in diameter and 900 nm to 1.5 μm
in length) grown on a gold coated l exible plastic electrode was success-
fully demonstrated using an electrostatic process for the immobilization of
uricase. h e ZnONWs provided a suitable microenvironment for enzyme
loading and an easy immobilization procedure [39]. h is proposed uricase/
ZnO sensor showed good features in terms of selectivity, fast response,
reproducibility, linearity, thermal stability and negligible foreign interfer-
ences. h e potentiometric response of the ZnO sensor versus an Ag/AgCl
reference electrode was found to be linear over a relatively wide logarith-
mic concentration range, from 1 to 650 μM (sensitivity = 32 mV decade
-1
)
