42 pages, 1680 KiB  
Review
Electrospun Polymer Fibers for Electronic Applications
by Alessandro Luzio 1,*, Eleonora Valeria Canesi 1, Chiara Bertarelli 1,2,* and Mario Caironi 1
1 Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy
2 Dipartimento di Chimica, Materiali e Ing. Chimica "G. Natta", Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano, Italy
Materials 2014, 7(2), 906-947; https://doi.org/10.3390/ma7020906 - 28 Jan 2014
Cited by 114 | Viewed by 15045
Abstract
Nano- and micro- fibers of conjugated polymer semiconductors are particularly interesting both for applications and for fundamental research. They allow an investigation into how electronic properties are influenced by size confinement and chain orientation within microstructures that are not readily accessible within thin [...] Read more.
Nano- and micro- fibers of conjugated polymer semiconductors are particularly interesting both for applications and for fundamental research. They allow an investigation into how electronic properties are influenced by size confinement and chain orientation within microstructures that are not readily accessible within thin films. Moreover, they open the way to many applications in organic electronics, optoelectronics and sensing. Electro-spinning, the technique subject of this review, is a simple method to effectively form and control conjugated polymer fibers. We provide the basics of the technique and its recent advancements for the formation of highly conducting and high mobility polymer fibers towards their adoption in electronic applications. Full article
(This article belongs to the Special Issue Conjugated Polymers)
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7 pages, 244 KiB  
Communication
Long-Term Stability of a Cellulose-Based Glucose Oxidase Membrane
by Soichi Yabuki *, Miho Iwamoto and Yoshiki Hirata
National Institute of Advanced Industrial Science and Technology, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan
Materials 2014, 7(2), 899-905; https://doi.org/10.3390/ma7020899 - 28 Jan 2014
Cited by 13 | Viewed by 5596
Abstract
A cellulose-based glucose oxidase membrane was prepared on a glassy carbon (GC) electrode. The current response of the electrode to glucose was measured by applying a potential of 1.0 V vs. Ag/AgCl on the base GC and was proportional to the concentration of [...] Read more.
A cellulose-based glucose oxidase membrane was prepared on a glassy carbon (GC) electrode. The current response of the electrode to glucose was measured by applying a potential of 1.0 V vs. Ag/AgCl on the base GC and was proportional to the concentration of glucose up to 1 mM. The long-term stability of the electrode was examined by measuring the daily glucose response. Over four months, the response magnitude was maintained and then gradually decreased. After 11 months, though the response magnitude decreased to 50% of the initial value, the linear response range did not change. Therefore, the electrode could be used as a glucose biosensor even after 11 months of use. The entrapment of the enzyme in the cellulose matrix promoted the stability of the enzyme, as revealed by data on the enzyme activity after the enzyme electrode was immersed in urea. Therefore, the cellulose matrix may be used to improve the performance of biosensors, bioreactors and bio-fuel cells. Full article
(This article belongs to the Special Issue Functional Materials and Proteins for Bio-Sensing Applications)
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12 pages, 389 KiB  
Article
Corrosion Resistance of Calcium Aluminate Cement Concrete Exposed to a Chloride Environment
by Ki Yong Ann 1 and Chang-Geun Cho 2,*
1 Department of Civil and Environmental Engineering, Hanyang University, Ansan 426, Korea
2 School of Architecture, Chosun University, Gwangju 501, Korea
Materials 2014, 7(2), 887-898; https://doi.org/10.3390/ma7020887 - 28 Jan 2014
Cited by 37 | Viewed by 7658
Abstract
The present study concerns a development of calcium aluminate cement (CAC) concrete to enhance the durability against an externally chemically aggressive environment, in particular, chloride-induced corrosion. To evaluate the inhibition effect and concrete properties, CAC was partially mixed with ordinary Portland cement (OPC), [...] Read more.
