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  • 1.
    Al-Soubaihi, Rola
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Saoud, K. M.
    Virginia Commonwealth University in Qatar, Libral Arts and Sciences Program, P.O. Box 8095, Doha, Qatar.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Zar Myint, M. T.
    Department of Physics, College of Science, Sultan Qaboos University, P.O. Box 36, Muscat, PC 123, Oman.
    Saeed, S.
    Department of Chemistry, Paksitan Institute of Engineering and Applied Sciences (PIEAS), PO Nilore, Islamabad, 45650, Pakistan.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Synthesis of hierarchically porous silica aerogel supported Palladium catalyst for low-temperature CO oxidation under ignition/extinction conditions2020In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 292, article id 109758Article in journal (Refereed)
    Abstract [en]

    Synthesis of well-dispersed palladium nanoparticles within silica aerogel pores with controlled size was carried out using sol-gel synthesis under supercritical ethanol drying. The high concentration of silanol groups on silica (SiO2) surface facilitated a superior palladium (Pd) loading up to 10 wt %. The synthesized Pd/SiO2 nanocomposite aerogels were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopic methods. The silica aerogel supported catalysts were found to have a wide pore size distribution. TEM investigations confirmed that Pd nanocrystals were located within the SiO2 microspores and mesopores. The catalyst was evaluated for carbon monoxide (CO) oxidation reaction under ignition/extinction conditions. The synthesized catalyst demonstrated a high catalytic activity at low operating temperatures (<200 °C) compared to unsupported Pd nanoparticles or bare SiO2 aerogels. This enhancement in CO oxidation activity with Pd/SiO2 aerogel catalysts are attributed to the small Pd particles, Pd interaction with the surface of the underlying SiO2 and the better dispersion of Pd particles within the SiO2 pores. Porosity played a more important role during the extinction cycle as a result of the slow dissipation of the heat leading to hysteresis. We demonstrate the influence of porosity of catalyst supports on the size, dispersion, and catalytic activity of Pd nanoparticles.

  • 2.
    Alvarado Ávila, María Isabel
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    De Luca, Stefano
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Edlund, Ulrica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Cellulose as sacrificial agents for enhanced photoactivated hydrogen production2023In: Sustainable Energy & Fuels, E-ISSN 2398-4902, Vol. 7, no 8, p. 1981-1991Article in journal (Refereed)
    Abstract [en]

    The search for new energy sources together with the need to control greenhouse gas emissions has led to continued interest in low-emitting renewable energy technologies. In this context, water splitting for hydrogen production is a reasonable alternative to replace fossil fuels due to its high energy density producing only water during combustion. Cellulose is abundant in nature and as residuals from human activity, and therefore a natural, ecological, and carbon-neutral source for hydrogen production. In the present work, we propose a sustainable method for hydrogen production using sunlight and cellulose as sacrificial agents during the photocatalytic water splitting process. Platinum (Pt) catalyst activates hydrogen production, and parameters such as pH of the system, cellulose concentration, and Pt loading were studied. Using different biomasses, we found that the presence of hemicellulose and xyloglucan as part of the molecular composition considerably increased the H-2 production rate from 36 mu mol L-1 in one hour for rapeseed cellulose to 167.44 mu mol L-1 for acid-treated cellulose isolated from Ulva fenestrata algae. Carboxymethylation and TEMPO-oxidation of cellulosic biomass both led to more stable suspensions with higher rates of H-2 production close to 225 mu mol L-1, which was associated with their water solubility properties. The results suggest that cellulosic biomass can be an attractive alternative as a sacrificial agent for the photocatalytic splitting of water for H-2 production.

  • 3. Andõn, F. T.
    et al.
    Kapralov, A. A.
    Yanamala, N.
    Feng, W.
    Baygan, Arjang
    Karolinska Institutet.
    Chambers, B. J.
    Hultenby, K.
    Ye, Fei
    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.
    Brandner, B. D.
    Fornara, Andrea
    Institute for Surface Chemistry, Stockholm.
    Klein-Seetharaman, J.
    Kotchey, G. P.
    Star, A.
    Shvedova, Anna A.
    West Virginia University, USA.
    Fadeel, B.
    Kagan, V. E.
    Biodegradation of Single-Walled Carbon Nanotubes by Eosinophil Peroxidase2013In: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 9, no 16, p. 2721-2729Article in journal (Refereed)
    Abstract [en]

    Eosinophil peroxidase (EPO) is one of the major oxidant-producing enzymes during inflammatory states in the human lung. The degradation of single-walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H2O 2 is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H2O2 alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV-visible-NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials. Human eosinophil peroxidase (EPO) is able to degrade SWCNTs in vitro in the presence of H2O2. EPO is one of the major oxidant-generating enzymes present in human lungs during inflammatory states. The biodegradation of SWCNTs is evidenced also in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. These results are relevant to potential respiratory exposure to carbon nanotubes.

  • 4.
    Bahari, Helma Sadat
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Univ Tehran, Coll Sci, Sch Phys, North Kargar St, POB 14395-547, Tehran, Iran..
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Toledo-Carrillo, Esteban Alejandro
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Leliopoulos, Christos
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Savaloni, Hadi
    Univ Tehran, Coll Sci, Sch Phys, North Kargar St,POB 14395-547, Tehran, Iran..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Chitosan nanocomposite coatings with enhanced corrosion inhibition effects for copper2020In: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 162, p. 1566-1577Article in journal (Refereed)
    Abstract [en]

    A biopolymer coating on copper was prepared based on chitosan nanocomposite and its corrosion inhibition efficiency was investigated. Inclusion of silica nanoparticles substantially reduces swelling ratio of chitosan coating while enhancing its thermal stability. The corrosion resistance of chitosan-based coatings is improved by introducing 2-mercaptobenzothiazole and silica in the matrix. It is found that upon crosslinking the chitosan coatings, a higher corrosion resistance could be achieved and the highest inhibition efficiency for chitosan nanocomposite coatings is calculated as 85%. The corrosion mechanism is found closely related to mass transition and diffusion process, and also the polarization resistance contributes to the impedance. Calculated impedance using Kramers-Kronig transformation shows good agreement with experimental values, thus validating the impedance measurements. This study exhibits the enhanced efficiency of nanocomposite and potential of chitosan coatings in corrosion prevention for copper.

  • 5. Barrefelt, Åsa
    et al.
    Saghafian, Maryam
    Kuiper, Raoul
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Egri, Gabriella
    Klickermann, Moritz
    Brismar, Torkel B.
    Aspelin, Peter
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Daehne, Lars
    Hassan, Moustapha
    Biodistribution, kinetics, and biological fate of SPION microbubbles in the rat2013In: International Journal of Nanomedicine, ISSN 1176-9114, E-ISSN 1178-2013, Vol. 8, p. 3241-3254Article in journal (Refereed)
    Abstract [en]

    Background: In the present investigation, we studied the kinetics and biodistribution of a contrast agent consisting of poly(vinyl alcohol) (PVA) microbubbles containing superparamagnetic iron oxide (SPION) trapped between the PVA layers (SPION microbubbles). Methods: The biological fate of SPION microbubbles was determined in Sprague-Dawley rats after intravenous administration. Biodistribution and elimination of the microbubbles were studied in rats using magnetic resonance imaging for a period of 6 weeks. The rats were sacrificed and perfusion-fixated at different time points. The magnetic resonance imaging results obtained were compared with histopathologic findings in different organs. Results: SPION microbubbles could be detected in the liver using magnetic resonance imaging as early as 10 minutes post injection. The maximum signal was detected between 24 hours and one week post injection. Histopathology showed the presence of clustered SPION microbubbles predominantly in the lungs from the first time point investigated (10 minutes). The frequency of microbubbles declined in the pulmonary vasculature and increased in pulmonary, hepatic, and splenic macrophages over time, resulting in a relative shift from the lungs to the spleen and liver. Meanwhile, macrophages showed increasing signs of cytoplasmic iron accumulation, initially in the lungs, then followed by other organs. Conclusion: The present investigation highlights the biological behavior of SPION microbubbles, including organ distribution over time and indications for biodegradation. The present results are essential for developing SPION microbubbles as a potential contrast agent and/or a drug delivery vehicle for specific organs. Such a vehicle will facilitate the use of multimodality imaging techniques, including ultrasound, magnetic resonance imaging, and single positron emission computed tomography, and hence improve diagnostics, therapy, and the ability to monitor the efficacy of treatment.

