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  • 101. Thaler, M.
    et al.
    Soumen, R.
    Fornara, A.
    Bitsche, M.
    Qin, J.
    Muhammed, M.
    Salvenmoser, W.
    Rieger, G.
    Schrott-Fischer, A.
    Glueckert, R.
    Investigation of Superparamagnetic Iron Oxide Nanoparticles across Scales in the Inner Ear2011In: Molecular Biology of the Cell, ISSN 1059-1524, E-ISSN 1939-4586, Vol. 22Article in journal (Other academic)
  • 102.
    Thaler, Marlene
    et al.
    Carl Zeiss NTS GmbH.
    Roy, Suomen
    Medical University of Innsbruck.
    Fornara, Andrea
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Bitsche, Mario
    Medical University of Innsbruck.
    Qin, Jian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Salvenmoser, Willi
    University of Innsbruck.
    Rieger, Gunde
    Medical University of Innsbruck.
    Schrott Fischer, Anneliese
    Medical University of Innsbruck.
    Glueckert, Rudolf
    Medical University of Innsbruck.
    Visualization and Analysis of Superparamagnetic Iron Oxide Nanoparticles in the Inner Ear by Light Microscopy and Energy Filtered TEM2011In: Nanomedicine: Nanotechnology, Biology, and Medicine, ISSN 1549-9634, Vol. 7, no 3, p. 360-369Article in journal (Refereed)
    Abstract [en]

    Nanoparticles as potential carriers for local drug transfer are an alternative to systemic drug delivery into the inner ear. We report on the first in vitro tests of a new ferrogel consisting of superparamagnetic iron oxide nanoparticles (SPIONs) and a Pluronic (R) F127 (PF127) copolymer. Pluronic copolymers possess a unique viscosity-adjustable property that makes PF127 gels easy to handle compared to conventional cross-linked hydrogels. This ferrogel was successfully tested in cadaver human temporal bones as well as in organotypic explant cultures of mouse inner ears. SPIONs were identified by light microscopy and localized with different imaging modes in energy-filtered transmission electron microscopy. Our approach shows a promising possibility to use iron oxide nanoparticles, which are suitable for visualization and characterization at both the light- and electron-microscopic levels.

    From the Clinical Editor: The authors report the first in vitro tests of a new ferrogel consisting of superparamagnetic iron oxide nanoparticles (SPIONs) and a Pluronic (R) F127 (PF127) copolymer for drug delivery in the inner ear, demonstrasting a promising possibility to use iron oxide nanoparticles, which are suitable for visualization and characterization at both the light- and electron-microscopic levels.

  • 103.
    Toprak, Muhammet
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Li, Shangua
    KTH, School of Engineering Sciences (SCI).
    Muhammed, Mamoun
    KTH, School of Engineering Sciences (SCI).
    Fabrication routes for nanostructured TE material architectures2017In: Materials, Preparation, and Characterization in Thermoelectrics, CRC Press , 2017, p. 17-1-17-18Chapter in book (Other academic)
    Abstract [en]

    Nanomaterials have been an emerging œeld of research due to the novel properties exhibited when the size of building blocks is reduced below 100 nm. Several size-dependent phenomena make nanomaterials attractive in terms of potential applicability compared to their larger-sized counterparts, justifying the importance and attention of this research.1-3 For thermoelectric research, nanomaterials are of great interest due to the possibility of decoupling electrical and thermal transport properties which may help attain higher ZT values for the currently available materials.4,5 še commonly accepted nomenclature of nanomaterials is based on the number of degrees of freedom of charge carriers for the description of their dimensionalities. šus, a thin œlm or superlattice is conœned in one dimension, but is a 2D nanomaterial. Similarly, a nanowire is conœned in two dimensions, hence is a 1D nanomaterial, and œnally a nanoparticle is conœned in three dimensions and is therefore a 0D nanomaterial. In the case of larger nanocrystals (not quantum conœned), the size and shape of the nanocrystals also affect their properties due to differences in surface-to-volume ratio. Bulk nanostructured (NS) TE materials are fabricated using a bulk process rather than a nanofabrication process, which has the important advantage of being produced in large quantities and in a form that is compatible with commercially available devices.6 šey are different from the advanced low-dimensional TE materials as they are consolidated under high T and P, resulting in larger-sized (40-200 nm) grains. še advanced low-dimensional TE materials are usually in quantum size and have well-deœned shapes such as rod-like or tube-like structures. še nanoeffects of bulk NS TE materials will not be as strong as in the case of advanced low-dimensional TE materials, but since the material is closer to bulk material, it can be easily handled the same way as bulk TE materials using conventional TE module/device technology for further steps toward direct applications. So far, of all the NS materials, only bulk NS materials have been produced in enough quantity to be used in this manner. 

