| 1. |
- Ali, A., et al.
(author)
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Potentiometric urea biosensor utilizing nanobiocomposite of chitosan-iron oxide magnetic nanoparticles
- 2013
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In: 21st International Laser Physics Workshop 23–27 July 2012, Calgary, Canada. - : Institute of Physics (IOP).
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Conference paper (peer-reviewed)abstract
- The iron oxide (Fe3O4) magnetic nanoparticles have been fabricated through a simple, cheap and reproducible approach. Scanning electron microscope, x-rays powder diffraction of the fabricated nanoparticles. Furthermore, the fabrication of potentiometric urea biosensor is carried out through drop casting the initially prepared isopropanol and chitosan solution, containing Fe3O4 nanoparticles, on the glass fiber filter with a diameter of 2 cm and a copper wire (of thickness −500 μm) has been utilized to extract the voltage signal from the functionalized nanoparticles. The functionalization of surface of the Fe3O4 nanoparticles is obtained by the electrostatically immobilization of urease onto the nanobiocomposite of the chitosan- Fe3O4 in order to enhance the sensitivity, specificity, stability and reusability of urea biosensor. Electrochemical detection procedure has been adopted to measure the potentiometric response over the wide logarithmic concentration range of the 0.1 mM to 80 mM. The Fe3O4 nanoparticles based urea biosensor depicts good sensitivity with ~42 mV per decade at room temperature. Durability of the biosensor could be considerably enhanced by applying a thin layer of the nafion. In addition, the reasonably stable output response of the biosensor has been found to be around 12 sec.
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| 2. |
- Hussain Ibupoto, Zafar, et al.
(author)
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Well aligned ZnO nanorods growth on the gold coated glass substrate by aqueous chemical growth method using seed layer of Fe3O4 and Co3O4 nanoparticles
- 2013
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In: Journal of Crystal Growth. - : Elsevier. - 0022-0248 .- 1873-5002. ; 368, s. 39-46
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Journal article (peer-reviewed)abstract
- In this study, Fe3O4 and Co3O4 nanoparticles were prepared by co-precipitation method and sol-gel method respectively. The synthesised nanoparticles were characterised by X-ray diffraction [XRD] and Raman spectroscopy techniques. The obtained results have shown the nanocrystalline phase of obtained Fe3O4 and Co3O4 nanoparticles. Furthermore, the Fe3O4 and Co3O4 nanoparticles were used as seed layer for the fabrication of well-aligned ZnO nanorods on the gold coated glass substrate by aqueous chemical growth method. Scanning electron microscopy (SEM), high resolution transmission electron microscopy [HRTEM], as well as XRD and energy dispersive X-ray techniques were used for the structural characterisation of synthesised ZnO nanorods. This study has explored highly dense, uniform, well-aligned growth pattern along 0001 direction and good crystal quality of the prepared ZnO nanorods. ZnO nanorods are only composed of Zn and O atoms. Moreover, X-ray photoelectron spectroscopy was used for the chemical analysis of fabricated ZnO nanorods. In addition, the structural characterisation and the chemical composition study and the optical investigation were carried out for the fabricated ZnO nanorods and the photoluminescence [PL] spectrum have shown strong ultraviolet (UV) peak at 381 nm for Fe3O4 nanoparticles seeded ZnO nanorods and the PL spectrum for ZnO nanorods grown with the seed layer of Co3O4 nanoparticles has shown a UV peak at 382 nm. The green emission and orange/red peaks were also observed for ZnO nanorods grown with both the seed layers. This study has indicated the fabrication of well aligned ZnO nanorods using the one inorganic nanomaterial on other inorganic nanomaterial due to their similar chemistry.
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| 3. |
- Khun, Kimleang, et al.
(author)
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Potentiometric glucose sensor based on the glucose oxidase immobilized iron ferrite magnetic particle/chitosan composite modified gold coated glass electrode
- 2012
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In: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 173, s. 698-703
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Journal article (peer-reviewed)abstract
- A potentiometric glucose sensor based on the glucose oxidase immobilized on iron ferrite (Fe3O4) nanoparticles/chitosan composite modified gold coated glass substrate was fabricated. The electrode has advantages of both the inorganic Fe3O4 magnetic nanoparticles and the organic substance chitosan. The freshly prepared iron ferrite magnetic nanoparticles were characterized by X-ray diffraction (xRD) and transmission electron microscopy (TEM) technique was used for the analysis of dispersed iron ferrite magnetic nanoparticles in the mixture of glucose oxidase and chitosan. The electrostatic interaction of Fe3O4 nanoparticles with chitosan and the glucose oxidase molecules was investigated by the infra-red reflection absorption spectroscopy (IRAS) study. The glucose oxidase enzyme was immobilized on the surface of iron ferrite/chitosan composite without the use of Nafion or cross linker molecules. The fabricated glucose sensor has shown acceptable potentiometric response for the wide range of glucose concentrations from 1.0 x 10(-6) to 3.0 x 10(-2) M. The sensor electrode showed a sensitivity of 27.3 +/- 0.8 mV/decade and also fast response time of 7.0s. Moreover, the present glucose sensor has demonstrated good reproducibility, repeatability, selectivity and the storage stability. All the obtained results indicated that the glucose sensor based on the glucose oxidase immobilized iron ferrite/chitosan composite modified gold coated glass electrode can be used for the monitoring of glucose concentrations in human serum, drugs and may be applicable to detect glucose in the presence of other analytes.
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