The present study concerns a development of calcium aluminate cement (CAC) concrete to enhance the durability against an externally chemically aggressive environment, in particular, chloride-induced corrosion. To evaluate the inhibition effect and concrete properties, CAC was partially mixed with ordinary Portland cement (OPC), ranging from 5% to 15%, as a binder. As a result, it was found that an increase in the CAC in binder resulted in a dramatic decrease in the setting time of fresh concrete. However, the compressive strength was lower, ranging about 20 MPa, while OPC indicated about 30–35 MPa at an equivalent age. When it comes to chloride transport, there was only marginal variation in the diffusivity of chloride ions. The corrosion resistance of CAC mixture was significantly enhanced: its chloride threshold level for corrosion initiation exceeded 3.0% by weight of binder, whilst OPC and CAC concrete indicated about 0.5%–1.0%. Full article
(This article belongs to the Special Issue Construction Materials)
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11 pages, 579 KiB  
Article
Study on Surface Permeability of Concrete under Immersion
by Jun Liu 1, Feng Xing 1,*, Biqin Dong 1, Hongyan Ma 2,* and Dong Pan 1
1 Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, College of Civil Engineering, Shenzhen University, Shenzhen 518060, China
2 Department of Civil and Environmental Engineering, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
Materials 2014, 7(2), 876-886; https://doi.org/10.3390/ma7020876 - 28 Jan 2014
Cited by 33 | Viewed by 8492
Abstract
In this paper, concrete specimens are immersed in ultrapure water, to study the evolutions of surface permeability, pore structure and paste microstructure following the prolonging of immersion period. According to the results, after 30-day immersion, the surface permeability of concrete becomes higher as [...] Read more.
In this paper, concrete specimens are immersed in ultrapure water, to study the evolutions of surface permeability, pore structure and paste microstructure following the prolonging of immersion period. According to the results, after 30-day immersion, the surface permeability of concrete becomes higher as compared with the value before immersion. However, further immersion makes the surface permeability decrease, so that the value measured after 150-day immersion is only half that measured after 30-day immersion. The early increase in surface permeability should be mainly attributed to the leaching of calcium hydroxide, while the later decrease to the refinement of pore structure due to hydration. The two effects work simultaneously and compete throughout the immersion period. The proposed mechanisms get support from microscopic measurements and observations. Full article
(This article belongs to the Section Porous Materials)
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71 pages, 3321 KiB  
Review
Fabrications and Applications of Stimulus-Responsive Polymer Films and Patterns on Surfaces: A Review
by Jem-Kun Chen 1 and Chi-Jung Chang 2,*
1 Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Section 4, Keelung Road, Taipei 106, Taiwan
2 Department of Chemical Engineering, Feng Chia University, 100 Wenhwa Road, Seatwen, Taichung 40724, Taiwan
Materials 2014, 7(2), 805-875; https://doi.org/10.3390/ma7020805 - 28 Jan 2014
Cited by 154 | Viewed by 20746
Abstract
In the past two decades, we have witnessed significant progress in developing high performance stimuli-responsive polymeric materials. This review focuses on recent developments in the preparation and application of patterned stimuli-responsive polymers, including thermoresponsive layers, pH/ionic-responsive hydrogels, photo-responsive film, magnetically-responsive composites, electroactive composites, [...] Read more.