  • 104.
    Toprak, Muhammet S.
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Darab, Mahdi
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Syvertsen, Guttorm Ernst
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Synthesis of nanostructured BSCF by oxalate co-precipitation - As potential cathode material for solid oxide fuels cells2010In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 35, no 17, p. 9448-9454Article in journal (Refereed)
    Abstract [en]

    BaxSr1-xCoyFe1-yO3 (BSCF) cathode material for solid oxide fuel cells (SOFC) was synthesized in nanocrystalline form by a novel chemical alloying approach. Thermodynamic modeling has been performed using Medusa software for obtaining the optimum conditions for the fabrication of a precursor with the desired composition. Precursor powder was then calcined and annealed to produce the final mixed oxide BSCF composition. The thermal properties, phase constituents, microstructure and elemental analysis of the samples were characterized by TGA, XRD, SEM and EDS techniques respectively. Spark Plasma Sintering (SPS) has been used at 1080 degrees C and under 50 MPa pressure to obtain the pellets of BSCF with preserved nanostructure and rather high compaction density for electrical conductivity measurements. The results show that the powders have cubic perovskite-type structure with a high homogeneity. Finer resultant powder, compared to earlier reports, and SPS sintered BSCF with nanosized grains exhibited a significantly higher electrical conductivity up to 900 degrees C. Specific conductivity values have been measured in air and N-2 and the maximum of 63 5 cm(-1) at 430 degrees C in air and 25 S cm(-1) at 375 degrees C in N-2 correspondingly show twice as much as conventional BSCF implying a high pledge for nano-BSCF as cathode material in intermediate-temperature SOFC. This is due to the lower interfacial resistance of preserved nanograins by the use of SPS sintering. Presented co-precipitation method is easy to handle and has a high promise to synthesize BSCF at large-scale for IT-SOFCs.

  • 105. Velichko, A.
    et al.
    Boriskov, P.
    Savenko, A.
    Grishin, Alexander
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Khartsev, Sergiy
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Yar, Mazher Ahmed
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Memory resistive switching in CeO2-based film microstructures patterned by a focused ion beam2014In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 556, p. 520-524Article in journal (Refereed)
    Abstract [en]

    Heteroepitaxial CeO2 (80 nm)/La0.5Sr0.5CoO3 (500 nm) film structure has been pulsed laser deposited on a sapphire substrate. The Ag/CeO2 microjunctions patterned by a focused ion beam on a La0.5Sr0.5CoO3 film exhibit reproducible reversible switching between a high resistance state (OFF) with insulating properties and a semiconducting or metallic low resistance state (ON) with resistance ratios up to 10(4). The influence of micro-scaling and defects formed at the cell boundaries during etching on its electrical characteristics has been analyzed. The appearance of a switching channel at the moment of the electrical forming, responsible for the memory effect, has been proved, along with a mechanism of a self-healing electrical breakdown.

  • 106.
    Vogt, Carmen M.
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Laurent, Sophie
    University of Mons-Hainaut, Belgium.
    Bridot, Jean-Luc
    University of Mons-Hainaut, Belgium.
    Müller, Robert N.
    University of Mons-Hainaut.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    High quality and tuneable silica shell-magnetic core nanoparticles2010In: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 12, no 4, p. 1137-1147Article in journal (Refereed)
    Abstract [en]

    Obtaining small (<50 nm), monodispersed, well-separated, single iron oxide core-silica SiO2) shell nanoparticles for biomedical applications is still a challenge. Preferably, they are synthesized by inverse microemulsion method. However, substantial amount of aggregated and multicore core- shell nanoparticles is the undesired outcome of the method. In this study, we report on the production of less than 50 nm overall size, monodispersed, free of necking, single core iron oxide-SiO2 shell nanoparticles with tuneable shell thickness by a carefully optimized inverse microemulsion method. The high degree of control over the process is achieved by understanding the mechanism of core-shell nanoparticles formation. By varying the reaction time and recursor concentration, the thickness of silica layer an the core nanoparticles can be finely adjusted from to 13 nm. Residual reactions during the workup were inhibited by a combination of pH control with hock freezing and ultracentrifuging. These highquality tuneable core-shell nanocomposite particles exhibit superparamagnetic character and sufficiently high magnetization with great potential for biomedical applications (e.g. MRI, cell separation and magnetically driven drug delivery systems) either as-prepared or by additional surface modification for improved biocompatibility.

  • 107.
    Wahlberg, Sverker
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Yar, Mazher Ahmed
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Abuelnaga, Mohammad Omar
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Salem, Handi G.
    Johnsson, Mats
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Fabrication of Nanostructured W-Y2O3 Materials by Chemical Methods2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 25, p. 12622-12628Article in journal (Refereed)
    Abstract [en]

    A novel method for the fabrication of highly uniform oxide dispersion-strengthened (ODS) materials made by chemical processing is presented. The powders are fabricated by a two-step route starting with a chemical synthesis at room temperature, producing nanocrystalline yttrium doped tungsten trioxide hydrate precursor powders. Thermogravimetric analysis with evolved gas analysis revealed the presence of ammonium nitrate in the precursors. The second step is the reduction of the precursor in a hydrogen atmosphere at 600 and 800 degrees C. The reduced powders, containing W-1.2%Y2O3, showed two types of tungsten particles, cube-shaped with a size less than 250 nm and finer particles (<50 nm) of both spherical and cubic shape. The powder was consolidated by spark plasma sintering at 1100 degrees C, producing a bulk material with a relative density of 88%. Characterization of the sintered materials by high resolution scanning electron microscopy revealed a uniform microstructure with tungsten grains of less than 300 nm and nanosized oxide particles uniformly dispersed at the tungsten grain boundaries, as well as inside the tungsten grains. Experimental determination of the elastic properties was conducted by nanoindentation tests and fracture toughness was studied by radial indentation cracking.

