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  • 1.
    Ali, A.
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Bahauddin Zakriya University, Multan, Pakistan.
    AlSalhi, M. S.
    King Saud University, Riyadh, Saudi Arabia and Bahauddin Zakriya University, Multan, Pakistan.
    Atif, M.
    King Saud University, Riyadh, Saudi Arabia.
    Ansari, Anees A.
    King Saud University, Riyadh, Saudi Arabia.
    Israr, Muhammad Qadir
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sadaf, J. R.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ahmed, E.
    Bahauddin Zakriya University, Multan, Pakistan.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Potentiometric urea biosensor utilizing nanobiocomposite of chitosan-iron oxide magnetic nanoparticles2013In: 21st International Laser Physics Workshop 23–27 July 2012, Calgary, Canada, Institute of Physics (IOP), 2013, Vol. 414, article id 012024Conference paper (Refereed)
    Abstract [en]

    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.

  • 2.
    Ali, A.
    et al.
    Riphah Int University, Pakistan.
    Israr-Qadir, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Wazir, Z.
    Riphah Int University, Pakistan.
    Tufail, M.
    Riphah Int University, Pakistan.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Jamil-Rana, Sadaf
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Atif, M.
    King Saud University, Saudi Arabia; National Institute Lasers and Optron, Pakistan.
    Khan, S. A.
    National Centre Phys, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Cobalt oxide magnetic nanoparticles-chitosan nanocomposite based electrochemical urea biosensor2015In: Indian Journal of Physics, ISSN 0973-1458, E-ISSN 0974-9845, Vol. 89, no 4, p. 331-336Article in journal (Refereed)
    Abstract [en]

    In this study, a potentiometric urea biosensor has been fabricated on glass filter paper through the immobilization of urease enzyme onto chitosan/cobalt oxide (CS/Co3O4) nanocomposite. A copper wire with diameter of 500 mu m is attached with nanoparticles to extract the voltage output signal. The shape and dimensions of Co3O4 magnetic nanoparticles are investigated by scanning electron microscopy and the average diameter is approximately 80-100 nm. Structural quality of Co3O4 nanoparticles is confirmed from X-ray powder diffraction measurements, while the Raman spectroscopy has been used to understand the chemical bonding between different atoms. The magnetic measurement has confirmed that Co3O4 nanoparticles show ferromagnetic behavior, which could be attributed to the uncompensated surface spins and/or finite size effects. The ferromagnetic order of Co3O4 nanoparticles is raised with increasing the decomposition temperature. A physical adsorption method is adopted to immobilize the surface of CS/Co3O4 nanocomposite. Potentiometric sensitivity curve has been measured over the concentration range between 1 x 10(-4) and 8 x 10(-2) M of urea electrolyte solution revealing that the fabricated biosensor holds good sensing ability with a linear slope curve of similar to 45 mV/decade. In addition, the presented biosensor shows good reusability, selectivity, reproducibility and resistance against interferers along with the stable output response of similar to 12 s.

  • 3.
    Batool, S S
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Imran, Z
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Pakistan Inst. Engn. and Appl Sci, Pakistan.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Usman, M
    Pakistan Institute Engn and Appl Science, Pakistan .
    Jamil, H
    Pakistan Institute Engn and Appl Science, Pakistan .
    Rafiq, M A
    Pakistan Institute Engn and Appl Science, Pakistan .
    Hasan, M M
    Pakistan Institute Engn and Appl Science, Pakistan .
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Silica nanofibers based impedance type humidity detector prepared on glass substrate2013In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 87, p. 1-6Article in journal (Refereed)
    Abstract [en]

    Impedance type relative humidity detector is fabricated by depositing electrospun silica nanofibers on glass substrate. The silica nanofibers with an average diameter similar to 150 nm and length similar to 100 mu m were used. Thermogravimetric and differential scanning calorimetric analysis confirm that the accurate annealing temperature is 500 degrees C for complete removal of PVP. Humidity detecting devices were fabricated by defining titanium electrodes on top of the silica nanofibers. The performance of silica nanofibers humidity detectors was tested by AC electrical measurements at 40-90% relative humidity. The response and the recovery times were 5 s and 3 s, respectively, between 40% and 90% relative humidity. Contribution of dipoles, space charge polarization, relaxation of these dipoles and low frequency dispersion phenomenon were observed during impedance measurements.

