Download - @@@tugas pak akhir noer
-
8/7/2019 @@@tugas pak akhir noer
1/19
Page 1
Nanostructured zinc oxide platform for
mycotoxin detection
Biophysic Department
Faculty of Natural Sciences and Mathematics
Bogor Agricultural University2010
NoerhayatiNoerhayati RofiahRofiah G751090021G751090021
Superviser Dr. Akhirudin Maddu
Anees A. Ansari , Ajeet Kaushik, Pratima
R. Solanki, B.D. MalhotraBioelectrochemistry Journal 77 (2010) 7581
-
8/7/2019 @@@tugas pak akhir noer
2/19
Page 2
Introduction
Electrochemical
immunosensors
for detection of :
desired proteins,
biomarkers,
biological toxins
bio-warfare agents
in critical situations,
food,
environment,
Pharmaceutical chemistry
clinical diagnostics
To obtain a sensitive,
compact and stable
immunosensorplatform
desired antibodies
should be directed
in a given
orientation on theelectrode
The selection
of a matrix for the
immobilization of
antibodies (Abs) is
extremely important toobtain desired
characteristics of an
immunoelectrode
-
8/7/2019 @@@tugas pak akhir noer
3/19
Page 3
Introduction
Nanostructured
metal oxides rs
electrocatalytic,
piezoelectric, Photonic,
tunable size dependent
surface properties
attractive for biosensing
applications
Zirconium oxide,
titanium oxide,
tin oxide ,
cerium oxide,zinc oxide (ZnO)
interesting
properties
large surface to volume ratio,
high surface reaction activity,
high catalytic efficiency,strong adsorption ability
-
8/7/2019 @@@tugas pak akhir noer
4/19
Page 4
Introduction
nanostructured
ZnO
high isoelectric point (IEP ~9.5) biocompatibility facilitate
immobilization of an enzyme and protein
friendly microenvironment for immobilizing negatively
charged antibodies(r-IgGs; IEP ~5.5)
non-toxicity
high electron transfer capabilitychemical stability
immunosensor for detectionof ochratoxin-A (OTA)
produce nephrotoxic,
tetratogenic,carcinogenic
and immune toxic
activity in several animal
species
-
8/7/2019 @@@tugas pak akhir noer
5/19
Page 5
Fabrication of solgel derived nanostructured
ZnO film/electrode
1 g of zinc acetate dihydrate is dissolved in 10 ml ethanol.
Then 3 ml (1 M) solution of ammonium hydroxide (NH4OH) is
added at room temperature to maintain pH=910.
A white milky precipitate of Zn(OH)2 thus obtained is
centrifuged and is followed by washing with deionized water
until neutral pH is achieved. this precipitate is dispersed in
distilledwater and dilute HNO3 (1 M) in ambient conditions for
peptization.
A transparent viscous solution is obtained for film fabrication
on ITO (indium tin oxide) coated glass plate via dip-coatingtechnique.
These films are then allowed to dry at 400 C for about 1 h.
-
8/7/2019 @@@tugas pak akhir noer
6/19
-
8/7/2019 @@@tugas pak akhir noer
7/19
Page 7
Methods
Schematic of fabrication of BSA/r-IgGs/Nano-ZnO/ITO immunosensor
-
8/7/2019 @@@tugas pak akhir noer
8/19
Page 8
e lt a i i
FTI pe tra f Na -Z O ele tr e (a), r-IgG /Na
Z O/ITO ele tr e (b) a BSA/r-IgG /Na -Z O/ITO
ele tr e ( )
-
8/7/2019 @@@tugas pak akhir noer
9/19
Page 9
e lt a i i
X-ray iffra ti patter f lgel erive Z O film; i et h w
ab rpti pe tr m f lgel erive Na -Z O film
-
8/7/2019 @@@tugas pak akhir noer
10/19
Page 10
e lt a i i
X-ray iffra ti patter f lgel erive Z O film; i et h w
ab rpti pe tr m f lgel erive Na -Z O film
-
8/7/2019 @@@tugas pak akhir noer
11/19
Page 11
TujuanResults and discussion
Nano-ZnO/ITO film
r-IgGs/Nano-ZnO/ITO electrode
BSA/r-IgGs/Nano-ZnO/ITO electrode
SEM image
-
8/7/2019 @@@tugas pak akhir noer
12/19
Page 12
Cyclic voltammetry studies
A) Cyclic voltammogram of bare ITO (a) solgel derived Nano-ZnO/ITO
electrode (b) r-IgGs/Nano-ZnO/ITO electrode (c) and BSA/r-IgGs/Nano-
ZnO/ITO electrode (d),
-
8/7/2019 @@@tugas pak akhir noer
13/19
Page 13
Cyclic voltammetry studies
B) DPV studies of solgel derived Nano-ZnO/ITO electrode (a), r-
IgGs/Nano-ZnO/ITO electrode (b) and BSA/r-IgGs/Nano-ZnO/ITO
electrode (c) in PBS solution (50 mM, pH =7.0, 0.9%
NaCl) containing 5 mM of [Fe(CN|6]3 and 5 mM of [Fe(CN|6]4
-
8/7/2019 @@@tugas pak akhir noer
14/19
Page 14
Cyclic voltammetry studies
C) CV of BSA/r-IgGs/Nano-ZnO/ITO electrode as a function of scan rate
(10100 mV/s1) in ascending order in PBS solution (50 mM, pH =7.0,
0.9% NaCl) containing 5 mM of [Fe(CN|6]3 and 5 mM of [Fe(CN|6]4
-
8/7/2019 @@@tugas pak akhir noer
15/19
Page 15
Cyclic voltammetry studies
D) Magnitude of cathodic and anodic response current as a function of
scan rate (10100 mV/s)
-
8/7/2019 @@@tugas pak akhir noer
16/19
-
8/7/2019 @@@tugas pak akhir noer
17/19
Page 17
Cyclic voltammetry studies
Linear response curve of BSA/r-IgGs/Nano-ZnO/ITO immunosensor
obtained between OTA concentration and RCT value.
-
8/7/2019 @@@tugas pak akhir noer
18/19
Page 18
Conclusion
solgel derived Nano-ZnO film can be used
for the immobilization of r-IgGs and BSA for
blocking nonspecific binding sites of r-IgGs
to detect OTA
Nano-ZnO electrode results in amplifiedelectrochemical signal due to strong r-IgGs-
OTA interaction occurring at the
immunoelectrode surface.
A good linear relationship between the
electron transfer resistance and OTA
concentration in the range, 0.0060.01
nM/dm3 with improved sensitivity and
detection limit etc has been obtaoined
-
8/7/2019 @@@tugas pak akhir noer
19/19
Page 19