  • 108.
    Wang, Xiaodi
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Ma, Ying
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Li, Shanghua
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Kashyout, Abdel-Hady
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Ceria-based nanocomposite with simultaneous proton and oxygen ion conductivity for low-temperature solid oxide fuel cells2011In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 196, no 5, p. 2754-2758Article in journal (Refereed)
    Abstract [en]

    The samarium doped ceria-carbonate (SDC/Na2CO3) nanocomposite systems have shown to be excellent electrolyte materials for low-temperature SOFCs, yet, the conduction mechanism is not well understood. In this study, a four-probe d.c. technique has been successfully employed to study the conduction behavior of proton and oxygen ion in SDC/Na2CO3 nanocomposite electrolyte. The results demonstrated that the SDC/Na2CO3 nanocomposite electrolyte possesses unique simultaneous proton and oxygen ion conduction property, with the proton conductivity 1-2 orders of magnitude higher than the oxygen ion conductivity in the temperature range of 200-600 degrees C, indicating the proton conduction in the nanocomposite mainly accounts for the enhanced total ionic conductivity. It is suggested that the interface in composite electrolyte supplies high conductive path for proton, while oxygen ions are probably transported by the SDC grain interiors. An empirical "Swing Model" has been proposed as a possible mechanism of superior proton conduction. (C) 2010 Elsevier B.V. All rights reserved.

  • 109.
    Wang, Xiaodi
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Ma, Ying
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Li, Shanghua
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    SDC/Na2CO3 nanocomposite: New freeze drying based synthesis and application as electrolyte in low-temperature solid oxide fuel cells2012In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 37, no 24, p. 19380-19387Article in journal (Refereed)
    Abstract [en]

    A key issue to develop low-temperature solid oxide fuel cells (LTSOFCs) is to develop new electrolyte materials with enhanced ionic conductivity. Recently, SDC/Na2CO3 nanocomposite, as a proton and oxide co-ion conductor, has been developed as promising electrolyte candidates for LTSOFCs, where Na2CO3 as the secondary phase performs several crucial functions. However, it's difficult to control the homogeneity of Na 2CO3 phase in the composite by the current methods for composite fabrication. In this study, we report a new freeze drying technique to fabricate SDC/Na2CO3 nanocomposites with different content of Na2CO3. Structural and morphological study confirmed that the homogeneity of both SDC and Na2CO3 phases in the nanocomposite is well controlled by the freeze drying technique. The effect of Na2CO3 content on proton and oxygen ion conductivities of SDC-carbonate samples were investigated by the four-probe d.c. measurement. Proton conductivity transformation around 350 °C has been observed for all the SDC/Na2CO3 nanocomposites due to the glass transition of amorphous Na2CO3 phase, and the proton conductivity is dependent on Na2CO3 content. While oxygen ion conductivity deceases with the increasing of Na2CO3 volume fraction in the nanocomposite. Finally, SOFCs were fabricated using SDC/Na2CO3 nanocomposite samples and tested for electrochemical performances. The excellent performance of SOFCs using SDC/Na2CO3 nanocomposite electrolyte verifies that nanocomposite approach is an effective way to fabricate electrolyte with enhanced ionic conductivity for LTSOFCs.

  • 110.
    Wang, Xiaodi
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Ma, Ying
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Sugunan, Abhilash
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Qin, Jian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Synthesis of uniform quasi-octahedral CeO2 mesocrystals via a surfactant-free route2011In: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 13, no 11, p. 5879-5885Article in journal (Refereed)
    Abstract [en]

    A facile surfactant-free nonaqueous method is presented to prepare uniform quasi-octahedral ceria, CeO 2 , mesocrystals, in which only Ce(NO 3 ) 3 and octanol were used as the reactants at a reaction temperature of 150 °C. CeO 2 sample synthesized using this technique consists of well-dispersed quasi-octahedrons and exhibits an uniform size and morphology. Based on structural characterization, it is proposed that the CeO 2 mesostructure was formed by self-assembly of primary nanocrystals based on unique 3D oriented-attachment mechanism. Optical characterization exhibited a strong quantum confinement, revealing small size of primary nanocrystals. The thermal stability and UV–Vis study reveal CeO 2 mesocrystal has various potential for high temperature applications and optical apparatus applications.