In the past two decades, we have witnessed significant progress in developing high performance stimuli-responsive polymeric materials. This review focuses on recent developments in the preparation and application of patterned stimuli-responsive polymers, including thermoresponsive layers, pH/ionic-responsive hydrogels, photo-responsive film, magnetically-responsive composites, electroactive composites, and solvent-responsive composites. Many important new applications for stimuli-responsive polymers lie in the field of nano- and micro-fabrication, where stimuli-responsive polymers are being established as important manipulation tools. Some techniques have been developed to selectively position organic molecules and then to obtain well-defined patterned substrates at the micrometer or submicrometer scale. Methods for patterning of stimuli-responsive hydrogels, including photolithography, electron beam lithography, scanning probe writing, and printing techniques (microcontact printing, ink-jet printing) were surveyed. We also surveyed the applications of nanostructured stimuli-responsive hydrogels, such as biotechnology (biological interfaces and purification of biomacromoles), switchable wettability, sensors (optical sensors, biosensors, chemical sensors), and actuators. Full article
(This article belongs to the Section Advanced Composites)
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18 pages, 1607 KiB  
Article
Inhibition of Mild Steel Corrosion in Sulfuric Acid Solution by New Schiff Base
by Ahmed A. Al-Amiery 1,2,*, Abdul Amir H. Kadhum 1, Abdulhadi Kadihum 2, Abu Bakar Mohamad 1, Chong K. How 1 and Sutiana Junaedi 1
1 Department of Chemical & Process Engineering, University Kebangsaan Malaysia (UKM), Bangi, Selangor 43000, Malaysia
2 Applied Science Department, University of Technology (UOT), Baghdad 10001, Iraq
Materials 2014, 7(2), 787-804; https://doi.org/10.3390/ma7020787 - 28 Jan 2014
Cited by 101 | Viewed by 9560
Abstract
The efficiency of Schiff base derived from 4-aminoantipyrine, namely 2-(1,5-dimethyl-4-(2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-ylidene) hydrazinecarbothioamide as a corrosion inhibitor on mild steel in 1.0 M H2SO4 was investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PD) and electrochemical frequently modulation (EFM) in addition to the adsorption isotherm, [...] Read more.
The efficiency of Schiff base derived from 4-aminoantipyrine, namely 2-(1,5-dimethyl-4-(2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-ylidene) hydrazinecarbothioamide as a corrosion inhibitor on mild steel in 1.0 M H2SO4 was investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PD) and electrochemical frequently modulation (EFM) in addition to the adsorption isotherm, corrosion kinetic parameters and scanning electron microscopy (SEM). The results showed that this inhibitor behaved as a good corrosion inhibitor, even at low concentration, with a mean efficiency of 93% and, also, a reduction of the inhibition efficiency as the solution temperature increases. A polarization technique and EIS were tested for different concentrations and different temperatures to reveal that this compound is adsorbed on the mild steel, therefore blocking the active sites, and the adsorption follows the Langmuir adsorption isotherm model. The excellent inhibition effectiveness of 2-(1,5-dimethyl-4-(2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-ylidene)hydrazinecarbothioamide was also verified by scanning electron microscope (SEM). Full article
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18 pages, 464 KiB  
Review
Biocompatibility of Coronary Stents
by Thamarasee M. Jeewandara 1,2, Steven G. Wise 1,2,3 and Martin K. C. Ng 1,4,*
1 The Heart Research Institute, Sydney NSW 2042, Australia
2 Sydney Medical School, University of Sydney, Sydney NSW 2006, Australia
3 School of Molecular Bioscience, University of Sydney, Sydney NSW 2006, Australia
4 Department of Cardiology, Royal Prince Alfred Hospital, University of Sydney, Sydney NSW 2050, Australia
Materials 2014, 7(2), 769-786; https://doi.org/10.3390/ma7020769 - 28 Jan 2014
Cited by 44 | Viewed by 9668
Abstract
Cardiovascular disease is the dominant cause of mortality in developed countries, with coronary artery disease (CAD) a predominant contributor. The development of stents to treat CAD was a significant innovation, facilitating effective percutaneous coronary revascularization. Coronary stents have evolved from bare metal compositions, [...] Read more.
