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Nanomaterials, Volume 9, Issue 11 (November 2019)

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Open AccessArticle
Synthesis of Mn0.5Zn0.5SmxEuxFe1.8−2xO4 Nanoparticles via the Hydrothermal Approach Induced Anti-Cancer and Anti-Bacterial Activities
Nanomaterials 2019, 9(11), 1635; https://doi.org/10.3390/nano9111635 (registering DOI) - 18 Nov 2019
Abstract
Manganese metallic nanoparticles are attractive materials for various biological and medical applications. In the present study, we synthesized unique Mn0.5Zn0.5SmxEuxFe1.8−2xO4 (0.01 ≤ x ≤ 0.05) nanoparticles (NPs) by using the hydrothermal approach. [...] Read more.
Manganese metallic nanoparticles are attractive materials for various biological and medical applications. In the present study, we synthesized unique Mn0.5Zn0.5SmxEuxFe1.8−2xO4 (0.01 ≤ x ≤ 0.05) nanoparticles (NPs) by using the hydrothermal approach. The structure and surface morphology of the products were determined by X-ray powder diffraction (XRD), transmission electron and scanning electron microcopies (TEM and SEM), along with energy dispersive X-ray spectroscopy (EDX). We evaluated the impact of Mn0.5Zn0.5SmxEuxFe1.8−2xO4 NPs on both human embryonic stem cells (HEK-293) (normal cells) and human colon carcinoma cells (HCT-116) (cancerous cells). We found that post-48 h of treatment of all products showed a significant decline in the cancer cell population as revealed by microscopically and the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium (MTT) assay. The inhibitory concentration (IC50) values of the products ranged between 0.75 and 2.25 µg/mL. When tested on normal and healthy cells (HEK-293), we found that the treatment of products did not produce any effects on the normal cells, which suggests that all products selectively targeted the cancerous cells. The anti-bacterial properties of the samples were also evaluated by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays, which showed that products also inhibited the bacterial growth. Full article
(This article belongs to the Special Issue Functional Nanomagnetics and Magneto-Optical Nanomaterials)
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Open AccessArticle
Reveal the Deformation Mechanism of (110) Silicon from Cryogenic Temperature to Elevated Temperature by Molecular Dynamics Simulation
Nanomaterials 2019, 9(11), 1632; https://doi.org/10.3390/nano9111632 - 18 Nov 2019
Abstract
Silicon undergoes a brittle-to-ductile transition as its characteristic dimension reduces from macroscale to nanoscale. The thorough understanding of the plastic deformation mechanism of silicon at the nanoscale is still challenging, although it is essential for developing Si-based micro/nanoelectromechanical systems (MEMS/NEMS). Given the wide [...] Read more.
Silicon undergoes a brittle-to-ductile transition as its characteristic dimension reduces from macroscale to nanoscale. The thorough understanding of the plastic deformation mechanism of silicon at the nanoscale is still challenging, although it is essential for developing Si-based micro/nanoelectromechanical systems (MEMS/NEMS). Given the wide application of silicon in extreme conditions, it is, therefore, highly desirable to reveal the nanomechanical behavior of silicon from cryogenic temperature to elevated temperature. In this paper, large-scale molecular dynamics (MD) simulations were performed to reveal the spherical nanoindentation response and plastic deformation mechanism of (110)Si at the temperature range of 0.5 K to 573 K. Special attention was paid to the effect of temperature. Multiple pop-ins detected in load/pressure-indentation strain curves are impacted by temperature. Four featured structures induced by nanoindentation, including high-pressure phases, extrusion of α-Si, dislocations, and crack, are observed at all temperatures, consistent with experiment results. The detailed structure evolution of silicon was revealed at the atomic scale and its dependence on temperature was analyzed. Furthermore, structure changes were correlated with pop-ins in load/pressure-indentation strain curves. These results may advance our understanding of the mechanical properties of silicon. Full article
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Open AccessArticle
Heteroepitaxial Growth of High-Quality and Crack-Free AlN Film on Sapphire Substrate with Nanometer-Scale-Thick AlN Nucleation Layer for AlGaN-Based Deep Ultraviolet Light-Emitting Diodes
Nanomaterials 2019, 9(11), 1634; https://doi.org/10.3390/nano9111634 - 17 Nov 2019
Abstract
High-quality and crack-free aluminum nitride (AlN) film on sapphire substrate is the foundation for high-efficiency aluminum gallium nitride (AlGaN)-based deep ultraviolet light-emitting diodes (DUV LEDs). We reported the growth of high-quality and crack-free AlN film on sapphire substrate with a nanometer-scale-thick AlN nucleation [...] Read more.
High-quality and crack-free aluminum nitride (AlN) film on sapphire substrate is the foundation for high-efficiency aluminum gallium nitride (AlGaN)-based deep ultraviolet light-emitting diodes (DUV LEDs). We reported the growth of high-quality and crack-free AlN film on sapphire substrate with a nanometer-scale-thick AlN nucleation layer (NL). Three kinds of nanometer-scale-thick AlN NLs, including in situ low-temperature AlN (LT-AlN) NL, oxygen-undoped ex situ sputtered AlN NL, and oxygen-doped ex situ sputtered AlN NL, were prepared for epitaxial growth of AlN films on sapphire substrates. The influence of nanoscale AlN NL thickness on the optical transmittance, strain state, surface morphology, and threading dislocation (TD) density of the grown AlN film on sapphire substrate were carefully investigated. The average optical transmittance of AlN film on sapphire substrate with oxygen-doped sputtered AlN NL was higher than that of AlN films on sapphire substrates with LT-AlN NL and oxygen-undoped sputtered AlN NL in the 200–270 nm wavelength region. However, the AlN film on sapphire substrate with oxygen-undoped sputtered AlN NL had the lowest TD density among AlN films on sapphire substrates. The AlN film on sapphire substrate with the optimum thickness of sputtered AlN NL showed weak tensile stress, a crack-free surface, and low TD density. Furthermore, a 270-nm AlGaN-based DUV LED was grown on the high-quality and crack-free AlN film. We believe that our results offer a promising and practical route for obtaining high-quality and crack-free AlN film for DUV LED. Full article
Open AccessArticle
The Growth of Graphene on Ni–Cu Alloy Thin Films at a Low Temperature and Its Carbon Diffusion Mechanism
Nanomaterials 2019, 9(11), 1633; https://doi.org/10.3390/nano9111633 - 17 Nov 2019
Abstract
Carbon solid solubility in metals is an important factor affecting uniform graphene growth by chemical vapor deposition (CVD) at high temperatures. At low temperatures, however, it was found that the carbon diffusion rate (CDR) on the metal catalyst surface has a greater impact [...] Read more.