  • 111.
    Yakhshi Tafti, Mohsen
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Jacquot, A.
    Jagle, M.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Fabrication and characterization of nanostructured bulk skutterudites2013In: 2013 MRS Spring Meeting - Symposium H/I/V – Nanoscale Thermoelectric Materials, Thermal and Electrical Transport, and Applications to Solid-State Cooling and Power Generation, Materials Research Society, 2013, p. 105-110Conference paper (Refereed)
    Abstract [en]

    Latest nanotechnology concepts applied in thermoelectric (TE) research have opened many new avenues to improve the ZT value. Low dimensional structures can improve the ZT value as compared to bulk materials by substantial reduction in the lattice thermal conductivity, κL. However, the materials were not feasible for the industrial scale production of macroscopic devices because of complicated and costly manufacturing processes involved. Bulk nanostructured (NS) TEs are normally fabricated using a bulk process rather than a nano- fabrication process, which has the important advantage of producing in large quantities and in a form that is compatible with commercially available TE devices. We developed fabrication strategies for bulk nanostructured skutterudite materials based on FexCo1-xSb3. The process is based on precipitation of a precursor material with the desired metal atom composition, which is then exposed to thermochemical processing of calcination followed by reduction. The resultant material thus formed maintains nanostructured particles which are then compacted using Spark Plasma Sintering (SPS) by utilizing previously optimized process parameters. Microstructure, crystallinity, phase composition, thermal stability and temperature dependent transport property evaluation has been performed for compacted NS Fe xCo1-xSb3. Evaluation results are presented in detail, suggesting the feasibility of devised strategy for bulk quantities of doped TE nanopowder fabrication.

  • 112.
    Yar, Mazher Ahmed
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Wahlberg, Sverker
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Abuelnaga, Mohammad Omar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Johnsson, Mats
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Processing and sintering of yttrium-doped tungsten oxide nanopowders to tungsten-based composites2014In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 49, no 16, p. 5703-5713Article in journal (Refereed)
    Abstract [en]

    Innovative chemical methods are capable of fabricating nanoscale tungsten oxide compounds doped with various rare-earth elements with high purity and homogeneity, which can be processed under hydrogen into nanostructured oxide-dispersed tungsten composite powders having several potential applications. However, hydrogen reduction of doped tungsten oxide compounds is rather complex, affecting the morphology and composition of the final powder. In this study, we have investigated the reduction of tungstic acid in the presence of Y and we provide the experimental evidence that Y2O3 can be separated from Y-doped tungstic acid via hydrogen reduction to produce Y2O3-W powders. The processed powders were further consolidated by spark plasma sintering at different temperatures and holding times at 75 MPa pressure and characterized. The optimized SPS conditions suggest sintering at 1400 A degrees C for 3 min holding time to achieve higher density composites with an optimum finer grain size (3 A mu m) and a hardness value up to 420 H (V). Major grain growth takes place at temperatures above 1300 A degrees C during sintering. From the density values obtained, it is recommend to apply higher pressure before 900 A degrees C to obtain maximum density. Oxides inclusions present in the matrix were identified as Y2O3 center dot 3WO(3) and Y2O3 center dot WO3 during high resolution microscopic investigations.

  • 113.
    Yar, Mazher Ahmed
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Wahlberg, Sverker
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Bergqvis, Hans
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Salem, Hanadi G.
    Johnsson, Mats
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Chemically produced nanostructured ODS-lanthanum oxide-tungsten composites sintered by spark plasma2011In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 408, no 2, p. 129-135Article in journal (Refereed)
    Abstract [en]

    High purity W and W-0.9La(2)O(3) (wt.%) nanopowders were produced by a wet chemical route. The precursor was prepared by the reaction of ammonium paratungstate (APT) with lanthanum salt in aqueous solutions. High resolution electron microscopy investigations revealed that the tungstate particles were coated with oxide precipitates. The precursor powder was reduced to tungsten metal with dispersed lanthanum oxide. Powders were consolidated by spark plasma sintering (SPS) at 1300 and 1400 degrees C to suppress grain growth during sintering. The final grain size relates to the SPS conditions, i.e. temperature and heating rate, regardless of the starting powder particle size. Scanning electron microscopy revealed that oxide phases were mainly accumulated at grain boundaries while the tungsten matrix constituted of nanosized sub-grains. The transmission electron microscopy revealed that the tungsten grains consist of micron-scale grains and finer sub-grains. EDX analysis confirmed the presence of W in dispersed oxide phases with varying chemical composition, which evidenced the presence of complex oxide phases (WO-La) in the sintered metals.

  • 114.
    Yar, Mazher Ahmed
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Wahlberg, Sverker
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Bergqvist, Hans
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Salem, H. G.
    Johnsson, Mats
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Spark plasma sintering of tungsten-yttrium oxide composites from chemically synthesized nanopowders and microstructural characterization2011In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 412, no 2, p. 227-232Article in journal (Refereed)
    Abstract [en]

    Nano-crystalline W-1%Y2O3 (wt.%) powder was produced by a modified solution chemical reaction of ammonium paratungstate (APT) and yttrium nitrate. The precursor powder was found to consist of particles of bimodal morphology i.e. large APT-like particles up to 20 pm and rectangular yttrium containing ultrafine plates. After thermal processing tungsten crystals were evolved from W-O-Y plate like particles. spark plasma sintering (SPS) was used to consolidate the powder at 1100 and 1200 degrees C for different holding times in order to optimize the sintering conditions to yield high density but with reduced grain growth. Dispersion of yttrium oxide enhanced the sinterability of W powder with respect to lanthanum oxide. W-1%Y2O3 composites with sub-micron grain size showed improved density and mechanical properties as compared to W-La2O3 composites. Sample sintered in two steps showed improved density, due to longer holding time at lower temperature (900 degrees C) and less grain growth due to shorter holding time at higher temperature i.e. 1 min at 1100 degrees C.

