Nanomaterials

11 pages, 3664 KiB

Open AccessArticle

The Effect of Hybridized Carbon Nanotubes, Silica Nanoparticles, and Core-Shell Rubber on Tensile, Fracture Mechanics and Electrical Properties of Epoxy Nanocomposites

by Ankur Bajpai and Stéphane Carlotti

Nanomaterials 2019, 9(7), 1057; https://doi.org/10.3390/nano9071057 - 23 Jul 2019

Cited by 27 | Viewed by 4975

Abstract

The paper investigates the effect of adding a combination of rigid nanoparticles and core-shell rubber nanoparticles on the tensile, fracture mechanics, electrical and thermo-mechanical properties of epoxy resins. SiO₂ nanoparticles, multi-walled carbon nanotubes (MWCNT’s), as rigid nanofillers, and core-shell rubber (CSR) nanoparticles, [...] Read more.

The paper investigates the effect of adding a combination of rigid nanoparticles and core-shell rubber nanoparticles on the tensile, fracture mechanics, electrical and thermo-mechanical properties of epoxy resins. SiO₂ nanoparticles, multi-walled carbon nanotubes (MWCNT’s), as rigid nanofillers, and core-shell rubber (CSR) nanoparticles, as soft nanofillers were used with bisphenol-A-based epoxy resin. Further, the rigid fillers were added systematically with core-shell rubber nanoparticles to investigate the commingled effect of rigid nanofillers and soft CSR nanoparticles. The resulting matrix will be broadly evaluated by standard methods to quantify tensile, fracture mechanics, electrical, and thermal properties. The results show that the electrical conductivity threshold is obtained at 0.075 wt. % for MWCNT-modified systems. For hybrid systems, the maximum increase of fracture toughness (218%) and fracture energy (900%) was obtained for a system containing 5 wt. % of CSR and 10 wt. % of SiO₂. The analysis of the fracture surfaces revealed the information about existing toughening micro-mechanisms in the nanocomposites. Full article

(This article belongs to the Special Issue Advanced Materials for Aerospace: Polymer Nanocomposites)

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8 pages, 2112 KiB

Open AccessArticle

Electrochemistry Studies of Hydrothermally Grown ZnO on 3D-Printed Graphene

by Dimitra Vernardou and George Kenanakis

Nanomaterials 2019, 9(7), 1056; https://doi.org/10.3390/nano9071056 - 23 Jul 2019

Cited by 14 | Viewed by 3547

Abstract

A three-dimensional (3D) printer was utilised for the three-dimensional production of graphene-based pyramids and an efficient hydrothermal procedure for ZnO growth. In particular, the 3D-printed graphene pyramids were forwarded in Pyrex glass bottles with autoclavable screw caps filled with 50 mL of an [...] Read more.

A three-dimensional (3D) printer was utilised for the three-dimensional production of graphene-based pyramids and an efficient hydrothermal procedure for ZnO growth. In particular, the 3D-printed graphene pyramids were forwarded in Pyrex glass bottles with autoclavable screw caps filled with 50 mL of an aqueous solution of zinc nitrate hexahydrate and hexamethylenetetramine for 1 h at 95 °C; sufficient enough time to deposit well-dispersed nanoparticles. X-ray diffraction patterns were in accordance with a Raman analysis and presented the characteristic peaks of graphite along with those of wurtzite ZnO. Different positions on the sample were tested, confirming the uniform dispersion of ZnO on graphene pyramids. From the electrochemical studies, it was found that the charging and discharging processes are affected by the presence of ZnO, indicating one well-defined plateau for each process compared to the previously reported bare graphene pyramids. In total, the material shows a value of 325 mAh g⁻¹, a capacitance retention factor of 92% after 5000 scans, and a coulombic efficiency of 100% for the first scan that drops to 85% for the 5000th scan. This excellent performance is the result of the effect of ZnO and graphene that combines two Li⁺ accommodation sites, and the contribution of graphene pyramids, which provides more available sites to favor lithium storage capacity. Hence, this anode may be a promising electrode material for lithium-ion batteries. Full article

(This article belongs to the Special Issue Nano Carbon for Batteries Applications)

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13 pages, 4645 KiB

Open AccessArticle

Activated Carbon-Decorated Spherical Silicon Nanocrystal Composites Synchronously-Derived from Rice Husks for Anodic Source of Lithium-Ion Battery

by Sankar Sekar, Abu Talha Aqueel Ahmed, Akbar I. Inamdar, Youngmin Lee, Hyunsik Im, Deuk Young Kim and Sejoon Lee

Nanomaterials 2019, 9(7), 1055; https://doi.org/10.3390/nano9071055 - 23 Jul 2019

Cited by 39 | Viewed by 6402

Abstract

The nanocomposites of activated-carbon-decorated silicon nanocrystals (AC<nc-Si>AC) were synchronously derived in a single step from biomass rice husks, through the simple route of the calcination method together with the magnesiothermic reduction process. The final product, AC<nc-Si>AC, exhibited an aggregated structure of activated-carbon-encapsulated nanocrystalline [...] Read more.

The nanocomposites of activated-carbon-decorated silicon nanocrystals (AC<nc-Si>AC) were synchronously derived in a single step from biomass rice husks, through the simple route of the calcination method together with the magnesiothermic reduction process. The final product, AC<nc-Si>AC, exhibited an aggregated structure of activated-carbon-encapsulated nanocrystalline silicon spheres, and reveals a high specific surface area (498.5 m²/g). Owing to the mutualization of advantages from both silicon nanocrystals (i.e., low discharge potential and high specific capacity) and activated carbon (i.e., high porosity and good electrical conductivity), the AC<nc-Si>AC nanocomposites are able to play a substantial role as an anodic source material for the lithium-ion battery (LIB). Namely, a high coulombic efficiency (97.5%), a high discharge capacity (716 mAh/g), and a high reversible specific capacity (429 mAh/g after 100 cycles) were accomplished when using AC<nc-Si>AC as an LIB anode. The results advocate that the simultaneous synthesis of biomass-derived AC<nc-Si>AC is beneficial for green energy-storage device applications. Full article

(This article belongs to the Special Issue Functional Carbon Nanocomposites for Energy Storage and Conversion)

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15 pages, 9311 KiB

Open AccessArticle

The Novel Z-Scheme Ternary-Component Ag/AgI/α-MoO₃ Catalyst with Excellent Visible-Light Photocatalytic Oxidative Desulfurization Performance for Model Fuel

by Yanzhong Zhen, Jie Wang, Feng Fu, Wenhao Fu and Yucang Liang

Nanomaterials 2019, 9(7), 1054; https://doi.org/10.3390/nano9071054 - 23 Jul 2019

Cited by 47 | Viewed by 5315

Abstract

The novel ternary-component Ag/AgI/α-MoO₃ (AAM) photocatalyst was successfully fabricated by a facile hydrothermal method combined with a charge-induced physical adsorption and photo-reduced deposition technique. X-ray diffraction, scanning/transmission electron microscope, X-ray photoelectron, UV-vis diffuse reflectance, photoluminescence and electrochemical impedance spectroscopy were employed to [...] Read more.