Carbon solid solubility in metals is an important factor affecting uniform graphene growth by chemical vapor deposition (CVD) at high temperatures. At low temperatures, however, it was found that the carbon diffusion rate (CDR) on the metal catalyst surface has a greater impact on the number and uniformity of graphene layers compared with that of the carbon solid solubility. The CDR decreases rapidly with decreasing temperatures, resulting in inhomogeneous and multilayer graphene. In the present work, a Ni–Cu alloy sacrificial layer was used as the catalyst based on the following properties. Cu was selected to increase the CDR, while Ni was used to provide high catalytic activity. By plasma-enhanced CVD, graphene was grown on the surface of Ni–Cu alloy under low pressure using methane as the carbon source. The optimal composition of the Ni–Cu alloy, 1:2, was selected through experiments. In addition, the plasma power was optimized to improve the graphene quality. On the basis of the parameter optimization, together with our previously-reported, in-situ, sacrificial metal-layer etching technique, relatively homogeneous wafer-size patterned graphene was obtained directly on a 2-inch SiO2/Si substrate at a low temperature (~600 °C). Full article
(This article belongs to the Section Nanocomposite Thin Films and 2D Materials)
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Open AccessReview
Metal Oxide Nanoparticles in Therapeutic Regulation of Macrophage Functions
Nanomaterials 2019, 9(11), 1631; https://doi.org/10.3390/nano9111631 - 16 Nov 2019
Abstract
Macrophages are components of the innate immune system that control a plethora of biological processes. Macrophages can be activated towards pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes depending on the cue; however, polarization may be altered in bacterial and viral infections, cancer, or autoimmune [...] Read more.
Macrophages are components of the innate immune system that control a plethora of biological processes. Macrophages can be activated towards pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes depending on the cue; however, polarization may be altered in bacterial and viral infections, cancer, or autoimmune diseases. Metal (zinc, iron, titanium, copper, etc.) oxide nanoparticles are widely used in therapeutic applications as drugs, nanocarriers, and diagnostic tools. Macrophages can recognize and engulf nanoparticles, while the influence of macrophage-nanoparticle interaction on cell polarization remains unclear. In this review, we summarize the molecular mechanisms that drive macrophage activation phenotypes and functions upon interaction with nanoparticles in an inflammatory microenvironment. The manifold effects of metal oxide nanoparticles on macrophages depend on the type of metal and the route of synthesis. While largely considered as drug transporters, metal oxide nanoparticles nevertheless have an immunotherapeutic potential, as they can evoke pro- or anti-inflammatory effects on macrophages and become essential for macrophage profiling in cancer, wound healing, infections, and autoimmunity. Full article
(This article belongs to the Special Issue Immune Responses to Nanomaterials for Biomedical Applications)
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Open AccessFeature PaperArticle
Fractal Silver Dendrites as 3D SERS Platform for Highly Sensitive Detection of Biomolecules in Hydration Conditions
Nanomaterials 2019, 9(11), 1630; https://doi.org/10.3390/nano9111630 - 16 Nov 2019
Abstract
In this paper, we report on the realization of a highly sensitive and low cost 3D surface-enhanced Raman scattering (SERS) platform. The structural features of the Ag dendrite network that characterize the SERS material were exploited, attesting a remarked self-similarity and scale invariance [...] Read more.
In this paper, we report on the realization of a highly sensitive and low cost 3D surface-enhanced Raman scattering (SERS) platform. The structural features of the Ag dendrite network that characterize the SERS material were exploited, attesting a remarked self-similarity and scale invariance over a broad range of length scales that are typical of fractal systems. Additional structural and optical investigations confirmed the purity of the metal network, which was characterized by low oxygen contamination and by broad optical resonances introduced by the fractal behavior. The SERS performances of the 3D fractal Ag dendrites were tested for the detection of lysozyme as probe molecule, attesting an enhancement factor of ~2.4 × 106. Experimental results assessed the dendrite material as a suitable SERS detection platform for biomolecules investigations in hydration conditions. Full article
(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)
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Open AccessReview
Application of Polyphenol-Loaded Nanoparticles in Food Industry
Nanomaterials 2019, 9(11), 1629; https://doi.org/10.3390/nano9111629 - 16 Nov 2019
Abstract
Nanotechnology is an emerging field of science, and nanotechnological concepts have been intensively studied for potential applications in the food industry. Nanoparticles (with dimensions ranging from one to several hundred nanometers) have specific characteristics and better functionality, thanks to their size and other [...] Read more.
Nanotechnology is an emerging field of science, and nanotechnological concepts have been intensively studied for potential applications in the food industry. Nanoparticles (with dimensions ranging from one to several hundred nanometers) have specific characteristics and better functionality, thanks to their size and other physicochemical properties. Polyphenols are recognized as active compounds that have several putative beneficial properties, including antioxidant, antimicrobial, and anticancer activity. However, the use of polyphenols as functional food ingredients faces numerous challenges, such as their poor stability, solubility, and bioavailability. These difficulties could be solved relatively easily by the application of encapsulation. The objective of this review is to present the most recent accomplishments in the usage of polyphenol-loaded nanoparticles in food science. Nanoparticles loaded with polyphenols and their applications as active ingredients for improving physicochemical and functional properties of food, or as components of active packaging materials, were critically reviewed. Potential adverse effects of polyphenol-loaded nanomaterials are also discussed. Full article
(This article belongs to the Special Issue Nanotechnology in Agriculture and Food Industry)
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Open AccessArticle
Effect of Heterointerface on NO2 Sensing Properties of In-Situ Formed TiO2 QDs-Decorated NiO Nanosheets
Nanomaterials 2019, 9(11), 1628; https://doi.org/10.3390/nano9111628 - 16 Nov 2019
Abstract
In this work, TiO2 QDs-modified NiO nanosheets were employed to improve the room temperature NO2 sensing properties of NiO. The gas sensing studies showed that the response of nanocomposites with the optimal ratio to 60 ppm NO2 was nearly 10 [...] Read more.
