| 1. |
- Fakhar-e-Alam, M, et al.
(författare)
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Role of ALA sensitivity in HepG2 cell in the presence of diode laser
- 2011
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Ingår i: LASER PHYSICS. - : Springer Science Business Media. - 1054-660X. ; 21:5, s. 972-980
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Tidskriftsartikel (refereegranskat)abstract
- 5-aminolevulinic acid (ALA) being an amazing second generation photosensitizer was studied as photodamaging drug on hepatocellular carcinoma (HepG2) cells. The mentioned photosensitizer is converted to PpIX in HepG2 cells in vitro, inducing haem in the cell causing generation of singlet oxygen leading to cell apoptosis. Cell uptake of 5-ALA was evaluated with different concentrations (ranging from 0-800 mu g/ml) for 0-49 h incubation period. ALA administered in HepG2 cells is converted into Protoporphyrin IX (PpIX) which has a short half life and constitute a good hematoporphyrin derivative (HPD). Cytotoxicity of ALA in dark and cellular viability without ALA in the presence of light was studied, showing minimal toxic effects in dark with no photodamaging effect on mentioned cells in absence of ALA were observed. The optimal uptake of photosensitizer (5-ALA) in HepG2 cells was investigated by means of spectrophotometeric measurements, cellular viability was determined by means of neutral red assay (NRA). It was observed that with different concentrations (0-800 mu g/ml) of ALA or light doses (0-160 J/cm(2)), there were no significant effect on cellular viability when studied independently. The novel of photocytotoxic study indicates that light dose of 120 J/cm(2) produces convincing Photodynamic therapy (PDT) results for HepG2 cells incubated with 262 mu g/ml of 5-ALA deducting that HepG2 cell line is sensitive to ALA mediated PDT. Finally morphological changes in HePG2 cells were determined before and after ALA-mediated PDT by confocal microscopy.
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| 2. |
- Ali, A., et al.
(författare)
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Potentiometric urea biosensor utilizing nanobiocomposite of chitosan-iron oxide magnetic nanoparticles
- 2013
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Ingår i: 21st International Laser Physics Workshop 23–27 July 2012, Calgary, Canada. - : Institute of Physics (IOP).
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Konferensbidrag (refereegranskat)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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| 3. |
- AlSalhi, M S., et al.
(författare)
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Growth and characterization of ZnO nanowires for optical applications
- 2013
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Ingår i: Laser physics. - : Institute of Physics Publishing (IOPP). - 1054-660X .- 1555-6611. ; 23:6
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, cerium oxide CeO2 nanoparticles were synthesized by the sol-gel method and used for the growth of ZnO nanorods. The synthesized nanoparticles were studied by x-ray diffraction (XRD) and Raman spectroscopic techniques. Furthermore, these nanoparticles were used as the seed layer for the growth of ZnO nanorods by following the hydrothermal growth method. The structural study of ZnO nanorods was carried out by means of field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and XRD techniques. This study demonstrated that the grown ZnO nanorods are well aligned, uniform, of good crystal quality and have diameters of less than 200 nm. Energy dispersive x-ray (EDX) analysis revealed that the ZnO nanorods are composed only of zinc, cerium as the seed atom, and oxygen atoms, with no other impurities in the grown nanorods. Moreover, a photoluminescence (PL) approach was applied for the optical characterization, and it was observed that the near-band-edge (NBE) emission was the same as that of the zinc acetate seed layer, however the green and orange/red emission peaks were slightly raised due to possibly higher levels of defects in the cerium oxide seeded ZnO nanorods. This study provides an alternative approach for the controlled synthesis of ZnO nanorods using cerium oxide nanoparticles as the seed nucleation layer, improving both the morphology of the nanorods and the performance of devices based upon them.
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| 4. |
- Atif, M., et al.
(författare)
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RETRACTED: Effect of Urea on the Morphology of Fe3O4 Magnetic Nanoparticles and Their Application in Potentiometric Urea Biosensors
- 2019
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Ingår i: Silicon. - : SPRINGER. - 1876-990X .- 1876-9918. ; 11:3, s. 1371-1376
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Tidskriftsartikel (refereegranskat)abstract
- The effect of different concentrations of urea on the morphology of iron oxide (Fe3O4) magnetic nanoparticles was studied. Fe3O4 magnetic nanoparticles were fabricated by the coprecipitation method. The morphology, crystallinity, compositional purity, and emission characteristics were tested by the techniques of scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and Raman characterization. The drop-casting technique was successfully used to fabricate a potentiometric urea biosensor producing initially isopropanol and chitosan solution, consisting of Fe3O4 nanoparticles, on a glass fiber filter. To measure the developed biosensors voltage signal from the functionalized nanoparticles, a copper wire was utilized. The Fe3O4 nanoparticle surface functionalization was performed through the electrostatic immobilization of urease with the Fe3O4-chitosan (CH) nanobiocomposite. The presented urea biosensor measured a wide logarithmic range of urea concentration of 0.1-80 mM with a sensitivity of 42 mV/decade, and indicated a fast response time of approximately 12 s. The developed urea biosensor showed enhanced sensitivity, stability, reusability, and specificity. All experimental results demonstrate the application potential of the developed urea sensor for the monitoring of urea concentrations in human serum, drugs, and food industry-related samples.