  • 4.
    Batool, S S.
    et al.
    Pakistan Institute Engn and Appl Science, Pakistan .
    Imran, Z
    Pakistan Institute Engn and Appl Science, Pakistan .
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Usman, M
    Pakistan Institute Engn and Appl Science, Pakistan .
    Jamil, H
    Pakistan Institute Engn and Appl Science, Pakistan .
    Rafiq, M A.
    Pakistan Institute Engn and Appl Science, Pakistan .
    Hassan, M M.
    Pakistan Institute Engn and Appl Science, Pakistan .
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Comparative Analysis of Ti, Ni, and Au Electrodes on Characteristics of TiO2 Nanofibers for Humidity Sensor Application2013In: Journal of Materials Science & Technology, ISSN 1005-0302, Vol. 29, no 5, p. 411-414Article in journal (Refereed)
    Abstract [en]

    The effect of metal (Ti, Ni, and Au) electrodes on humidity sensing properties of electrospun TiO2 nanofibers was investigated in this work. The devices were fabricated by evaporating metal contacts on SiO2 layer thermally grown on silicon substrate. The separation between the electrodes was 90 mm for all sensors. The sensors were tested from 40% to 90% relative humidity (RH) by AC electrical characterization at room temperature. When sensors are switched between 40% and 90% RH, the corresponding response and recovery time are 3 s and 5 s for Ti-electrode sensor, 4 s and 7 s for Ni-electrode sensor, and 7 s and 13 s for Au-electrode sensor. The hysteresis was 3%, 5% and 15% for Ti-, Ni-, and Au-electrode sensor, respectively. The sensitivity of Ti, Ni, and Au-electrode sensors are 7.53 M Omega/% RH, 5.29 MU/% RH and 4.01 M Omega/% RH respectively at 100 Hz. Therefore Ti-electrode sensor is found to have linear response, fast response and recovery time and higher sensitivity as compared with those of Ni- and Au-electrode sensors. Comparison of humidity sensing properties of sensors with different electrode material may propose a compelling route for designing and optimizing humidity sensors.

  • 5.
    Fakhar-e-Alam, M
    et al.
    Pakistan Institute for Engineering and Science.
    Atif, M
    Pakistan Institute for Engineering and Science.
    AlSalhi, M S
    King Saud University.
    Siddique, M
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Kishwar, S
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Role of ALA sensitivity in HepG2 cell in the presence of diode laser2011In: LASER PHYSICS, ISSN 1054-660X, Vol. 21, no 5, p. 972-980Article in journal (Refereed)
    Abstract [en]

    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.

  • 6.
    Imran, Z.
    et al.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Batool, S. S.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Jamil, H.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Usman, M.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Shah, S. H.
    PINSTECH, Islamabad, Pakistan.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Rafiq, M. A.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Hasan, M. M.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Excellent humidity sensing properties of cadmium titanate nanofibers2013In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 39, no 1, p. 457-462Article in journal (Refereed)
    Abstract [en]

    We report humidity sensing characteristics of CdTiO3 nanofibers prepared by electrospinning. The nanofibers were porous having an average diameter and length of similar to 50-200 nm and similar to 100 mu m, respectively. The nanofiber humidity sensor was fabricated by defining aluminum electrodes using photolithography on top of the nanofibers deposited on glass substrate. The performance of the CdTiO3 nanofiber humidity sensor was evaluated by AC electrical characterization from 40% to 90% relative humidity at 25 degrees C. The frequency of the AC signal was varied from 10(-1) to 10(6) Hz. Fast response time and recovery time of 4 s and 6 s were observed, respectively. The sensor was highly sensitive and exhibited a reversible response with small hysteresis of less than 7%. Long term stability of the sensor was confirmed during 30 day test. The excellent sensing characteristics prove that the CdTiO3 nanofibers are potential candidate for use in high performance humidity sensors.

  • 7.
    Israr, Muhammad Qadir
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Larsson, L. A.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Natural oxidation based controlled synthesis and characterization of ZnO nanodisks through structural transition of ZnO nanorods at 55 °CManuscript (preprint) (Other academic)
    Abstract [en]

    A novel, reproducible and natural oxidation based low temperature (55 °C) synthesis of ZnO nanodisks has been carried out using metallic zinc foil and formamide solution. The concentration of the formamide and the reaction duration are optimized to achieve the controlled fabrication. The morphological evolution of the ZnO nanodisks has been observed using scanning electron microscopy, energy dispersive spectroscopy and transmission electron microscopy. It is observed that ZnO nanodisks are of a good crystalline quality and have hexagonal wurtzite structure. The mechanism behind the growth and the breaking of nanorods into nanodisks is also suggested. Microphotoluminescence spectrum exhibits a strong ultraviolet emission and a very weak deep level related emission. In addition, temperature dependent studies reveal a decrease in the emission intensity of the ultraviolet peak combined with a red shift with increasing temperature from 20 to 300 K.

  • 8.
    Israr, Muhammad Qadir
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    ul Hasan, Kamran
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Engquist, Isak
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Danielsson, B.
    Pure and Applied Biochemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
    Structural characterization and biocompatible applications of graphene nanosheets for miniaturization of potentiometric cholesterol biosensor2011In: Journal of Biosensors & Bioelectronics, ISSN 2155-6210, Vol. 2, no 3Article in journal (Refereed)
    Abstract [en]

    The potentiometric cholesterol biosensor based on graphene nanosheets has been successfully miniaturized. Cholesterol oxidase (ChOx) has been immobilized onto graphene nanosheets exfoliated on copper wire through the process of physical adsorption,. The presented potentiometric biosensor renders effective selectivity and sensitivity (~82 mV/decade) for the detection of cholesterol biomolecules in 1 × 10−6 M to 1 × 10−3 M logarithmic range and quick output response within ~ 4 sec. The stability and reusability of the biosensor has also been investigated for the above mentioned range of cholesterol concentrations. The enzyme activity measurements on graphene nanosheets are studied using UV-Visible and FTIR spectrophotometers. Additionally, the functioning of the presented biosensor is studied for a range of temperatures (15-70 °C) and pH values (4-9).

