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- Imani, Roghayeh, et al.
(författare)
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Electrochemical detection of DNA damage through visible-light-induced ROS using mesoporous TiO2 microbeads
- 2014
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Ingår i: Electrochemistry communications. - Philadelphia, PA, United States : Elsevier. - 1388-2481 .- 1873-1902. ; 40, s. 84-87
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Tidskriftsartikel (refereegranskat)abstract
- Rapid detection of DNA damage could serve as a basis for genotoxicity studies of new bio-nanoconjugations. A novel TiO2 bio-nanoconjugation, consisting of mesoporous TiO2 microbeads, dopamine (DA) and ss-DNA, was constructed on fluorine-doped tin oxide-coated glass (FTO) and used for the detection of DNA damage in the photocatalytic reaction of TiO2 under visible light. Stable mesoporous TiO2 microbeads films were coated on FTO by the doctor-blade method; dopamine with oxygen containing ligands, was tightly coupled to the titanium surface prepaired under phase coordination. Specific single-strands of DNA were electronically linked to TiO2 by using a dopamine bridge. DNA damage, caused by reactive oxygen species (ROS) that were photogenerated through the photocatalytic reaction, was detected with square wave voltammetry (SWV) by recording the catalytic oxidation current of [Ru(NH3)6]3 +, an intercalated electroactive probe. The ability of antioxidant to protect DNA against damage in the photocatalytic reaction was also tested.
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| 2. |
- Imani, Roghayeh, et al.
(författare)
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Fabrication of Microfibre-nanowire Junction Arrays of ZnO/SnO2 Composite by the Carbothermal Evaporation Method
- 2014
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Ingår i: Nanomaterials and Nanotechnology. - : SAGE Publications. - 1847-9804. ; 4, s. 21-
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Tidskriftsartikel (refereegranskat)abstract
- A cotton-like ZnO/SnO2 nanocomposite was grown by the carbothermal evaporation of a mixture of ZnO and SnO2 powders at 1100 degrees C by the vapour-liquid-solid process, in which the Sn particles produced by the reduction of SnO2 act as the catalyst. Field-emission scanning electron microscope images suggest that the composites are made of microfibre-nanowire junction arrays. The structure is formed due to the fast growth of the ZnO microfibre and the subsequent epitaxial radial growth of the ZnO nanowires with Sn particles at the tips. The photovoltaic performance of the ZnO/SnO2 nanocomposite sensitized with a D35-cpdt dye was investigated. A dye-sensitized solar cell (DSSC) with a ZnO/SnO2 nanocomposite photoanode based on a cobalt electrolyte achieved a solar-to-electricity conversion efficiency of similar to 0.34% with a short circuit current (JSC) of 0.66 mA/cm(2), an open circuit voltage (VOC) of 870 mV, and a fill factor (FF) of 59. The results show the potential of this one dimensional structure in cobalt electrolyte-based DSSCs; the further optimization which is needed to achieve higher efficiencies is also discussed.
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| 3. |
- Patra, Hirak, et al.
(författare)
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Novel anti-neoplastic approach for photodynamic theranostics by biocompatible TiO2 popcorn nanostructure for a high-throughput flash ROS generator
- 2014
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Ingår i: 24<sup>th </sup>Anniversary World Congress on Biosensors – Biosensors 2014. - : Elsevier.
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Konferensbidrag (refereegranskat)abstract
- Reactive oxygen species (ROS) are important secondary messengers in the intracellular signaling system for regulating redox homeostasis in normal cells. Compared to normal cells, cancer cells have increased ROS levels due to a faster metabolic rate. We have used this discriminating overproduction of ROS levels in cancer cells as a target for a photodynamic anti-neoplastic theranostic approach using mesoporous TiO2 microbeads with a popcorn nanostructure. We have created a novel flash ROS generator using a two-step procedure consisting of sol-gel and solvothermal processes to obtain mesoporous TiO2 microbeads with high photocatalytic efficiency. A photon-induced comparative study has been carried out for the ROS generation ability using TiO2 nanoparticles and mesoporous TiO2 microbeads. We have shown that in under otherwise identical conditions the extent of photocatalytical ROS generated by mesoporous TiO2 microbeads is more than twice that produced by TiO2 nanoparticles. In vitro in the absence of irradiation, the mesoporous TiO2 microbeads are exceptionally biocompatible, allowing almost ~100% cellular survival rate even at a dose of 100 µg/mL. In contrast, commercial nanoparticles showed concentration dependent cytotoxicity of nearly 15% within 24h in the absence of any irradiation. Upon photo activation, the mesoporous TiO2 microbead structures delivered their potential anticancer effect by interfering with the mitochondrial activity by producing ROS in the intracellular environment and thus reducing the survival rate of cells by more than 30% in comparison with commercial nanoparticles, where only an increase of 5% in cell death was observed. Thus we have developed a smart on/off switchable photodynamic anti-neoplastic theranostic approach that can be combined with specific cell recognition elements for future cancer management.
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