Cardiovascular disease is the dominant cause of mortality in developed countries, with coronary artery disease (CAD) a predominant contributor. The development of stents to treat CAD was a significant innovation, facilitating effective percutaneous coronary revascularization. Coronary stents have evolved from bare metal compositions, to incorporate advances in pharmacological therapy in what are now known as drug eluting stents (DES). Deployment of a stent overcomes some limitations of balloon angioplasty alone, but provides an acute stimulus for thrombus formation and promotes neointimal hyperplasia. First generation DES effectively reduced in-stent restenosis, but profoundly delay healing and are susceptible to late stent thrombosis, leading to significant clinical complications in the long term. This review characterizes the development of coronary stents, detailing the incremental improvements, which aim to attenuate the major clinical complications of thrombosis and restenosis. Despite these enhancements, coronary stents remain fundamentally incompatible with the vasculature, an issue which has largely gone unaddressed. We highlight the latest modifications and research directions that promise to more holistically design coronary implants that are truly biocompatible. Full article
(This article belongs to the Section Biomaterials)
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18 pages, 814 KiB  
Article
Shape Memory Properties of PBS-Silica Hybrids
by Katia Paderni 1,3, Paola Fabbri 1,3, Maurizio Toselli 2,3 and Massimo Messori 1,3,*
1 Dipartimento di Ingegneria "Enzo Ferrari", Università di Modena e Reggio Emilia, via Vignolese 905/A, Modena 41125, Italy
2 Dipartimento di Chimica Industriale "Toso Montanari", Università di Bologna, Viale Risorgimento 2, Bologna 40136, Italy
3 Consorzio Interuniversitario per la Scienza e Tecnologia dei Materiali (INSTM), Via G. Giusti 9, Firenze 50121, Italy
Materials 2014, 7(2), 751-768; https://doi.org/10.3390/ma7020751 - 27 Jan 2014
Cited by 3 | Viewed by 6350
Abstract
A series of novel Si–O–Si crosslinked organic/inorganic hybrid semi-crystalline polymers with shape memory properties was prepared from alkoxysilane-terminated poly(butylene succinate) (PBS) by water-induced silane crosslinking under organic solvent-free and catalyst-free conditions. The hydrolyzation and condensation of alkoxysilane end groups allowed for the generation [...] Read more.
A series of novel Si–O–Si crosslinked organic/inorganic hybrid semi-crystalline polymers with shape memory properties was prepared from alkoxysilane-terminated poly(butylene succinate) (PBS) by water-induced silane crosslinking under organic solvent-free and catalyst-free conditions. The hydrolyzation and condensation of alkoxysilane end groups allowed for the generation of silica-like crosslinking points between the polymeric chains, acting not only as chemical net-points, but also as inorganic filler for a reinforcement effect. The resulting networks were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic-mechanical analysis (DMA) and tensile and shape memory tests to gain insight into the relationship between the polymeric structure, the morphology and the properties. By controlling the molecular weight of the PBS precursor, a fine tuning of the crosslinking density and the inorganic content of the resulting network was possible, leading to different thermal, mechanical and shape memory properties. Thanks to their suitable morphology consisting of crystalline domains, which represent the molecular switches between the temporary and permanent shapes, and chemical net-points, which permit the shape recovery, the synthesized materials showed good shape memory characteristics, being able to fix a significant portion of the applied strain in a temporary shape and to restore their original shape above their melting temperature. Full article
(This article belongs to the Special Issue Advances in Functional Hybrid Materials)
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9 pages, 515 KiB  
Article
Synthesis of Silver Particle onto Bamboo Charcoal by Tripropylene Glycol and the Composites Characterization
by Tzu Hsuan Chiang * and Hung Che Yeh
Department of Energy Engineering, National United University, Miaoli 36003, Taiwan
Materials 2014, 7(2), 742-750; https://doi.org/10.3390/ma7020742 - 27 Jan 2014
Cited by 4 | Viewed by 5759
Abstract
In this study, tripropylene glycol was used as a reducting agent in the polyol process to reduce silver nitrate to the form of silver particles deposited onto the surface of bamboo charcoal (BC). The reduction temperature and time were critical parameters as they [...] Read more.
