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Nanomaterials, Volume 7, Issue 11 (November 2017)

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Cover Story (view full-size image) Mesoporous Cu-doped SnO2 powders are satisfactorily prepared by hard-templating from KIT-6 silica. [...] Read more.
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Open AccessReview Review of the Functions of Archimedes’ Spiral Metallic Nanostructures
Nanomaterials 2017, 7(11), 405; https://doi.org/10.3390/nano7110405
Received: 28 September 2017 / Revised: 16 November 2017 / Accepted: 18 November 2017 / Published: 22 November 2017
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Abstract
Here, we have reviewed some typical plasmonic structures based on Archimedes’ spiral (AS) architectures, which can produce polarization-sensitive focusing phenomenon and generate plasmonic vortices (PVs) carrying controllable orbital angular momentum (OAM) because of the relation between the incident polarized states and the chiralities
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Here, we have reviewed some typical plasmonic structures based on Archimedes’ spiral (AS) architectures, which can produce polarization-sensitive focusing phenomenon and generate plasmonic vortices (PVs) carrying controllable orbital angular momentum (OAM) because of the relation between the incident polarized states and the chiralities of the spiral structures. These features can be used to analyze different circular polarization states, which has been one of the rapidly developing researching topics in nanophotonics in recent years. Many investigations demonstrate that the multifunctional spiral-based plasmonic structures are excellent choices for chiral selection and generating the transmitted field with well-defined OAM. The circular polarization extinction ratio, as an evaluation criterion for the polarization selectivity of a designed structure, could be effectively improved by properly modulating the parameters of spiral structures. Such functional spiral plasmonic nanostructures are promising for applications in analyzing circular polarization light, full Stokes vector polarimetric sensors, near-field imaging, and so on. Full article
(This article belongs to the Special Issue Multifunctional Metallic Nanomaterials)
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Open AccessArticle Enhanced Oxygen Reduction Reaction by In Situ Anchoring Fe2N Nanoparticles on Nitrogen-Doped Pomelo Peel-Derived Carbon
Nanomaterials 2017, 7(11), 404; https://doi.org/10.3390/nano7110404
Received: 17 October 2017 / Revised: 14 November 2017 / Accepted: 17 November 2017 / Published: 22 November 2017
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Abstract
The development of effective oxygen electrode catalysts for renewable energy technologies such as metal-air batteries and fuel cells remains challenging. Here, we prepared a novel high-performance oxygen reduction reaction (ORR) catalyst comprised of Fe2N nanoparticles (NPs) in situ decorated over an
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The development of effective oxygen electrode catalysts for renewable energy technologies such as metal-air batteries and fuel cells remains challenging. Here, we prepared a novel high-performance oxygen reduction reaction (ORR) catalyst comprised of Fe2N nanoparticles (NPs) in situ decorated over an N-doped porous carbon derived from pomelo peel (i.e., Fe2N/N-PPC). The decorated Fe2N NPs provided large quantities of Fe-N-C bonding catalytic sites. The as-obtained Fe2N/N-PPC showed superior onset and half-wave potentials (0.966 and 0.891 V, respectively) in alkaline media (0.1 M KOH) compared to commercial Pt/C through a direct four-electron reaction pathway. Fe2N/N-PPC also showed better stability and methanol tolerance than commercial Pt/C. The outstanding ORR performance of Fe2N/N-PPC was attributed to its high specific surface area and the synergistic effects of Fe2N NPs. The utilization of agricultural wastes as a precursor makes Fe2N/N-PPC an ideal non-precious metal catalyst for ORR applications. Full article
(This article belongs to the Special Issue Nanomaterials Based Fuel Cells and Supercapacitors)
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Open AccessArticle Comparison of Anionic, Cationic and Nonionic Surfactants as Dispersing Agents for Graphene Based on the Fluorescence of Riboflavin
Nanomaterials 2017, 7(11), 403; https://doi.org/10.3390/nano7110403
Received: 23 October 2017 / Revised: 14 November 2017 / Accepted: 16 November 2017 / Published: 22 November 2017
Cited by 3 | PDF Full-text (3148 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Fluorescence quenching is a valuable tool to gain insight about dynamic changes of fluorophores in complex systems. Graphene (G), a single-layered 2D nanomaterial with unique properties, was dispersed in surfactant aqueous solutions of different nature: non-ionic polyoxyethylene-23-lauryl ether (Brij L23), anionic sodium dodecylsulphate