  • 115. Ye, Fei
    et al.
    Barrefelt, Asa
    Asem, Heba
    Abedi-Valugerdi, Manuchehr
    El-Serafi, Ibrahim
    Saghafian, Maryam
    Abu-Salah, Khalid
    Alrokayan, Salman
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Hassan, Moustapha
    Biodegradable polymeric vesicles containing magnetic nanoparticles, quantum dots and anticancer drugs for drug delivery and imaging2014In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 35, no 12, p. 3885-3894Article in journal (Refereed)
    Abstract [en]

    We have developed biodegradable polymeric vesicles as a nanocarrier system for multimodal bioimaging and anticancer drug delivery. The poly(lactic-co-glycolic acid) (PLGA) vesicles were fabricated by encapsulating inorganic imaging agents of superparamagnetic iron oxide nanoparticles (SPION), manganese-doped zinc sulfide (Mn:ZnS) quantum dots (QDs) and the anticancer drug busulfan into PLGA nanoparticles via an emulsion-evaporation method. T-2(*)-weighted magnetic resonance imaging (MRI) of PLGA-SPION-Mn:ZnS phantoms exhibited enhanced negative contrast with r(2)(*) relaxivity of approximately 523 s(-1) mM(-1) Fe. Murine macrophage (J774A) cellular uptake of PLGA vesicles started fluorescence imaging at 2 h and reached maximum intensity at 24 h incubation. The drug delivery ability of PLGA vesicles was demonstrated in vitro by release of busulfan. PLGA vesicle degradation was studied in vitro, showing that approximately 32% was degraded into lactic and glycolic acid over a period of 5 weeks. The biodistribution of PLGA vesicles was investigated in vivo by MRI in a rat model. Change of contrast in the liver could be visualized by MRI after 7 min and maximal signal loss detected after 4 h post-injection of PLGA vesicles. Histological studies showed that the presence of PLGA vesicles in organs was shifted from the lungs to the liver and spleen over time.

  • 116.
    Ye, Fei
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Brismar, Torkel
    Shi, Jingwen
    Lin, Dong
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Sayed, Ramy El
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Gold nanorod/mesoporoussilica/gadolinium oxide carbonate hydrate core/shell nanoparticles: A multimodalcontrast agent for MRI, CT and fluorescence imaging2012Manuscript (preprint) (Other academic)
  • 117.
    Ye, Fei
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Laurent, Sophie
    Fornara, Andrea
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Astolfi, Laura
    Qin, Jian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Roch, Alain
    Martini, Alessandro
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muller, Robert N.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Uniform mesoporous silica coated iron oxide nanoparticles as a highly efficient, nontoxic MRI T2 contrast agent with tunable proton relaxivities2012In: Contrast Media & Molecular Imaging, ISSN 1555-4309, E-ISSN 1555-4317, Vol. 7, no 5, p. 460-468Article in journal (Refereed)
    Abstract [en]

    Monodisperse mesoporous silica (mSiO2) coated superparamagnetic iron oxide (Fe3O4@mSiO2) nanoparticles (NPs) have been developed as a potential magnetic resonance imaging (MRI) T2 contrast agent. To evaluate the effect of surface coating on MRI contrast efficiency, we examined the proton relaxivities of Fe3O4@mSiO2 NPs with different coating thicknesses. It was found that the mSiO2 coating has a significant impact on the efficiency of Fe3O4 NPs for MRI contrast enhancement. The efficiency increases with the thickness of mSiO2 coating and is much higher than that of the commercial contrast agents. Nuclear magnetic resonance (NMR) relaxometry of Fe3O4@mSiO2 further revealed that mSiO2 coating is partially permeable to water molecules and therefore induces the decrease of longitudinal relaxivity, r1. Biocompatibility evaluation of various sized (ca. 3595 nm) Fe3O4@mSiO2 NPs was tested on OC-k3 cells and the result showed that these particles have no negative impact on cell viability. The enhanced MRI efficiency of Fe3O4@mSiO2 highlights these coreshell particles as highly efficient T2 contrast agents with high biocompatibility.