The novel ternary-component Ag/AgI/α-MoO₃ (AAM) photocatalyst was successfully fabricated by a facile hydrothermal method combined with a charge-induced physical adsorption and photo-reduced deposition technique. X-ray diffraction, scanning/transmission electron microscope, X-ray photoelectron, UV-vis diffuse reflectance, photoluminescence and electrochemical impedance spectroscopy were employed to characterize the composition, morphology, light-harvesting properties and charge transfer character of the as-synthesized catalysts. The ternary-component AAM heterojunctions exhibited an excellent visible-light photocatalytic oxidative desulfurization activity, in which the AAM-35 (35 represents weight percent of AgI in AAM sample) possessed the highest photocatalytic activity of the conversion of 97.5% in 2 h. On the basis of band structure analysis, radical trapping experiments and electron spin resonance (ESR) spectra results, two different catalytic mechanisms were suggested to elucidate how the photogenerated electron-hole pairs can be effectively separated for the enhancement of photocatalytic performance for dual composites AM-35 and ternary composites AAM-35 during the photocatalytic oxidative desulfurization (PODS) of thiophene. This investigation demonstrates that Z-scheme Ag/AgI/α-MoO₃ will be a promising candidate material for refractory sulfur aromatic pollutant’s removal in fossil fuel. Full article

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8 pages, 3430 KiB

Open AccessArticle

Deposition of Silicon-Based Stacked Layers for Flexible Encapsulation of Organic Light Emitting Diodes

by Chia-Hsun Hsu, Yang-Shih Lin, Hsin-Yu Wu, Xiao-Ying Zhang, Wan-Yu Wu, Shui-Yang Lien, Dong-Sing Wuu and Yeu-Long Jiang

Nanomaterials 2019, 9(7), 1053; https://doi.org/10.3390/nano9071053 - 23 Jul 2019

Cited by 7 | Viewed by 3564

Abstract

In this study, inorganic silicon oxide (SiO_x)/organic silicon (SiC_xH_y) stacked layers were deposited by a radio frequency inductively coupled plasma chemical vapor deposition system as a gas diffusion barrier for organic light-emitting diodes (OLEDs). The effects of [...] Read more.

In this study, inorganic silicon oxide (SiO_x)/organic silicon (SiC_xH_y) stacked layers were deposited by a radio frequency inductively coupled plasma chemical vapor deposition system as a gas diffusion barrier for organic light-emitting diodes (OLEDs). The effects of thicknesses of SiO_x and SiC_xH_y layers on the water vapor transmission rate (WVTR) and residual stress were investigated to evaluate the encapsulation capability. The experimental results showed that the lowest WVTR and residual stress were obtained when the thicknesses of SiO_x and SiC_xH_y were 300 and 30 nm, respectively. Finally, different numbers of stacked pairs of SiO_x/SiC_xH_y were applied to OLED encapsulation. The OLED encapsulated with the six-pair SiO_x/SiC_xH_y exhibited a low turn-on voltage and low series resistance, and device lifetime increased from 7 h to more than 2000 h. Full article

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12 pages, 1597 KiB

Open AccessArticle

Codelivery of Genistein and miRNA-29b to A549 Cells Using Aptamer-Hybrid Nanoparticle Bioconjugates

by Koita Sacko, Karthik Thangavel and Sunday A. Shoyele

Nanomaterials 2019, 9(7), 1052; https://doi.org/10.3390/nano9071052 - 23 Jul 2019

Cited by 37 | Viewed by 4692

Abstract

This study aimed to evaluate the anti-cancer effect of a combination therapy of miRNA-29b and genistein loaded in mucin-1 (MUC 1)-aptamer functionalized hybrid nanoparticles in non-small cell lung cancer (NSCLC) A549 cell line. Genistein-miRNA-29b-loaded hybrid nanoparticles (GMLHN) was prepared and characterized. Particle size [...] Read more.

This study aimed to evaluate the anti-cancer effect of a combination therapy of miRNA-29b and genistein loaded in mucin-1 (MUC 1)-aptamer functionalized hybrid nanoparticles in non-small cell lung cancer (NSCLC) A549 cell line. Genistein-miRNA-29b-loaded hybrid nanoparticles (GMLHN) was prepared and characterized. Particle size and zeta potential were measured using photon correlation spectroscopy (PCS). Encapsulation efficiency and loading efficiency were determined using HPLC. Preferential internalization of MUC 1-aptamer functionalized GMLHN by A549 cells was evaluated and compared to normal MRC-5 cells. The ability of GMLHN to downregulate targeted oncoproteins Phosphorylated protein kinase, strain AK, Thymoma (Phosphorylated protein kinase B) (pAKT), Phosphorylated phosphoinositide 3-kinase (p-PI3K), DNA (cytosine-5-)-methyltransferase 3 beta (DNMT3B) and Myeloid Cell Leukemia Sequence 1 (MCL 1) was evaluated using western blot, while antiproliferative effect and ability to initiate apoptosis was also assessed in A549 cells. MUC 1-aptamer functionalized GMLHN nanoparticles were prepared. These nanoparticles were preferentially internalized by A549 cells but less so, in MRC-5 cells. pAKT, p-PI3K, DNMT3B and MCL 1 were efficiently downregulated by these nanoparticles without affecting the levels of AKT and PI3K in A549 cells. GMLHN demonstrated a superior antiproliferative effect compared to individual genistein and miRNA-29b-loaded nanoparticles. Results generated were able to demonstrate that genistein-miRNA-29b-loaded hybrid nanoparticles (GMLHN) could be a potential treatment modality for NSCLC because of the ability of the payloads to attack multiple targets. Full article

(This article belongs to the Special Issue Anti-Cancer, Biochemical and Immunological Activity of Nanoparticles )

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15 pages, 3840 KiB

Open AccessArticle

Aerogel Perfusion-Prepared h-BN/CNF Composite Film with Multiple Thermally Conductive Pathways and High Thermal Conductivity

by Xiu Wang, Zhihuai Yu, Liang Jiao, Huiyang Bian, Weisheng Yang, Weibing Wu, Huining Xiao and Hongqi Dai

Nanomaterials 2019, 9(7), 1051; https://doi.org/10.3390/nano9071051 - 23 Jul 2019

Cited by 25 | Viewed by 6421

Abstract

Hexagonal boron nitride (h-BN)-based heat-spreading materials have drawn considerable attention in electronic diaphragm and packaging fields because of their high thermal conductivity and desired electrical insulation properties. However, the traditional approach to fabricate thermally conductive composites usually suffers from low thermal conductivity, and [...] Read more.

Hexagonal boron nitride (h-BN)-based heat-spreading materials have drawn considerable attention in electronic diaphragm and packaging fields because of their high thermal conductivity and desired electrical insulation properties. However, the traditional approach to fabricate thermally conductive composites usually suffers from low thermal conductivity, and cannot meet the requirement of thermal management. In this work, novel h-BN/cellulose-nano fiber (CNF) composite films with excellent thermal conductivity in through plane and electrical insulation properties are fabricated via an innovative process, i.e., the perfusion of h-BN into porous three dimensional (3D) CNF aerogel skeleton to form the h-BN thermally conductive pathways by filling the CNF aerogel voids. When at an h-BN loading of 9.51 vol %, the thermal conductivity of h-BN/CNF aerogel perfusion composite film is 1.488 W·m⁻¹·K⁻¹ at through plane, an increase by 260.3%. The volume resistivity is 3.83 × 10¹⁴ Ω·cm, superior to that of synthetic polymer materials (about 10⁹~10¹³ Ω·cm). Therefore, the resulting h-BN/CNF film is very promising to replace the traditional synthetic polymer materials for a broad spectrum of applications, including the field of electronics. Full article

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31 pages, 30969 KiB

Open AccessReview

A Review on Brittle Fracture Nanomechanics by All-Atom Simulations

by Sandeep P. Patil and Yousef Heider

Nanomaterials 2019, 9(7), 1050; https://doi.org/10.3390/nano9071050 - 22 Jul 2019

Cited by 21 | Viewed by 6320

Abstract

Despite a wide range of current and potential applications, one primary concern of brittle materials is their sudden and swift collapse. This failure phenomenon exhibits an inability of the materials to sustain tension stresses in a predictable and reliable manner. However, advances in [...] Read more.