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Fluorescence quenching is a valuable tool to gain insight about dynamic changes of fluorophores in complex systems. Graphene (G), a single-layered 2D nanomaterial with unique properties, was dispersed in surfactant aqueous solutions of different nature: non-ionic polyoxyethylene-23-lauryl ether (Brij L23), anionic sodium dodecylsulphate (SDS), and cationic hexadecyltrimethylammonium bromide (CTAB) and dodecyltrimethylammonium bromide (DTAB). The influence of the surfactant type, chain length and concentration, G total concentration and G/surfactant weight ratio on the fluorescence intensity of vitamin B2 (riboflavin) was investigated. The quality of the different G dispersions was assessed by scanning and transmission electron microscopies (SEM and TEM). A quenching phenomenon of the fluorescence of riboflavin was found for G dispersions in all the surfactants, which generally becomes stronger with increasing G/surfactant weight ratio. For dispersions in the ionic surfactants, the quenching is more pronounced as the surfactant concentration raises, whilst the non-ionic one remains merely unchanged for the different G/Brij L23 weight ratios. More importantly, results indicate that DTAB solutions are the optimum media for dispersing G sheets, leading to an up to 16-fold drop in the fluorescence intensity. Understanding the mechanism in fluorescence quenching of G dispersions in surfactants could be useful for several optical applications. Full article
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Open AccessArticle Biomass-Derived Oxygen and Nitrogen Co-Doped Porous Carbon with Hierarchical Architecture as Sulfur Hosts for High-Performance Lithium/Sulfur Batteries
Nanomaterials 2017, 7(11), 402; https://doi.org/10.3390/nano7110402
Received: 2 October 2017 / Revised: 6 November 2017 / Accepted: 10 November 2017 / Published: 21 November 2017
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Abstract
In this work, a facile strategy to synthesize oxygen and nitrogen co-doped porous carbon (ONPC) is reported by one-step pyrolysis of waste coffee grounds. As-prepared ONPC possesses highly rich micro/mesopores as well as abundant oxygen and nitrogen co-doping, which is applied to sulfur
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In this work, a facile strategy to synthesize oxygen and nitrogen co-doped porous carbon (ONPC) is reported by one-step pyrolysis of waste coffee grounds. As-prepared ONPC possesses highly rich micro/mesopores as well as abundant oxygen and nitrogen co-doping, which is applied to sulfur hosts as lithium/sulfur batteries’ appropriate cathodes. In battery testing, the sulfur/oxygen and nitrogen co-doped porous carbon (S/ONPC) composite materials reveal a high initial capacity of 1150 mAh·g−1 as well as a reversible capacity of 613 mAh·g−1 after the 100th cycle at 0.2 C. Furthermore, when current density increases to 1 C, a discharge capacity of 331 mAh·g−1 is still attainable. Due to the hierarchical porous framework and oxygen/nitrogen co-doping, the S/ONPC composite exhibits a high utilization of sulfur and good electrochemical performance via the immobilization of the polysulfides through strong chemical binding. Full article
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Open AccessArticle An In Vitro Study of the Photodynamic Effectiveness of GO-Ag Nanocomposites against Human Breast Cancer Cells
Nanomaterials 2017, 7(11), 401; https://doi.org/10.3390/nano7110401
Received: 18 August 2017 / Revised: 29 September 2017 / Accepted: 4 October 2017 / Published: 21 November 2017
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Abstract
Graphene-based materials have garnered significant attention because of their versatile bioapplications and extraordinary properties. Graphene oxide (GO) is an extremely oxidized form of graphene accompanied by the functional groups of oxygen on its surface. GO is an outstanding platform on which to pacify
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Graphene-based materials have garnered significant attention because of their versatile bioapplications and extraordinary properties. Graphene oxide (GO) is an extremely oxidized form of graphene accompanied by the functional groups of oxygen on its surface. GO is an outstanding platform on which to pacify silver nanoparticles (Ag NPs), which gives rise to the graphene oxide-silver nanoparticle (GO-Ag) nanocomposite. In this experimental study, the toxicity of graphene oxide-silver (GO-Ag) nanocomposites was assessed in an in vitro human breast cancer model to optimize the parameters of photodynamic therapy. GO-Ag was prepared using the hydrothermal method, and characterization was done by X-ray diffraction, field-emission scanning electron microscope (FE-SEM), transmission Electron Microscopy (TEM), energy dispersive X-rays Analysis (EDAX), atomic force microscopy and ultraviolet-visible spectroscopy. The experiments were done both with laser exposure, as well as in darkness, to examine the phototoxicity and cytotoxicity of the nanocomposites. The cytotoxicity of the GO-Ag was confirmed via a methyl-thiazole-tetrazolium (MTT) assay and intracellular reactive oxygen species production analysis. The phototoxic effect explored the dose-dependent decrease in the cell viability, as well as provoked cell death via apoptosis. An enormously significant escalation of 1O2 in the samples when exposed to daylight was perceived. Statistical analysis was performed on the experimental results to confirm the worth and clarity of the results, with p-values < 0.05 selected as significant. These outcomes suggest that GO-Ag nanocomposites could serve as potential candidates for targeted breast cancer therapy. Full article
(This article belongs to the Special Issue Graphene and Nanotube Based Devices)
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Open AccessArticle Self-Assembled InAs Nanowires as Optical Reflectors
Nanomaterials 2017, 7(11), 400; https://doi.org/10.3390/nano7110400
Received: 19 October 2017 / Revised: 11 November 2017 / Accepted: 16 November 2017 / Published: 21 November 2017
Cited by 1 | PDF Full-text (4659 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Subwavelength nanostructured surfaces are realized with self-assembled vertically-aligned InAs nanowires, and their functionalities as optical reflectors are investigated. In our system, polarization-resolved specular reflectance displays strong modulations as a function of incident photon energy and angle. An effective-medium model allows one to rationalize
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Subwavelength nanostructured surfaces are realized with self-assembled vertically-aligned InAs nanowires, and their functionalities as optical reflectors are investigated. In our system, polarization-resolved specular reflectance displays strong modulations as a function of incident photon energy and angle. An effective-medium model allows one to rationalize the experimental findings in the long wavelength regime, whereas numerical simulations fully reproduce the experimental outcomes in the entire frequency range. The impact of the refractive index of the medium surrounding the nanostructure assembly on the reflectance was estimated. In view of the present results, sensing schemes compatible with microfluidic technologies and routes to innovative nanowire-based optical elements are discussed. Full article
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Open AccessArticle Synthesis and Swelling Behavior of pH-Sensitive Semi-IPN Superabsorbent Hydrogels Based on Poly(acrylic acid) Reinforced with Cellulose Nanocrystals
Nanomaterials 2017, 7(11), 399; https://doi.org/10.3390/nano7110399
Received: 11 October 2017 / Revised: 13 November 2017 / Accepted: 14 November 2017 / Published: 20 November 2017
Cited by 1 | PDF Full-text (4200 KB) | HTML Full-text | XML Full-text
Abstract
pH-sensitive poly(acrylic acid) (PAA) hydrogel reinforced with cellulose nanocrystals (CNC) was prepared. Acrylic acid (AA) was subjected to chemical cross-linking using the cross-linking agent MBA (N,N-methylenebisacrylamide) with CNC entrapped in the PAA matrix. The quantity of CNC was varied
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pH-sensitive poly(acrylic acid) (PAA) hydrogel reinforced with cellulose nanocrystals (CNC) was prepared. Acrylic acid (AA) was subjected to chemical cross-linking using the cross-linking agent MBA (N,N-methylenebisacrylamide) with CNC entrapped in the PAA matrix. The quantity of CNC was varied between 0, 5, 10, 15, 20, and 25 wt %. X-ray diffraction (XRD) data showed an increase in crystallinity with the addition of CNC, while rheology tests demonstrated a significant increase in the storage modulus of the hydrogel with an increase in CNC content. It was found that the hydrogel reached maximum swelling at pH 7. The potential of the resulting hydrogels to act as drug carriers was then evaluated by means of the drug encapsulation efficiency test using theophylline as a model drug. It was observed that 15% CNC/PAA hydrogel showed the potential to be used as drug carrier system. Full article
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Open AccessReview Fabrication of Semiconductor ZnO Nanostructures for Versatile SERS Application
Nanomaterials 2017, 7(11), 398; https://doi.org/10.3390/nano7110398
Received: 1 October 2017 / Revised: 3 November 2017 / Accepted: 6 November 2017 / Published: 19 November 2017
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Abstract