  • 6. Ciobanu, V.
    et al.
    Ceccone, G.
    Jin, I.
    Braniste, T.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Fumagalli, F.
    Colpo, P.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Linnros, Jan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Tiginyanu, I.
    Large-Sized Nanocrystalline Ultrathin β-Ga2 O3 Membranes Fabricated by Surface Charge Lithography2022In: Nanomaterials, E-ISSN 2079-4991, Vol. 12, no 4, article id 689Article in journal (Refereed)
    Abstract [en]

    Large-sized 2D semiconductor materials have gained significant attention for their fascinat-ing properties in various applications. In this work, we demonstrate the fabrication of nanoperforated ultrathin β-Ga2 O3 membranes of a nanoscale thickness. The technological route includes the fabrication of GaN membranes using the Surface Charge Lithography (SCL) approach and subsequent thermal treatment in air at 900◦ C in order to obtain β-Ga2 O3 membranes. The as-grown GaN membranes were discovered to be completely transformed into β-Ga2 O3, with the morphology evolving from a smooth topography to a nanoperforated surface consisting of nanograin structures. The oxidation mechanism of the membrane was investigated under different annealing conditions followed by XPS, AFM, Raman and TEM analyses. 

  • 7.
    Dai, Jin
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Light absorber based on nano-spheres on a substrate reflector2013In: Optics Express, E-ISSN 1094-4087, Vol. 21, no 6, p. 6697-6706Article in journal (Refereed)
    Abstract [en]

    We systematically study a type of plasmonic light absorber based on a monolayer of gold nano-spheres with less than 30 nm in diameters deposited on top of a continuous gold substrate. The influences of particle size, inter-particle distance, particle-substrate spacer size etc on the resonance are studied thoroughly with a 3D finite-element method. We identified that the high-absorption resonance is mainly due to gap plasmon (coupled through particle bodies) when the separation between neighboring nano-spheres is small enough, such as close to 1 nm; at larger particle separations, the resonance is dominated by particle dipoles (coupled through the host dielectric). Experimentally, an absorber was fabricated based on chemically-synthesized gold nanoparticles coated with silica shell. The absorber shows a characteristic absorption band around 810 nm with a maximum absorbance of approximately 90%, which agrees reasonably well with our numerical calculation. The fabrication technique can be easily adapted for devising efficient light absorbers of large areas.

  • 8. Das, B.
    et al.
    Toledo-Carrillo, Esteban Alejandro
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Li, L.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Chen, J.
    Slabon, A.
    Verho, O.
    Eriksson, L.
    Göthelid, Mats
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Åkermark, B.
    Cobalt Electrocatalyst on Fluorine Doped Carbon Cloth – a Robust and Partially Regenerable Anode for Water Oxidation2022In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 14, no 18, article id e202200538Article in journal (Refereed)
    Abstract [en]

    The low stability of the electrocatalysts at water oxidation (WO) conditions and the use of expensive noble metals have obstructed large-scale H2 production from water. Herein, we report the electrocatalytic WO activity of a cobalt-containing, water-soluble molecular WO electrocatalyst [CoII(mcbp)(OH2)] (1) [mcbp2−=2,6-bis(1-methyl-4-(carboxylate)benzimidazol-2-yl)pyridine] in homogeneous conditions (overpotential of 510 mV at pH 7 phosphate buffer) and after anchoring it on pyridine-modified fluorine-doped carbon cloth (PFCC). The formation of cobalt phosphate was identified only after 4 h continuous oxygen evolution in homogeneous conditions. Interestingly, a significant enhancement of the stability and WO activity (current density of 5.4 mA/cm2 at 1.75 V) was observed for 1 after anchoring onto PFCC, resulting in a turnover (TO) of >3.6×103 and average TOF of 0.05 s−1 at 1.55 V (pH 7) over 20 h. A total TO of >21×103 over 8 days was calculated. The electrode allowed regeneration of∼ 85 % of the WO activity electrochemically after 36 h of continuous oxygen evolution. 

  • 9.
    Das, Biswanath
    et al.
    Department of Organic Chemistry, Arrhenius Laboratory Stockholm University, Svante Arrhenius väg 16C Stockholm 10691 Sweden, Svante Arrhenius väg 16C.
    Toledo-Carrillo, Esteban Alejandro
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Li, Guoqi
    School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210 China.
    Ståhle, Jonas
    Department of Organic Chemistry, Arrhenius Laboratory Stockholm University, Svante Arrhenius väg 16C Stockholm 10691 Sweden, Svante Arrhenius väg 16C.
    Thersleff, Thomas
    Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius väg 16C Stockholm 10691 Sweden, Svante Arrhenius väg 16C.
    Chen, Jianhong
    Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius väg 16C Stockholm 10691 Sweden, Svante Arrhenius väg 16C.
    Li, Lin
    School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210 China.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Slabon, Adam
    Inorganic Chemistry, University of Wuppertal Gaußstr. 20, Wuppertal 42119 Germany.
    Göthelid, Mats
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Weng, Tsu Chien
    School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210 China.
    Yuwono, Jodie A.
    School of Chemical Engineering, University of New South Wales, Sydney 2052 Australia.
    Kumar, Priyank V.
    School of Chemical Engineering, University of New South Wales, Sydney 2052 Australia.
    Verho, Oscar
    Department of Medicinal Chemistry, Biomedicinskt Centrum BMC, Uppsala University, SE-75123 Uppsala Sweden.
    Kärkäs, Markus D.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Åkermark, Björn
    Department of Organic Chemistry, Arrhenius Laboratory Stockholm University, Svante Arrhenius väg 16C Stockholm 10691 Sweden, Svante Arrhenius väg 16C.
    Bifunctional and regenerable molecular electrode for water electrolysis at neutral pH2023In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 11, no 25, p. 13331-13340Article in journal (Refereed)
    Abstract [en]

    The instability of molecular electrodes under oxidative/reductive conditions and insufficient understanding of the metal oxide-based systems have slowed down the progress of H2-based fuels. Efficient regeneration of the electrode's performance after prolonged use is another bottleneck of this research. This work represents the first example of a bifunctional and electrochemically regenerable molecular electrode which can be used for the unperturbed production of H2 from water. Pyridyl linkers with flexible arms (-CH2-CH2-) on modified fluorine-doped carbon cloth (FCC) were used to anchor a highly active ruthenium electrocatalyst [RuII(mcbp)(H2O)2] (1) [mcbp2− = 2,6-bis(1-methyl-4-(carboxylate)benzimidazol-2-yl)pyridine]. The pyridine unit of the linker replaces one of the water molecules of 1, which resulted in RuPFCC (ruthenium electrocatalyst anchored on -CH2-CH2-pyridine modified FCC), a high-performing electrode for oxygen evolution reaction [OER, overpotential of ∼215 mV] as well as hydrogen evolution reaction (HER, overpotential of ∼330 mV) at pH 7. A current density of ∼8 mA cm−2 at 2.06 V (vs. RHE) and ∼−6 mA cm−2 at −0.84 V (vs. RHE) with only 0.04 wt% loading of ruthenium was obtained. OER turnover of >7.4 × 103 at 1.81 V in 48 h and HER turnover of >3.6 × 103 at −0.79 V in 3 h were calculated. The activity of the OER anode after 48 h use could be electrochemically regenerated to ∼98% of its original activity while it serves as a HE cathode (evolving hydrogen) for 8 h. This electrode design can also be used for developing ultra-stable molecular electrodes with exciting electrochemical regeneration features, for other proton-dependent electrochemical processes.