Despite a wide range of current and potential applications, one primary concern of brittle materials is their sudden and swift collapse. This failure phenomenon exhibits an inability of the materials to sustain tension stresses in a predictable and reliable manner. However, advances in the field of fracture mechanics, especially at the nanoscale, have contributed to the understanding of the material response and failure nature to predict most of the potential dangers. In the following contribution, a comprehensive review is carried out on molecular dynamics (MD) simulations of brittle fracture, wherein the method provides new data and exciting insights into fracture mechanism that cannot be obtained easily from theories or experiments on other scales. In the present review, an abstract introduction to MD simulations, advantages, current limitations and their applications to a range of brittle fracture problems are presented. Additionally, a brief discussion highlights the theoretical background of the macroscopic techniques, such as Griffith’s criterion, crack tip opening displacement, J-integral and other criteria that can be linked to the fracture mechanical properties at the nanoscale. The main focus of the review is on the recent advances in fracture analysis of highly brittle materials, such as carbon nanotubes, graphene, silicon carbide, amorphous silica, calcium carbonate and silica aerogel at the nanoscale. These materials are presented here due to their extraordinary mechanical properties and a wide scope of applications. The underlying review grants a more extensive unravelling of the fracture behaviour and mechanical properties at the nanoscale of brittle materials. Full article

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18 pages, 4995 KiB

Open AccessArticle

TiO₂ and PEEK Reinforced 3D Printing PMMA Composite Resin for Dental Denture Base Applications

by Sheng-Gui Chen, Junzhong Yang, Yong-Guang Jia, Bingheng Lu and Li Ren

Nanomaterials 2019, 9(7), 1049; https://doi.org/10.3390/nano9071049 - 22 Jul 2019

Cited by 100 | Viewed by 9496

Abstract

The future of manufacturing applications in three-dimensional (3D) printing depends on the improvement and the development of materials suitable for 3D printing technology. This study aims to develop an applicable and convenient protocol for light-curing resin used in 3D industry, which could enhance [...] Read more.

The future of manufacturing applications in three-dimensional (3D) printing depends on the improvement and the development of materials suitable for 3D printing technology. This study aims to develop an applicable and convenient protocol for light-curing resin used in 3D industry, which could enhance antibacterial and mechanical properties of polymethyl methacrylate (PMMA) resin through the combination of nano-fillers of surface modified titanium dioxide (TiO₂) and micro-fillers of polyetheretherketone (PEEK). PMMA-based composite resins with various additions of TiO₂ and PEEK were prepared and submitted to characterizations including mechanical properties, distribution of the fillers (TiO₂ or/and PEEK) on the fractured surface, cytotoxicity, antibacterial activity, and blood compatibility assessment. These results indicated that the reinforced composite resins of PMMA (TiO₂-1%-PEEK-1%) possessed the most optimized properties compared to the other groups. In addition, we found the addition of 1% of TiO₂ would be an effective amount to enhance both mechanical and antibacterial properties for PMMA composite resin. Furthermore, the model printed by PMMA (TiO₂-1%-PEEK-1%) composite resin showed a smooth surface and a precise resolution, indicating this functional dental restoration material would be a suitable light-curing resin in 3D industry. Full article

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28 pages, 4601 KiB

Open AccessReview

Nanophosphors-Based White Light Sources

by Maura Cesaria and Baldassare Di Bartolo

Nanomaterials 2019, 9(7), 1048; https://doi.org/10.3390/nano9071048 - 22 Jul 2019

Cited by 18 | Viewed by 6259

Abstract

Miniaturization requests and progress in nanofabrication are prompting worldwide interest in nanophosphors as white-emission mercury-free lighting sources. By comparison with their bulk counterparts, nanophosphors exhibit reduced concentration quenching effects and a great potential to enhance luminescence efficiency and tunability. In this paper, the [...] Read more.

Miniaturization requests and progress in nanofabrication are prompting worldwide interest in nanophosphors as white-emission mercury-free lighting sources. By comparison with their bulk counterparts, nanophosphors exhibit reduced concentration quenching effects and a great potential to enhance luminescence efficiency and tunability. In this paper, the physics of the nanophoshors is overviewed with a focus on the impact of spatial confinement and surface-to-volume ratio on the luminescence issue, as well as rare earth-activated multicolor emission for white light (WL) output. In this respect, the prominently practiced strategies to achieve WL emission are single nanophosphors directly yielding WL by means of co-doping and superposition of the individual red, green, and blue emissions from different nanophosphors. Recently, a new class of efficient broadband WL emitting nanophosphors has been proposed, i.e., nominally un-doped rare earth free oxide (yttrium oxide, Y₂O₃) nanopowders and Cr transition metal-doped garnet nanocrystals. In regard to this unconventional WL emission, the main points are: it is strictly a nanoscale phenomenon, the presence of an emitting center may favor WL emission without being necessary for observing it, and, its inherent origin is still unknown. A comparison between such an unconventional WL emission and the existing literature is presented to point out its novelty and superior lighting performances. Full article

(This article belongs to the Special Issue Luminescent Rare-Earth Based Nanomaterials)

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10 pages, 1795 KiB

Open AccessArticle

Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride

by Marie Krečmarová, Daniel Andres-Penares, Ladislav Fekete, Petr Ashcheulov, Alejandro Molina-Sánchez, Rodolfo Canet-Albiach, Ivan Gregora, Vincent Mortet, Juan P. Martínez-Pastor and Juan F. Sánchez-Royo

Nanomaterials 2019, 9(7), 1047; https://doi.org/10.3390/nano9071047 - 22 Jul 2019

Cited by 22 | Viewed by 8009

Abstract

The successful integration of few-layer thick hexagonal boron nitride (hBN) into devices based on two-dimensional materials requires fast and non-destructive techniques to quantify their thickness. Optical contrast methods and Raman spectroscopy have been widely used to estimate the thickness of two-dimensional semiconductors and [...] Read more.

