Researcher:
Kharratian, Soheila

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PhD Student

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Soheila

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Kharratian

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Kharratian, Soheila

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2018 - 20205

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Researcher Of Publications: search.filters.isAuthorOfPublication.f3aa80fe-e1d2-48ff-9069-8d5ac1e93e25

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    Anisotropic gold nanostructures: optimization via in silico modeling for hyperthermia
    (Amer Chemical Soc, 2018) Singh, Ajay Vikram; Jahnke, Timotheus; Wang, Shuo; Xiao, Yang; Alapan, Yunus; Kozielski, Kristen; David, Hilda; Richter, Gunther; Bill, Joachim; Laux, Peter; Luch, Andreas; Sitti, Metin; Department of Electrical and Electronics Engineering; N/A; Onbaşlı, Mehmet Cengiz; Kharratian, Soheila; Faculty Member; PhD Student; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; 258783; N/A
    Protein- and peptide-based manufacturing of self-assembled supramolecular functional materials has been a formidable challenge for biomedical applications, being complex in structure and immunogenic in nature. In this context, self assembly of short amino acid sequences as simplified building blocks to design metal-biomolecule frameworks (MBioFs) is an emerging field of research. Here, we report a facile, bioinspired route of anisotropic nanostructure synthesis using gold binding peptides (10-15mers) secreted by cancer cells. The bioinformatics tool i-TASSER predicts the effect of amino acid sequences on metal binding sites and the secondary structures of the respective peptide sequence. Electron microscopy, X-ray, infrared, and Raman spectroscopy validated the versatile anisotropic gold nanostructures and the metal-bioorganic nature of this biomineralization. We studied the influence of precursor salt, pH, and peptide concentration on the evolution of nanoleaf, nanoflower, nanofiber, and dendrimer-like anisotropic MBioFs. Characterization of photothermal properties using infrared laser (785 nm) revealed excellent conversion of light into heat. Exposure of bacterial cells in culture exhibits high rate of photothermal death using lower laser power (1.9 W/cm(2)) compared with recent reports. The MBioF's self-assembly process shown here can readily be extended and adapted to superior plasmonic material synthesis with a promising photothermal effect for in vivo biofilm destruction and cancer hyperthermia applications.
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    PublicationOpen Access
    Advanced materials and device architectures for magnetooptical spatial light modulators
    (Wiley-VCH, 2019) N/A; Department of Electrical and Electronics Engineering; Kharratian, Soheila; Onbaşlı, Mehmet Cengiz; Ürey, Hakan; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; N/A; 258783; 8579
    Faraday and Kerr rotations are magnetooptical (MO) effects used for rotating the polarization of light in transmission and reflection from a magnetized medium, respectively. MO effects combined with intrinsically fast magnetization reversal, which can go down to a few tens of femtoseconds or less, can be applied in magnetooptical spatial light modulators (MOSLMs) promising for nonvolatile, ultrafast, and high-resolution spatial modulation of light. With the recent progress in low-power switching of magnetic and MO materials, MOSLMs may lead to major breakthroughs and benefit beyond state-of-the-art holography, data storage, optical communications, heads-up displays, virtual and augmented reality devices, and solid-state light detection and ranging (LIDAR). In this study, the recent developments in the growth, processing, and engineering of advanced materials with high MO figures of merit for practical MOSLM devices are reviewed. The challenges with MOSLM functionalities including the intrinsic weakness of MO effect and large power requirement for switching are assessed. The suggested solutions are evaluated, different driving systems are investigated, and resulting device architectures are benchmarked. Finally, the research opportunities on MOSLMs for achieving integrated, high-contrast, and low-power devices are presented.
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    PublicationOpen Access
    Seed-mediated synthesis of plasmonic gold nanoribbons using cancer cells for hyperthermia applications
    (Royal Society of Chemistry (RSC), 2018) Singh, Ajay Vikram; Alapan, Yunus; Jahnke, Timotheus; Laux, Peter; Luch, Andreas; Aghakhani, Amirreza; Bill, Joachim; Sitti, Metin; N/A; Department of Electrical and Electronics Engineering; Kharratian, Soheila; Onbaşlı, Mehmet Cengiz; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 258783