  • 9.
    Israr, Muhammed Qadir
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Yang, Li-Li
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Trimming of aqueous chemically grown ZnO nanorods into ZnO nanotubes and their comparative optical properties2009In: APPLIED PHYSICS LETTERS, ISSN 0003-6951, Vol. 95, no 7, p. 073114-Article in journal (Refereed)
    Abstract [en]

    Highly oriented ZnO nanotubes were fabricated on a silicon substrate by aqueous chemical growth at low temperature (andlt; 100 degrees C) by trimming of ZnO nanorods. The yield of nanotubes in the sample was 100%. Photoluminescence spectroscopy of the nanotubes reveals an enhanced and broadened ultraviolet (UV) emission peak, compared with the initial nanorods. This effect is attributed to whispering gallery mode resonance. In addition, a redshift of the UV emission peak is also observed. Enhancement in the deep defect band emission in the nanotubes compared to nanorods was also manifested as a result of the increased surface area.

  • 10.
    Israr Qadir, Muhammad
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Larsson, L.A.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Fabrication of ZnO nanodisks from structural transformation of ZnO nanorods through natural oxidation and their emission characteristics2014In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 40, no 1, p. 2435-2439Article in journal (Refereed)
    Abstract [en]

    An environmentally benign natural oxidation based synthetic technique has been developed to grow and transform the ZnO nanorods into nanodisks at a very mild temperature of 55 degrees C with excellent features of its novelty and reproducibility. Metallic zinc foil and formamide solution have been utilized as substrate and reacting solution, respectively, for the growth of ZnO nanostructures. The optimized values of temperature, concentration of formamide and the reaction time are achieved to obtain the controlled and desired nanoscale morphologies. Detailed mechanism of the structural transformation of the nanorods into nanodisks has been discussed. Strong ultraviolet emission peak along with the much weaker deep level defects related emission has been realized in the microphotoluminescence spectrum. A visible red-shift and decrease in the intensity of ultraviolet peak are observed with increasing range of temperature from 20 to 300 K.

  • 11.
    Israr Qadir, Muhammad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Cathodoluminescence characterization of ZnO nanorods synthesized by chemical solution and of its conversion to ellipsoidal morphology2014In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 29, no 20, p. 2425-2431Article in journal (Refereed)
    Abstract [en]

    A facile and reproducible low-temperature (80 degrees C) solution route has been introduced to synthesize ZnO ellipsoids on silicon substrate without any pretreatment of the substrate or organic/inorganic additives. Scanning electron microscopy, transmission electron microscopy, and x-ray diffraction spectroscopy are performed to analyze the structural evolution, the single crystalline nature, and growth orientation at different stages of the synthetic process. The sequential formation mechanisms of heterogeneous nucleation in primary and secondary crystal growth behaviors have been discussed in detail. The presented results reveal that the morphology of micro/nanostructures with desired features can be optimized. The optical properties of grown structures at different stages were investigated using cathodoluminescence (CL). The monochromatic CL images were recorded to examine the UV and visible band emission contributions from the different positions of the intermediate and final structures of the individual ZnO ellipsoid. Significant enhancement in the defect level emission intensity at the central position of the structure reveals that the quality of the material improves as the reaction time is extended.

  • 12.
    Jamil-Rana, Sadaf
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Israr-Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Naturally oxidized synthesis of ZnO dahlia-flower nanoarchitecture2014In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 40, no 8, p. 13667-13671Article in journal (Refereed)
    Abstract [en]

    Three dimensional ZnO dahlia-flowers have been engineered at room temperature relying on natural oxidation based aqueous chemical synthetic approach. Glycine abetted multicomponent isotropic morphology has been synthesized through the conglomeration of thin nanopetals as building blocks with highly large surface area to volume ratio. Highly controllable morphology of thin nanopetals is achieved by stabilizing their polar faces through the adsorption of reactive hydroxyl and amide functions of glycine. Fourier transform infrared conclusions also exemplify good corroboration towards the use of organic additives. Moreover, the synthesized ZnO flowers have been utilized to fabricate cholesterol biosensor and biosensing measurements which have been performed over the cholesterol concentration range of 1 x 10(-6) M to 1 x 10(-3) M.