In this work, TiO2 QDs-modified NiO nanosheets were employed to improve the room temperature NO2 sensing properties of NiO. The gas sensing studies showed that the response of nanocomposites with the optimal ratio to 60 ppm NO2 was nearly 10 times larger than that of bare NiO, exhibiting a potential application in gas sensing. Considering the commonly reported immature mechanism that the effective charge transfer between two phases contributes to an enhanced sensitivity, the QDs sensitization mechanism was further detailed by designing a series of contrast experiments. First, the important role of the QDs size effect was revealed by comparing the little enhanced sensitivity of TiO2 particle-modified NiO with the largely enhanced sensitivity of TiO2 QDs-NiO. Second, and more importantly, direct evidence of the heterointerface charge transfer efficiency was detailed by the extracted interface bond (Ti-O-Ni) using XPS peak fitting. This work can thus provide guidelines to design more QDs-modified nanocomposites with higher sensitivity for practical applications. Full article
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Open AccessArticle
Optimizing the Interface between Hole Transporting Material and Nanocomposite for Highly Efficient Perovskite Solar Cells
Nanomaterials 2019, 9(11), 1627; https://doi.org/10.3390/nano9111627 - 16 Nov 2019
Abstract
The performances of organometallic halide perovskite-based solar cells severely depend on the device architecture and the interface between each layer included in the device stack. In particular, the interface between the charge transporting layer and the perovskite film is crucial, since it represents [...] Read more.
The performances of organometallic halide perovskite-based solar cells severely depend on the device architecture and the interface between each layer included in the device stack. In particular, the interface between the charge transporting layer and the perovskite film is crucial, since it represents both the substrate where the perovskite polycrystalline film grows, thus directly influencing the active layer morphology, and an important site for electrical charge extraction and/or recombination. Here, we focus on engineering the interface between a perovskite-polymer nanocomposite, recently developed by our group, and different commonly employed polymeric hole transporters, namely PEDOT: PSS [poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)], PEDOT, PTAA [poly(bis 4-phenyl}{2,4,6-trimethylphenyl}amine)], Poly-TPD [Poly(N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine] Poly-TPD, in inverted planar perovskite solar cell architecture. The results show that when Poly-TPD is used as the hole transfer material, perovskite film morphology improved, suggesting an improvement in the interface between Poly-TPD and perovskite active layer. We additionally investigate the effect of the Molecular Weight (MW) of Poly-TPD on the performance of perovskite solar cells. By increasing the MW, the photovoltaic performances of the cells are enhanced, reaching power conversion efficiency as high as 16.3%. Full article
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Open AccessArticle
Development of Superparamagnetic Nanoparticles Coated with Polyacrylic Acid and Aluminum Hydroxide as an Efficient Contrast Agent for Multimodal Imaging
Nanomaterials 2019, 9(11), 1626; https://doi.org/10.3390/nano9111626 - 15 Nov 2019
Abstract
Early diagnosis of disease and follow-up of therapy is of vital importance for appropriate patient management since it allows rapid treatment, thereby reducing mortality and improving health and quality of life with lower expenditure for health care systems. New approaches include nanomedicine-based diagnosis [...] Read more.
Early diagnosis of disease and follow-up of therapy is of vital importance for appropriate patient management since it allows rapid treatment, thereby reducing mortality and improving health and quality of life with lower expenditure for health care systems. New approaches include nanomedicine-based diagnosis combined with therapy. Nanoparticles (NPs), as contrast agents for in vivo diagnosis, have the advantage of combining several imaging agents that are visible using different modalities, thereby achieving high spatial resolution, high sensitivity, high specificity, morphological, and functional information. In this work, we present the development of aluminum hydroxide nanostructures embedded with polyacrylic acid (PAA) coated iron oxide superparamagnetic nanoparticles, Fe3O4@Al(OH)3, synthesized by a two-step co-precipitation and forced hydrolysis method, their physicochemical characterization and first biomedical studies as dual magnetic resonance imaging (MRI)/positron emission tomography (PET) contrast agents for cell imaging. The so-prepared NPs are size-controlled, with diameters below 250 nm, completely and homogeneously coated with an Al(OH)3 phase over the magnetite cores, superparamagnetic with high saturation magnetization value (Ms = 63 emu/g-Fe3O4), and porous at the surface with a chemical affinity for fluoride ion adsorption. The suitability as MRI and PET contrast agents was tested showing high transversal relaxivity (r2) (83.6 mM−1 s−1) and rapid uptake of 18F-labeled fluoride ions as a PET tracer. The loading stability with 18F-fluoride was tested in longitudinal experiments using water, buffer, and cell culture media. Even though the stability of the 18F-label varied, it remained stable under all conditions. A first in vivo experiment indicates the suitability of Fe3O4@Al(OH)3 nanoparticles as a dual contrast agent for sensitive short-term (PET) and high-resolution long-term imaging (MRI). Full article
(This article belongs to the Special Issue Frontiers in Nanomaterials for Clinical Imaging and Selective Therapy)
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Open AccessArticle
Polymer Membranes Sonocoated and Electrosprayed with Nano-Hydroxyapatite for Periodontal Tissues Regeneration
Nanomaterials 2019, 9(11), 1625; https://doi.org/10.3390/nano9111625 - 15 Nov 2019
Abstract
Diseases of periodontal tissues are a considerable clinical problem, connected with inflammatory processes and bone loss. The healing process often requires reconstruction of lost bone in the periodontal area. For that purpose, various membranes are used to prevent ingrowth of epithelium in the [...] Read more.
Diseases of periodontal tissues are a considerable clinical problem, connected with inflammatory processes and bone loss. The healing process often requires reconstruction of lost bone in the periodontal area. For that purpose, various membranes are used to prevent ingrowth of epithelium in the tissue defect and enhance bone regeneration. Currently-used membranes are mainly non-resorbable or are derived from animal tissues. Thus, there is an urgent need for non-animal-derived bioresorbable membranes with tuned resorption rates and porosity optimized for the circulation of body nutrients. We demonstrate membranes produced by the electrospinning of biodegradable polymers (PDLLA/PLGA) coated with nanohydroxyapatite (nHA). The nHA coating was made using two methods: sonocoating and electrospraying of nHA suspensions. In a simulated degradation study, for electrosprayed membranes, short-term calcium release was observed, followed by hydrolytic degradation. Sonocoating produced a well-adhering nHA layer with full coverage of the fibers. The layer slowed the polymer degradation and increased the membrane wettability. Due to gradual release of calcium ions the degradation-associated acidity of the polymer was neutralized. The sonocoated membranes exhibited good cellular metabolic activity responses against MG-63 and BJ cells. The collected results suggest their potential use in Guided Tissue Regeneration (GTR) and Guided Bone Regeneration (GBR) periodontal procedures. Full article
(This article belongs to the Special Issue Nanomaterials and Nanotechnology in Dentistry)
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Open AccessArticle
A Facile, One-Step Synthesis of Silicon/Silicon Carbide/Carbon Nanotube Nanocomposite as a Cycling-Stable Anode for Lithium Ion Batteries
Nanomaterials 2019, 9(11), 1624; https://doi.org/10.3390/nano9111624 - 15 Nov 2019
Abstract
Silicon/carbon nanotube (Si/CNTs) nanocomposite is a promising anode material for lithium ion batteries (LIBs). Challenges related to the tricky synthesis process, as well as the weak interaction between Si and CNTs, hinder practical applications. To address these issues, a facile, one-step method to [...] Read more.