The successful integration of few-layer thick hexagonal boron nitride (hBN) into devices based on two-dimensional materials requires fast and non-destructive techniques to quantify their thickness. Optical contrast methods and Raman spectroscopy have been widely used to estimate the thickness of two-dimensional semiconductors and semi-metals. However, they have so far not been applied to two-dimensional insulators. In this work, we demonstrate the ability of optical contrast techniques to estimate the thickness of few-layer hBN on SiO₂/Si substrates, which was also measured by atomic force microscopy. Optical contrast of hBN on SiO₂/Si substrates exhibits a linear trend with the number of hBN monolayers in the few-layer thickness range. We also used bandpass filters (500–650 nm) to improve the effectiveness of the optical contrast methods for thickness estimations. We also investigated the thickness dependence of the high frequency in-plane E_2g phonon mode of atomically thin hBN on SiO₂/Si substrates by micro-Raman spectroscopy, which exhibits a weak thickness-dependence attributable to the in-plane vibration character of this mode. Ab initio calculations of the Raman active phonon modes of atomically thin free-standing crystals support these results, even if the substrate can reduce the frequency shift of the E_2g phonon mode by reducing the hBN thickness. Therefore, the optical contrast method arises as the most suitable and fast technique to estimate the thickness of hBN nanosheets. Full article

(This article belongs to the Special Issue Optics and Transport on 2D Materials)

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3 pages, 175 KiB

Open AccessEditorial

Special Issue “Synthesis and Applications of Functionalized Gold Nanosystems”

by Paolo Scrimin

Nanomaterials 2019, 9(7), 1046; https://doi.org/10.3390/nano9071046 - 22 Jul 2019

Cited by 1 | Viewed by 2304

Abstract

When I launched this Special Issue, I wrote: “Gold-based nanosystems are among the most interesting systems in the nanoworld because of their broad spectrum of applications, ranging from analyte detection to nanomedicine and the mimicry of enzymes, just to mention a few examples [...] Read more.

When I launched this Special Issue, I wrote: “Gold-based nanosystems are among the most interesting systems in the nanoworld because of their broad spectrum of applications, ranging from analyte detection to nanomedicine and the mimicry of enzymes, just to mention a few examples [...] Full article

(This article belongs to the Special Issue Synthesis and Applications of Functionalized Gold Nanosystems)

18 pages, 4439 KiB

Open AccessReview

Carbon Nanofiber-Based Functional Nanomaterials for Sensor Applications

by Zhuqing Wang, Shasha Wu, Jian Wang, Along Yu and Gang Wei

Nanomaterials 2019, 9(7), 1045; https://doi.org/10.3390/nano9071045 - 22 Jul 2019

Cited by 134 | Viewed by 8108

Abstract

Carbon nanofibers (CNFs) exhibit great potentials in the fields of materials science, biomedicine, tissue engineering, catalysis, energy, environmental science, and analytical science due to their unique physical and chemical properties. Usually, CNFs with flat, mesoporous, and porous surfaces can be synthesized by chemical [...] Read more.

Carbon nanofibers (CNFs) exhibit great potentials in the fields of materials science, biomedicine, tissue engineering, catalysis, energy, environmental science, and analytical science due to their unique physical and chemical properties. Usually, CNFs with flat, mesoporous, and porous surfaces can be synthesized by chemical vapor deposition and electrospinning techniques with subsequent chemical treatment. Meanwhile, the surfaces of CNFs are easy to modify with various materials to extend the applications of CNF-based hybrid nanomaterials in multiple fields. In this review, we focus on the design, synthesis, and sensor applications of CNF-based functional nanomaterials. The fabrication strategies of CNF-based functional nanomaterials by adding metallic nanoparticles (NPs), metal oxide NPs, alloy, silica, polymers, and others into CNFs are introduced and discussed. In addition, the sensor applications of CNF-based nanomaterials for detecting gas, strain, pressure, small molecule, and biomacromolecules are demonstrated in detail. This work will be beneficial for the readers to understand the strategies for fabricating various CNF-based nanomaterials, and explore new applications in energy, catalysis, and environmental science. Full article

(This article belongs to the Special Issue Carbon-Based Nanomaterials for (Bio)Sensors Development)

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12 pages, 4540 KiB

Open AccessArticle

Molecular Dynamics Simulation on Mechanical and Piezoelectric Properties of Boron Nitride Honeycomb Structures

by Lu Xie, Tianhua Wang, Chenwei He, Zhihui Sun and Qing Peng

Nanomaterials 2019, 9(7), 1044; https://doi.org/10.3390/nano9071044 - 21 Jul 2019

Cited by 10 | Viewed by 4534

Abstract

Boron nitride honeycomb structure is a new three-dimensional material similar to carbon honeycomb, which has attracted a great deal of attention due to its special structure and properties. In this paper, the tensile mechanical properties of boron nitride honeycomb structures in the zigzag, [...] Read more.

Boron nitride honeycomb structure is a new three-dimensional material similar to carbon honeycomb, which has attracted a great deal of attention due to its special structure and properties. In this paper, the tensile mechanical properties of boron nitride honeycomb structures in the zigzag, armchair and axial directions are studied at room temperature by using molecular dynamics simulations. Effects of temperature and strain rate on mechanical properties are also discussed. According to the observed tensile mechanical properties, the piezoelectric effect in the zigzag direction was analyzed for boron nitride honeycomb structures. The obtained results showed that the failure strains of boron nitride honeycomb structures under tensile loading were up to 0.83, 0.78 and 0.55 in the armchair, zigzag and axial directions, respectively, at room temperature. These findings indicated that boron nitride honeycomb structures have excellent ductility at room temperature. Moreover, temperature had a significant effect on the mechanical and tensile mechanical properties of boron nitride honeycomb structures, which can be improved by lowering the temperature within a certain range. In addition, strain rate affected the maximum tensile strength and failure strain of boron nitride honeycomb structures. Furthermore, due to the unique polarization of boron nitride honeycomb structures, they possessed an excellent piezoelectric effect. The piezoelectric coefficient e obtained from molecular dynamics was

0.702 {C / m}^{2}

, which was lower than that of the monolayer boron nitride honeycomb structures,

e = {0.79}^{} {C / m}^{2}

. Such excellent piezoelectric properties and failure strain detected in boron nitride honeycomb structures suggest a broad prospect for the application of these new materials in novel nanodevices with ultrahigh tensile mechanical properties and ultralight-weight materials. Full article

(This article belongs to the Special Issue Modeling and Experimental Characterization of Nanocomposite Materials)

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18 pages, 11255 KiB

Open AccessArticle

Zinc Oxide Nanoparticles Induce Autophagy and Apoptosis via Oxidative Injury and Pro-Inflammatory Cytokines in Primary Astrocyte Cultures

by Woo-Ju Song, Myung-Seon Jeong, Dong-Min Choi, Kil-Nam Kim and Myung-Bok Wie

Nanomaterials 2019, 9(7), 1043; https://doi.org/10.3390/nano9071043 - 21 Jul 2019

Cited by 45 | Viewed by 4848

Abstract

The present study examined the potential toxic concentrations of zinc oxide nanoparticles (ZnO NPs) and associated autophagy and apoptosis-related injuries in primary neocortical astrocyte cultures. Concentrations of ZnO NPs ≥3 μg/mL induced significant toxicity in the astrocytes. At 24 h after exposure to [...] Read more.

