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Al-Soubaihi, R., Saoud, K. M., Fei, Y., Zar Myint, M. T., Saeed, S. & Dutta, J. (2020). Synthesis of hierarchically porous silica aerogel supported Palladium catalyst for low-temperature CO oxidation under ignition/extinction conditions. Microporous and Mesoporous Materials, 292, Article ID 109758.
Open this publication in new window or tab >>Synthesis of hierarchically porous silica aerogel supported Palladium catalyst for low-temperature CO oxidation under ignition/extinction conditions
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2020 (English)In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 292, article id 109758Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Vapor-Phase Synthesis, Carbon-Monoxide, Nanoparticle Catalysts, Pd/Sio2 Catalysts, Methane, Pd, Behavior, Oxygen, Reduction, Kinetics
National Category
Nano Technology Other Physics Topics
Research subject
Physics, Material and Nano Physics
Identifiers
urn:nbn:se:kth:diva-263430 (URN)10.1016/j.micromeso.2019.109758 (DOI)000498292200033 ()2-s2.0-85072675475 (Scopus ID)
Note

QC 20191205

Available from: 2019-12-05 Created: 2019-12-05 Last updated: 2019-12-20Bibliographically approved
Tofa, T. S., Fei, Y., Laxman, K. & Dutta, J. (2019). Enhanced Visible Light Photodegradation of Microplastic Fragments with Plasmonic Platinum/Zinc Oxide Nanorod Photocatalysts. Catalysts, 9(10), Article ID 819.
Open this publication in new window or tab >>Enhanced Visible Light Photodegradation of Microplastic Fragments with Plasmonic Platinum/Zinc Oxide Nanorod Photocatalysts
2019 (English)In: Catalysts, ISSN 2073-4344, Vol. 9, no 10, article id 819Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
microplastics, visible light photodegradation, ZnO nanorod, platinum nanoparticle, nanocomposite, LDPE film
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-265446 (URN)10.3390/catal9100819 (DOI)000498266100035 ()2-s2.0-85073602074 (Scopus ID)
Note

QC 20191217

Available from: 2019-12-17 Created: 2019-12-17 Last updated: 2020-01-02Bibliographically approved
Zheng, W., Boada, R., He, R., Xiao, T., Fei, Y., Simonelli, L., . . . Hassan, M. (2019). Extracellular albumin covalently sequesters selenocompounds and determines cytotoxicity. International Journal of Molecular Sciences, 20(19), Article ID 4734.
Open this publication in new window or tab >>Extracellular albumin covalently sequesters selenocompounds and determines cytotoxicity
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2019 (English)In: International Journal of Molecular Sciences, ISSN 1661-6596, Vol. 20, no 19, article id 4734Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
MDPI AG, 2019
Keywords
Albumin, Cellular uptake, Cytotoxicity, Selenium, X-ray absorption spectroscopy
National Category
Biomedical Laboratory Science/Technology
Research subject
Medical Technology; Applied Medical Technology; Biotechnology
Identifiers
urn:nbn:se:kth:diva-263540 (URN)10.3390/ijms20194734 (DOI)000494798300075 ()31554226 (PubMedID)2-s2.0-85072656402 (Scopus ID)
Note

QC 20191128

Available from: 2019-11-28 Created: 2019-11-28 Last updated: 2019-12-04Bibliographically approved
El-Sayed, R., Fei, Y., Asem, H., Ashour, R., Zheng, W., Muhammed, M. & Hassan, M. (2017). Importance of the surface chemistry of nanoparticles on peroxidaselikeactivity. Biochemical and Biophysical Research Communications - BBRC, 491, 15-18
Open this publication in new window or tab >>Importance of the surface chemistry of nanoparticles on peroxidaselikeactivity
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2017 (English)In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 491, p. 15-18Article in journal (Refereed) Published
Abstract [en]