  • 10.
    Doddapaneni, Venkatesh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Gati, R.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    On the electrical arc interruption by using PMMA/iron oxide nanocomposites2016In: Materials Research Express, E-ISSN 2053-1591, Vol. 3, no 10, article id 105043Article in journal (Refereed)
    Abstract [en]

    An experimental study is undertaken on the fabrication of poly (methyl methacrylate) (PMMA)/iron oxide nanocomposites to determine their potential use for electrical arc interruption in the electrical switching applications such as circuit breakers. Monodisperse iron oxide nanoparticles of average size ¡«11 nmare synthesized via thermal decomposition method and then homogeneously dispersed in the PMMAmatrix by in situ polymerization.PMMA/iron oxide nanocomposites with different nanoparticle loading have been fabricated to study the effect of loading content on the thermal energy absorption. Detailed physicochemical characterizations on synthesized material are performed using X-ray powder diffraction, scanning electron microscopy, TEM, thermogravimetric analysis and differential scanning calorimetry at different processing stages. Atest-setup was designed to evaluate the quality of the nanocomposites for electric arc interruption capability. The results showed that PMMA/iron oxide nanocomposites have a clear impact on the electric arc interruption and therefore should be considered as promising candidates for electrical switching applications.

  • 11.
    Doddapaneni, Venkatesh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Gati, R.
    Toprak, Muhammet Sadaka
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Engineered PMMA-ZnO nanocomposites for improving the electric arc interruption capability in electrical switching applications: Unprecedented experimental insights2017In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 141, p. 113-119Article in journal (Refereed)
    Abstract [en]

    Polymer inorganic nanocomposites (PINCs) have been engineered for controlling the electrical arc and to improve the arc interruption capability of the electrical switching applications, like circuit breakers. Several PINCs are fabricated by formation of ZnO quantum dots (QDs) in a poly (methyl methacrylate) (PMMA) matrix via in-situ polymerization method to avoid agglomeration of QDs, leading to a good spatial distribution of QDs in the polymer matrix. These PINCs have been characterized in detail for the morphology of QDs, interaction between QDs and polymer matrix, and ultraviolet (UV) radiation absorption. ZnO QDs have been assessed to have particle diameter of 3.5 nm, and their presence in the PMMA is revealed by the unique luminescence characteristics of the QDs under UV light. The presence of ZnO QDs broadened the range of UV radiation absorption of PMMA and the absorption edge is gradually shifted from 270 nm to 338 nm with step-wise loading of ZnO QDs. The PINCs are tested to determine their reproducibility and impact on the electrical arcs of current 1.6 kA generated using a specially designed test-setup. Interaction of PINCs with the electrical arcs generates ablation of chemical species towards core of the electrical arc, resulting in increase of voltage leading to cool-down the arc temperature. This experimental study demonstrates for the first time that these PINCs are reproducible, reliable and provides superior arc interruption capability.

  • 12.
    Doddapaneni, Venkatesh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Gati, Rudolf
    ABB Switzerland.
    Toprak, Muhammet Sadaka
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    New experimental insights for controlling the electrical arcs in electrical switching applications: a comparative study on PMMA nanocomposites of Au and ZnO2017In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050Article in journal (Other academic)
    Abstract [en]

    Polymer inorganic nanocomposites (PINCs) are developed, not only due to scientific interest but also improving theelectric arc interruption process in the electrical switching applications like circuit breakers. The novelty of this work isin integrating the current developments in PINCs into electrical switching application in order to extend the limits of thepower switching devices. Several PINCs are fabricated by using pre-synthesized Au nanoparticles (NPs) of size 2.75 ±0.4 nm and poly (methyl methacrylate) (PMMA) matrix via in-situ polymerization method. Six homogeneous PINCsamples with ultra-low wt% of Au NPs varying from 0.0003 to 0.005 wt% have been fabricated. We find that thepresence of Au NPs improved the convective heat transfer and visible optical radiation absorption of PMMA. Thefabricated PINCs are tested for their arc interruption performance and the results are compared with ZnO PINCs in ourearlier work. The results of the experiments insights demonstrate the impact of PINCs on the electrical arcs and theirpotential advantages of having PINCs for the electric arc interruption process in high power switching devices.

  • 13.
    Doddapaneni, Venkatesh
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Zhao, Yichen
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Gati, R.
    Edin, Hans
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Improving Uv Radiation Absorption by Copper Oxide NPs/PMMA Nanocomposites for Electrical Switching Applications2015In: Powder metallurgy and metal ceramics, ISSN 1068-1302, E-ISSN 1573-9066, Vol. 54, no 7-8, p. 397-401Article in journal (Refereed)
    Abstract [en]

    Nanocomposites based on the radiation absorbing polymer (PNCs) are of interest for a variety of applications including circuit breakers, UV-shielding windows, contact lenses, and glasses among others. Such PNCs can be made by incorporating suitable radiation absorbing nanoparticles into a polymeric matrix by in situ polymerization. In this study, spherical nanoparticles (5-6 nm) of oleic acid (OA) surface modified cupric oxide (CuO) are synthesized and used to improve the ultra-violet (UV) radiation absorption property of a polymer matrix, i.e., polymethylmethacrylate (PMMA). The synthesis of spherical CuO nanoparticles, surface modification using OA, dispersion of CuO nanoparticles with different concentrations in PMMA, and UV radiation absorption property of the resultant PNC are investigated. Two different PNCs are produced using OA modified CuO nanoparticles with different concentrations. As synthesized CuO nanoparticles and OA modified CuO nanoparticles are examined by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) techniques. The UV absorption edges are evaluated from the UV-Vis absorption spectra by using UV-Visible absorption spectroscopy. The results show that the UV radiation absorption of the PNC with higher concentration of CuO nanoparticles is improved compared with PMMA and the absorption edge moved towards longer wavelengths i.e., from 271 to 281 nm. These PNCs are successful in arc interruption process by absorbing a broad range of radiation emitted from high-energy copper arcs produced in the circuit breakers.

  • 14.
    Dong, Lin
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Hu, Jun
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. Zhejiang University, China.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Friberg, Ari T.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. Helsinki University of Technology, Finland.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Influence of nanoparticles concentration on fluorescence quenching in gold/rhodamine 6G nanoassemblies2009In: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009, Optical Society of America, 2009, p. 5377045-Conference paper (Refereed)
    Abstract [en]

    Fluorescence enhancement of dye solution doped with gold nanoparticles is a well-known effect. However, depending on size and concentration, nanoparticles can also deteriorate dye lasing properties due to increased quenching of the excited molecules. Here we report experimental results on such dependence of fluorescence degradation on the nanoparticle concentration.

  • 15.
    Dong, Lin
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Chughtai, Adnan
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Liuolia, Vytautas
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Friberg, Ari T.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Lasing From Water Solution of Rhodamine 6G/Gold Nanoparticles: Impact of SiO2-Coating on Metal Surface2012In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 48, no 9, p. 1220-1226Article in journal (Refereed)
    Abstract [en]

    Gold nanoparticles embedded in an optical gain material, particularly in a water solution of Rhodamine 6G, used in dye lasers can both increase and damp dye flourescence, thus changing the laser output intensity. Simultaneously, such nanoparticles influence the gain material's resistance against photobleaching. In this paper, we report our study on the impact of the SiO2 coating of nanoparticles on the enhancement or quenching and photobleaching of the fluorescence. The investigation demonstrates a noticeable improvement of the gain material's photostability compared to uncoated gold nanoparticles when silicon dioxide coating is implemented.

  • 16.
    Dong, Lin
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Chughtai, Adnan
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Friberg, Ari T.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Enhanced photostability of aqueous solution of Rhodamine 6G with gold nanoparticles in lasing process by silica coating2012In: 2012 Conference on Lasers and Electro-Optics, CLEO 2012, IEEE , 2012, p. 6325399-Conference paper (Refereed)
    Abstract [en]

    Gold nanoparticles are mixed in aqueous solution of Rhodamine 6G to modify the lasing output intensity. The photostability deterioration of the gain medium by gold nanoparticles is successfully compensated by silica coating on the nanoparticles.