  • 13.
    Kishwar, Sultana
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Siddique, M.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Fakhar-e-Alam, M.
    Pakistan Institute of Engineering and Applied Sciences, NILORE, 45650, Islamabad, Pakistan.
    Israr, Muhammad Qadir
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Larsson, P.O.
    Pure and Applied Biochemistry, Lund University, P. O. Box 124, SE-22100, Lund, Sweden.
    Svanberg, K.
    University Hospital Division of oncology SE-22185 Lund, Sweden.
    Nour, Omer
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Biotoxicity of nanometallic oxides and their ligands with photosensitizers in osteosarcom a cellsManuscript (preprint) (Other academic)
    Abstract [en]

    The cytotoxic effects in osteosarcoma (U2OS) cells to different nanosized metallic oxides e.g. zinc oxide nanowires (ZnO-NWs), manganese di-oxide nanowires (MnO2 NWs), ferric oxide nanoparticles (Fe2O3 NPs) individually and their complex forms with photosensitizers photofrin®, 5-Aminolevulinic acid (5-ALA), and protoporphyrin IX (Pp IX) were studied. The cellular effects were assayed by analyzing the cellular morphology. The reactive oxygen species (ROS) were detected using 2', 7'-Dichlorofluorescein diacetate, and cell viability were assessed using MTT assay under ultraviolet (UV), visible light and laser exposed conditions. Prominent cell death with above cited nanomaterials in their complex forms with photosensitizer was observed in labeled U2OS cells. This cell death might be due to their synergetic effect via the release of singlet oxygen species in osteosarcoma cells showing their anticancer-cell effects.

  • 14.
    Kishwar, Sultana
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Siddique, M.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Israr, Muhammad Qadir
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Öllinger, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Pathology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pathology and Clinical Genetics.
    Investigation of the phototoxic effect of ZnO nanorods on fibroblasts and melanoma human cells2014In: Laser Physics Letters, ISSN 1612-2011, E-ISSN 1612-202X, Vol. 11, no 11, article id 115606Article in journal (Refereed)
    Abstract [en]

    Photo-cytotoxicity of zinc oxide (ZnO) nanowires (NWs) either bare or conjugated with photosensitizers was studied in dark and after ultraviolet light exposure, in human melanoma and foreskin fibroblast cells. ZnO NWs were grown on the capillary tip and then coated with photosensitizer. This coated tip was used as pointer for intracellular insertion of ZnO NWs and photosensitizer. ZnO NWs pointer was inserted into a specific cell and then irradiated with ultraviolet (UVA), which led to loss of mitochondrial membrane potential, as estimated by loss of the Mitotracker Red staining. Dissolved ZnO NWs showed cytotoxicity as detected by MTT viability assay and morphological evaluation. UVA-irradiation enhanced the toxicity and caused the production of reactive oxygen species (ROS) resulting in cell necrosis. ZnO NWs were photo-toxic for both normal and cancer cells, questioning their bio-safety.

  • 15.
    Psychoyios, Vasillios N.
    et al.
    National Technical University of Athens, Greece .
    Nikoleli, Georgia-Paraskevi
    National Technical University of Athens, Greece .
    Tzamtzis, Nikolaos
    National Technical University of Athens, Greece .
    Nikolelis, Dimitrios P.
    University of Athens, Greece .
    Psaroudakis, Nikolas
    University of Athens, Greece .
    Danielsson, Bengt
    Acromed Invest AB, Lund, Sweden .
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Potentiometric Cholesterol Biosensor Based on ZnO Nanowalls and Stabilized Polymerized Lipid Film2013In: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 25, no 2, p. 367-372Article in journal (Refereed)
    Abstract [en]

    A novel potentiometric cholesterol biosensor was fabricated by immobilization of cholesterol oxidase into stabilized lipid films using zinc oxide (ZnO) nanowalls as measuring electrode. Cholesterol oxidase was incorporated into the lipid film prior polymerization on the surface of ZnO nanowalls resulting in a sensitive, selective, stable and reproducible cholesterol biosensor. The potentiometric response was 57mV/ decade concentration. The sensor response had no interferences by normal concentrations of ascorbic acid, glucose, and urea, proteins and lipids. The present biosensor could be implanted in the human body because of the biocompatibility of the lipid film.

  • 16.
    Qadir Israr, Muhammed
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Rana Sadaf, Jamil
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Asif, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Danielsson, B.
    Lund University.
    Potentiometric cholesterol biosensor based on ZnO nanorods chemically grown on Ag wire2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, no 3, p. 1106-1109Article in journal (Refereed)
    Abstract [en]

    An electrochemical biosensor based on ZnO nanorods for potentiometric cholesterol determination is proposed. Hexagon-shaped ZnO nanorods were directly grown on a silver wire having a diameter of 250 mu m using low temperature aqueous chemical approach that produced ZnO nanorods with a diameter of 125250 nm and a length of similar to 1 mu m. Cholesterol oxidase (ChOx) was immobilized by a physical adsorption method onto ZnO nanorods. The electrochemical response of the ChOx/ZnO/Ag biosensor against a standard reference electrode (Ag/AgCl) was investigated as a logarithmic function of the cholesterol concentration (1 x 10(-6)M to 1 x 10(-2)M) showing good linearity with a sensitivity of 35.2 mV per decade and the stable output signal was attained at around 10 s.