Silicon/carbon nanotube (Si/CNTs) nanocomposite is a promising anode material for lithium ion batteries (LIBs). Challenges related to the tricky synthesis process, as well as the weak interaction between Si and CNTs, hinder practical applications. To address these issues, a facile, one-step method to synthesize Si/CNTs nanocomposite by using silica (SiO2) as a reactant via a magnesium reduction process was developed. In this synthesis, the heat released enables the as-obtained Si to react with CNTs in the interfacial region to form silicon carbide (SiC). By virtue of the unique structure composed of Si nanoparticles strongly anchored to conductive CNTs network with stable Si–C chemical bonding, the Si/SiC/CNT nanocomposite delivers a stable capacity of ~1100 mAh g−1 and a capacity retention of about 83.8% after 200 cycles at a current density of 100 mA g−1. Our studies may provide a convenient strategy for the preparation of the Si/C anode of LIBs. Full article
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Open AccessArticle
Synergistical Use of Electrostatic and Hydrophobic Interactions for the Synthesis of a New Class of Multifunctional Nanohybrids: Plasmonic Magneto-Liposomes
Nanomaterials 2019, 9(11), 1623; https://doi.org/10.3390/nano9111623 - 15 Nov 2019
Abstract
By carefully controlling the electrostatic interactions between cationic liposomes, which already incorporate magnetic nanoparticles in the bilayers, and anionic gold nanoparticles, a new class of versatile multifunctional nanohybrids (plasmonic magneto-liposomes) that could have a major impact in drug delivery and controlled release applications [...] Read more.
By carefully controlling the electrostatic interactions between cationic liposomes, which already incorporate magnetic nanoparticles in the bilayers, and anionic gold nanoparticles, a new class of versatile multifunctional nanohybrids (plasmonic magneto-liposomes) that could have a major impact in drug delivery and controlled release applications has been synthesized. The experimental results confirmed the successful synthesis of hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs) and polyethylene glycol functionalized (PEGylated) gold nanoparticles (AuNPs). The SPIONs were incorporated in the liposomal lipidic bilayers, thus promoting the formation of cationic magnetoliposomes. Different concentrations of SPIONs were loaded in the membrane. The cationic magnetoliposomes were decorated with anionic PEGylated gold nanoparticles using electrostatic interactions. The successful incorporation of SPIONs together with the modifications they generate in the bilayer were analyzed using Raman spectroscopy. The plasmonic properties of the multifunctional nanohybrids were investigated using UV-Vis absorption and (surface-enhanced) Raman spectroscopy. Their hyperthermic properties were recorded at different frequencies and magnetic field intensities. After the synthesis, the nanosystems were extensively characterized in order to properly evaluate their potential use in drug delivery applications and controlled release as a result of the interaction with an external stimulus, such as an NIR laser or alternating magnetic field. Full article
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Open AccessArticle
Preparation of Anisotropic Aerogels with Pristine Graphene by Heat Flow and Study of Their Effects on Heat Transfer in Paraffin
Nanomaterials 2019, 9(11), 1622; https://doi.org/10.3390/nano9111622 - 15 Nov 2019
Abstract
In this study, anisotropic graphene/graphene oxide (GO) aerogels (AGAs) were obtained by freeze-drying after direct participation of pristine graphene in the self-assembly of anisotropic gel by the heat flow method. After vacuum microwave treatment, the physical, chemical and structural characteristics of the AGAs [...] Read more.
In this study, anisotropic graphene/graphene oxide (GO) aerogels (AGAs) were obtained by freeze-drying after direct participation of pristine graphene in the self-assembly of anisotropic gel by the heat flow method. After vacuum microwave treatment, the physical, chemical and structural characteristics of the AGAs were investigated. The results show that AGAs, in which the internal graphene sheets are parallel to the heat flow direction, are successfully prepared. After microwave treatment, the amount of oxygen and nitrogen reduces significantly and the sp2 domain increases. However, at the same time, many fragments and holes are generated in the graphene sheets. The effects of AGAs on the phase transition of paraffin is studied, and the results show that the melting enthalpy, solidification enthalpy and initial melting temperature of AGA/paraffin composites decreases as the GO content in the AGAs increases, whereas the melting range, solidifying range and subcooling degree increases. The highest axial thermal conductivity of the AGA/paraffin composite is 1.45 W/(mK), and the thermal conductivity enhancement efficiency is 884% (AGA content was 0.53 vol %). Compared with previously investigated, similar AGA/paraffin composites, the aerogels fabricated in this study have the obvious advantages of a simple fabrication process, a low cost and a high thermal conductivity enhancement efficiency. These aerogels possess the potential for application in phase-change energy storage (PES), thermal energy management and other fields. Full article
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Open AccessArticle
Complexes Formed by Hydrophobic Interaction between Ag-Nanospheres and Adsorbents for the Detection of Methyl Salicylate VOC
Nanomaterials 2019, 9(11), 1621; https://doi.org/10.3390/nano9111621 - 15 Nov 2019
Abstract
Surface-enhanced Raman spectroscopy (SERS) has been widely investigated in many applications. However, only little work has been done on using SERS for the detection of volatile organic compounds (VOCs), primarily due to the challenges associated with fabricating SERS substrates with sufficient hotspots for [...] Read more.
Surface-enhanced Raman spectroscopy (SERS) has been widely investigated in many applications. However, only little work has been done on using SERS for the detection of volatile organic compounds (VOCs), primarily due to the challenges associated with fabricating SERS substrates with sufficient hotspots for signal enhancement and with the surface interfacially compatible for the VOCs. This study investigated the phase transfer of Ag-nanospheres (AgNSs) from the aqueous phase to the non-aqueous phase by electrostatic interaction induced by cationic surfactants, and the feasibility of the transferred AgNSs as SERS substrates for the determination of methyl salicylate VOC. Results indicated that one of three cationic surfactants, tetraoctylammonium bromide (TOAB) dissolved in organic solvent showed successful phase transfer of the AgNSs confirmed by several characterization analyses. The complex formed by hydrophobic interaction between the transferred AgNSs and Tenax-TA adsorbent polymer was able to be utilized as a SERS substrate, and the volatile of methyl salicylate could be easily determined from SERS measurements at 4 h static volatile collection. Therefore, the proposed new techniques can be effectively employed to areas where many VOCs relevant to food and agriculture need to be analyzed. Full article
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Open AccessArticle
Reconfigurable Local Photoluminescence of Atomically-Thin Semiconductors via Ferroelectric-Assisted Effects
Nanomaterials 2019, 9(11), 1620; https://doi.org/10.3390/nano9111620 - 15 Nov 2019
Abstract
Combining a pair of materials of different structural dimensions and functional properties into a hybrid material system may realize unprecedented multi-functional device applications. Especially, two-dimensional (2D) materials are suitable for being incorporated into the heterostructures due to their colossal area-to-volume ratio, excellent flexibility, [...] Read more.
