Nanobioelectronics Laboratory (NBEL) Potential (V) Vs Ag/AgCl · Cyclic voltammograms of...
Transcript of Nanobioelectronics Laboratory (NBEL) Potential (V) Vs Ag/AgCl · Cyclic voltammograms of...
Carbon Nanotube Biopolymer based Biosensor for the Electrochemical
Detection of Neurotransmitters
Sudheesh K. Shukla, Avia Lavon, Offir Shmulevich, Hadar Ben-Yoav*
Department of Biomedical Engineering,
Ben-Gurion University of the Negev, Beer Sheva, 8410501, Israel * Tel: (+972) 8-6479717; E-mail: [email protected]
Acknowledgment: The authors thanks the Ilse Katz Institute for Nanoscale Science & Technology for their help in material characterization tests.
Conclusions and future work
Carbon nanotube (optimized %)-chitosan composites is a promising electrochemical interface for the neurotransmitter
detection have 0.16 µA current with the electron transfer rate of 1.339 cm s-1 and diffusion co-efficient of 1.18 x 10-14 cm2s-1.
Surface characterization validating the controlled distribution and encapsulation of optimized CNT ratio in chitosan matrix
and enhancing the roughness of the CNT-CHIT composite and differentiating the potential of interfering species.
The result exploring the understanding of CNT-CHIT interface for its better utilization in electrochemical micro-systems for
the molecular detection different analytes.
Future work involves validating the developed NTs sensor in in vitro and in vivo settings with living cells and brain tissue.
Challenge
Accurate detection of NTs is
prevented by co-exiting
interfering species (e.g. uric
acid).
Motivation
Neurotransmitters (NTs), are the biochemical messengers that transfer biological signal
from the brain to the whole body and govern their metabolic and physiological functions.
Deficiency of neurotransmitters can cause severe brain disorder, such as Schizophrenia
and Parkinson's disease with symptoms of coma, depression and sleepiness.
Our Research Aim
Development of a carbon nanotubes-
biopolymer and its integration in
microfabricated devices for the selective and
sensitive detection of redox-active NTs.
Nanobioelectronics Laboratory (NBEL)
Material Synthesis and Integration Approach of the Electrochemical Biosensor
Carbon Nanotube -0
.1 0.0
0.1
0.2
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0.0
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0.9
1.2
Cu
rre
nt
(A
)
Potential (V)
Chitosan
Optical and Electrochemical Characterization
D
Scanning electron microscope (SEM) characterization of (a) chitosan, (b) CNT, (c)
CNT-CHIT composite. Energy dispersive X-ray spectroscopy of (d) chitosan and (e)
CNT-CHIT composite. SEM results reveals the surface morphology of chitosan and
encapsulation of CNT in chitosan to relay the organized conductance of materials. The EDS
result supporting the incorporation of CNT with chitosan by increasing counting percentages
of element in CNT-CHIT composite than chitosan alone.
X-ray diffraction
(XRD) pattern of
chitosan and CNT-
CHIT composite.
XRD study supporting
the crystalline
behaviour of CNT-
chitosan thank
chitosan alone.
0.1 0.2 0.3 0.4 0.5 0.6
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
Cu
rre
nt
(A
)
Potential (V) Vs Ag/AgCl
Bare Au electrode
CHIT modified Au electrode
1% CNT-CHIT modified Au electrode
1.50 % CNT-CHIT modified Au electrode
1.75% CNT-CHIT modified Au electrode
-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
-1.2x100
-9.0x10-1
-6.0x10-1
-3.0x10-1
0.0
3.0x10-1
6.0x10-1
9.0x10-1
1.2x100
5 mVs-1
10 000 mVs-1
Cu
rre
nt
(A
)
Potential (V) Vs Ag/AgCl
References
o E. Kim et al., Adv. Funct. Mater. 2015, 25, 2156-2165.
o M.A. Mohammed, A.K. Attia, H.M. Elwy, Electroanalysis, 2016, 28,
Early view.
o A. Joshi, S.N. Chava, D. Mandal, T.C. Nagaiah, Electroanalysis,
2016,
28, Early view .
Scheme for the fabrication of electrochemical sensor approach based on carbon nanotube-chitosan (CNT-CHIT) composites for the detection of neurotransmitters.
Dopamine Biosensor
Introduction
(a) (b)
20 30 40 50 60
Chitosan-CNT
Inte
nsi
ty (
a.u
.)
2(degree)
Chitosan
Atomic force microscopy (AFM) of (a) chitosan and (b) CNT-CHIT composite. AFM studies reporting the
surface information, roughness and size distribution of the materials.
(a) (b)
(d)
(e)
(c)
Cyclic voltammograms of comparative CV response of bare Au electrode, chitosan
modified and different ratio of CNT (1%, 1.5% and 1.75%) -CHIT modified Au
electrode. CVs show the high current response with the highest loading of CNT due to
its conducting behavior.
Cyclic voltammograms of 1.75% CNT-CHIT composite/Au in 5 mM [Fe(CN)6]3-/4- on
increasing scan rate from 5 mVs-1 to 10 000 mVs-1. Results shows the stability of the CNT-
chitosan composite materials over the Au electrode. CNT-CHIT composite materials showed
the promising electron transfer rate and diffusion coefficient .
-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
20
25
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35
40
45
50
Cu
rre
nt
(A
)
Potential (V) vs Ag/AgCl
a
j
-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
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25
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35
40
45
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55
60
(f)
(e)
(d)
(c)
Cu
rre
nt
(A
)
Potential (V) vs Ag/AgCl
(a) PBS
(b) PBS+Uric Acid
(c) 1 +dopamine+Uric Acid
(d) 5 +dopamine+Uric Acid
(e) 10 +dopamine+Uric Acid
(f) 25 +dopamine+Uric Acid
(a)
(b)
Detection of
dopamine using
differential pulse
voltammetry (DPV)
of CNT-CHIT
electrode in
phosphate buffer
(0.1 M, pH 7.4)
containing various
level of dopamine
concentration (0
µM, 0.1µM, 0.5µM,
1µM, 5 µM, 10 µM,
25 µM, 50 µM, 100
µM, 200 µM).
Detection of dopamine using DPV of CNT-CHIT electrode in phosphate buffer (0.1 M, pH
7.4) containing various level of dopamine (c to f) the presence of respecting interference
uric acid.
0 50 100 150 200
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50
55
60
(b)
y= 1.369 x + 28.18
R2= 0.7854
Cu
rre
nt
(A
)
[DA] in M
y=0.140 x+24.89
R2=0.9453
(a)
Current peak response vs
dopamine concentration in the
presence (b) and the absence (a)
of uric acid. The resulted
sensitivity and limit of detection in
the absence of uric acid were 1.369
µA/µM and 0.1 µM, respectively.
The resulted sensitivity and limit of
detection in the presence of uric
acid were 0.140 µA/µM and 5 µM,
respectively. These variations in
sensing performance are due to the
interference of the uric acid.