  • 118.
    Ye, Fei
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Qin, Jian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Engineering Sciences (SCI), Applied Physics, Functional Materials, FNM.
    Multifunctional core-shell nanoparticles: superparamagnetic, mesoporous, and thermosensitive2011In: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 13, no 11, p. 6157-6167Article in journal (Refereed)
    Abstract [en]

    Multifunctional core-shell composite nanoparticles (NPs) have been developed by the combination of three functionalities into one entity, which is composed of a single Fe3O4 NP as the magnetic core, mesoporous silica (mSiO2) with cavities as the sandwiched layer, and thermosensitive poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAAm-co-AAm)) copolymer as the outer shell. The mSiO2-coated Fe3O4 NPs (Fe3O4@mSiO2) are monodisperse and the particle sizes were varied from 25 to 95 nm by precisely controlling the thickness of mSiO2-coating layer. The P(NIPAAm-co-AAm) were then grown onto surface-initiator-modified Fe3O4@mSiO2 NPs through free radical polymerization. These core-shell composite NPs (designated as Fe3O4@mSiO2@P(NIPAAm-co-AAm)) were found to be superparamagnetic with high r2 relaxivity. To manipulate the phase transition behavior of these thermosensitive polymer-coated NPs for future in vivo applications, the characteristic lower critical solution temperature (LCST) was subtly tuned by adjusting the composition of the monomers to be around the human body temperature (i.e. 37 °C), from ca. 34 to ca. 42 °C. The thermal response of the core-shell composite NPs to the external magnetic field was also demonstrated. Owing to their multiple functionality characteristics, these porous superparamagnetic and thermosensitive NPs may prove valuable for simultaneous magnetic resonance imaging (MRI), temperature-controlled drug release, and temperature-programed magnetic targeting and separation applications.

  • 119.
    Ye, Fei
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Vallhov, Helen
    Clinical Allergy Research Unit, Department of Medicine, Karolinska Institute and University Hospital Solna, Sweden.
    Qin, Jian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Daskalaki, Evangelia
    Clinical Allergy Research Unit, Department of Medicine, Karolinska Institutet and Universty Hospital Solan, Sweden.
    abhilash, Sugunan
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Fornara, Andrea
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Gabrielsson, Susanne
    Clinical Allergy Research Unit, Department of Medicine, Karolinska Institutet and Universty Hospital Solan, Sweden.
    Scheynius, Annika
    Clinical Allergy Research Unit, Department of Medicine, Karolinska Institutet and Universty Hospital Solan, Sweden.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Synthesis of high aspect ratio gold nanorods and their effects on human antigen presenting dendritic cells2011In: International Journal Of Nanotechnology, ISSN 1475-7435, Vol. 8, no 8-9, p. 631-652Article in journal (Refereed)
    Abstract [en]

    High aspect ratio (AR) gold nanorods (NRs) attract great interest for biomedical applications due to their novel physicochemical properties. Here, we report a facile method for preparation of high AR gold NRs through a seedless surfactant-mediated protocol with the additive of nitric acid. High-resolution transmission electron microscopy studies showed that the concentration of nitric acid has great effects on the crystal structures of the initially formed nuclei and consequently the growth of gold NRs. A mechanism based on the effect of nitrate ions on surfactant micelle elongation and Ostwald ripening process is proposed for the growth of high AR gold NRs. The biocompatibility of high AR NRs was evaluated on primary human monocyte derived dendritic cells (MDDCs), and compared with that of spherical gold nanoparticles (NPs) and low AR NRs. Low AR (similar to 4.5) gold NRs induced considerable cell death due to CTAB, while spherical gold NPs (7 nm) and high AR (similar to 21) gold NRs showed no or minor effects on viability and immune regulatory markers, which supports the further development of high AR gold NRs for medical applications.

  • 120. Ye, Fei
    et al.
    Zhao, Ying
    Ei-Sayed, Ramy
    Muhammed, Mamoun
    KTH. Alexandria University, Egypt.
    Hassan, Moustapha
    Advances in nanotechnology for cancer biomarkers2018In: Nano Today, ISSN 1748-0132, E-ISSN 1878-044X, Vol. 18, p. 103-123Article in journal (Refereed)
    Abstract [en]

    Cancer biomarkers with high selectivity, specificity and reproducibility play essential role in diagnosis, prognosis and prediction of treatment efficacy in cancer patients. However, the current biomarker assays used in clinics could be improved due to low sensitivity and specificity. Nanoparticle-based assays are emerging as an upcoming approach, providing ultra-high sensitivity and specificity in cancer biomarker detection. The current survey presents an overview of strategies used in the development and integration of nanoparticles for cancer biomarker detection, including mass spectrometry, optical and electrical detection methods. Moreover, we discuss the future trends in the field in correlation to new approaches from fundamental and practical standpoints.

  • 121.
    Zhao, Yichen
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Sugunan, A.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Synthesis of nanostructured antimony telluride for thermoelectric applications2015In: Materials Research Society Symposium Proceedings, Elsevier, 2015, Vol. 1742, p. 1-6Conference paper (Refereed)
    Abstract [en]

    Thermoelectric (TE) materials have been studied during past decades since they can generate electricity directly from waste heat. Antimony chalcogenides (Sb2M3, M = S, Se, Te) are well known as one of the promising candidates among the inorganic TE materials. We report on the synthesis of Sb2Te3 nanoparticle via thermolysis method. A systematic study was done to investigate the effect of reaction time and ratio between the precursors as well as the method of cooling on the morphology and composition of obtained nanoparticles. The ratio between precursors was varied to study the effect on the morphology. Furthermore, the high purity phase Sb2Te3 was obtained by a rapid cooling process.