Combining a pair of materials of different structural dimensions and functional properties into a hybrid material system may realize unprecedented multi-functional device applications. Especially, two-dimensional (2D) materials are suitable for being incorporated into the heterostructures due to their colossal area-to-volume ratio, excellent flexibility, and high sensitivity to interfacial and surface interactions. Semiconducting molybdenum disulfide (MoS2), one of the well-studied layered materials, has a direct band gap as one molecular layer and hence, is expected to be one of the promising key materials for next-generation optoelectronics. Here, using lateral 2D/3D heterostructures composed of MoS2 monolayers and nanoscale inorganic ferroelectric thin films, reversibly tunable photoluminescence has been demonstrated at the microscale to be over 200% upon ferroelectric polarization reversal by using nanoscale conductive atomic force microscopy tips. Also, significant ferroelectric-assisted modulation in electrical properties has been achieved from field-effect transistor devices based on the 2D/3D heterostructrues. Moreover, it was also shown that the MoS2 monolayer can be an effective electric field barrier in spite of its sub-nanometer thickness. These results would be of close relevance to exploring novel applications in the fields of optoelectronics and sensor technology. Full article
(This article belongs to the Special Issue Preparation and Properties of 2D Materials)
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Open AccessArticle
Ullmann Reactions of Carbon Nanotubes—Advantageous and Unexplored Functionalization toward Tunable Surface Chemistry
Nanomaterials 2019, 9(11), 1619; https://doi.org/10.3390/nano9111619 - 15 Nov 2019
Abstract
We demonstrate Ullmann-type reactions as novel and advantageous functionalization of carbon nanotubes (CNTs) toward tunable surface chemistry. The functionalization routes comprise O-, N-, and C-arylation of chlorinated CNTs. We confirm the versatility and efficiency of the reaction allowing functionalization degrees [...] Read more.
We demonstrate Ullmann-type reactions as novel and advantageous functionalization of carbon nanotubes (CNTs) toward tunable surface chemistry. The functionalization routes comprise O-, N-, and C-arylation of chlorinated CNTs. We confirm the versatility and efficiency of the reaction allowing functionalization degrees up to 3.5 mmol g−1 by applying both various nanotube substrates, i.e., single-wall (SWCNTs) and multi-wall CNTs (MWCNTs) of various chirality, geometry, and morphology as well as diverse Ullmann-type reagents: phenol, aniline, and iodobenzene. The reactivity of nanotubes was correlatable with the nanotube diameter and morphology revealing SWCNTs as the most reactive representatives. We have determined the optimized conditions of this two-step synthetic protocol as: (1) chlorination using iodine trichloride (ICl3), and (2) Ullmann-type reaction in the presence of: copper(I) iodide (CuI), 1,10-phenanthroline as chelating agent and caesium carbonate (Cs2CO3) as base. We have analyzed functionalized CNTs using a variety of techniques, i.e., scanning and transmission electron microscopy, energy dispersive spectroscopy, thermogravimetry, comprehensive Raman spectroscopy, and X-ray photoelectron spectroscopy. The analyses confirmed the purely covalent nature of those modifications at all stages. Eventually, we have proved the elaborated protocol as exceptionally tunable since it enabled us: (a) to synthesize superhydrophilic films from—the intrinsically hydrophobic—vertically aligned MWCNT arrays and (b) to produce printable highly electroconductive pastes of enhanced characteristics—as compared for non-modified and otherwise modified MWCNTs—for textronics. Full article
(This article belongs to the Special Issue Carbon Nanotube: Synthesis, Characteristics and Applications)
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Open AccessArticle
Hall Amplifier Nanoscale Device (HAND): Modeling, Simulations and Feasibility Analysis for THz Sensor
Nanomaterials 2019, 9(11), 1618; https://doi.org/10.3390/nano9111618 - 14 Nov 2019
Abstract
HAND (Hall Amplifier Nanoscale Device), a new nano-metric device, was designed, simulated, and modeled for feasibility analysis, with the challenge of combining a well-known macro effect into the nanoscale world. HAND is based on the well-known Hall Effect, and it may enable circuitry [...] Read more.
HAND (Hall Amplifier Nanoscale Device), a new nano-metric device, was designed, simulated, and modeled for feasibility analysis, with the challenge of combining a well-known macro effect into the nanoscale world. HAND is based on the well-known Hall Effect, and it may enable circuitry working at very high frequencies (tens of Tera-Hertz). The architecture, design, and simulations were performed while using Comsol Multi-Physics Package Software. Complementary accurate analytical models were developed to support the understanding of the device functionality, including treatment of specific phenomena, such as heat transfer, and mega-magnet feasibility inside integrated circuits. This new device, combining both the Hall Effect and nanoscale dimensions, holds the potential to change the computing rates in the microelectronics circuitry world, and can serve as a game changer. Full article
(This article belongs to the Special Issue Nano Fabrications of Solid-State Sensors and Sensor Systems)
Open AccessArticle
Influence of Nanoscale Textured Surfaces and Subsurface Defects on Friction Behaviors by Molecular Dynamics Simulation
Nanomaterials 2019, 9(11), 1617; https://doi.org/10.3390/nano9111617 - 14 Nov 2019
Abstract
In nanomaterials, the surface or the subsurface structures influence the friction behaviors greatly. In this work, nanoscale friction behaviors between a rigid cylinder tip and a single crystal copper substrate are studied by molecular dynamics simulation. Nanoscale textured surfaces are modeled on the [...] Read more.