The present study examined the potential toxic concentrations of zinc oxide nanoparticles (ZnO NPs) and associated autophagy and apoptosis-related injuries in primary neocortical astrocyte cultures. Concentrations of ZnO NPs ≥3 μg/mL induced significant toxicity in the astrocytes. At 24 h after exposure to the ZnO NPs, transmission electron microscopy revealed swelling of the endoplasmic reticulum (ER) and increased numbers of autophagolysosomes in the cultured astrocytes, and increased levels of LC3 (microtubule-associated protein 1 light chain 3)-mediated autophagy were identified by flow cytometry. Apoptosis induced by ZnO NP exposure was confirmed by the elevation of caspase-3/7 activity and 4′,6′-diamidino-2-phenylindole (DAPI) staining. Significant (p < 0.05) changes in the levels of glutathione peroxidase, superoxide dismutase, tumor necrosis factor (TNF-α), and interleukin-6 were observed by enzyme-linked immunoassay (ELISA) assay following the exposure of astrocyte cultures to ZnO NPs. Phosphatidylinositol 3-kinase (PI3K)/mitogen-activated protein kinase (MAPK) dual activation was induced by ZnO NPs in a dose-dependent manner. Additionally, the Akt (protein kinase B) inhibitor BML257 and the mTOR (mammalian target of rapamycin) inhibitor rapamycin contributed to the survival of astrocytes. Inhibitors of cyclooxygenase-2 and lipoxygenase attenuated ZnO NP-induced toxicity. Calcium-modulating compounds, antioxidants, and zinc/iron chelators also decreased ZnO NP-induced toxicity. Together, these results suggest that ZnO NP-induced autophagy and apoptosis may be associated with oxidative stress and the inflammatory process in primary astrocyte cultures. Full article

(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)

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20 pages, 4386 KiB

Open AccessArticle

Biosynthesis of Silver Nanoparticles Mediated by Extracellular Pigment from Talaromyces purpurogenus and Their Biomedical Applications

by Sharad Bhatnagar, Toshiro Kobori, Deepak Ganesh, Kazuyoshi Ogawa and Hideki Aoyagi

Nanomaterials 2019, 9(7), 1042; https://doi.org/10.3390/nano9071042 - 21 Jul 2019

Cited by 81 | Viewed by 6553

Abstract

In recent years, green syntheses have been researched comprehensively to develop inexpensive and eco-friendly approaches for the generation of nanoparticles. In this context, plant and microbial sources are being examined to discover potential reducing agents. This study aims to utilize an extracellular pigment [...] Read more.

In recent years, green syntheses have been researched comprehensively to develop inexpensive and eco-friendly approaches for the generation of nanoparticles. In this context, plant and microbial sources are being examined to discover potential reducing agents. This study aims to utilize an extracellular pigment produced by Talaromyces purpurogenus as a prospective reducing agent to synthesize silver nanoparticles (AgNPs). Biosynthesized AgNPs were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), electron probe micro analyser (EPMA), and zeta potential. The pigment functional groups involved in the generation of AgNPs were investigated using Fourier transform infrared spectroscopy. TEM images showed that the generated nanoparticles were spherical, hexagonal, rod-shaped, and triangular-shaped with a particle size distribution from 4 to 41 nm and exhibited a surface plasmon resonance at around 410 nm. DLS and zeta potential studies revealed that the particles were polydispersed and stable (−24.8 mV). EPMA confirmed the presence of elemental silver in the samples. Biosynthesized AgNPs exhibited minimum inhibitory concentrations of 32 and 4 μg/mL against E. coli and S. epidermidis, respectively. Further, cytotoxicity of the AgNPs was investigated against human cervical cancer (HeLa), human liver cancer (HepG2), and human embryonic kidney (HEK-293) cell lines using 5-fluorouracil as a positive control. A significant activity was recorded against HepG2 cell line with a half-maximal inhibitory concentration of 11.1 μg/mL. Full article

(This article belongs to the Special Issue Advanced Biocompatible Nanomaterials)

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20 pages, 6328 KiB

Open AccessArticle

In Vitro Toxicity of TiO₂:SiO₂ Nanocomposites with Different Photocatalytic Properties

by Rossella Bengalli, Simona Ortelli, Magda Blosi, Anna Costa, Paride Mantecca and Luisa Fiandra

Nanomaterials 2019, 9(7), 1041; https://doi.org/10.3390/nano9071041 - 21 Jul 2019

Cited by 23 | Viewed by 4305

Abstract

The enormous technological relevance of titanium dioxide (TiO₂) nanoparticles (NPs) and the consequent concerns regarding potentially hazardous effects that exposure during production, use, and disposal can generate, encourage material scientists to develop and validate intrinsically safe design solution (safe-by-design). Under this [...] Read more.

The enormous technological relevance of titanium dioxide (TiO₂) nanoparticles (NPs) and the consequent concerns regarding potentially hazardous effects that exposure during production, use, and disposal can generate, encourage material scientists to develop and validate intrinsically safe design solution (safe-by-design). Under this perspective, the encapsulation in a silica dioxide (SiO₂) matrix could be an effective strategy to improve TiO₂ NPs safety, preserving photocatalytic and antibacterial properties. In this work, A549 cells were used to investigate the toxic effects of silica-encapsulated TiO₂ having different ratios of TiO₂ and SiO₂ (1:1, 1:3, and 3:1). NPs were characterized by electron microscopy and dynamic light scattering, and cell viability, oxidative stress, morphological changes, and cell cycle alteration were evaluated. Resulting data demonstrated that NPs with lower content of SiO₂ are able to induce cytotoxic effects, triggered by oxidative stress and resulting in cell necrosis and cell cycle alteration. The physicochemical properties of NPs are responsible for their toxicity. Particles with small size and high stability interact with pulmonary cells more effectively, and the different ratio among silica and titania plays a crucial role in the induced cytotoxicity. These results strengthen the need to take into account a safe(r)-by-design approach in the development of new nanomaterials for research and manufacturing. Full article

(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)

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14 pages, 5429 KiB

Open AccessArticle

Surface, Interface, and Temperature Effects on the Phase Separation and Nanoparticle Self Assembly of Bi-Metallic Ni0.5Ag0.5: A Molecular Dynamics Study

by Ryan H. Allaire, Abhijeet Dhakane, Reece Emery, P. Ganesh, Philip D. Rack, Lou Kondic, Linda Cummings and Miguel Fuentes-Cabrera

Nanomaterials 2019, 9(7), 1040; https://doi.org/10.3390/nano9071040 - 21 Jul 2019

Cited by 7 | Viewed by 4754

Abstract

Classical molecular dynamics (MD) simulations were used to investigate how free surfaces, as well as supporting substrates, affect phase separation in a NiAg alloy. Bulk samples, droplets, and droplets deposited on a graphene substrate were investigated at temperatures that spanned regions of interest [...] Read more.

Classical molecular dynamics (MD) simulations were used to investigate how free surfaces, as well as supporting substrates, affect phase separation in a NiAg alloy. Bulk samples, droplets, and droplets deposited on a graphene substrate were investigated at temperatures that spanned regions of interest in the bulk NiAg phase diagram, i.e., miscible and immiscible liquid, liquid-crystal, and crystal-crystal regions. Using MD simulations to cool down a bulk sample from 3000 K to 800 K, it was found that phase separation below 2400 K takes place in agreement with the phase diagram. When free surface effects were introduced, phase separation was accompanied by a core-shell transformation: spherical droplets created from the bulk samples became core-shell nanoparticles with a shell made mostly of Ag atoms and a core made of Ni atoms. When such droplets were deposited on a graphene substrate, the phase separation was accompanied by Ni layering at the graphene interface and Ag at the vacuum interface. Thus, it should be possible to create NiAg core-shell and layer-like nanostructures by quenching liquid NiAg samples on tailored substrates. Furthermore, interesting bimetallic nanoparticle morphologies might be tuned via control of the surface and interface energies and chemical instabilities of the system. Full article

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12 pages, 50218 KiB

Open AccessArticle

Effect of Ce Doping on the Structure and Chemical Stability of Nano-α-Fe₂O₃

by Junxiang Ning, Peiyang Shi, Maofa Jiang, Chengjun Liu and Xiaoliang Li

Nanomaterials 2019, 9(7), 1039; https://doi.org/10.3390/nano9071039 - 21 Jul 2019

Cited by 16 | Viewed by 4159

Abstract

Ce-doped nano-α-Fe₂O₃ was successfully synthesized via the hydrothermal method. The properties of the prepared particles were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and electrochemical methods. [...] Read more.