  • 17.
    Dong, Lin
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Chughtai, Adnan
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Friberg, Ari T.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Photostability of lasing process from water solution of Rhodamine 6G with gold nanoparticles2012In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 37, no 1, p. 34-36Article in journal (Refereed)
    Abstract [en]

    We report the lasing performance and photobleaching of gain material containing a water solution of Rhodamine 6G dye and gold nanoparticles (NPs). In comparison to a pure dye solution, the investigated material demonstrated both enhancement and quenching of the lasing output, depending on the relative concentration of the gold NPs. Although the presence of NPs with an optimized concentration looks preferable in terms of the lasing output enhancement, such additives deteriorate the operational resource of the gain material; i.e., the photobleaching rate speeds up.

  • 18.
    Dong, Lin
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Hu, Jun
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Friberg, Ari T.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Fluorescence quenching and photobleaching in Au/Rh6G nanoassemblies: impact of competition between radiative and non-radiative decay2011In: Journal of the European Optical Society-Rapid Publications, E-ISSN 1990-2573, Vol. 6, p. 11019-Article in journal (Refereed)
    Abstract [en]

    We report the study of fluorescence quenching from nanoassemblies formed by Rhodamine 6G and gold nanoparticles (Au NPs) of 2.6 nm radius. The presence of Au NPs induces long-term degradation of the photostability (photobleaching) of Rhodamine 6G used as a gain medium in a Fabry-Perot laser cavity. We found that the degradation gets profound when the Au NPs concentration is significantly increased. Calculation of the radiative rate and direct time-resolved measurement of the fluorescence decay indicates that both the decrease of radiative decay rate and increase of non-radiative decay rate are responsible for the fluorescence quenching and photostability degradation. An energy transfer from the dye molecules to gold nanoparticles is dominating within small distance between them and suppresses the quantum efficiency of Rhodamine 6G drastically. In a long time scale, the photobleaching rate was slowing down, and the laser output intensity reached a stabilized level which depends on the gold nanoparticles concentration.

  • 19.
    Falfushynska, Halina I.
    et al.
    Univ Rostock, Inst Biol Sci, Dept Marine Biol, Rostock, Germany.;Ternopil V Hnatiuk Natl Pedagog Univ, Dept Human Hlth Phys Rehabil & Vital Act, Ternopol, Ukraine..
    Wu, Fangli
    Univ Rostock, Inst Biol Sci, Dept Marine Biol, Rostock, Germany..
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Kasianchuk, Nadiia
    Ternopil V Hnatiuk Natl Pedagog Univ, Dept Human Hlth Phys Rehabil & Vital Act, Ternopol, Ukraine..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dobretsov, Sergey
    Sultan Qaboos Univ, Coll Agr & Marine Sci, Dept Marine Sci & Fisheries, Al Khoud 123,POB 34, Muscat, Oman.;Sultan Qaboos Univ, Ctr Excellence Marine Biotechnol, Al Khoud 123,POB 50, Muscat, Oman..
    Sokolova, Inna M.
    Univ Rostock, Inst Biol Sci, Dept Marine Biol, Rostock, Germany.;Univ Rostock, Dept Marine Syst, Interdisciplinary Fac, Rostock, Germany..
    The effects of ZnO nanostructures of different morphology on bioenergetics and stress response biomarkers of the blue mussels Mytilus edulis2019In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 694, article id UNSP 133717Article in journal (Refereed)
    Abstract [en]

    Biofouling causes massive economical losses in the maritime sector creating an urgent need for effective and ecologically non-harmful antifouling materials. Zinc oxide (ZnO) nanorod coatings show promise as an antifouling material; however, the toxicity of ZnO nanorods to marine organisms is not known. We compared the toxicity of suspended ZnO nanorods (NR) with that of ZnO nanoparticles (NP) and ionic Zn2+ in amarine bivalve Mytilus edulis exposed for two weeks to 10 or 100 mu g Zn L-1 of ZnO NPs, NRs or Zn2+, or to immobilized NRs. The multi-biomarker assessment included bioenergetics markers (tissue energy reserves, activity ofmitochondrial electron transport system and autophagic enzymes), expression of apoptotic and inflammatory genes, and general stress biomarkers (oxidative lesions, lysosomalmembrane stability and metallothionein expression). Exposure to ZnO NPs, NRs and Zn2+ caused accumulation of oxidative lesions in proteins and lipids, stimulated autophagy, and led to lysosomal membrane destabilization indicating toxicity. However, these responses were not specific for the form of Zn (NPs, NR or Zn2+) and showed no monotonous increase with increasing Zn concentrations in the experimental exposures. No major disturbance of the energy status was found in the mussels exposed to ZnO NPs, NRs, or Zn2+. Exposure to ZnO NPs and NRs led to a strong induction of apoptosis- and inflammation-related genes, which was not seen in Zn2+ exposures. Based on the integrated biomarker response, the overall toxicity as well as the pro-apoptotic and pro-inflammatory action was stronger in ZnO NPs compared with the NRs. Given the stability of ZnO NR coatings and the relatively low toxicity of suspended ZnO NR, ZnO NR coating might be considered a promising low-toxicity material for antifouling paints.

  • 20.
    Fornara, Andrea
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Recalenda, Alberto
    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.
    Sugunan, Abhilash
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Fei, Ye
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Laurent, Sophie
    University of Mons.
    Muller, Robert
    University of Mons.
    Zou, Jing
    University of Tampere.
    Usama, Abo-RAmadan
    University of Helsinki.
    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.
    Polymeric/inorganic multifunctional nanoparticles for simultaneous drug delivery and visualization2010In: Materials Research Society Symposium Proceedings, ISSN 0272-9172, E-ISSN 1946-4274, Vol. 1257Article in journal (Refereed)
    Abstract [en]

    Nanoparticles consisting of different biocompatible materials are attracting a lot of interest in the biomedical area as useful tools for drug delivery, photo-therapy and contrast enhancement agents in MRI, fluorescence and confocal microscopy. This work mainly focuses on the synthesis of polymeric/inorganic multifunctional nanoparticles (PIMN) based on biocompatible di-block copolymer poly(L,L-lactide-co-ethylene glycol) (PLLA-PEG) via an emulsion-evaporation method. Besides containing a hydrophobic drug (Indomethacin), these polymeric nanoparticles incorporate different visualization agents such as superparamagnetic iron oxide nanoparticles (SPION) and fluorescent Quantum Dots (QDs) that are used as contrast agents for Magnetic Resonance Imaging (MRI) and fluorescence microscopy together. Gold Nanorods are also incorporated in such nanostructures to allow simultaneous visualization and photodynamic therapy. MRI studies are performed with different loading of SPION into PIMN, showing an enhancement in T2 contrast superior to commercial contrast agents. Core-shell QDs absorption and emission spectra are recorded before and after their loading into PIMN. With these polymeric/inorganic multifunctional nanoparticles, both MRI visualization and confocal fluorescence microscopy studies can be performed. Gold nanorods are also synthesized and incorporated into PIMN without changing their longitudinal absorption peak usable for lased excitation and phototherapy. In-vitro cytotoxicity studies have also been performed to confirm the low cytotoxicity of PIMN for further in-vivo studies.

  • 21.
    Kumar, Santosh
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Department of Food Engineering and Technology, Central Institute of Technology Kokrajhar, BTR, Assam, India.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dobretsov, S.
    Department of Marine Science and Fisheries, Sultan Qaboos University, Muscat, Oman ; Center of Excellence in Marine Biotechnology, Sultan Qaboos University, Muscat, Oman.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Nanocoating Is a New Way for Biofouling Prevention2021In: Frontiers in Nanotechnology, ISSN 2673-3013, Vol. 3, article id 771098Article in journal (Refereed)
    Abstract [en]

    Biofouling is a major concern to the maritime industry. Biofouling increases fuel consumption, accelerates corrosion, clogs membranes and pipes, and reduces the buoyancy of marine installations, such as ships, platforms, and nets. While traditionally marine installations are protected by toxic biocidal coatings, due to recent environmental concerns and legislation, novel nanomaterial-based anti-fouling coatings are being developed. Hybrid nanocomposites of organic-inorganic materials give a possibility to combine the characteristics of both groups of material generating opportunities to prevent biofouling. The development of bio-inspired surface designs, progress in polymer science and advances in nanotechnology is significantly contributing to the development of eco-friendly marine coatings containing photocatalytic nanomaterials. The review mainly discusses photocatalysis, antifouling activity, and formulation of coatings using metal and metal oxide nanomaterials (nanoparticles, nanowires, nanorods). Additionally, applications of nanocomposite coatings for inhibition of micro- and macro-fouling in marine environments are reviewed.

