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Khosroshahi M.E.,Amirkabir University of Technology | Khosroshahi M.E.,Optics and Photonics Research Center | Ghazanfari L.,Amirkabir University of Technology | Hasan-Nejad Z.,Amirkabir University of Technology
Iranian Journal of Medical Physics

Introduction: In this study, we describe the results of controlled synthesis and application of gold coated Fe3O4/SiO2 nanoshells combined with the optical property of gold for enhancement of selective photothermal interaction with cancerous cells based on the surface plasmon resonance (SPR) Phenomena. Materials and Methods: Magnetite Nano-Particles (MNPs) were prepared by means of co-precipitation. MNPs were modified with a thin layer of Silica using the Stober method. The amino-modified Fe3O4/SiO2 nano-shells were covered with gold colloids as a self-assembeled process. In-vitro assays were performed to determine the effect of apoptosis of the cells based on the cells morphological changes. Results: The biologically inert nano-shells (85 nm) with a Magnetite/Silica core and a gold shell were optically activated. A successful laser-hyperthermia based on the thermal effect of surface plasmon resonance was performed using different gold concentrations. The thermal profile effects of laser power are presented as ideal cases of nanoshell-assisted photo-thermal therapy. The thermally-induced cell death has been shown to be dependent on NPs concentration and laser power density. The power densities of 157 and 184 W/cm2 caused complete cell death at the focal point of the laser beam. Cell damage was reduced by decreasing the power density of laser. Also, a larger area of damage on cell culture plates was observed at longer intervals of laser irradiation. Conclusion: An optimized laser-(SPR) hyperthermia was obtained using a concentration of gold coated Fe3O4/SiO2 nanoshells concentration=0.1 mg/ml at intensity=157 W/cm2 at 60s. Source

Belancon M.P.,Optics and Photonics Research Center | Belancon M.P.,Federal Technological University of Parana | Marconi J.D.,Optics and Photonics Research Center | Marconi J.D.,Federal University of ABC | And 3 more authors.
Optical Materials

A study of the broadband near-infrared emission in Pr3+ single doped and Pr3+/Yb3+ codoped tellurite-tungstate glasses for optical amplification is presented. In the Pr3+ single doped samples pumped at 474 nm the emission band at 1480 nm presents a FWHM of ∼140 nm. The Yb3+ addition produces a FWHM broadening up to ∼155 nm, achieved through the 1G4-3H 5 transition. The emission spectra when the codoped sample is pumped at 980 nm shows efficient energy transfer from Yb3+ to Pr 3+, resulting in an intense Pr3+ emission around 1330 nm. This shows that changing the pump wavelength it is possible to select the 1D2-1G4 or the 1G 4-3H5 transition, displacing the emission band from ∼1480 to ∼1330 nm. © 2014 Elsevier B.V. All rights reserved. Source

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