  • 17.
    Qadir, Muhammad Israr
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Chemical fabrication of ZnO nanostructures and their emission properties: Cholesterol biosensing applications utilizing ZnO and Graphene2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Zinc oxide (ZnO) is an inorganic compound, owing to wide band gap and large binding energy, and holds promising potential in the fields of semiconducting as well as piezoelectric applications with excellent stability and reliability. In addition, ZnO has a plenteous number of nanoscale structures containing unique physical, chemical, electrical, sensing and optical properties. These properties of nanostructures are being unrevealed extensively since last two decades and have become a prominent field of research in nanoscience and nanotechnology.

    More specifically, the present dissertation deals with the low temperature synthesis of ZnO nanostructures (nanorods, nanotubes, nanodisks and nanowalls) on a variety of substrates such as silicon, gallium nitride, zinc foil, silver and aluminum; structural characterization and study of their luminescence properties. In paper 1 we investigated the synthesis mechanism of chemically fashioned ZnO nanotubes and their superior emission capability compared to ZnO nanorods with significant enhancements in ultraviolet and visible regions has been studied. These chemically synthesized ZnO nanotubes are further utilized to fabricate a heterostructure with p-GaN thin film in order to achieve white emission (Paper 2). The aim of Paper 3 is to understand the synthesis of ZnO nanorods and their transition into ZnO nanodisks at 55 °C along with temperature dependent micro-photoluminescence studies. However, the second half of the dissertation is devoted to the fabrication of potentiometric cholesterol biosensors through the conjugation of ZnO nanostructures and graphene nanosheets with a thin film of cholesterol oxidase. Paper 4 contains the fabrication of cholesterol biosensor by the deposition of ZnO nanorods on thin silver wire followed by their functionalization under the physical adsorption method. The specificity, reproducibility and stability of the biosensor have been investigated with good linearity slope curve of ~35 mV/ decade. The purpose of papers 5 and 6 is to enhance the sensitivity of the cholesterol biosensor by using ZnO nanowalls and graphene nanosheets as a matrix where the sensitivity of the slope curve is achieved as ~53 and ~82 mV/ decade, respectively.

    List of papers
    1. Trimming of aqueous chemically grown ZnO nanorods into ZnO nanotubes and their comparative optical properties
    Open this publication in new window or tab >>Trimming of aqueous chemically grown ZnO nanorods into ZnO nanotubes and their comparative optical properties
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    2009 (English)In: APPLIED PHYSICS LETTERS, ISSN 0003-6951, Vol. 95, no 7, p. 073114-Article in journal (Refereed) Published
    Abstract [en]

    Highly oriented ZnO nanotubes were fabricated on a silicon substrate by aqueous chemical growth at low temperature (andlt; 100 degrees C) by trimming of ZnO nanorods. The yield of nanotubes in the sample was 100%. Photoluminescence spectroscopy of the nanotubes reveals an enhanced and broadened ultraviolet (UV) emission peak, compared with the initial nanorods. This effect is attributed to whispering gallery mode resonance. In addition, a redshift of the UV emission peak is also observed. Enhancement in the deep defect band emission in the nanotubes compared to nanorods was also manifested as a result of the increased surface area.

    Keywords
    crystal growth from solution, II-VI semiconductors, nanofabrication, red shift, semiconductor growth, semiconductor nanotubes, whispering gallery modes, wide band gap semiconductors, zinc compounds
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-20618 (URN)10.1063/1.3211124 (DOI)
    Available from: 2009-09-16 Created: 2009-09-15 Last updated: 2015-03-09
    2. White Electroluminescence Using ZnO Nanotubes/GaN Heterostructure Light-Emitting Diode
    Open this publication in new window or tab >>White Electroluminescence Using ZnO Nanotubes/GaN Heterostructure Light-Emitting Diode
    Show others...
    2010 (English)In: NANOSCALE RESEARCH LETTERS, ISSN 1931-7573, Vol. 5, no 6, p. 957-960Article in journal (Refereed) Published
    Abstract [en]

    We report the fabrication of heterostructure white light-emitting diode (LED) comprised of n-ZnO nanotubes (NTs) aqueous chemically synthesized on p-GaN substrate. Room temperature electroluminescence (EL) of the LED demonstrates strong broadband white emission spectrum consisting of predominating peak centred at 560 nm and relatively weak violet-blue emission peak at 450 nm under forward bias. The broadband EL emission covering the whole visible spectrum has been attributed to the large surface area and high surface states of ZnO NTs produced during the etching process. In addition, comparison of the EL emission colour quality shows that ZnO nanotubes have much better quality than that of the ZnO nanorods. The colour-rendering index of the white light obtained from the nanotubes was 87, while the nanorods-based LED emit yellowish colour.