  • 22.
    Kumar, Santosh
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Cent Inst Technol, Dept Food Engn & Technol, Kokrajhar 783370, India.;KTH Royal Inst Technol, Funct Mat Grp, Dept Appl Phys, Sch Engn Sci, Hannes Alfvens Vag 12, S-11419 Stockholm, Sweden..
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Mazinani, Babak
    Malayer Univ, Dept Mat Engn, Malayer 6571995863, Iran..
    Dobretsov, Sergey
    Sultan Qaboos Univ, Dept Marine Sci, POB 34, Muscat 123, Oman.;Sultan Qaboos Univ, Ctr Excellence Marine Biotechnol, POB 50, Muscat 123, Oman..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Chitosan Nanocomposite Coatings Containing Chemically Resistant ZnO-SnOx Core-shell Nanoparticles for Photocatalytic Antifouling2021In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 22, no 9, article id 4513Article in journal (Refereed)
    Abstract [en]

    Functional nanocomposites with biopolymers and zinc oxide (ZnO) nanoparticles is an emerging application of photocatalysis in antifouling coatings. The reduced chemical stability of ZnO in the acidic media in which chitosan is soluble affects the performance of chitosan nanocomposites in antifouling applications. In this study, a thin shell of amorphous tin dioxide (SnOx) was grown on the surface of ZnO to form ZnO-SnOx core-shell nanoparticles that improved the chemical stability of the photocatalyst nanoparticles, as examined at pH 3 and 6. The photocatalytic activity of ZnO-SnOx in the degradation of methylene blue (MB) dye under visible light showed a higher efficiency than that of ZnO nanoparticles due to the passivation of electronic defects. Chitosan-based antifouling coatings with varying percentages of ZnO or ZnO-SnOx nanoparticles, with or without the glutaraldehyde (GA) crosslinking of chitosan, were developed and studied. The incorporation of photocatalysts into the chitosan matrix enhanced the thermal stability of the coatings. Through a mesocosm study using running natural seawater, it was found that chitosan/ZnO-SnOx/GA coatings enabled better inhibition of bacterial growth compared to chitosan coatings alone. This study demonstrates the antifouling potential of chitosan nanocomposite coatings containing core-shell nanoparticles as an effective solution for the prevention of biofouling.

  • 23.
    Kunzmann, Andrea
    et al.
    Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
    Andersson, Britta
    Clinical Allergy Research Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.
    Vogt, Carmen
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Feliu, Neus
    Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Gabrielsson, Susanne
    Clinical Allergy Research Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Buerki-Thurnherr, Tina
    Labortory for Materials, Biology Interactions, Swiss Federal Laboratories of Materials Testing and Research, St. Gallen, Switzerland.
    Laurent, Sophie
    NMR and Molecular Imaging Laboratory, Department of General, Organic and Biomedical Chemistry, University of Mons, Belgium.
    Vahter, Marie
    Krug, Harald
    Division of Metals and Health, Institute of Environmental Medicine, Karolinska Insitutetet, Stockholm, Sweden.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Scheynius, Annika
    Clinical Allergy Research Unit, Department of Medicine, Karolinska Institutet and Universty Hospital Solan, Sweden.
    Fadeel, Bengt
    Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
    Efficient internalization of silica-coated iron oxide nanoparticles of different sizes by primary human macrophages and dendritic cells2011In: Toxicology and Applied Pharmacology, ISSN 0041-008X, E-ISSN 1096-0333, Vol. 253, no 2, p. 81-93Article in journal (Refereed)
    Abstract [en]

    Engineered nanoparticles are being considered for a wide range of biomedical applications, from magnetic resonance imaging to "smart" drug delivery systems. The development of novel nanomaterials for biomedical applications must be accompanied by careful scrutiny of their biocompatibility. In this regard, particular attention should be paid to the possible interactions between nanoparticles and cells of the immune system, our primary defense system against foreign invasion. On the other hand, labeling of immune cells serves as an ideal tool for visualization, diagnosis or treatment of inflammatory processes, which requires the efficient internalization of the nanoparticles into the cells of interest. Here, we compare novel monodispersed silica-coated iron oxide nanoparticles with commercially available dextran-coated iron oxide nanoparticles. The silica-coated iron oxide nanoparticles displayed excellent magnetic properties. Furthermore, they were nontoxic to primary human monocyte-derived macrophages at all doses tested whereas dose-dependent toxicity of the smaller silica-coated nanoparticles (30 nm and 50 nm) was observed for primary monocyte-derived dendritic cells, but not for the similarly small dextran-coated iron oxide nanoparticles. No macrophage or dendritic cell secretion of pro-inflammatory cytokines was observed upon administration of nanoparticles. The silica-coated iron oxide nanoparticles were taken up to a significantly higher degree when compared to the dextran-coated nanoparticles, irrespective of size. Cellular internalization of the silica-coated nanoparticles was through an active, actin cytoskeleton-dependent process. We conclude that these novel silica-coated iron oxide nanoparticles are promising materials for medical imaging, cell tracking and other biomedical applications. (C) 2011 Elsevier Inc. All rights reserved.

  • 24.
    Li, Jiantong
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Vaziri, Sam
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Lemme, Max C.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    A simple route towards high-concentration surfactant-free graphene dispersions2012In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 50, no 8, p. 3113-3116Article in journal (Refereed)
    Abstract [en]

    A simple solvent exchange method is introduced to prepare high-concentration and surfactant-free graphene liquid dispersion. Natural graphite flakes are first exfoliated into graphene in dimethylformamide (DMF). DMF is then exchanged by terpineol through distillation, relying on their large difference in boiling points. Graphene can then be concentrated thanks to the volume difference between DMF and terpineol. The concentrated graphene dispersions are used to fabricate transparent conductive thin films, which possess comparable properties to those prepared by more complex methods.

  • 25.
    Li, Jiantong
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Vaziri, Sam
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Lemme, Max C.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Efficient inkjet printing of graphene2013In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 25, no 29, p. 3985-3992Article in journal (Refereed)
    Abstract [en]

    An efficient and mature inkjet printing technology is introduced for mass production of coffee-ring-free patterns of high-quality graphene at high resolution (unmarked scale bars are 100 μm). Typically, several passes of printing and a simple baking allow fabricating a variety of good-performance electronic devices, including transparent conductors, embedded resistors, thin film transistors, and micro-supercapacitors.

  • 26. Li, L.
    et al.
    Das, B.
    Rahaman, A.
    Shatskiy, Andrey
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Cheng, P.
    Yuan, C.
    Yang, Z.
    Verho, O.
    Kärkäs, Markus D.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Weng, T. -C
    Åkermark, B.
    Ruthenium containing molecular electrocatalyst on glassy carbon for electrochemical water splitting2022In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 51, no 20, p. 7957-7965Article in journal (Refereed)
    Abstract [en]

    Electrochemical water splitting constitutes one of the most promising strategies for converting water into hydrogen-based fuels, and this technology is predicted to play a key role in the transition towards a carbon-neutral energy economy. To enable the design of cost-effective electrolysis cells based on this technology, new and more efficient anodes with augmented water splitting activity and stability will be required. Herein, we report an active molecular Ru-based catalyst for electrochemically-driven water oxidation (overpotential of ∼395 mV at pH 7 phosphate buffer) and two simple methods for preparing anodes by attaching this catalyst onto glassy carbon through multi-walled carbon nanotubes to improve stability as well as reactivity. The anodes modified with the molecular catalyst were characterized by a broad toolbox of microscopy and spectroscopy techniques, and interestingly no RuO2 formation was detected during electrocatalysis over 4 h. These results demonstrate that the herein presented strategy can be used to prepare anodes that rival the performance of state-of-the-art metal oxide anodes. 