Ce-doped nano-α-Fe₂O₃ was successfully synthesized via the hydrothermal method. The properties of the prepared particles were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and electrochemical methods. It was found that the Ce element can be doped into the α-Fe₂O₃ lattice resulting in lattice distortion, which can refine the grain and improve the crystal surface’s integrity significantly. In addition, doping of Ce element can shorten the Fe–O bond length in the α-Fe₂O₃ crystal, cause a blue shift of the stretching vibration band, enhance binding energy of Fe–O and the chemical stability of the α-Fe₂O₃ crystal. Full article

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16 pages, 4567 KiB

Open AccessArticle

Ethynylation of Formaldehyde over Binary Cu-Based Catalysts: Study on Synergistic Effect between Cu⁺ Species and Acid/Base Sites

by Zhipeng Wang, Lijun Ban, Pingfan Meng, Haitao Li and Yongxiang Zhao

Nanomaterials 2019, 9(7), 1038; https://doi.org/10.3390/nano9071038 - 20 Jul 2019

Cited by 14 | Viewed by 3976

Abstract

Most studies on the Cu-based catalysts in the ethynylation of formaldehyde are merely focused on the tuning of electronic configuration and dispersion of the Cu⁺ species. So far, little attention has been paid to the synergy between Cu species and promoters. Herein, [...] Read more.

Most studies on the Cu-based catalysts in the ethynylation of formaldehyde are merely focused on the tuning of electronic configuration and dispersion of the Cu⁺ species. So far, little attention has been paid to the synergy between Cu species and promoters. Herein, binary nano-CuO-MO_x catalysts (M = Si, Al, and Mg) were synthesized and the effects of the promoter on the surface basicity/acidity were systematically studied as well as the ethynylation performance of the nano-CuO-based catalysts. The results show that the introduction of MgO provided a large number of basic sites, which could coordinate with the active Cu⁺ species and facilitate the dissociation of acetylene as HC≡C^δ− and H^δ+. The strongly nucleophilic acetylenic carbon (HC≡C^δ−) is favorable to the attack at the electropositive carbonyl C^δ+ of formaldehyde. The MgO-promoted CuO catalyst showed the highest yield of BD (94%) and the highest stability (the BD yield decreased only from 94% to 82% after eight reaction cycles). SiO₂ effectively dispersed Cu species, which improved catalytic activity and stability. However, the introduction of Al₂O₃ resulted in a large number of acidic sites on the catalyst’s surface. This led to the polymerization of acetylene, which covered the active sites and decreased the catalyst’s activity. Full article

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16 pages, 6493 KiB

Open AccessArticle

Sustained Release of Basic Fibroblast Growth Factor (bFGF) Encapsulated Polycaprolactone (PCL) Microspheres Promote Angiogenesis In Vivo

by Pala Arunkumar, Julie A. Dougherty, Jessica Weist, Naresh Kumar, Mark G. Angelos, Heather M. Powell and Mahmood Khan

Nanomaterials 2019, 9(7), 1037; https://doi.org/10.3390/nano9071037 - 20 Jul 2019

Cited by 32 | Viewed by 5511

Abstract

Coronary heart disease (CHD) is the leading cause of death in the Unites States and globally. The administration of growth factors to preserve cardiac function after myocardial infarction (MI) is currently being explored. Basic fibroblast growth factor (bFGF), a potent angiogenic factor has [...] Read more.

Coronary heart disease (CHD) is the leading cause of death in the Unites States and globally. The administration of growth factors to preserve cardiac function after myocardial infarction (MI) is currently being explored. Basic fibroblast growth factor (bFGF), a potent angiogenic factor has poor clinical efficacy due to its short biological half-life and low plasma stability. The goal of this study was to develop bFGF-loaded polycaprolactone (PCL) microspheres for sustained release of bFGF and to evaluate its angiogenic potential. The bFGF-PCL microspheres (bFGF-PCL-MS) were fabricated using the emulsion solvent-evaporation method and found to have spherical morphology with a mean size of 4.21 ± 1.28 µm. In vitro bFGF release studies showed a controlled release for up to 30 days. Treatment of HUVECs with bFGF-PCL-MS in vitro enhanced their cell proliferation and migration properties when compared to the untreated control group. Treatment of HUVECs with release media from bFGF-PCL-MS also significantly increased expression of angiogenic genes (bFGF and VEGFA) as compared to untreated cells. The in vivo angiogenic potential of these bFGF-PCL-MS was further confirmed in rats using a Matrigel plug assay with subsequent immunohistochemical staining showing increased expression of angiogenic markers. Overall, bFGF-PCL-MS could serve as a potential angiogenic agent to promote cell survival and angiogenesis following an acute myocardial infarction. Full article

(This article belongs to the Special Issue Application of Nanotechnology in Cardiology)

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25 pages, 5158 KiB

Open AccessFeature PaperReview

Polymer-II-VI Nanocrystals Blends: Basic Physics and Device Applications to Lasers and LEDs

by Marco Anni

Nanomaterials 2019, 9(7), 1036; https://doi.org/10.3390/nano9071036 - 19 Jul 2019

Cited by 27 | Viewed by 5090

Abstract

Hybrid thin films that combine organic conjugated molecules and semiconductors nanocrystals (NCs) have been deeply investigated in the previous years, due to their capability to provide an extremely broad tuning of their electronic and optical properties. In this paper we review the main [...] Read more.

Hybrid thin films that combine organic conjugated molecules and semiconductors nanocrystals (NCs) have been deeply investigated in the previous years, due to their capability to provide an extremely broad tuning of their electronic and optical properties. In this paper we review the main aspects of the basic physics of the organic–inorganic interaction and the actual state of the art of lasers and light emitting diodes based on hybrid active materials. Full article

(This article belongs to the Special Issue II-VI Semiconductor Nanocrystals and Hybrid Polymer-Nanocrystal Systems)

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14 pages, 9593 KiB

Open AccessArticle

ToF-SIMS 3D Analysis of Thin Films Deposited in High Aspect Ratio Structures via Atomic Layer Deposition and Chemical Vapor Deposition

by Alireza M. Kia, Nora Haufe, Sajjad Esmaeili, Clemens Mart, Mikko Utriainen, Riikka L. Puurunen and Wenke Weinreich

Nanomaterials 2019, 9(7), 1035; https://doi.org/10.3390/nano9071035 - 19 Jul 2019

Cited by 23 | Viewed by 8314

Abstract

For the analysis of thin films, with high aspect ratio (HAR) structures, time-of-flight secondary ion mass spectrometry (ToF-SIMS) overcomes several challenges in comparison to other frequently used techniques such as electron microscopy. The research presented herein focuses on two different kinds of HAR [...] Read more.