In nanomaterials, the surface or the subsurface structures influence the friction behaviors greatly. In this work, nanoscale friction behaviors between a rigid cylinder tip and a single crystal copper substrate are studied by molecular dynamics simulation. Nanoscale textured surfaces are modeled on the surface of the substrate to represent the surface structures, and the spacings between textures are seen as defects on the surface. Nano-defects are prepared at the subsurface of the substrate. The effects of depth, orientation, width and shape of textured surfaces on the average friction forces are investigated, and the influence of subsurface defects in the substrate is also studied. Compared with the smooth surface, textured surfaces can improve friction behaviors effectively. The textured surfaces with a greater depth or smaller width lead to lower friction forces. The surface with 45° texture orientation produces the lowest average friction force among all the orientations. The influence of the shape is slight, and the v-shape shows a lower average friction force. Besides, the subsurface defects in the substrate make the sliding process unstable and the influence of subsurface defects on friction forces is sensitive to their positions. Full article
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Open AccessArticle
Nanoparticulate Metal Oxide Top Electrode Interface Modification Improves the Thermal Stability of Inverted Perovskite Photovoltaics
Nanomaterials 2019, 9(11), 1616; https://doi.org/10.3390/nano9111616 - 14 Nov 2019
Abstract
Solution processed γ-Fe2O3 nanoparticles via the solvothermal colloidal synthesis in conjunction with ligand-exchange method are used for interface modification of the top electrode in inverted perovskite solar cells. In comparison to more conventional top electrodes such as PC(70)BM/Al and PC(70)BM/AZO/Al, [...] Read more.
Solution processed γ-Fe2O3 nanoparticles via the solvothermal colloidal synthesis in conjunction with ligand-exchange method are used for interface modification of the top electrode in inverted perovskite solar cells. In comparison to more conventional top electrodes such as PC(70)BM/Al and PC(70)BM/AZO/Al, we show that incorporation of a γ-Fe2O3 provides an alternative solution processed top electrode (PC(70)BM/γ-Fe2O3/Al) that not only results in comparable power conversion efficiencies but also improved thermal stability of inverted perovskite photovoltaics. The origin of improved stability of inverted perovskite solar cells incorporating PC(70)BM/ γ-Fe2O3/Al under accelerated heat lifetime conditions is attributed to the acidic surface nature of γ-Fe2O3 and reduced charge trapped density within PC(70)BM/ γ-Fe2O3/Al top electrode interfaces. Full article
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Open AccessArticle
Fabrication of Cu2ZnSnS4 Thin Films from Ball-Milled Nanoparticle inks under Various Annealing Temperatures
Nanomaterials 2019, 9(11), 1615; https://doi.org/10.3390/nano9111615 - 14 Nov 2019
Abstract
Cu2ZnSnS4 (CZTS) has been recognized as a promising thin-film absorber material of chalcopyrite-related solar cells. A two-stage method for fabricating CZTS films using CZTS nanoparticles was developed. Nanocrystal inks fabricated by a ball-milling method was utilized to °C deposit CZTS [...] Read more.
Cu2ZnSnS4 (CZTS) has been recognized as a promising thin-film absorber material of chalcopyrite-related solar cells. A two-stage method for fabricating CZTS films using CZTS nanoparticles was developed. Nanocrystal inks fabricated by a ball-milling method was utilized to °C deposit CZTS precursors by spin-coating approach. The CZTS precursors were annealed in the sulfur atmosphere under different annealing temperatures ranging from 550 °C to 650 °C. Influences of annealing temperature on grain growth, composition, crystallinity, and photovoltaic properties of CZTS films were characterized. With the increase of annealing temperature, grain growth was enhanced, while the sulfur atomic ratio fist increased then decreased. The crystallinity of the films was significantly improved after the annealing, and the obvious peak of the secondary phase of ZnS, were observed from the X-ray diffraction results, when the annealing temperature increased to 625 °C. However, the secondary phase was not detected from the surface Raman spectrum. Through comparing the Raman spectrum of different areas of the CZTS film, secondary phases of ZnS and SnS were observed, indicating the decomposition of CZTS films, due to the high temperature. The highest conversion efficiency of 7.5% was obtained when the annealing temperature was 600 °C. Full article
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Open AccessReview
Biosensing and Delivery of Nucleic Acids Involving Selected Well-Known and Rising Star Functional Nanomaterials
Nanomaterials 2019, 9(11), 1614; https://doi.org/10.3390/nano9111614 - 14 Nov 2019
Abstract
In the last fifteen years, the nucleic acid biosensors and delivery area has seen a breakthrough due to the interrelation between the recognition of nucleic acid’s high specificity, the great sensitivity of electrochemical and optical transduction and the unprecedented opportunities imparted by nanotechnology. [...] Read more.
In the last fifteen years, the nucleic acid biosensors and delivery area has seen a breakthrough due to the interrelation between the recognition of nucleic acid’s high specificity, the great sensitivity of electrochemical and optical transduction and the unprecedented opportunities imparted by nanotechnology. Advances in this area have demonstrated that the assembly of nanoscaled materials allows the performance enhancement, particularly in terms of sensitivity and response time, of functional nucleic acids’ biosensing and delivery to a level suitable for the construction of point-of-care diagnostic tools. Consequently, this has propelled detection methods using nanomaterials to the vanguard of the biosensing and delivery research fields. This review overviews the striking advancement in functional nanomaterials’ assisted biosensing and delivery of nucleic acids. We highlight the advantages demonstrated by selected well-known and rising star functional nanomaterials (metallic, magnetic and Janus nanomaterials) focusing on the literature produced in the past five years. Full article
(This article belongs to the Special Issue Functional Nanomagnetics and Magneto-Optical Nanomaterials)
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Open AccessArticle
Fibrillar Self-Assembly of a Chimeric Elastin-Resilin Inspired Engineered Polypeptide
Nanomaterials 2019, 9(11), 1613; https://doi.org/10.3390/nano9111613 - 14 Nov 2019
Abstract
In the field of tissue engineering, recombinant protein-based biomaterials made up of block polypeptides with tunable properties arising from the functionalities of the individual domains are appealing candidates for the construction of medical devices. In this work, we focused our attention on the [...] Read more.
In the field of tissue engineering, recombinant protein-based biomaterials made up of block polypeptides with tunable properties arising from the functionalities of the individual domains are appealing candidates for the construction of medical devices. In this work, we focused our attention on the preparation and structural characterization of nanofibers from a chimeric-polypeptide-containing resilin and elastin domain, designed on purpose to enhance its cell-binding ability by introducing a specific fibronectin-derived Arg-Gly-Asp (RGD) sequence. The polypeptide ability to self-assemble was investigated. The molecular and supramolecular structure was characterized by Scanning Electronic Microscopy (SEM) and Atomic Force Microscopy (AFM), circular dichroism, state-of-the-art synchrotron radiation-induced techniques X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The attained complementary results allow us to assess as H-bonds influence the morphology of the aggregates obtained after the self-assembling of the chimeric polypeptide. Finally, a preliminary investigation of the potential cytotoxicity of the polypeptide was performed by culturing human fetal foreskin fibroblast (HFFF2) for its use as biomedical device. Full article
(This article belongs to the Special Issue Advanced Biocompatible Nanomaterials)
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Open AccessFeature PaperArticle
Polyimide-Coated Glass Microfiber as Polysulfide Perm-Selective Separator for High-Performance Lithium-Sulphur Batteries
Nanomaterials 2019, 9(11), 1612; https://doi.org/10.3390/nano9111612 - 13 Nov 2019
Abstract
Although numerous research efforts have been made for the last two decades, the chronic problems of lithium-sulphur batteries (LSBs), i.e., polysulfide shuttling of active sulphur material and surface passivation of the lithium metal anode, still impede their practical application. In order to mitigate [...] Read more.