  • 27. Mutafela, R. N.
    et al.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Jani, Y.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Center of Nanotechnology, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
    Hogland, W.
    Sustainable extraction of hazardous metals from crystal glass waste using biodegradable chelating agents2022In: Journal of Material Cycles and Waste Management, ISSN 1438-4957, E-ISSN 1611-8227, Vol. 24, no 2, p. 692-701Article in journal (Refereed)
    Abstract [en]

    Extraction of hazardous metals from dumped crystal glass waste was investigated for site decontamination and resource recovery. Mechanically activated glass waste was leached with biodegradable chelating agents of ethylenediamine-N,N′-disuccinic acid (EDDS) and nitrilotriacetic acid (NTA), where the concentration and reaction time were determined by using Box–Wilson experimental design. Hazardous metals of lead (Pb), arsenic (As), antimony (Sb) and cadmium (Cd) with concentrations higher than regulatory limits were extracted wherein the extraction yield was found to vary Pb > Sb > As > Cd. Extraction was influenced more by type and concentration of chelator rather than by reaction time. A maximum of 64% of Pb could be extracted by EDDS while 42% using NTA. It is found that increase of chelator concentrations from 0.05 M to 1 M did not show improved metal extraction and the extraction improved with reaction time until 13 h. This study provides sustainable alternative for treating hazardous glass waste by mechanical activation followed by extraction using biodegradable chelator, instead of acid leaching. Graphical abstract: [Figure not available: see fulltext.]. 

  • 28.
    Raji, Mahdieh
    et al.
    Faculty of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran.
    Mirbagheri, Seyed Ahmed
    Faculty of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Nano zero-valent iron on activated carbon cloth support as Fenton-like catalyst for efficient color and COD removal from melanoidin wastewater2021In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 263, article id 127945Article in journal (Refereed)
    Abstract [en]

    To reduce undesired iron leaching in Fenton reaction and to realize reusability of catalyst, chitosan-coated activated carbon cloth support loaded with nano zero-valent iron (ACC–CH–nZVI) was applied as a heterogeneous Fenton catalyst to treat melanoidin wastewater. Chitosan coating on ACC by chemical crosslinking results in 6% chitosan on ACC subsequently loading 3.5% iron. At optimum conditions, ACC–CH–nZVI leads to 88.4% and 76.2% of color and chemical oxygen demand (COD) removal, respectively, upon treating synthetic melanoidin wastewater of 8000 mg/l COD. The corresponding weight ratio of consumed H2O2 to COD is 1.02, far below the stoichiometric ratio 2.125, indicating the economic value of this catalyst. Reusability of ACC–CH–nZVI is demonstrated for five cycles of treatment with minimal iron leaching (<2%). The high removal efficiency and very low levels of iron leaching suggests that ACC–CH–nZVI is a highly efficient and cost-effective catalyst for Fenton-like oxidation of non-biodegradable organic wastes in water.

  • 29.
    Raji, Mahdieh
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. KN Toosi Univ Technol, Fac Civil Engn, Tehran, Iran..
    Tahroudi, Mohammad Nazeri
    Univ Birjand, Dept Water Engn, Birjand, Iran..
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Prediction of heterogeneous Fenton process in treatment of melanoidin-containing wastewater using data-based models2022In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 307, article id 114518Article in journal (Refereed)
    Abstract [en]

    Predictive capability of response surface methodology (RSM) and ant colony optimization combined with support vector regression (ACO-SVR) models are applied for determining optimal parameters in the process of heterogeneous Fenton oxidation of melanoidin, a high molecular weight polymer widely produced during fermentation processes generating large quantities of wastewater with intense brown color and extremely high chemical oxygen demand (COD). Prediction of the performance of nano zero-valent iron supported on activated carbon cloth-chitosan (ACC-CH-nZVI) catalysts was carried out using Box-Behnken design (BBD) and analysis of variance to evaluate the interaction of independent variables involved in heterogeneous Fenton reaction. The optimized condition with minimal consumption of H2O2 (173 mM) resulted in 77.1% decolorization of melanoidin-contaminated water corresponding to 74.4% COD removal at pH 3 (600 mg/l Fe dosage) for 90 min reaction time. The corresponding weight ratio of H2O2 to COD was 0.98, much lower than the stoichiometric value 2.125, indicating the effectiveness of ACC-CH-nZVI as a heterogeneous Fenton-like catalyst. In comparison to previously published experimental results, ACO-SVR model shows higher coefficient of determination (R-2; 0.9983) but lower root mean squared error (RMSE) and mean absolute error (MAE) than those of RSM model, indicating relative superiority in prediction capability. Besides, ACO algorithm appears to be a promising tool for improving forecasting accuracy of SVR model. This work demonstrates the applicability of ACO-SVR model in predicting the performance of wastewater treatment using Fenton process with limited number of experiment and exhibits satisfactory prediction results.

  • 30.
    Tofa, Tajkia Syeed
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. Islamic Univ Technol, Dept Civil & Environm Engn CEE, Dhaka 1704, Bangladesh..
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Laxman, Karthik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Enhanced Visible Light Photodegradation of Microplastic Fragments with Plasmonic Platinum/Zinc Oxide Nanorod Photocatalysts2019In: Catalysts, E-ISSN 2073-4344, Vol. 9, no 10, article id 819Article in journal (Refereed)
    Abstract [en]

    Microplastics are persistent anthropogenic pollutants which have become a global concern owing to their widespread existence and unfamiliar threats to the environment and living organisms. This study demonstrates the degradation of fragmented microplastics particularly low-density polyethylene (LDPE) film in water, through visible light-induced plasmonic photocatalysts comprising of platinum nanoparticles deposited on zinc oxide (ZnO) nanorods (ZnO-Pt). The ZnO-Pt nanocomposite photocatalysts were observed to have better degradation kinetics for a model organic dye (methylene blue) compared to bare ZnO nanorods, attributed to the plasmonic effects leading to better interfacial exciton separation and improved hydroxyl radical activity along with a 78% increase in visible light absorption. These demonstrations of the plasmonically enhanced photocatalyst enabled it to effectively degrade microplastic fragments as confirmed following the changes in carbonyl and vinyl indices in infrared absorption. In addition, visual proof of physical surface damage of the LDPE film establishes the efficacy of using plasmonically enhanced nanocomposite photocatalytic materials to tackle the microplastic menace using just sunlight for a clean and green approach towards mitigation of microplastics in the ecosystem.

  • 31.
    Vasileva, Elena
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Fei, Ye
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Marinins, Aleksandrs
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Etcheverry, Sebastián
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Popov, Sergei Yu
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Optimization of optical gain in composite materials containing Rh6G dye and gold nanoparticles2015In: Asia Communications and Photonics Conference, ACPC 2015, 2015Conference paper (Refereed)
    Abstract [en]

    The existence of metal nanoparticles in a dye material can lead not only to quenching or enhancement of dye luminescence, or random lasing action, but also to the change of the fundamental material characteristic as optical gain.

  • 32.
    Wang, Wujun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Photothermal performance of three chromia-forming refractory alloys for high-temperature solar absorber applications2023In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 225, article id 120189Article in journal (Refereed)
    Abstract [en]

    Spectral hemispherical emissivity is a crucial material characteristic that determines radiation heat transfer. In high-temperature solar thermal applications, it affects not only the efficiency of the solar energy absorption but also the heat losses caused by thermal radiation and the radiative heat transfer within the receiver. Due to the limitations of the working temperature of existing solar absorber coatings, the spectral hemispherical emissivity of the oxidized surface is a key performance indicator for evaluating the potential of a candidate refractory alloy for high-temperature (> 1000 degrees C) solar receiver/reactor designs. In this work, we systematically studied the photothermal performances of the oxidized surfaces of three widely used high-performance commercial chromia-forming alloys (Haynes 230, Hastelloy X, and SS 253MA) by analyzing the spectral hemispherical reflectance in the band 0.25-25 mu m. The stability of the optical properties of the formed oxide layers have also been studied by exposing the three alloys at 1150 degrees C in air for three different exposure periods (10 h, 100 h, and 200 h). The results show that the solar absorptivity of all the samples is in the range of 0.800-0.855, with SS 253MA showing the best performances in offering both high and stable solar absorptivity in the range of 0.837-0.855. The evaluation of the photothermal performances suggest the potential of these three alloys in solar-thermal applications.