In this study, tripropylene glycol was used as a reducting agent in the polyol process to reduce silver nitrate to the form of silver particles deposited onto the surface of bamboo charcoal (BC). The reduction temperature and time were critical parameters as they control the size of the silver particles formed as well as their distribution onto the surface of the BC. The reduction of silver nitrate by the tripropylene glycol occurred at a temperature of 120 °C for 3 h, and the silver particles, which had a face-centered cubic lattice structure, were distributed onto the surface of the BC. These synthesis conditions should work well with tripropylene glycol as reducing agent that can be helpful in the convenient preparation of Ag/BC particles. When Ag/BC powders were manufactured using 3 g of silver nitrate content, the prepared composites had the largest thermal conductivity at 0.2490 W/(m·K). Full article
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15 pages, 1549 KiB  
Article
Effective Optical Properties of Plasmonic Nanocomposites
by Christoph Etrich 1, Stephan Fahr 1, Mehdi Keshavarz Hedayati 2, Franz Faupel 3, Mady Elbahri 2,4 and Carsten Rockstuhl 1,5,*
1 Institute of Condensed Matter Theory and Optics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany
2 Nanochemistry and Nanoengineering, Institute for Materials Science, Faculty of Engineering, Christian-Albrechts-Universität zu Kiel, Kaiserstrasse 2, 24143 Kiel, Germany
3 Chair for Multicomponent Materials, Institute for Materials Science, Faculty of Engineering, Christian-Albrechts-Universität zu Kiel, Kaiserstrasse 2, Kiel 24143, Germany
4 Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht, Germany
5 Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology, Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany
Materials 2014, 7(2), 727-741; https://doi.org/10.3390/ma7020727 - 27 Jan 2014
Cited by 49 | Viewed by 11643
Abstract
Plasmonic nanocomposites find many applications, such as nanometric coatings in emerging fields, such as optotronics, photovoltaics or integrated optics. To make use of their ability to affect light propagation in an unprecedented manner, plasmonic nanocomposites should consist of densely packed metallic nanoparticles. This [...] Read more.
Plasmonic nanocomposites find many applications, such as nanometric coatings in emerging fields, such as optotronics, photovoltaics or integrated optics. To make use of their ability to affect light propagation in an unprecedented manner, plasmonic nanocomposites should consist of densely packed metallic nanoparticles. This causes a major challenge for their theoretical description, since the reliable assignment of effective optical properties with established effective medium theories is no longer possible. Established theories, e.g., the Maxwell-Garnett formalism, are only applicable for strongly diluted nanocomposites. This effective description, however, is a prerequisite to consider plasmonic nanocomposites in the design of optical devices. Here, we mitigate this problem and use full wave optical simulations to assign effective properties to plasmonic nanocomposites with filling fractions close to the percolation threshold. We show that these effective properties can be used to properly predict the optical action of functional devices that contain nanocomposites in their design. With this contribution we pave the way to consider plasmonic nanocomposites comparably to ordinary materials in the design of optical elements. Full article
(This article belongs to the Special Issue Nanocomposites of Polymers and Inorganic Particles 2013)
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54 pages, 3949 KiB  
Review
Organic-Inorganic Hybrid Polymers as Adsorbents for Removal of Heavy Metal Ions from Solutions: A Review
by Babak Samiey 1,*,†, Chil-Hung Cheng 2,*,† and Jiangning Wu 2,*,†
1 Department of Chemistry, Faculty of Science, Lorestan University, Khoramabad 68137-17133, Iran
2 Department of Chemical Engineering, Ryerson University, Toronto, ON M5B 2K3, Canada
These authors contributed equally to this work.
Materials 2014, 7(2), 673-726; https://doi.org/10.3390/ma7020673 - 27 Jan 2014
Cited by 320 | Viewed by 26425
Abstract
Over the past decades, organic-inorganic hybrid polymers have been applied in different fields, including the adsorption of pollutants from wastewater and solid-state separations. In this review, firstly, these compounds are classified. These compounds are prepared by sol-gel method, self-assembly process (mesopores), assembling of [...] Read more.