    Place, publisher, year, edition, pages
    Springer Science Business Media, 2010
    Keywords
    ZnO nanotubes, Light-emitting diodes, Electroluminescence, Lightning, White light sources
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-57167 (URN)10.1007/s11671-010-9588-z (DOI)000278096000008 ()
    Available from: 2010-06-11 Created: 2010-06-11 Last updated: 2014-09-25
    3. Natural oxidation based controlled synthesis and characterization of ZnO nanodisks through structural transition of ZnO nanorods at 55 °C
    Open this publication in new window or tab >>Natural oxidation based controlled synthesis and characterization of ZnO nanodisks through structural transition of ZnO nanorods at 55 °C
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    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    A novel, reproducible and natural oxidation based low temperature (55 °C) synthesis of ZnO nanodisks has been carried out using metallic zinc foil and formamide solution. The concentration of the formamide and the reaction duration are optimized to achieve the controlled fabrication. The morphological evolution of the ZnO nanodisks has been observed using scanning electron microscopy, energy dispersive spectroscopy and transmission electron microscopy. It is observed that ZnO nanodisks are of a good crystalline quality and have hexagonal wurtzite structure. The mechanism behind the growth and the breaking of nanorods into nanodisks is also suggested. Microphotoluminescence spectrum exhibits a strong ultraviolet emission and a very weak deep level related emission. In addition, temperature dependent studies reveal a decrease in the emission intensity of the ultraviolet peak combined with a red shift with increasing temperature from 20 to 300 K.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-71321 (URN)
    Available from: 2011-10-11 Created: 2011-10-11 Last updated: 2014-01-15Bibliographically approved
    4. Potentiometric cholesterol biosensor based on ZnO nanorods chemically grown on Ag wire
    Open this publication in new window or tab >>Potentiometric cholesterol biosensor based on ZnO nanorods chemically grown on Ag wire
    Show others...
    2010 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, no 3, p. 1106-1109Article in journal (Refereed) Published
    Abstract [en]

    An electrochemical biosensor based on ZnO nanorods for potentiometric cholesterol determination is proposed. Hexagon-shaped ZnO nanorods were directly grown on a silver wire having a diameter of 250 mu m using low temperature aqueous chemical approach that produced ZnO nanorods with a diameter of 125250 nm and a length of similar to 1 mu m. Cholesterol oxidase (ChOx) was immobilized by a physical adsorption method onto ZnO nanorods. The electrochemical response of the ChOx/ZnO/Ag biosensor against a standard reference electrode (Ag/AgCl) was investigated as a logarithmic function of the cholesterol concentration (1 x 10(-6)M to 1 x 10(-2)M) showing good linearity with a sensitivity of 35.2 mV per decade and the stable output signal was attained at around 10 s.

    Place, publisher, year, edition, pages
    Elsevier Science B.V., Amsterdam., 2010
    Keywords
    Potentiometric biosensor; Cholesterol; Cholesterol oxidase; Electrostatic immobilization; ZnO nanorods
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-63930 (URN)10.1016/j.tsf.2010.08.052 (DOI)000285075300032 ()
    Available from: 2011-01-11 Created: 2011-01-10 Last updated: 2017-12-11
    5. Chemically fashioned ZnO nanowalls and their potential application for potentiometric cholesterol biosensor
    Open this publication in new window or tab >>Chemically fashioned ZnO nanowalls and their potential application for potentiometric cholesterol biosensor
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    2011 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 98, no 25, p. 253705-Article in journal (Refereed) Published
    Abstract [en]

    Chemically fashioned zinc oxide (ZnO) nanowalls on aluminum wire have been characterized and utilized to fabricate a potentiometric cholesterol biosensor by an electrostatic conjugation with cholesterol oxidase. The sensitivity, specificity, reusability, and stability of the conjugated surface of ZnO nanowalls with thickness of similar to 80 nm have been investigated over a wide logarithmic concentrations of cholesterol electrolyte solution ranging from 1x10(-6)-1x10(-3) M. The presented biosensor illustrates good linear sensitivity slope curve (similar to 53 mV/decade) corresponding to cholesterol concentrations along with rapid output response time of similar to 5 s.

    Place, publisher, year, edition, pages
    American Institute of Physics, 2011
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-69852 (URN)10.1063/1.3599583 (DOI)000292039900075 ()
    Note
    Original Publication: M.Q. Israr, J.R. Sadaf, Omer Nur, Magnus Willander, S. Salman and B. Danielsson, Chemically fashioned ZnO nanowalls and their potential application for potentiometric cholesterol biosensor, 2011, Applied Physics Letters, (98), 25, 253705. http://dx.doi.org/10.1063/1.3599583 Copyright: American Institute of Physics http://www.aip.org/ Available from: 2011-08-10 Created: 2011-08-08 Last updated: 2017-12-08
    6. Structural characterization and biocompatible applications of graphene nanosheets for miniaturization of potentiometric cholesterol biosensor
    Open this publication in new window or tab >>Structural characterization and biocompatible applications of graphene nanosheets for miniaturization of potentiometric cholesterol biosensor
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    2011 (English)In: Journal of Biosensors & Bioelectronics, ISSN 2155-6210, Vol. 2, no 3Article in journal (Refereed) Published
    Abstract [en]

    The potentiometric cholesterol biosensor based on graphene nanosheets has been successfully miniaturized. Cholesterol oxidase (ChOx) has been immobilized onto graphene nanosheets exfoliated on copper wire through the process of physical adsorption,. The presented potentiometric biosensor renders effective selectivity and sensitivity (~82 mV/decade) for the detection of cholesterol biomolecules in 1 × 10−6 M to 1 × 10−3 M logarithmic range and quick output response within ~ 4 sec. The stability and reusability of the biosensor has also been investigated for the above mentioned range of cholesterol concentrations. The enzyme activity measurements on graphene nanosheets are studied using UV-Visible and FTIR spectrophotometers. Additionally, the functioning of the presented biosensor is studied for a range of temperatures (15-70 °C) and pH values (4-9).