We report the studies on origin of peroxidase-like activity for gold nanoparticles, as well as the impact from morphology and surface charge of nanoparticles. For this purpose, we have synthesized hollow gold nanospheres (HAuNS) and gold nanorods (AuNR) with different morphology and surface chemistry to investigate their influence on the catalytic activity. We found that citrate-capped HAuNS show catalyzing efficiency in oxidation reaction of 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) and it is superior to that of cetyltrimethylammonium bromide (CTAB)-capped AuNR. The kinetics of catalytic activities from HAuNS and AuNR were respectively studied under varied temperatures. The results indicated that surface chemistry rather than morphology of nanoparticles plays an important role in the catalytic reaction of substrate. Furthermore, influencing factors such as pH, amount of nanoparticle and H2O2 concentration were also investigated on HAuNS-catalyzed system. The great impact of nanoparticle surface properties on catalytic reactions makes a paradigm in constructing nanozymes as peroxidase mimic for sensing application.

National Category
Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-266130 (URN)10.1016/j.bbrc.2017.07.014 (DOI)28687493 (PubMedID)
Note

QC 20200102

Available from: 2019-12-23 Created: 2019-12-23 Last updated: 2020-01-02Bibliographically approved
Doddapaneni, V., Zhao, Y., Ye, F., Gati, R., Edin, H. & Toprak, M. S. (2015). Improving Uv Radiation Absorption by Copper Oxide NPs/PMMA Nanocomposites for Electrical Switching Applications. Powder metallurgy and metal ceramics, 54(7-8), 397-401
Open this publication in new window or tab >>Improving Uv Radiation Absorption by Copper Oxide NPs/PMMA Nanocomposites for Electrical Switching Applications
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2015 (English)In: Powder metallurgy and metal ceramics, ISSN 1068-1302, E-ISSN 1573-9066, Vol. 54, no 7-8, p. 397-401Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Springer, 2015
Keywords
polymer-based nanocomposites, cupric oxide, UV-absorption, nanoparticles, circuit breaker
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-180142 (URN)10.1007/s11106-015-9728-1 (DOI)000366156700003 ()2-s2.0-84957429698 (Scopus ID)
Note

QC 20160113

Available from: 2016-01-13 Created: 2016-01-07 Last updated: 2017-11-30Bibliographically approved
Vasileva, E., Fei, Y., Marinins, A., Etcheverry, S., Toprak, M. & Popov, S. Y. (2015). Optimization of optical gain in composite materials containing Rh6G dye and gold nanoparticles. In: Asia Communications and Photonics Conference, ACPC 2015: . Paper presented at Asia Communications and Photonics Conference, ACPC 2015, 19 November 2015 through 23 November 2015.
Open this publication in new window or tab >>Optimization of optical gain in composite materials containing Rh6G dye and gold nanoparticles
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2015 (English)In: Asia Communications and Photonics Conference, ACPC 2015, 2015Conference paper, Published 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. © 2015 OSA.

National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-195162 (URN)2-s2.0-84971656710 (Scopus ID)9781943580064 (ISBN)
Conference
Asia Communications and Photonics Conference, ACPC 2015, 19 November 2015 through 23 November 2015
Note

Conference Paper. QC 20161108

Available from: 2016-11-08 Created: 2016-11-02 Last updated: 2016-11-08Bibliographically approved
Fei, Y., Barrefelt, Å., Asem, H., Abedi-Valugerdi, M., El-Serafi, I., Saghafian, M., . . . Hassan, M. (2014). Biodegradable polymeric vesicles containing magnetic nanoparticles,quantum dots and anticancer drugs for drug delivery and imaging. Biomaterials, 35, 3885-3894
Open this publication in new window or tab >>Biodegradable polymeric vesicles containing magnetic nanoparticles,quantum dots and anticancer drugs for drug delivery and imaging
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2014 (English)In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 35, p. 3885-3894Article in journal (Refereed) Published
Abstract [en]

We have developed biodegradable polymeric vesicles as a nanocarrier system for multimodal bio-imaging 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. T2∗-weighted magnetic resonance imaging (MRI) of PLGA-SPION-Mn:ZnS phantoms exhibited enhanced negative contrast with r2∗ 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.

