Development Of Working Electrode Modified By Iron Oxide Nanoparticles For Glucose Biosensor Applications
Glucose biosensor that is capable to provide wide linearity of detection, high sensitivity, and low limit of detection is important in clinical diagnosis. This has motivated the research into development of a better glucose biosensor. In this study, iron oxide nanoparticles (IONPs) were synthesiz...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2019
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| Subjects: | |
| Online Access: | http://eprints.usm.my/51259/1/Development%20Of%20Working%20Electrode%20Modified%20By%20Iron%20Oxide%20Nanoparticles%20For%20Glucose%20Biosensor%20Applications.pdf |
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| Summary: | Glucose biosensor that is capable to provide wide linearity of detection, high
sensitivity, and low limit of detection is important in clinical diagnosis. This has
motivated the research into development of a better glucose biosensor. In this study,
iron oxide nanoparticles (IONPs) were synthesized using the precipitation method and
surface functionalized with varying citric acid (CA) concentration (0.10, 0.25, 0.50,
and 0.70 g/ml) to produce stable colloidal IONPs in water. The effect of varying CA
concentration on the crystallinity and morphology, of the IONPs–CA in water were
studied using X-ray diffraction (XRD) and transmission electron microscope (TEM).
From the XRD patterns, high crystallinity of spinel cubic lattice of maghemite (γ-
Fe2O3) was obtained, while observation using transmission electron microscopy
(TEM) showed particle size was in the range of 17–22 nm. The optimum CA
concentration to functionalize IONPs–CA forming stable colloidal IONPs in water and
exhibited excellent electrochemical performance was 0.25 g/ml. The stable colloidal
IONPs–0.25 CA in water was then applied for fabrication of enzymatic and nonenzymatic
glucose biosensor by modification of working electrode using drop casting
method. In enzymatic glucose biosensor, the indium tin oxide (ITO) electrode and
screen printed carbon electrode (SPCE) were modified with IONPs–0.25 CA, glucose
oxidase (GOx) enzymes and Nafion layer. As for non-enzymatic glucose biosensor,
the SPCE electrode was modified with IONPs–0.25 CA and Nafion layer. The
optimization parameters of enzymatic and non-enzymatic glucose biosensors
performance were conducted, such as effect of IONPs concentration, effect of GOx enzyme loading concentration, effect of working potential, effect of buffer solution pH
and effect of operating temperature. The sensing performance of the developed
enzymatic and non-enzymatic glucose biosensor exhibit excellent glucose detection
performance with sensitivity of Nafion/GOx/IONPs–0.25 CA/ITO (941 μAmM-1cm-2
and limit of detection of 0.10 μM), Nafion/GOx/IONPs–0.25 CA/SPCE (164 μAmM-
1cm-2 and limit of detection of 14 μM), and 5Nafion/IONPs–0.25 CA/SPCE (2802
μAmM-1cm-2 and limit of detection 0.60 μM). The wide linearity of detection, high
sensitivity and low limit of detection of enzymatic and non-enzymatic glucose
biosensors were successfully developed based on modification of working electrode
with IONPs–0.25 C |
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