    Keywords
    Graphene nanosheets; Cholesterol; Potentiometric; Biosensor
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-71322 (URN)10.4172/2155-6210.1000109 (DOI)
    Note

    On the day of the defence day the status of this arcile was "Manuscript".

    Available from: 2011-10-11 Created: 2011-10-11 Last updated: 2014-11-24Bibliographically approved
  • 18.
    Sadaf, Jamal Rana
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Israr, Muhammad Qadir
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Kishwar, Sultana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    White Electroluminescence Using ZnO Nanotubes/GaN Heterostructure Light-Emitting Diode2010In: NANOSCALE RESEARCH LETTERS, ISSN 1931-7573, Vol. 5, no 6, p. 957-960Article in journal (Refereed)
    Abstract [en]

    We report the fabrication of heterostructure white light-emitting diode (LED) comprised of n-ZnO nanotubes (NTs) aqueous chemically synthesized on p-GaN substrate. Room temperature electroluminescence (EL) of the LED demonstrates strong broadband white emission spectrum consisting of predominating peak centred at 560 nm and relatively weak violet-blue emission peak at 450 nm under forward bias. The broadband EL emission covering the whole visible spectrum has been attributed to the large surface area and high surface states of ZnO NTs produced during the etching process. In addition, comparison of the EL emission colour quality shows that ZnO nanotubes have much better quality than that of the ZnO nanorods. The colour-rendering index of the white light obtained from the nanotubes was 87, while the nanorods-based LED emit yellowish colour.

  • 19.
    Tzamtzis, Nikolaos
    et al.
    National Technical University of Athens, Greece .
    Psychoyios, Vasillios N
    National Technical University of Athens, Greece .
    Nikoleli, Georgia-Paraskevi
    National Technical University of Athens, Greece .
    Nikolelis, Dimitrios P
    University of Athens, Greece .
    Psaroudakis, Nikolas
    University of Athens, Greece .
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Flow Potentiometric Injection Analysis of Uric Acid Using Lipid Stabilized Films with Incorporated Uricase on ZnO Nanowires2012In: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 24, no 8, p. 1719-1725Article in journal (Refereed)
    Abstract [en]

    A novel potentiometric uric acid biosensor was fabricated by immobilization of uricase into stabilized lipid films using zinc oxide (ZnO) nanowires as measuring electrode. Uricase was incorporated into the lipid film prior polymerization on the surface of well aligned ZnO nanowires resulting in a sensitive, selective, stable and reproducible uric acid biosensor. The potentiometric response was twice as large from previously reported values due to the presence of a cationic lipid in the lipid film. The sensor response had no interferences by normal concentrations of ascorbic acid, glucose, urea, proteins and lipids.

  • 20.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Qadir, Muhammad Israr
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    One- and two-dimensional nanostructures for chemical- and biosensing2011In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 25, p. 745-748Article in journal (Refereed)
    Abstract [en]

    Nanostructures have been very popular for several years to do research on sensing. In this paper we will demonstrate the advantage of using nanowires of zinc oxide (ZnO) as one dimensional structure for potentiometric measurements in biological environments. The developed procedures show suitability for the accurate determination of most of the important metal ions and to characterize cells and thin bio-layers. We will also show how to use these structures for biosensing of glucose, cholesterol, and the application of extended gate metal oxide semiconductor field effect transistors as the signal transducer. In the second part, we will show how to use a two-dimensional nanostructure, specifically graphene, for cholesterol and glucose biosensing.

  • 21.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Fakhar-e-Alam, M.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Sultana, Kishwar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ali, Syed M. Usman
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Asif, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Applications of Zinc Oxide Nanowires for Bio-photonics and Bio-electronics2011In: Proceedings of SPIE Volume 7940 / [ed] Ferechteh Hosseini Teherani, David C. Look, David J. Rogers, Bellingham, Washington, USA: SPIE - International Society for Optical Engineering, 2011Conference paper (Other academic)
    Abstract [en]

    Using zinc oxide (ZnO) nanostructures, nanorods (NRs) and nanoparticles (NPs) grown on different substrates (sub-micrometer glass pipettes, thin silver wire and on plastic substrate) different bio-sensors were demonstrated. The demonstrated sensors are based on potentiometric approach and are sensitive to the ionic metals and biological analyte in question. For each case a selective membrane or enzyme was used. The measurements were performed for intracellular environment as well as in some cases (cholesterol and uric acid). The selectivity in each case is tuned according to the element to be sensed. Moreover we also developed photodynamic therapy approach based on the use of ZnO NRs and NPs. Necrosis/apoptosis was possible to achieve for different types of cancerous cell. The results indicate that the ZnO with its UV and white band emissions is beneficial to photodynamic therapy technology.