    A surfactant-less, seed mediated, biological synthesis of two dimensional (2-D) nanoribbons in the presence of breast cancer cells (MCF7) is demonstrated. The diameter and yield of nanoribbons are tunable via seeds and gold precursor concentration. Such crystalline nanoribbons serve to enhance the Raman signals over MCF7 cells. The side and slopes of the triangular nanoplatelets fused as nanoribbons exhibit plasmon excitement in quadrupole resonance modes in the infrared region. Consequently, when irradiated with an infrared laser they show an excellent photothermal effect and rapid rise in temperature. The experimental results verified by finite-difference time-domain (FTDT) calculations reveal the presence of wedge-plasmon polaritons propagating along the edges of the nanoribbons. These simulations confirm that long aspect ratio nanoribbon's edges and vertices act as an active optical waveguide, allowing for heat propagation along the long axis, killing cancer cells in the process at lower power doses.
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    PublicationOpen Access
    Broadband enhancement of Faraday effect using magnetoplasmonic metasurfaces
    (Springer, 2020) N/A; Department of Electrical and Electronics Engineering; Kharratian, Soheila; Ürey, Hakan; Onbaşlı, Mehmet Cengiz; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579; 258783
    Magnetooptical Faraday effect enables ultrafast photonic devices based on nonreciprocal polarization rotation; however, the intrinsic weakness of Faraday effect prevents miniaturization and practical applications of nonreciprocal photonic devices. Magnetoplasmonics offers new mechanisms for enhancing magnetooptical effects using surface plasmon resonances, which generally have narrow bandwidths. Using finite-difference time-domain modeling, we demonstrate a magnetoplasmonic metasurface, which remarkably enhances the Faraday effect in a wide spectral range. While Faraday rotation in a bare bismuth-substituted yttrium iron garnet film is below 0.02 degrees in the studied range of 600-1600 nm, the proposed metasurface yields few degrees of rotation in a broad band with a maximum exceeding 6.5 degrees, which indicates about three orders of magnitude enhancement. We also show that by optimizing the configuration of the system including the geometry and excitation parameters, the metasurface response and operation band can be tuned further, and rotation values higher than 20 degrees can be achieved. Finally, we present guidelines for designing magnetoplasmonic metasurfaces.
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    PublicationOpen Access
    RGB magnetophotonic crystals for high-contrast magnetooptical spatial light modulators
    (Nature Publishing Group (NPG), 2019) Department of Electrical and Electronics Engineering; N/A; Onbaşlı, Mehmet Cengiz; Ürey, Hakan; Kharratian, Soheila; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; 258783; 8579; N/A
    Magnetooptical spatial light modulators (MOSLMs) are photonic devices that encode information in photonic waveforms by changing their amplitude and phase using magnetooptical Faraday or Kerr rotation. Despite the progress on both MO materials and switching methods, significant improvements on materials engineering and SLM design are needed for demonstrating low-power, multicolor, analog and high-contrast MOSLM devices. In this study, we present design rules and example designs for a high-contrast and large figure-of-merit MOSLM using three-color magnetophotonic crystals (MPC). We demonstrate for the first time, a three-defect MPC capable of simultaneously enhancing Faraday rotation, and high-contrast modulation at three fundamental wavelengths of red, green and blue (RGB) within the same pixel. We show using 2D finite-difference time-domain simulations that bismuth-substituted yttrium iron garnet films are promising for low-loss and high Faraday rotation MOSLM device in the visible band. Faraday rotation and loss spectra as well as figure-of-merit values are calculated for different magnetophotonic crystals of the form (H/L)(p)/(D/L)(q)/(H/L)(p). After an optimization of layer thicknesses and MPC configuration, Faraday rotation values were found to be between 20-55 degrees for losses below 20 dB in an overall thickness less than 1.5 mu m including three submicron garnet defect layers. The experimental demonstration of our proposed 3-color MOSLM devices can enable bistable photonic projectors, holographic displays, indoor visible light communication devices, photonic beamforming for 5 G telecommunications and beyond.