Although numerous research efforts have been made for the last two decades, the chronic problems of lithium-sulphur batteries (LSBs), i.e., polysulfide shuttling of active sulphur material and surface passivation of the lithium metal anode, still impede their practical application. In order to mitigate these issues, we utilized polyimide functionalized glass microfibers (PI-GF) as a functional separator. The water-soluble precursor enabled the formation of a homogenous thin coating on the surface of the glass microfiber (GF) membrane with the potential to scale and fine-tune: the PI-GF was prepared by simple dipping of commercial GF into an aqueous solution of poly(amic acid), (PAA), followed by thermal imidization. We found that a tiny amount of polyimide (PI) of 0.5 wt.% is more than enough to endow the GF separator with useful capabilities, both retarding polysulfide migration. Combined with a free-standing microporous carbon cloth-sulphur composite cathode, the PI-GF-based LSB cell exhibits a stable cycling over 120 cycles at a current density of 1 mA/cm2 and an areal sulphur loading of 2 mgS/cm2 with only a marginal capacity loss of 0.099%/cycle. This corresponds to an improvement in cycle stability by 200%, specific capacity by 16.4%, and capacity loss per cycle by 45% as compared to those of the cell without PI coating. Our study revealed that a simple but synergistic combination of porous carbon supporting material and functional separator enabled us to achieve high-performance LSBs, but could also pave the way for the development of practical LSBs using the commercially viable method without using complicated synthesis or harmful and expensive chemicals. Full article
(This article belongs to the Special Issue Emerging Nanomaterials for Lithium-Sulfur Batteries and Beyond)
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Open AccessArticle
Co2TiO4/Reduced Graphene Oxide Nanohybrids for Electrochemical Sensing Applications
Nanomaterials 2019, 9(11), 1611; https://doi.org/10.3390/nano9111611 - 13 Nov 2019
Abstract
For the first time, the synthesis, characterization, and analytical application for hydrogen peroxide quantification of the hybrid materials of Co2TiO4 (CTO) and reduced graphene oxide (RGO) is reported, using in situ (CTO/RGO) and ex situ (CTO+RGO) preparations. This synthesis for [...] Read more.
For the first time, the synthesis, characterization, and analytical application for hydrogen peroxide quantification of the hybrid materials of Co2TiO4 (CTO) and reduced graphene oxide (RGO) is reported, using in situ (CTO/RGO) and ex situ (CTO+RGO) preparations. This synthesis for obtaining nanostructured CTO is based on a one-step hydrothermal synthesis, with new precursors and low temperatures. The morphology, structure, and composition of the synthesized materials were examined using scanning electron microscopy, X-ray diffraction (XRD), neutron powder diffraction (NPD), and X-ray photoelectron spectroscopy (XPS). Rietveld refinements using neutron diffraction data were conducted to determine the cation distributions in CTO. Hybrid materials were also characterized by Brunauer–Emmett–Teller adsorption isotherms, Scanning Electron microscopy, and scanning electrochemical microscopy. From an analytical point of view, we evaluated the electrochemical reduction of hydrogen peroxide on glassy carbon electrodes modified with hybrid materials. The analytical detection of hydrogen peroxide using CTO/RGO showed 11 and 5 times greater sensitivity in the detection of hydrogen peroxide compared with that of pristine CTO and RGO, respectively, and a two-fold increase compared with that of the RGO+CTO modified electrode. These results demonstrate that there is a synergistic effect between CTO and RGO that is more significant when the hybrid is synthetized through in situ methodology. Full article
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Open AccessArticle
Polymerization-Induced Phase Segregation and Self-Assembly of Siloxane Additives to Provide Thermoset Coatings with a Defined Surface Topology and Biocidal and Self-Cleaning Properties
Nanomaterials 2019, 9(11), 1610; https://doi.org/10.3390/nano9111610 - 13 Nov 2019
Abstract
In this work, we report on the incorporation of a siloxane copolymer additive, poly((2-phenylethyl) methylsiloxane)-co(1-phenylethyl) methylsiloxane)-co-dimethylsiloxane), which is fully soluble at room temperature, in a rapid-cure thermoset polyester coating formulation. The additive undergoes polymerization-induced phase segregation (PIPS) to self-assemble on the coating surface [...] Read more.
In this work, we report on the incorporation of a siloxane copolymer additive, poly((2-phenylethyl) methylsiloxane)-co(1-phenylethyl) methylsiloxane)-co-dimethylsiloxane), which is fully soluble at room temperature, in a rapid-cure thermoset polyester coating formulation. The additive undergoes polymerization-induced phase segregation (PIPS) to self-assemble on the coating surface as discrete discoid nanofeatures during the resin cure process. Moreover, the copolymer facilitates surface co-segregation of titanium dioxide pigment microparticulate present in the coating. Depending on the composition, the coatings can display persistent superhydrophobicity and self-cleaning properties and, surprisingly, the titanium dioxide pigmented coatings that include the siloxane copolymer additive display high levels of antibacterial performance against Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria. This antibacterial performance is believed to be associated with the unique surface topology of these coatings, which comprise stimuli-responsive discoid nanofeatures. This paper provides details of the surface morphology of the coatings and how these relates to the antimicrobial properties of the coating. Full article
(This article belongs to the Special Issue Antibacterial Nanomaterials Coating: Fabrication and Applications)
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Open AccessArticle
Effects of Divacancy and Extended Line Defects on the Thermal Transport Properties of Graphene Nanoribbons
Nanomaterials 2019, 9(11), 1609; https://doi.org/10.3390/nano9111609 - 13 Nov 2019
Abstract
The effects of divacancy, including isolated defects and extended line defects (ELD), on the thermal transport properties of graphene nanoribbons (GNRs) are investigated using the Nonequilibrium Green’s function method. Different divacancy defects can effectively tune the thermal transport of GNRs and the thermal [...] Read more.