For the analysis of thin films, with high aspect ratio (HAR) structures, time-of-flight secondary ion mass spectrometry (ToF-SIMS) overcomes several challenges in comparison to other frequently used techniques such as electron microscopy. The research presented herein focuses on two different kinds of HAR structures that represent different semiconductor technologies. In the first study, ToF-SIMS is used to illustrate cobalt seed layer corrosion by the copper electrolyte within the large through-silicon-vias (TSVs) before and after copper electroplating. However, due to the sample’s surface topography, ToF-SIMS analysis proved to be difficult due to the geometrical shadowing effects. Henceforth, in the second study, we introduce a new test platform to eliminate the difficulties with the HAR structures, and again, use ToF-SIMS for elemental analysis. We use data image slicing of 3D ToF-SIMS analysis combined with lateral HAR test chips (PillarHall™) to study the uniformity of silicon dopant concentration in atomic layer deposited (ALD) HfO₂ thin films. Full article

(This article belongs to the Special Issue Characterization of Nanomaterials: Selected Papers from 6th Dresden Nanoanalysis Symposiumc)

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14 pages, 3823 KiB

Open AccessArticle

A Comparison Study of Functional Groups (Amine vs. Thiol) for Immobilizing AuNPs on Zeolite Surface

by Xi Rao, Michaël Tatoulian, Cédric Guyon, Stephanie Ognier, Chenglin Chu and Ali Abou Hassan

Nanomaterials 2019, 9(7), 1034; https://doi.org/10.3390/nano9071034 - 19 Jul 2019

Cited by 30 | Viewed by 6720

Abstract

Immobilization of gold nanoparticles (AuNPs) on the surface of zeolite has received a great interest due to Au@zeolite’s unique characteristics and high performance for catalysis. In this work we studied the grafting of two different functional molecules; one having an amine group (3-aminopropyl)triethoxysilane [...] Read more.

Immobilization of gold nanoparticles (AuNPs) on the surface of zeolite has received a great interest due to Au@zeolite’s unique characteristics and high performance for catalysis. In this work we studied the grafting of two different functional molecules; one having an amine group (3-aminopropyl)triethoxysilane (APTES) and the second having a thiol group (3-mercaptopropyl)trimethoxysilane (MPTES) on the surface of zeolite using the same wet chemistry method. The modified zeolite surfaces were characterized using zeta potential measurements; diffuse reflectance infrared fourier transform (DRIFT) and X-ray photoelectron spectroscopy (XPS). The results confirmed a successful deposition of both functional groups at the topmost surface of the zeolite. Furthermore; transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectroscopy and XPS results clearly evidenced that APTES provided a better AuNPs immobilization than MPTES as a result of; (1) less active functions obtained after MPTES deposition, and (2) the better attaching ability of thiol to the gold surface. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Related Applications)

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14 pages, 2831 KiB

Open AccessArticle

Homogeneous Core/Shell NiMoO₄@NiMoO₄ and Activated Carbon for High Performance Asymmetric Supercapacitor

by Jia Yi Dong, Jin Cheng Xu, Kwun Nam Hui, Ye Yang, Shi Chen Su, Lin Li, Xi Tian Zhang, Kar Wei Ng, Shuang Peng Wang and Zi Kang Tang

Nanomaterials 2019, 9(7), 1033; https://doi.org/10.3390/nano9071033 - 19 Jul 2019

Cited by 13 | Viewed by 4840

Abstract

Here, we report the extraordinary electrochemical energy storage capability of NiMoO₄@NiMoO₄ homogeneous hierarchical nanosheet-on-nanowire arrays (SOWAs), synthesized on nickel substrate by a two-stage hydrothermal process. Comparatively speaking, the SOWAs electrode displays superior electrochemical performances over the pure NiMoO₄ nanowire [...] Read more.

Here, we report the extraordinary electrochemical energy storage capability of NiMoO₄@NiMoO₄ homogeneous hierarchical nanosheet-on-nanowire arrays (SOWAs), synthesized on nickel substrate by a two-stage hydrothermal process. Comparatively speaking, the SOWAs electrode displays superior electrochemical performances over the pure NiMoO₄ nanowire arrays. Such improvements can be ascribed to the characteristic homogeneous hierarchical structure, which not only effectively increases the active surface areas for fast charge transfer, but also reduces the electrode resistance significantly by eliminating the potential barrier at the nanowire/nanosheet junction, an issue usually seen in other reported heterogeneous architectures. We further evaluate the performances of the SOWAs by constructing an asymmetric hybrid supercapacitor (ASC) with the SOWAs and activated carbon (AC). The optimized ASC shows excellent electrochemical performances with 47.2 Wh/kg in energy density of 1.38 kW/kg at 0–1.2 V. Moreover, the specific capacity retention can be as high as 91.4% after 4000 cycles, illustrating the remarkable cycling stability of the NiMoO₄@NiMoO₄//AC ASC device. Our results show that this unique NiMoO₄@NiMoO₄ SOWA has great prospects for future energy storage applications. Full article

(This article belongs to the Special Issue Metal-Oxide Nanomaterials for Energy Application)

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15 pages, 6658 KiB

Open AccessArticle

Characterization of Sn₄P₃–Carbon Composite Films for Lithium-Ion Battery Anode Fabricated by Aerosol Deposition

by Toki Moritaka, Yuh Yamashita, Tomohiro Tojo, Ryoji Inada and Yoji Sakurai

Nanomaterials 2019, 9(7), 1032; https://doi.org/10.3390/nano9071032 - 19 Jul 2019

Cited by 15 | Viewed by 5757

Abstract

We fabricated tin phosphide–carbon (Sn₄P₃/C) composite film by aerosol deposition (AD) and investigated its electrochemical performance for a lithium-ion battery anode. Sn₄P₃/C composite powders prepared by a ball milling was used as raw material and [...] Read more.

We fabricated tin phosphide–carbon (Sn₄P₃/C) composite film by aerosol deposition (AD) and investigated its electrochemical performance for a lithium-ion battery anode. Sn₄P₃/C composite powders prepared by a ball milling was used as raw material and deposited onto a stainless steel substrate to form the composite film via impact consolidation. The Sn₄P₃/C composite film fabricated by AD showed much better electrochemical performance than the Sn₄P₃ film without complexing carbon. Although both films showed initial discharge (Li⁺ extraction) capacities of approximately 1000 mAh g⁻¹, Sn₄P₃/C films retained higher reversible capacity above 700 mAh g⁻¹ after 100 cycles of charge and discharge processes while the capacity of Sn₄P₃ film rapidly degraded with cycling. In addition, by controlling the potential window in galvanostatic testing, Sn₄P₃/C composite film retained the reversible capacity of 380 mAh g⁻¹ even after 400 cycles. The complexed carbon works not only as a buffer to suppress the collapse of electrodes by large volume change of Sn₄P₃ in charge and discharge reactions but also as an electronic conduction path among the atomized active material particles in the film. Full article

(This article belongs to the Special Issue New Perspectives for the Development of Li-Ion Batteries of the 21st Century)

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9 pages, 9216 KiB

Open AccessArticle

Formation of Highly Ordered Platinum Nanowire Arrays on Silicon via Laser-Induced Self-Organization

by Michael Dasbach, Hendrik M. Reinhardt and Norbert A. Hampp

Nanomaterials 2019, 9(7), 1031; https://doi.org/10.3390/nano9071031 - 18 Jul 2019

Cited by 8 | Viewed by 3352

Abstract

Laser-induced periodic surface structures (LIPSS) provide an elegant solution for the generation of highly ordered periodic patterns on the surface of solids. In this study, LIPSS are utilized for the formation of periodic platinum nanowire arrays. In a process based on laser-stimulated self-organization, [...] Read more.