  • 33.
    Wang, Wujun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Mu, Wangzhong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. KTH Royal Inst Technol, Dept Appl Phys, S-11419 Stockholm, Sweden.;King Abdulaziz Univ, Ctr Nanotechnol, Jeddah 21589, Saudi Arabia..
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A New High-Temperature Durable Absorber Material Solution through a Spinel-Type High Solar Absorptivity Coating on Ti2AlC MAX Phase Material2021In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 13, no 37, p. 45008-45017Article in journal (Refereed)
    Abstract [en]

    Enhancing the operating temperature of concentrating solar power systems is a promising way to obtain higher system efficiency and thus enhance their competitiveness. One major barrier is the unavailability of suitable solar absorber materials for operation at higher temperatures. In this work, we report on a new high-temperature absorber material by combining Ti2AlC MAX phase material and iron-cobalt-chromite spinel coating/paint. This durable material solution exhibits excellent performance, passing the thermal stability test in an open-air environment at a temperature of 1250 degrees C for 400 h and at 1300 degrees C for 200 h. The results show that the black spinel coating can offer a stable high solar absorptivity in the range of 0.877-0.894 throughout the 600 h test under high temperatures. These solar absorptivity values are even 1.6-3.3% higher than that for the sintered SiC ceramic that is a widely used solar absorber material. Divergence of solar absorptivity during these relatively long testing periods is less than 1.1%, indicating remarkable stability of the absorber material. Furthermore, considering the simple application process of the coating/painting utilizing a brush followed by curing at relatively low temperatures (room temperature, 95 and 260 degrees C in sequence), this absorber material shows the potential for large-scale, high-temperature solar thermal applications.

  • 34.
    Wang, Wujun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Mu, Wangzhong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Trevisan, Silvia
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Solar selective reflector materials: Another option for enhancing the efficiency of the high-temperature solar receivers/reactors2021In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, Vol. 224, article id 110995Article in journal (Refereed)
    Abstract [en]

    The cavity wall is an important part of a cavity receiver in determining the receiver efficiency. Using solar selective reflector (SSR) materials with low solar absorptivity and high thermal emissivity for the cavity wall design is one efficient way to improve the receiver efficiency. In this work, we present a systematic study of the optical and high-temperature stability performances of six different SSR materials: one refractory ceramic fiber-based substrate material (Fiberfrax 140) and five metallic oxide coatings which are prepared by mixing metallic oxide powders of alumina, magnesium oxide and titanium dioxide with commercial inorganic adhesives. The thermal stability was studied by heating up and keeping the six candidate materials in atmospheric conditions at a temperature of 1250 ◦C for 200 h. The spectrum of hemispherical reflectance in the spectrum band 0.25–25 μmwas measured for analyzing the optical performance of the candidate materials. The obtained results show that all the six materials studied have good solar selective reflection characteristics, i.e, low solar absorptivity and relatively high thermal emissivity. Especially, the alumina-coated substrate material shows excellent performances both for thermal stability and solar selective reflection. The solar reflectivity can reach 94.6%.

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  • 35.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Chemically Synthesized Nano-Structured Materials for Biomedical and Photonic Applications2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nanostructured materials have attracted a broad interest for applications in scientific and engineering fields due to their extraordinary properties stemming from the nanoscale dimensions. This dissertation presents the development of nanomaterials used for different applications, namely biomedicine and dye lasing.

    Various inorganic nanoparticles have been developed as contrast agents for non-invasive medical imaging, such as magnetic resonance imaging (MRI) and X-ray computed tomography (CT), owing to their unique properties for efficient contrasting effect. Superparamagnetic iron oxide nanoparticles (SPIONs) are synthesized by thermo-decomposition method and phase-transferred to be hydrophilic used as MRI T2 (negative) contrast agents. Effects of surface modification of SPIONs by mesoporous silica (mSiO2) coating have been examined on the magnetic relaxivities. These contrast agents (Fe3O4@mSiO2) were found to have a coating-thickness dependent relaxation behavior and exhibit much higher contrast efficiency than that for the commercial ones. By growing thermo-sensitive poly(N-isopropylacrylamide -co-acrylamide) (P(NIPAAm-co-AAm)) as the outermost layer on Fe3O4@mSiO2 through free radical polymerization, a multifunctional core-shell nano-composite has been built up. Responding to the temperature change, these particles demonstrate phase transition behavior and were used for thermo-triggered magnetic separation. Their lower critical solution temperature (LCST) can be subtly tuned from ca. 34 to ca. 42 ˚C, suitable for further in vivo applications. An all-in-one contrast agent for MRI, CT and fluorescence imaging has been synthesized by depositing gadolinium oxide carbonate hydrate [Gd2O(CO3)2·H2O] shell on mSiO2-coated gold nanorod (Au NR), and then the particles were grafted with antibiofouling copolymer which can further link with the fluorescent dye. It shows both a higher CT and MRI contrast than the clinical iodine and gadolinium chelate contrast agent, respectively. Apart from the imaging application, owing to the morphology of Au NR, the particle has a plasmonic property of absorbing near-infrared (NIR) irradiation and suitable for future photothermal therapy. Cytotoxicity and biocompatibility of aforementioned nanoparticles have been evaluated and minor negative effects were found, which support their further development for medical applications.

    Gold nanoparticles embedded in the optical gain material, water solution of Rhodamine 6G (Rh6G) in particular, used in dye lasers can both increase and damp the dye fluorescence, thus, changing the laser output intensity. The studies of size effect and coating of gold nanoparticles on photostability of the gain media reveal that small sized (ca. 5.5 nm) gold nanoparticles are found detrimental to the photostability, while for the larger ones (ca. 25 nm) fluorescence enhancement rather than quenching is likely to occur. And a noticeable improvement of the photostability for the gain material is achieved when gold is coated with SiO2.

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    Fei Ye_PhD
  • 36.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Synthesis of nanostructured and hierarchical materials for bio-applications2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In recent years, nanostructured materials incorporated with inorganic particles and polymers have attracted attention for simultaneous multifunctional biomedical applications. This thesis summarized three works, which are preparation of mesoporous silica coated superparamagnetic iron oxide (Fe3O4@mSiO2) nanoparticles (NPs) as magnetic resonance imaging T2 contrast agents, polymer grafted Fe3O4@mSiO2 NPs response to temperature change, synthesis and biocompatibility evaluation of high aspect ratio (AR) gold nanorods.

    Monodisperse Fe3O4@mSiO2 NPs have been prepared through a sol-gel process. The coating thickness and particle sizes can be precisely controlled by varying the synthesis parameters. Impact of surface coatings on magnetometric and relaxometric properties of Fe3O4 NPs is studied. The efficiency of these contrast agents, evaluated by MR relaxivities ratio (r2/r1), is much higher than that of the commercial ones. This coating-thickness dependent relaxation behavior is explained due to the effects of mSiO2 coatings on water exclusion.

    Multifunctional core-shell composite NPs have been developed by growing thermo-sensitive poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAAm-co-AAm)) on Fe3O4@mSiO2 NPs through free radical polymerization. Their phase transition behavior is studied, and their lower critical solution temperature (LCST) can be subtly tuned from ca. 34 to ca. 42 °C, suitable for further in vivo applications.

    A seedless surfactant-mediated protocol has been applied for synthesis of high AR gold nanorods with the additive of HNO3. A growth mechanism based on the effect of nitrate ions on surfactant micelle elongation and Ostwald ripening process is proposed. The biocompatibility of high AR nanorods was evaluated on primary human monocyte derived dendritic cells (MDDCs). Their minor effects on viability and immune regulatory markers support further development for medical applications.

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  • 37. 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.

  • 38.
    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)
  • 39.
    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.

  • 40.
    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.

  • 41.
    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.