Over the past decades, organic-inorganic hybrid polymers have been applied in different fields, including the adsorption of pollutants from wastewater and solid-state separations. In this review, firstly, these compounds are classified. These compounds are prepared by sol-gel method, self-assembly process (mesopores), assembling of nanobuilding blocks (e.g., layered or core-shell compounds) and as interpenetrating networks and hierarchically structures. Lastly, the adsorption characteristics of heavy metals of these materials, including different kinds of functional groups, selectivity of them for heavy metals, effect of pH and synthesis conditions on adsorption capacity, are studied. Full article
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11 pages, 539 KiB  
Article
Novel Corrosion Inhibitor for Mild Steel in HCl
by Ahmed A. Al-Amiery 1,2,*, Abdul Amir H. Kadhum 1, Abdul Hameed M. Alobaidy 2, Abu Bakar Mohamad 1 and Pua Soh Hoon 1
1 Department of Chemical and Process Engineering, Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor 43000, Malaysia
2 Environmental Research Center, University of Technology (UOT), Baghdad 10001, Iraq
Materials 2014, 7(2), 662-672; https://doi.org/10.3390/ma7020662 - 27 Jan 2014
Cited by 142 | Viewed by 9000
Abstract
Corrosion inhibitory effects of new synthesized compound namely 5,5'- ((1Z,1'Z)-(1,4-phenylenebis(methanylylidene))bis(azanylylidene))bis(1,3,4-thiadiazole-2-thiol) (PBB) on mild steel in 1.0 M HCl was investigated at different temperatures using open circuit potential (OCP), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Results showed that PBB inhibited mild steel [...] Read more.
Corrosion inhibitory effects of new synthesized compound namely 5,5'- ((1Z,1'Z)-(1,4-phenylenebis(methanylylidene))bis(azanylylidene))bis(1,3,4-thiadiazole-2-thiol) (PBB) on mild steel in 1.0 M HCl was investigated at different temperatures using open circuit potential (OCP), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Results showed that PBB inhibited mild steel corrosion in acid solution and indicated that the inhibition efficiencies increased with the concentration of inhibitor, but decreased proportionally with temperature. Changes in impedance parameters suggested the adsorption of PBB on the mild steel surface, leading to the formation of protective films. Full article
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9 pages, 588 KiB  
Article
Preparation of Multifunctional Fe@Au Core-Shell Nanoparticles with Surface Grafting as a Potential Treatment for Magnetic Hyperthermia
by Ren-Jei Chung * and Hui-Ting Shih
Department of Chemical Engineering and Biotechnology, National Taipei University of Technology (Taipei Tech), Taipei 10608, Taiwan
Materials 2014, 7(2), 653-661; https://doi.org/10.3390/ma7020653 - 24 Jan 2014
Cited by 31 | Viewed by 8560
Abstract
Iron core gold shell nanoparticles grafted with Methotrexate (MTX) and indocyanine green (ICG) were synthesized for the first time in this study, and preliminarily evaluated for their potential in magnetic hyperthermia treatment. The core-shell Fe@Au nanoparticles were prepared via the microemulsion process and [...] Read more.
Iron core gold shell nanoparticles grafted with Methotrexate (MTX) and indocyanine green (ICG) were synthesized for the first time in this study, and preliminarily evaluated for their potential in magnetic hyperthermia treatment. The core-shell Fe@Au nanoparticles were prepared via the microemulsion process and then grafted with MTX and ICG using hydrolyzed poly(styrene-alt-maleic acid) (PSMA) to obtain core-shell Fe@Au-PSMA-ICG/MTX nanoparticles. MTX is an anti-cancer therapeutic, and ICG is a fluorescent dye. XRD, TEM, FTIR and UV-Vis spectrometry were performed to characterize the nanoparticles. The data indicated that the average size of the nanoparticles was 6.4 ± 09 nm and that the Au coating protected the Fe core from oxidation. MTX and ICG were successfully grafted onto the surface of the nanoparticles. Under exposure to high frequency induction waves, the superparamagnetic nanoparticles elevated the temperature of a solution in a few minutes, which suggested the potential for an application in magnetic hyperthermia treatment. The in vitro studies verified that the nanoparticles were biocompatible; nonetheless, the Fe@Au-PSMA-ICG/MTX nanoparticles killed cancer cells (Hep-G2) via the magnetic hyperthermia mechanism and the release of MTX. Full article
(This article belongs to the Section Biomaterials)
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16 pages, 885 KiB  
Article
Comparative Performance of Three Magnesium Compounds on Thermal Degradation Behavior of Red Gum Wood
by Yiqiang Wu 1,*, Chunhua Yao 1, Yunchu Hu 1, Xiaodan Zhu 1, Yan Qing 1 and Qinglin Wu 2,*
1 College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
2 School of Renewable Natural Resources, Louisiana State University AgCenter, Baton Rouge, LA 70803, USA
Materials 2014, 7(2), 637-652; https://doi.org/10.3390/ma7020637 - 24 Jan 2014
Cited by 16 | Viewed by 8248
Abstract
The effect of basic magnesium carbonate (BMC), magnesium hydroxide (MH), and magnesium chloride hydrate (MCH) on thermal degradation of red gum wood was studied using cone calorimetry, Thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, and X-ray diffraction (XRD) characterization. The results showed common fire retardation [...] Read more.