Laser-induced periodic surface structures (LIPSS) provide an elegant solution for the generation of highly ordered periodic patterns on the surface of solids. In this study, LIPSS are utilized for the formation of periodic platinum nanowire arrays. In a process based on laser-stimulated self-organization, platinum thin films, sputter-deposited onto silicon, are transformed into nanowire arrays with an average periodicity of 538 nm. The width of the platinum nanowires is adjustable in a range from 20 nm to 250 nm by simply adjusting the thickness of the initial platinum thin films in a range from 0.3 nm to 4.3 nm. With increasing width, platinum nanowires show a rising tendency to sink into the surface of the silicon wafer, thus indicating alloying between platinum and silicon upon LIPSS-formation by a nanosecond-pulsed laser. The Pt/silicon wires may be etched away, leaving a complementary nanostructure in the silicon surface. Full article

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19 pages, 3838 KiB

Open AccessReview

Recent Advances and Perspectives of Molecularly Imprinted Polymer-Based Fluorescent Sensors in Food and Environment Analysis

by Guangyang Liu, Xiaodong Huang, Lingyun Li, Xiaomin Xu, Yanguo Zhang, Jun Lv and Donghui Xu

Nanomaterials 2019, 9(7), 1030; https://doi.org/10.3390/nano9071030 - 18 Jul 2019

Cited by 75 | Viewed by 7294

Abstract

Molecular imprinting technology (MIT), also known as molecular template technology, is a new technology involving material chemistry, polymer chemistry, biochemistry, and other multi-disciplinary approaches. This technology is used to realize the unique recognition ability of three-dimensional crosslinked polymers, called the molecularly imprinted polymers [...] Read more.

Molecular imprinting technology (MIT), also known as molecular template technology, is a new technology involving material chemistry, polymer chemistry, biochemistry, and other multi-disciplinary approaches. This technology is used to realize the unique recognition ability of three-dimensional crosslinked polymers, called the molecularly imprinted polymers (MIPs). MIPs demonstrate a wide range of applicability, good plasticity, stability, and high selectivity, and their internal recognition sites can be selectively combined with template molecules to achieve selective recognition. A molecularly imprinted fluorescence sensor (MIFs) incorporates fluorescent materials (fluorescein or fluorescent nanoparticles) into a molecularly imprinted polymer synthesis system and transforms the binding sites between target molecules and molecularly imprinted materials into readable fluorescence signals. This sensor demonstrates the advantages of high sensitivity and selectivity of fluorescence detection. Molecularly imprinted materials demonstrate considerable research significance and broad application prospects. They are a research hotspot in the field of food and environment safety sensing analysis. In this study, the progress in the construction and application of MIFs was reviewed with emphasis on the preparation principle, detection methods, and molecular recognition mechanism. The applications of MIFs in food and environment safety detection in recent years were summarized, and the research trends and development prospects of MIFs were discussed. Full article

(This article belongs to the Special Issue Nanoscale Optical Sensing)

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21 pages, 6386 KiB

Open AccessReview

Plasmonic Nanofactors as Switchable Devices to Promote or Inhibit Neuronal Activity and Function

by Karrer M. Alghazali, Rabab N. Hamzah, Zeid A. Nima, Richard Steiner, Madhu Dhar, David E. Anderson, Abdallah Hayar, Robert J. Griffin and Alexandru S. Biris

Nanomaterials 2019, 9(7), 1029; https://doi.org/10.3390/nano9071029 - 18 Jul 2019

Cited by 6 | Viewed by 3978

Abstract

Gold nanosystems have been investigated extensively for a variety of applications, from specific cancer cell targeting to tissue regeneration. Specifically, a recent and exciting focus has been the gold nanosystems’ interface with neuronal biology. Researchers are investigating the ability to use these systems [...] Read more.

Gold nanosystems have been investigated extensively for a variety of applications, from specific cancer cell targeting to tissue regeneration. Specifically, a recent and exciting focus has been the gold nanosystems’ interface with neuronal biology. Researchers are investigating the ability to use these systems neuronal applications ranging from the enhancement of stem cell differentiation and therapy to stimulation or inhibition of neuronal activity. Most of these new areas of research are based on the integration of the plasmonic properties of such nanosystems into complex synthetic extracellular matrices (ECM) that can interact and affect positively the activity of neuronal cells. Therefore, the ability to integrate the plasmonic properties of these nanoparticles into multidimensional and morphological structures to support cellular proliferation and activity is potentially of great interest, particularly to address medical conditions that are currently not fully treatable. This review discusses some of the promising developments and unique capabilities offered by the integration of plasmonic nanosystems into morphologically complex ECM devices, designed to control and study the activity of neuronal cells. Full article

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18 pages, 3090 KiB

Open AccessArticle

Preparation and Characterization of Self Nano-Emulsifying Drug Delivery System Loaded with Citraland Its Antiproliferative Effect on Colorectal Cells In Vitro

by Mira Nadiah Mohd Izham, Yazmin Hussin, Muhammad Nazirul Mubin Aziz, Swee Keong Yeap, Heshu Sulaiman Rahman, Mas Jaffri Masarudin, Nurul Elyani Mohamad, Rasedee Abdullah and Noorjahan Banu Alitheen

Nanomaterials 2019, 9(7), 1028; https://doi.org/10.3390/nano9071028 - 18 Jul 2019

Cited by 63 | Viewed by 6579

Abstract

Citral is an active compound naturally found in lemongrass, lemon, and lime. Although this pale-yellow liquid confers low water solubility, the compound has been reported to possess good therapeutic features including antiproliferative and anticancer modalities. The self nano-emulsifying drug delivery system (SNEDDS) is [...] Read more.

Citral is an active compound naturally found in lemongrass, lemon, and lime. Although this pale-yellow liquid confers low water solubility, the compound has been reported to possess good therapeutic features including antiproliferative and anticancer modalities. The self nano-emulsifying drug delivery system (SNEDDS) is a type of liquid-lipid nanocarrier that is suitable for the loading of insolubilized oil-based compound such as Citral. This study reports the design and optimization of a SNEDDS formulation, synthesis and characterization as well as loading with Citral (CIT-SNEDDS). Further assessment of theantiproliferative effects of CIT-SNEDDS towards colorectal cancer cells was also conducted. SNEDDS composed of coconut oil, dimethyl sulfoxide (DMSO) and Tween 80. CIT-SNEDDS was prepared via gentle agitation of SNEDDS with 0.5% Citral for 72 h at room temperature. Physicochemical characterization was performed using several physicochemical analyses. The average particle size of CIT-SNEDDS was16.86 ± 0.15 nm, zeta potential of 0.58 ± 0.19 mV, and polydispersity index (PDI) of 0.23 ± 0.01. In vitro drug release of Citral from CIT-SNEDDS was 79.25% of release, and for Citral the release percentage was 93.56% over 72 h. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was done to determine the cytotoxicity effect of CIT-SNEDDS in human colorectal cancer cell lines HT29 and SW620. The half maximal inhibitory concentrations (IC₅₀) for 72 hof CIT-SNEDDS and Citral on SW620 were 16.50 ± 0.87 µg/mL and 22.50 ± 2.50 µg/mL, respectively. The IC₅₀ values of CIT-SNEDDS and Citral after 72 h of treatment on HT29 were 34.10 ± 0.30 µg/mL and 21.77 ± 0.23 µg/mL, respectively. This study strongly suggests that CIT-SNEDDS has permitted the sustained release of Citral and that CIT-SNEDDS constitutes a potential soluble drug nanocarrier that is effective against colorectal cancer cells. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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