| 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. |
- Kishwar, S, et al.
(författare)
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Electro-optical and Cathodoluminescence properties of low temperature grown ZnO nanorods/p-GaN white light emitting diodes
- 2010
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Ingår i: PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE. - : Wiley. - 1862-6300. ; 207:1, s. 67-72
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Tidskriftsartikel (refereegranskat)abstract
- Vertically aligned ZnO nanorods (NRs) with a diameter in the range of 160-200 nm were grown on p-GaN/sapphire substrates by aqueous chemical growth technique and white light emitting I diodes (LEDs) are fabricated. The properties of this LED were investigated by parameter analyzer, cathodoluminescence (CL), electroluminescence (EL), and photoluminescence (PL). The I-V characteristics of the fabricated ZnO/GaN heterojunction revealed rectifying behavior and the LED emits visible EL when bias is applied. From the CL it was confirmed that both the ZnO NRs and the p-GaN are contributing to the observed peaks. The observed EL measurements showed two emission hands centered at 450 nm and a second broad deep level defect related emission centered at 630 nm and extending from 500 rim and up to over 700 rim. Moreover, the room temperature PL spectrum of the ZnO NRs/p-GaN reveals an extra peak at the green color wavelength centered at 550 nm. Comparison of the PL, CL, and EL data suggest that the blue and near red emissions in the EL spectra are originating from Mg acceptor levels in the p-GaN and from the deep levels defects present in the ZnO NRs, respectively. The mixture of high and low energy colors, i.e., blue, green, and red, has led to the white observed luminescence.
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| 3. |
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| 4. |
- Fakhar-E-Alam, Muhammad, et al.
(författare)
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RETRACTED: Empirical Modeling of Physiochemical Immune Response of Multilayer Zinc Oxide Nanomaterials under UV Exposure to Melanoma and Foreskin Fibroblasts
- 2017
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Carcinogenesis is a complex molecular process starting with genetic and epigenetic alterations, mutation stimulation, and DNA modification, which leads to proteomic adaptation ending with an uncontrolled proliferation mechanism. The current research focused on the empirical modelling of the physiological response of human melanoma cells (FM55P) and human foreskin fibroblasts cells (AG01518) to the multilayer zinc oxide (ZnO) nanomaterials under UV-A exposure. To validate this experimental scheme, multilayer ZnO nanomaterials were grown on a femtotip silver capillary and conjugated with protoporphyrin IX (PpIX). Furthermore, PpIX-conjugated ZnO nanomaterials grown on the probe were inserted into human melanoma (FM55P) and foreskin fibroblasts cells (AG01518) under UV-A light exposure. Interestingly, significant cell necrosis was observed because of a loss in mitochondrial membrane potential just after insertion of the femtotip tool. Intense reactive oxygen species (ROS) fluorescence was observed after exposure to the ZnO NWs conjugated with PpIX femtotip model under UV exposure. Results were verified by applying several experimental techniques, e.g., ROS detection, MTT assay, and fluorescence spectroscopy. The present work reports experimental modelling of cell necrosis in normal human skin as well as a cancerous tissue. These obtained results pave the way for a more rational strategy for biomedical and clinical applications.
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| 5. |
- Fakhar-e-Alam, M., et al.
(författare)
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Tumoricidal Effects of Nanomaterials in HeLa Cell Line
- 2011
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Ingår i: Laser physics. - : MAIK Nauka/Interperiodica. - 1054-660X .- 1555-6611. ; 21:11, s. 1978-1988
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Tidskriftsartikel (refereegranskat)abstract
- The current study exhibits the cellular response of HeLa (cervical cancer) cells to metal oxides ultrafine nanomaterials e.g. manganese dioxide nanowires (MnO(2) NRs), iron oxide nanoparticles (Fe(2)O(3) NPs) and zinc oxide nanorods (ZnO NRs) as bare and as conjugated with photosensitizers. For cytotoxic evaluations, the cellular morphology, (MTT) assay, reactive oxygen species (ROS) production were used for cases with and without photo sensitizer as well illuminated with UV-visible laser exposed conditions. Three different photosensitizers were tested. These are 5-aminolevulinic acid (5-ALA), Photofrin (R), and protoporphyrin dimethyl ester (PPDME). Significant loss in cell viability was noted with 100-500 mu g/ml in bare and conjugated forms of the metal oxides used. The effect was insignificant with lower concentrations (0.05-50 mu g/ml). While notable anticancer effect of 5-ALA under 30 J/cm(2) of diode laser irradiation was noted as compared to other photo sensitizer. By increasing the UV irradiation time of labeled cells, generation of ROS was observed, indicating the possibility of achieving efficient photodynamic therapy (PDT).
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| 6. |
- Sadaf, J R, et al.
(författare)
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Forward- and reverse-biased electroluminescence behavior of chemically fabricated ZnO nanotubes/GaN interface
- 2011
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Ingår i: SEMICONDUCTOR SCIENCE AND TECHNOLOGY. - : Iop Publishing Ltd. - 0268-1242 .- 1361-6641. ; 26:7, s. 075003-
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Tidskriftsartikel (refereegranskat)abstract
- Electroluminescence characteristics of an n-ZnO nanotubes/p-GaN heterostructure light-emitting diode (LED) have been investigated at forward and reverse bias. Distinctly different emission spectra have been observed and the location of the recombination of electron-hole is analyzed under both configurations. The forward-biased emission spectrum shows two peaks centered at around 450 and 560 nm, while the reverse-biased spectrum exhibits a single emission peak at 650 nm. By comparing the current transport mechanisms, it is suggested that the violet-blue emission peak (450 nm) observed only under forward bias is originating from the heterojunction of the ZnO nanotubes/p-GaN LED. The influence on the emission intensity of the device with the increase in temperature at constant current is studied in the range from 25 to 65 degrees C, to check its compatibility for practical applications and under harsh conditions.
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