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| 5. |
- Atif, M., et al.
(författare)
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The synthesis and optical characterization of well aligned ZnO nanorods using seed layer of Mn3O4 nanoparticles
- 2014
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Ingår i: Optoelectronics and Advanced Materials Rapid Communications. - : National Institute of Optoelectronics.. - 1842-6573 .- 2065-3824. ; 8:7-8, s. 643-646
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Tidskriftsartikel (refereegranskat)abstract
- In this study, vertically aligned ZnO nanorods were fabricated by hydrothermal growth method using manganese oxide Mn3O4 nanoparticles as a seed layer. X-ray diffraction and Raman studies have shown the nano meter size of Mn3O4 nanoparticles. ZnO nanorods were characterized by field emission scanning electron microscopy and X-ray diffraction techniques. The prepared ZnO nanorods are highly dense, uniform and verily aligned and possess good crystal quality. Photoluminescence analysis has demonstrated that the ZnO nanorods exhibit deep level emission in green region due to oxygen vacancy related emission and the orange/red region is resulted due to interstitial oxygen defects related emission. This method for the fabrication of well aligned ZnO nanorods can be adapted for the development of optoelectronic devices.
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| 6. |
- Hussain Ibupoto, Zafar, et al.
(författare)
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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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Ingår i: Journal of Crystal Growth. - : Elsevier. - 0022-0248 .- 1873-5002. ; 368, s. 39-46
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Khun, Kimleang, et al.
(författare)
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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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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 173, s. 698-703
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Tidskriftsartikel (refereegranskat)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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| 8. |
- Ibupoto, Zafar Hussain, et al.
(författare)
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Effect of Urea on the Morphology of Co3O4 Nanostructures and Their Application for Potentiometric Glucose Biosensor
- 2014
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Ingår i: Electroanalysis. - : Wiley-VCH Verlagsgesellschaft. - 1040-0397 .- 1521-4109. ; 26:8, s. 1773-1781
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Tidskriftsartikel (refereegranskat)abstract
- In this study, an effect of different concentrations of urea on the morphology of cobalt oxide (Co3O4) nanostructures was investigated. The Co3O4 nanostructures are fabricated on gold coated glass substrate by the hydrothermal method. The morphological and structural characterization was performed by scanning electron microscopy, and X-ray diffraction techniques. The Co3O4 nanostructures exhibit morphology of flowers-like and have comprised on nanowires due to the increasing amount of urea. The nanostructures were highly dense on the substrate and possess a good crystalline quality. The Co3O4 nanostructures were successfully used for the development of a sensitive glucose biosensor. The presented glucose biosensor detected a wide range of glucose concentrations from 1 x 10(-6) M to 1 x 10(-2) M with sensitivity of a -56.85 mV/decade and indicated a fast response time of less than 10 s. This performance could be attributed to the heterogeneous catalysis effect at glucose oxidase enzyme, nanoflowers, and nanowires interfaces, which have enhanced the electron transfer process on the electrode surface. Moreover, the reproducibility, repeatability, stability and selectivity were also investigated. All the obtained results indicate the potential use of the developed glucose sensor for monitoring of glucose concentrations at drugs, human serum and food industry related samples.
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| 9. |
- Ibupoto, Zafar Hussain, et al.
(författare)
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The Synthesis of NiO/TiO2 Heterostructures and Their Valence Band Offset Determination
- 2014
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Ingår i: Journal of Nanomaterials. - : Hindawi Publishing Corporation. - 1687-4110 .- 1687-4129. ; :928658
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a heterojunction based on p-type NiO/n-type TiO2 nanostructures has been prepared on the fluorine doped tin oxide (FTO) glass substrate by hydrothermal method. Scanning electron microscopy (SEM) and X-Ray diffraction techniques were used for the morphological and crystalline arrays characterization. The X-ray photoelectron spectroscopy was employed to determine the valence-band offset (VBO) of the NiO/TiO2 heterojunction prepared on FTO glass substrate. The core levels of Ni 2p and Ti 2p were utilized to align the valence-band offset of p-type NiO/n-type TiO2 heterojunction. The valence band offset was found to be similar to 0.41 eV and the conduction band was calculated about similar to 0.91 eV. The ratio of conduction band offset and the valence-band offset was found to be 2.21.
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