  • 42.
    Yu, Dongkun
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Basumatary, Indra Bhusan
    Cent Inst Technol, Dept Food Engn & Technol, Kokrajhar 783370, India..
    Kumar, Santosh
    Cent Inst Technol, Dept Food Engn & Technol, Kokrajhar 783370, India..
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Chitosan modified with bio-extract as an antibacterial coating with UV filtering feature2023In: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 230, article id 123145Article in journal (Refereed)
    Abstract [en]

    Benzophenone-3 grafted chitosan (CS-BP-3) was successfully synthesized and applied as an antibacterial coating for the first time. The grafting mechanism is based on the reaction between ketone and primary amine to form imine derivatives and the chemical structure of grafted chitosan was studied by Fourier transform infrared (FTIR) spectroscopy. Water solubility of BP-3 is enhanced after covalently grafted on chitosan and consequently renders the chitosan coating with UV blocking property. Results of thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) further confirmed the thermal stability of BP-3 modified chitosan is enhanced. The CS-BP-3 coating was applied on a variety of substrates of glass, plastics, wood, and metal. The surface features of the coatings such as morphology, water contact angle (WCA), and surface roughness were investigated. The optical and thermal stabilities of the coatings under UV irradiation were studied for 16 h. Antibacterial activity of CS-BP-3 was evaluated against both Gram-negative and Gram-positive bacteria. And the results of bacterial inhibition by CS-BP-3 coating indicate its potential for future application in food packaging.

  • 43.
    Yu, Dongkun
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Basumatary, Indra Bhusan
    Department of Food Engineering and Technology, Central Institute of Technology Kokrajhar, Kokrajhar, Assam 783370, India, Assam.
    Liu, You
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Zhang, Xingyan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Kumar, Santosh
    Department of Food Engineering and Technology, Central Institute of Technology Kokrajhar, Kokrajhar, Assam 783370, India, Assam.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Chitosan-photocatalyst nanocomposite on polyethylene films as antimicrobial coating for food packaging2024In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 186, article id 108069Article in journal (Refereed)
    Abstract [en]

    Chitosan (CS), an edible and non-toxic natural biopolymer, has been widely used in food preservation attributed to its intrinsic antimicrobial, biodegradable, and excellent film-forming properties. In this work, we report photocatalyst-loaded chitosan coating on commercial polyethylene (PE) film with enhanced antimicrobial properties for food packaging application. To improve the chemical stability of zinc oxide (ZnO) photocatalyst in acidic chitosan matrix, a thin layer (1–5 nm) of amorphous tin oxide (SnOx) was coated on ZnO nanoparticles. Consequently, the charge transfer efficiency of ZnO is improved and most of the surface defects are retained according to the studies of UV–Vis and fluorescence spectroscopy. The thin SnOx coating on ZnO was observed by high-resolution transmission electron microscopy (HRTEM) and its effects on crystallinity and particle size of ZnO were examined using X-ray diffraction (XRD) and particle sizer, respectively. The addition of ZnO@SnOx particles in chitosan coating increases water contact angle (WCA) and enhances thermal stability of chitosan coating. The antimicrobial activity of chitosan, ZnO-SnOx nanoparticles, and CS-ZnO@SnOx coated PE films were examined against both Gram-negative (E. coli, A. faecalis) and Gram-positive (S. aureus, B. subtilis) bacteria. Compared to the limited antimicrobial effects of chitosan, ZnO-SnOx demonstrates an improved inhibition effect on bacterial growth over 48 h period under light. For the CS-ZnO@SnOx nanocomposite coated PE films, no inhibition zone was observed due to the limitation of disc diffusion method. Meanwhile, there were no bacterial colonies found to develop on the film, rendering this CS nanocomposite coating a good candidate for food packaging applications.

  • 44.
    Zhang, Xingyan
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Alvarado Ávila, M. I.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Liu, You
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Yu, Dongkun
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Self-sacrificial growth of hierarchical P(Ni, Co, Fe) for enhanced asymmetric supercapacitors and oxygen evolution reactions2023In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 438, article id 141582Article in journal (Refereed)
    Abstract [en]

    Highly efficient and environmentally friendly multifunctional electrode materials for application in super -capacitors to electrocatalysis are important for advances in the future of electrical energy storage and green hydrogen production. This work reports a simple growth strategy to obtain hierarchical P(Ni, Co, Fe) modified electrodes by phosphating a core/shell composite of nickel-cobalt (NiCo) Prussian blue analogues fabricated through an in situ self-sacrificial growth process. Due to the unique microstructure, abundant surface-active sites, and enhanced interfacial conductivity, the hybrid electrode exhibits specific capacitance as high as 1125.8 F g-1 (3.7 F cm-2) at 2 mA cm-2, excellent rate capability and improved cycling stability (97.1% retention capacitance after 5000 cycles at 50 mA cm-2 and 89.9% after continuous 5000 cycles at 100 mA cm-2). Furthermore, the hybrid structure shows excellent oxygen evolution reaction performance with an overpotential of 252 mV at 100 mA cm-2 and 283 mV at 300 mA cm-2, with a low Tafel slope of 68 mV dec- 1, and overall water splitting abilities with a cell voltage of 1.55 V at 100 mA cm-2. This work provides insights into the design of next -generation high-performance multifunctional electrode materials by controlling the surface/interface of multi -component structures for enhancing their properties.

  • 45.
    Zheng, W.
    et al.
    Department of Laboratory Medicine, Karolinska Institute, Huddinge, 141 86, Sweden.
    Boada, R.
    Centre GTS, Department of Chemistry, Autonomous University of Barcelona, Barcelona, 08193, Spain.
    He, R.
    Department of Laboratory Medicine, Karolinska Institute, Huddinge, 141 86, Sweden.
    Xiao, T.
    Centre GTS, Department of Chemistry, Autonomous University of Barcelona, Barcelona, 08193, Spain.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Simonelli, L.
    CELLS-ALBA Synchrotron Radiation Facility, Carrer de la Llum 2-26, Barcelona, 08290, Spain.
    Valiente, M.
    Centre GTS, Department of Chemistry, Autonomous University of Barcelona, Barcelona, 08193, Spain.
    Zhao, Y.
    Department of Laboratory Medicine, Karolinska Institute, Huddinge, 141 86, Sweden. ECM, Clinical Research Center, Karolinska University Hospital, Huddinge, 141 86, Sweden.
    Hassan, M.
    Department of Laboratory Medicine, Karolinska Institute, Huddinge, 141 86, Sweden. ECM, Clinical Research Center, Karolinska University Hospital, Huddinge, 141 86, Sweden.
    Extracellular albumin covalently sequesters selenocompounds and determines cytotoxicity2019In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 20, no 19, article id 4734Article in journal (Refereed)
    Abstract [en]

    Selenocompounds (SeCs) are well-known nutrients and promising candidates for cancer therapy; however, treatment efficacy is very heterogeneous and the mechanism of action is not fully understood. Several SeCs have been reported to have albumin-binding ability, which is an important factor in determining the treatment efficacy of drugs. In the present investigation, we hypothesized that extracellular albumin might orchestrate SeCs efficacy. Four SeCs representing distinct categories were selected to investigate their cytotoxicity, cellular uptake, and species transformation. Concomitant treatment of albumin greatly decreased cytotoxicity and cellular uptake of SeCs. Using both X-ray absorption spectroscopy and hyphenated mass spectrometry, we confirmed the formation of macromolecular conjugates between SeCs and albumin. Although the conjugate was still internalized, possibly via albumin scavenger receptors expressed on the cell surface, the uptake was strongly inhibited by excess albumin. In summary, the present investigation established the importance of extracellular albumin binding in determining SeCs cytotoxicity. Due to the fact that albumin content is higher in humans and animals than in cell cultures, and varies among many patient categories, our results are believed to have high translational impact and clinical implications.

  • 46.
    Zheng, Wenyi
    et al.
    Karolinska Inst, Stockholm, Sweden..
    Boada, Roberto
    Autonomous Univ Barcelona, Barcelona, Spain..
    Xiao, Tingting
    Autonomous Univ Barcelona, Barcelona, Spain..
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Valiente, Manuel
    Autonomous Univ Barcelona, Barcelona, Spain..
    Hassan, Moustapha
    Karolinska Inst, Stockholm, Sweden..
    Extracellular albumin covalently sequesters selenium compounds and determines cytotoxicity2020In: British Journal of Pharmacology, ISSN 0007-1188, E-ISSN 1476-5381, Vol. 177, no 11, p. 2511-2511Article in journal (Other academic)
1 - 46 of 46
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