The effect of basic magnesium carbonate (BMC), magnesium hydroxide (MH), and magnesium chloride hydrate (MCH) on thermal degradation of red gum wood was studied using cone calorimetry, Thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, and X-ray diffraction (XRD) characterization. The results showed common fire retardation actions of the three compounds by releasing incombustible gas and/or water vapor to dilute combustible gas in the flaming zone, and by converting to MgO, which had a satisfactory protective wall effect on the wood. Individually, BMC absorbed heat from the wood at the pre-decomposition stage and, thus, slowed down wood pyrolysis process. It slightly increased the char yield by charring in both the charring stage and the char calcination stage. MH lost water at about 270 °C, close to the temperature at which wood thermally degraded. MH rendered wood char quickly, and the compact char layer impeded further carbonization and burning of inner wood. MCH promoted charring with Mg2+ as a Lewis acid, and increased wood char yield. MCH also released Cl· free radical and HCl at 167 °C, which easily coordinated with combustion reaction radical, and slowed down, even inhibited, the combustion chain reaction. Full article
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14 pages, 877 KiB  
Article
In vitro Endothelialization and Platelet Adhesion on Titaniferous Upgraded Polyether and Polycarbonate Polyurethanes
by Karla Lehle 1,*, Jing Li 1, Hanngörg Zimmermann 2, Björn Hartmann 2, Daniel Wehner 3, Thomas Schmid 3 and Christof Schmid 1
1 Department of Cardiothoracic Surgery, University Medical Centre Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany
2 PFM medical titanium, Höfener Str. 45, 90431 Nürnberg, Germany
3 Dualis Medtech GmbH, Am Technologiepark 8+10, 82229 Seefeld, Germany
Materials 2014, 7(2), 623-636; https://doi.org/10.3390/ma7020623 - 24 Jan 2014
Cited by 6 | Viewed by 8444
Abstract
Polycarbonateurethanes (PCU) and polyetherurethanes (PEU) are used for medical devices, however their bio- and haemocompatibility is limited. In this study, the effect of titaniferous upgrading of different polyurethanes on the bio- and haemocompatibility was investigated by endothelial cell (EC) adhesion/proliferation and platelet adhesion [...] Read more.
Polycarbonateurethanes (PCU) and polyetherurethanes (PEU) are used for medical devices, however their bio- and haemocompatibility is limited. In this study, the effect of titaniferous upgrading of different polyurethanes on the bio- and haemocompatibility was investigated by endothelial cell (EC) adhesion/proliferation and platelet adhesion (scanning electron microscopy), respectively. There was no EC adhesion/proliferation and only minor platelet adhesion on upgraded and pure PCU (Desmopan). PEUs (Texin 985, Tecothane 1085, Elastollan 1180A) differed in their cyto- and haemocompatibility. While EC adhesion depended on the type of PEU, any proliferative activity was inhibited. Additional titaniferous upgrading of PEU induced EC proliferation and increased metabolic activity. However, adherent ECs were significantly activated. While Texin was highly thrombotic, only small amounts of platelets adhered onto Tecothane and Elastollan. Additional titaniferous upgrading reduced thrombogenicity of Texin, preserved haemocompatibility of Elastollan, and increased platelet activation/aggregation on Tecothane. In conclusion, none of the PUs was cytocompatible; only titaniferous upgrading allowed EC proliferation and metabolism on PEUs. Haemocompatibility depended on the type of PU. Full article
(This article belongs to the Special Issue Titanium Materials for Biomedical Application 2013)
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