The effects of divacancy, including isolated defects and extended line defects (ELD), on the thermal transport properties of graphene nanoribbons (GNRs) are investigated using the Nonequilibrium Green’s function method. Different divacancy defects can effectively tune the thermal transport of GNRs and the thermal conductance is significantly reduced. The phonon scattering of a single divacancy is mostly at high frequencies while the phonon scattering at low frequencies is also strong for randomly distributed multiple divacancies. The collective effect of impurity scattering and boundary scattering is discussed, which makes the defect scattering vary with the boundary condition. The effect on thermal transport properties of a divacancy is also shown to be closely related to the cross section of the defect, the internal structure and the bonding strength inside the defect. Both low frequency and high frequency phonons are scattered by 48, d5d7 and t5t7 ELD. However, the 585 ELD has almost no influence on phonon scattering at low frequency region, resulting in the thermal conductance of GNRs with 585 ELD being 50% higher than that of randomly distributed 585 defects. All these results are valuable for the design and manufacture of graphene nanodevices. Full article
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Open AccessReview
Bare Iron Oxide Nanoparticles: Surface Tunability for Biomedical, Sensing and Environmental Applications
Nanomaterials 2019, 9(11), 1608; https://doi.org/10.3390/nano9111608 - 12 Nov 2019
Abstract
Surface modification is widely assumed as a mandatory prerequisite for the real applicability of iron oxide nanoparticles. This is aimed to endow prolonged stability, electrolyte and pH tolerance as well as a desired specific surface chemistry for further functionalization to these materials. Nevertheless, [...] Read more.
Surface modification is widely assumed as a mandatory prerequisite for the real applicability of iron oxide nanoparticles. This is aimed to endow prolonged stability, electrolyte and pH tolerance as well as a desired specific surface chemistry for further functionalization to these materials. Nevertheless, coating processes have negative consequences on the sustainability of nanomaterial production contributing to high costs, heavy environmental impact and difficult scalability. In this view, bare iron oxide nanoparticles (BIONs) are arousing an increasing interest and the properties and advantages of pristine surface chemistry of iron oxide are becoming popular among the scientific community. In the authors’ knowledge, rare efforts were dedicated to the use of BIONs in biomedicine, biotechnology, food industry and environmental remediation. Furthermore, literature lacks examples highlighting the potential of BIONs as platforms for the creation of more complex nanostructured architectures, and emerging properties achievable by the direct manipulation of pristine iron oxide surfaces have been little studied. Based on authors’ background on BIONs, the present review is aimed at providing hints on the future expansion of these nanomaterials emphasizing the opportunities achievable by tuning their pristine surfaces. Full article
Open AccessReview
Recent Advances and Future Prospects in Spark Plasma Sintered Alumina Hybrid Nanocomposites
Nanomaterials 2019, 9(11), 1607; https://doi.org/10.3390/nano9111607 - 12 Nov 2019
Abstract
Although ceramics have many advantages when compared to metals in specific applications, they could be more widely applied if their low properties (fracture toughness, strength, and electrical and thermal conductivities) are improved. Reinforcing ceramics by two nano-phases that have different morphologies and/or properties, [...] Read more.
Although ceramics have many advantages when compared to metals in specific applications, they could be more widely applied if their low properties (fracture toughness, strength, and electrical and thermal conductivities) are improved. Reinforcing ceramics by two nano-phases that have different morphologies and/or properties, called the hybrid microstructure design, has been implemented to develop hybrid ceramic nanocomposites with tailored nanostructures, improved mechanical properties, and enhanced functionalities. The use of the novel spark plasma sintering (SPS) process allowed for the sintering of hybrid ceramic nanocomposite materials to maintain high relative density while also preserving the small grain size of the matrix. As a result, hybrid nanocomposite materials that have better mechanical and functional properties than those of either conventional composites or nanocomposites were produced. The development of hybrid ceramic nanocomposites is in its early stage and it is expected to continue attracting the interest of the scientific community. In the present paper, the progress made in the development of alumina hybrid nanocomposites, using spark plasma sintering, and their properties are reviewed. In addition, the current challenges and potential applications are highlighted. Finally, future prospects for developing alumina hybrid nanocomposites that have better performance are set. Full article
(This article belongs to the Special Issue Nanocomposites: Nanoscience & Nanotechnology in Advanced Composites)
Open AccessArticle
A Metabolomic Approach for the In Vivo Study of Gold Nanospheres and Nanostars after a Single-Dose Intravenous Administration to Wistar Rats
Nanomaterials 2019, 9(11), 1606; https://doi.org/10.3390/nano9111606 - 12 Nov 2019
Abstract
Gold nanoparticles (AuNPs) are promising nanoplatforms for drug therapy, diagnostic and imaging. However, biological comparison studies for different types of AuNPs fail in consistency due to the lack of sensitive methods to detect subtle differences in the expression of toxicity. Therefore, innovative and [...] Read more.
Gold nanoparticles (AuNPs) are promising nanoplatforms for drug therapy, diagnostic and imaging. However, biological comparison studies for different types of AuNPs fail in consistency due to the lack of sensitive methods to detect subtle differences in the expression of toxicity. Therefore, innovative and sensitive approaches such as metabolomics are much needed to discriminate toxicity, specially at low doses. The current work aims to compare the in vivo toxicological effects of gold nanospheres versus gold nanostars (of similar ~40 nm diameter and coated with 11-mercaptoundecanoic acid) 24 h after an intravenous administration of a single dose (1.33 × 1011 AuNPs/kg) to Wistar rats. The biodistribution of both types of AuNPs was determined by graphite furnace atomic absorption spectroscopy. The metabolic effects of the AuNPs on their main target organ, the liver, were analyzed using a GC-MS-based metabolomic approach. Conventional toxicological endpoints, including the levels of ATP and reduced and oxidized glutathione, were also investigated. The results show that AuNPs preferentially accumulate in the liver and, to a lesser extent, in the spleen and lungs. In other organs (kidney, heart, brain), Au content was below the limit of quantification. Reduced glutathione levels increased for both nanospheres and nanostars in the liver, but ATP levels were unaltered. Multivariate analysis showed a good discrimination between the two types of AuNPs (sphere- versus star-shaped nanoparticles) and compared to control group. The metabolic pathways involved in the discrimination were associated with the metabolism of fatty acids, pyrimidine and purine, arachidonic acid, biotin, glycine and synthesis of amino acids. In conclusion, the biodistribution, toxicological, and metabolic profiles of gold nanospheres and gold nanostars were described. Metabolomics proved to be a very useful tool for the comparative study of different types of AuNPs and raised awareness about the pathways associated to their distinct biological effects. Full article
(This article belongs to the Special Issue Advances in Nanotoxicology)
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