  • 22.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Qadir, Muhammad Israr
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Saima
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zainelabdin, Ahmed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain, Ijaz
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Luminescence from Zinc Oxide Nanostructures and Polymers and their Hybrid Devices2010In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 3, no 4, p. 2643-2667Article, review/survey (Refereed)
    Abstract [en]

    Zinc oxide (ZnO) is a strong luminescent material, as are several polymers. These two materials have distinct drawbacks and advantages, and they can be combined to form nanostructures with many important applications, e. g., large-area white lighting. This paper discusses the origin of visible emission centers in ZnO nanorods grown with different approaches. White light emitting diodes (LEDs) were fabricated by combining n-ZnO nanorods and hollow nanotubes with different p-type materials to form heterojunctions. The p-type component of the hybrids includes p-SiC, p-GaN, and polymers. We conclude by analyzing the electroluminescence of the different light emitting diodes we fabricated. The observed optical, electrical, and electro-optical characteristics of these LEDs are discussed with an emphasis on the deep level centers that cause the emission.

  • 23.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Siama
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zainelabdin, Ahmed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Amin, Gul
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain, I
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Alvi, Naveed ul Hassan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Intrinsic White Light Emission from Zinc Oxide Nanorods Heterojunctions on Large Area Substrates2011In: Proceedings of SPIE Volume 7940 / [ed] Ferechteh Hosseini Teherani, David C. Look, David J. Rogers, Bellingham, Washington, USA: SPIE - International Society for Optical Engineering, 2011Conference paper (Other academic)
    Abstract [en]

    Zinc oxide (ZnO) and especially in the nanostructure form is currently being intensively investigated world wide for the possibility of developing different new photonic devices. We will here present our recent findings on the controlled low temperature chemical growth of ZnO nanorods (NRs) on different large area substrates. Many different heterojunctions of ZnO NRs and p-substrates including those of crystalline e. g. p-GaN, p-SiC or amorphous nature e. g. p-polymer coated plastic and p-polymer coated paper will be shown. Moreover, the effect of the p-electrode of these heterojunctions on tuning the emitted wavelength and changing the light quality will be discussed. An example using ZnO NR/p-GaN will be shown and the electrical and electro-optical characteristics will be analyzed. For these heterojunctions the effect of post growth annealing and its effect on the electroluminescence (EL) spectrum will be shown. Finally, intrinsic white light emitting diodes based on ZnO NRs on foldable and disposable amorphous substrates (plastic and paper) will also be presented.

  • 24.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Qadir, Muhammad Israr
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Rana, Sadaf Jamil
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Progress on one-dimensional zinc oxide nanomaterials based photonic devices2012In: Nanophotonics, ISSN 2192-8606, Vol. 1, no 1, p. 99-115Article in journal (Refereed)
    Abstract [en]

    One-dimensional nanostructures hold the most attractive and excellent physiochemical characteristics which exhibit the paramount influence on the fundamental and technological nanoelectronic as well as nanophotonic applications. In this review article, we present a detailed introduction to the diverse synthetic procedures which can be utilized for the fabrication of single-, planar- and three-dimensional ZnO nanostructures. More specifically, a thorough discussion regarding luminescence characteristics of the one-dimensional ZnO nanostructures is presented for ultraviolet and visible regions. We summarize the room temperature spontaneous emission and stimulated emission along with the interaction of the incident beam with material cavity to produce resonant optical modes and low-temperature time resolved photoluminescence studies. The most recent published results on the white light emitting diodes fabricated with the combination of ZnO nanotubes with p-GaN and ZnO nanorods with p-organic polymers on glass and disposable paper are discussed. Additionally, the significant results on optically and electrically pumped lasers are discussed; along with an overview on the future of ZnO nanostructures based photonic devices.

  • 25.
    Yang, Li Li
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zhao, Qingxiang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Israr, Muhammad Qadir
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Yang, J. H.
    Institute of Condensed State Physics, Jilin Normal University, Siping, 136000, People's Republic of China.
    Indirect optical transition due to surface band bending in ZnO nanotubes2010In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, no 10Article in journal (Refereed)
    Abstract [en]

    ZnO nanotubes (ZNTs) have been successfully evolved from ZnO nanorods (ZNRs) by a simple chemical etching process. Two peaks located at 382 nm and 384 nm in the UV emission region has been observed in the room temperature photoluminescence (PL) spectrum of ZNTs since the surface band bending in ZNTs induces the coexistence of indirect and direct transitions in their emission process. In addition, a strong enhancement of total luminescence intensity at room temperature in ZNTs has also be observed in comparison with that of ZNRs. Both temperature-dependent PL and time-resolved PL results not only further testify the coexistence of indirect and direct transitions due to the surface band bending, but also reveal that less nonradiative contribution to the emission process in ZNTs finally causes their stronger luminescence intensity.

1 - 25 of 25
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