Place, publisher, year, edition, pages
Elsevier: , 2014
Keywords
Anticancer drug delivery; Biodegradable polymer; Busulfan; Fluorescence imaging; Magnetic resonance imaging; Multifunctional nanoparticles
National Category
Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-266129 (URN)10.1016/j.biomaterials.2014.01.041 (DOI)24495486 (PubMedID)
Note

QC 20200102

Available from: 2019-12-23 Created: 2019-12-23 Last updated: 2020-01-02Bibliographically approved
Andõn, F. T., Kapralov, A. A., Yanamala, N., Feng, W., Baygan, A., Chambers, B. J., . . . Kagan, V. E. (2013). Biodegradation of Single-Walled Carbon Nanotubes by Eosinophil Peroxidase. Small, 9(16), 2721-2729
Open this publication in new window or tab >>Biodegradation of Single-Walled Carbon Nanotubes by Eosinophil Peroxidase
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2013 (English)In: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 9, no 16, p. 2721-2729Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2013
Keywords
biodegradable materials, carbon nanotubes, eosinophil peroxidase, molecular modeling, Biodegra-dable materials, Catalytic sites, Confocal Raman imaging, Culture systems, Oxidized groups, Positively charged, Single-walled carbon nanotube (SWCNTs), Enzymes, Microbiology, Near infrared spectroscopy, Oxidants, Respiratory system, Single-walled carbon nanotubes (SWCN), Transmission electron microscopy, Biodegradation
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-133837 (URN)10.1002/smll.201202508 (DOI)000327738600011 ()2-s2.0-84879786954 (Scopus ID)
Funder
FormasEU, FP7, Seventh Framework Programme, 263215
Note

QC 20131113

Available from: 2013-11-13 Created: 2013-11-11 Last updated: 2017-12-06Bibliographically approved
Barrefelt, Å., Saghafian, M., Kuiper, R., Ye, F., Egri, G., Klickermann, M., . . . Hassan, M. (2013). Biodistribution, kinetics, and biological fate of SPION microbubbles in the rat. International Journal of Nanomedicine, 8, 3241-3254
Open this publication in new window or tab >>Biodistribution, kinetics, and biological fate of SPION microbubbles in the rat
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2013 (English)In: International Journal of Nanomedicine, ISSN 1176-9114, E-ISSN 1178-2013, Vol. 8, p. 3241-3254Article in journal (Refereed) Published
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.

Keywords
biodistribution, microbubbles, superparamagnetic iron oxide, pharmacokinetics, magnetic resonance imaging, histopathology
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-127786 (URN)10.2147/IJN.S49948 (DOI)000323410400001 ()2-s2.0-84883180976 (Scopus ID)
Funder
EU, FP7, Seventh Framework Programme
Note

QC 20130906

Available from: 2013-09-06 Created: 2013-09-05 Last updated: 2017-12-06Bibliographically approved
Li, J., Ye, F., Vaziri, S., Muhammed, M., Lemme, M. C. & Östling, M. (2013). Efficient inkjet printing of graphene. Advanced Materials, 25(29), 3985-3992
Open this publication in new window or tab >>Efficient inkjet printing of graphene
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2013 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 25, no 29, p. 3985-3992Article in journal (Refereed) Published
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.

Keywords
graphene, inkjet printing, micro-supercapacitors, thin film transistors, transparent conductors
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-134046 (URN)10.1002/adma.201300361 (DOI)000327692400009 ()2-s2.0-84881156476 (Scopus ID)
Funder
EU, European Research Council, 228229
Note

QC 20131118

Available from: 2013-11-18 Created: 2013-11-15 Last updated: 2017-12-06Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1679-1316

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