  • 122.
    Zhao, Yichen
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Sugunan, Abhilash
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Rihtnesberg, David B.
    Wang, Qin
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Size-tuneable synthesis of photoconducting poly-(3-hexylthiophene) nanofibres and nanocomposites2012In: Physica Status Solidi. C, Current topics in solid state physics, ISSN 1610-1634, E-ISSN 1610-1642, Vol. 9, no 7, p. 1546-1550Article in journal (Refereed)
    Abstract [en]

    Poly-(3-hexylthiophene) (P3HT) has been applied in many fields such as organic solar cells, printed electronic circuits, due to superior semiconducting properties compared to other semiconducting polymers. The presence of p-p interaction causes regio-regular P3HT to form ordered lamellar stacks during crystallisation. Here we report a simple room temperature, solution based method to synthesise P3HT nanofibres with controllable sizes. Our method is based on differing solubility of P3HT in various solvents. In a mixed solvent environment, we could control the precipitation of P3HT to obtain nanofibres with various diameters by varying the ratios of the solvents. We found that the lengths of the nanofibres could be controlled with concentration of the solution. Other methods to obtain nanofibres of P3HT invariably involves heating and controlled cooling which makes reproducibility and morphology control difficult. Furthermore, we synthesised a nanocomposite consisting of P3HT nanofibres and quasi-type-II quantum dots and evaluated the photoelectric properties of the nanofibres as well as the nanocomposites using interdigitated gold microelectrodes.

  • 123.
    Zhao, Yichen
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Sugunan, Abhilash
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF. SP Tech Res Inst Sweden, Chem Mat & Surfaces Unit, Sweden.
    Schmidt, Torsten
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Fornara, Andrea
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Relaxation is the key to longer life: suppressed degradation of P3HT films on conductive substrates2014In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 2, no 33, p. 13270-13276Article in journal (Refereed)
    Abstract [en]

    Here we show the dependence of the degree of degradation of poly-3-hexylthiophene (P3HT) films on the conductivity of the supporting substrate. P3HT is widely used for organic solar cells and electronic devices because it allows simple, low cost fabrication and has potential for the fabrication of flexible devices. However, P3HT is known to have a relatively low photostability, and investigating the photodegradation mechanism is an active research field. We find that P3HT films on conductive substrates show significantly retarded degradation and retain their chemical and morphological features when compared to similar films on glass substrates. This 'substrate effect' in retarding the degradation of P3HT films is evident even upon prolonged exposure to air for up to five months.

  • 124.
    Zhao, Ying
    et al.
    Karolinska Inst, Div Expt Canc Med, Dept Lab Med LABMED, SE-14186 Stockholm, Sweden.;Karolinska Univ Hosp Huddinge, Clin Res Ctr, SE-14186 Stockholm, Sweden.;Karolinska Univ Hosp Huddinge, Ctr Allogene Stem Cell Transplantat CAST, SE-14186 Stockholm, Sweden..
    Ye, Fei
    Karolinska Inst, Div Expt Canc Med, Dept Lab Med LABMED, SE-14186 Stockholm, Sweden..
    Brismar, Torkel B.
    Karolinska Inst, Dept Clin Sci Intervent & Technol CLINTEC, Div Med Imaging & Technol, SE-14186 Stockholm, Sweden..
    Li, Xuan
    Karolinska Inst, Dept Clin Sci Intervent & Technol CLINTEC, Pancreat Canc Res Lab, SE-14186 Stockholm, Sweden..
    He, Rui
    Karolinska Inst, Div Expt Canc Med, Dept Lab Med LABMED, SE-14186 Stockholm, Sweden.;Karolinska Univ Hosp Huddinge, Clin Res Ctr, SE-14186 Stockholm, Sweden.;Karolinska Univ Hosp Huddinge, Ctr Allogene Stem Cell Transplantat CAST, SE-14186 Stockholm, Sweden..
    Heuchel, Rainer
    Karolinska Inst, Dept Clin Sci Intervent & Technol CLINTEC, Pancreat Canc Res Lab, SE-14186 Stockholm, Sweden..
    El-Sayed, Ramy
    Karolinska Inst, Div Expt Canc Med, Dept Lab Med LABMED, SE-14186 Stockholm, Sweden..
    Feliu, Neus
    Karolinska Inst, Div Expt Canc Med, Dept Lab Med LABMED, SE-14186 Stockholm, Sweden.;Univ Hamburg, Ctr Hybrid Nanostruct CHyN, D-22607 Hamburg, Germany..
    Zheng, Wenyi
    Karolinska Inst, Div Expt Canc Med, Dept Lab Med LABMED, SE-14186 Stockholm, Sweden.;Karolinska Univ Hosp Huddinge, Clin Res Ctr, SE-14186 Stockholm, Sweden.;Karolinska Univ Hosp Huddinge, Ctr Allogene Stem Cell Transplantat CAST, SE-14186 Stockholm, Sweden..
    Oerther, Sandra
    Karolinska Inst, Div Expt Canc Med, Dept Lab Med LABMED, SE-14186 Stockholm, Sweden.;Karolinska Univ Hosp Huddinge, Clin Res Ctr, SE-14186 Stockholm, Sweden.;Karolinska Univ Hosp Huddinge, Ctr Allogene Stem Cell Transplantat CAST, SE-14186 Stockholm, Sweden..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Parak, Wolfgang J.
    Univ Hamburg, Ctr Hybrid Nanostruct CHyN, D-22607 Hamburg, Germany..
    Muhammed, Mamoun
    KTH. Alexandria Univ, Inst Grad Studies & Res IGSR, Alexandria 21526, Egypt..
    Hassan, Moustapha
    Karolinska Inst, Div Expt Canc Med, Dept Lab Med LABMED, SE-14186 Stockholm, Sweden.;Karolinska Univ Hosp Huddinge, Clin Res Ctr, SE-14186 Stockholm, Sweden.;Karolinska Univ Hosp Huddinge, Ctr Allogene Stem Cell Transplantat CAST, SE-14186 Stockholm, Sweden.;Alexandria Univ, Inst Grad Studies & Res IGSR, Alexandria 21526, Egypt..
    Multimodal Imaging of Pancreatic Ductal Adenocarcinoma Using Multifunctional Nanoparticles as Contrast Agents2020In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 48, p. 53665-53681Article in journal (Refereed)
    Abstract [en]

    Late diagnosis and refractory behavior toward current treatment protocols make pancreatic ductal adenocarcinoma (PDAC) one of the most difficult cancer forms to treat. The imaging-based approach plays an important role to identify potentially curable PDAC patients in high-risk groups at the early stage. In the present study, we developed a core-shell structured gold nanorod (AuNR) as a contrast agent for multimodal imaging and investigated its application for PDAC diagnosis. The composite nanopartides composed of a AuNR core inside a layer of mesoporous silica that was then coated with a gadolinium oxide carbonate shell (AuNR-SiO2 -Gd) are designed to be used in magnetic resonance imaging (MRI), X-ray computed tomography (CT), and photoacoustic imaging (PM). A phantom study with the AuNR-SiO2-Gd NPs demonstrated higher MRI contrast compared to Gadovist and higher X-ray attenuation than Visipaque. A strong, stable, and broad wavelength range signal with a peak at 800 nm was observed in PAI. The AuNR-SiO2-Gd NPs showed significant contrast enhancement under PAI/MRI/CT in both the liver and spleen of control mice after intravenous administration. The utility in PDAC was studied in a genetically engineered mouse model carrying Kras and p53 mutations, which develops spontaneous tumors and keeps the desmoplasia and hypovascularity feature of PDAC in patients. The AuNR-SiO2-Gd NPs were highly accumulated in the surrounding soft tissues but were sparsely distributed throughout the tumor due to dense stroma infiltration and poor tumor vascularization. Hence, a negative contrast within the tumor area in CT/PAI and a positive contrast in MRI were observed. In conclusion, AuNR-SiO2-Gd NPs have good potential to be developed as a multimodal contrast agent for PDAC, which might improve early diagnosis and benefit the clinical outcome for PDAC patients.

  • 125.
    Zhou, Jing
    et al.
    University of Tampere.
    Zhang, Weikai
    University of Tampere.
    Poe, Dennis
    University of Tampere.
    Qin, Jian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Fornara, Andrea
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Zhang, Ya
    University of Tampere.
    Ramadan, Usama
    University of Helsinki.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Pyykkö, Ilmari
    University of Tampere.
    MRI manifestation of novel superparamagnetic iron oxide nanoparticles in the rat inner ear2010In: Nanomedicine, ISSN 1743-5889, Vol. 5, no 5, p. 739-754Article in journal (Refereed)
    Abstract [en]

    Aim: Superparamagnetic iron oxide nanoparticles hierarchically coated with oleic acid and Pluronic F127 copolymers (POA@SPION) have shown exceptional 12 contrast enhancement. The aim of the present work was to investigate the MRI manifestation of POA@SPION in the inner ear. Materials & methods: A total of 26 male Wister rats were selected for testing POA@SPION administered through intracochlear, intratympanic and intravenous routes. MRI was performed with a 4.7 T MR scanner. Results & conclusion: POA@SPION can be introduced into the perilymph space, after which it becomes widely distributed and can demonstrate the integrity of the perilymph-endolymph barrier. Positive highlighting of the endolymph compartment against the darkened perilymph was visualized for the first time. POA@SPION passed through the middle-inner ear barriers in only small amounts, but stayed in the perilymph for 3 days. They did not traverse the blood-perilymph barrier or blood-endolymph barrier. The inner ear distribution of POA@SPION was confirmed by histology. POA@SPION is a promising T2 negative contrast agent.

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