Since the initial discovery of surface-enhanced Raman scattering (SERS) in the 1970s, it has exhibited a huge potential application in many fields due to its outstanding advantages. Since the ultra-sensitive noble metallic nanostructures have increasingly exposed themselves as having some problems during application,
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Since the initial discovery of surface-enhanced Raman scattering (SERS) in the 1970s, it has exhibited a huge potential application in many fields due to its outstanding advantages. Since the ultra-sensitive noble metallic nanostructures have increasingly exposed themselves as having some problems during application, semiconductors have been gradually exploited as one of the critical SERS substrate materials due to their distinctive advantages when compared with noble metals. ZnO is one of the most representative metallic oxide semiconductors with an abundant reserve, various and cost-effective fabrication techniques, as well as special physical and chemical properties. Thanks to the varied morphologies, size-dependent exciton, good chemical stability, a tunable band gap, carrier concentration, and stoichiometry, ZnO nanostructures have the potential to be exploited as SERS substrates. Moreover, other distinctive properties possessed by ZnO such as biocompatibility, photocatcalysis and self-cleaning, and gas- and chemo-sensitivity can be synergistically integrated and exerted with SERS activity to realize the multifunctional potential of ZnO substrates. In this review, we discuss the inevitable development trend of exploiting the potential semiconductor ZnO as a SERS substrate. After clarifying the root cause of the great disparity between the enhancement factor (EF) of noble metals and that of ZnO nanostructures, two specific methods are put forward to improve the SERS activity of ZnO, namely: elemental doping and combination of ZnO with noble metals. Then, we introduce a distinctive advantage of ZnO as SERS substrate and illustrate the necessity of reporting a meaningful average EF. We also summarize some fabrication methods for ZnO nanostructures with varied dimensions (0–3 dimensions). Finally, we present an overview of ZnO nanostructures for the versatile SERS application. Full article
(This article belongs to the Special Issue ZnO and TiO2 Based Nanostructures)
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Open AccessArticle Plasmonic Spectral Splitting in Ring/Rod Metasurface
Nanomaterials 2017, 7(11), 397; https://doi.org/10.3390/nano7110397
Received: 6 October 2017 / Revised: 6 November 2017 / Accepted: 16 November 2017 / Published: 19 November 2017
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Abstract
We report spectral splitting behaviors based on Fano resonances in a novel simple planar metasurface composed of gold nanobars and nanorings. Multiple plasmonic modes and sharp Fano effects are achieved in a broadband transmittance spectrum by exploiting the rotational symmetry of the metasurface.
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We report spectral splitting behaviors based on Fano resonances in a novel simple planar metasurface composed of gold nanobars and nanorings. Multiple plasmonic modes and sharp Fano effects are achieved in a broadband transmittance spectrum by exploiting the rotational symmetry of the metasurface. The transmission properties are effectively modified and tuned by modulating the structural parameters. The highest single side Q-factor and FoM which reaches 196 and 105 are observed at Fano resonances. Our proposed design is relatively simple and can be applied for various applications such as multi-wavelength highly sensitive plasmonic sensors, switching, and slow light devices. Full article
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Open AccessReview Nanostructured MnO2 as Electrode Materials for Energy Storage
Nanomaterials 2017, 7(11), 396; https://doi.org/10.3390/nano7110396
Received: 14 October 2017 / Revised: 31 October 2017 / Accepted: 5 November 2017 / Published: 17 November 2017
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Abstract
Manganese dioxides, inorganic materials which have been used in industry for more than a century, now find great renewal of interest for storage and conversion of energy applications. In this review article, we report the properties of MnO2 nanomaterials with different morphologies.
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Manganese dioxides, inorganic materials which have been used in industry for more than a century, now find great renewal of interest for storage and conversion of energy applications. In this review article, we report the properties of MnO2 nanomaterials with different morphologies. Techniques used for the synthesis, structural, physical properties, and electrochemical performances of periodic and aperiodic frameworks are discussed. The effect of the morphology of nanosized MnO2 particles on their fundamental features is evidenced. Applications as electrodes in lithium batteries and supercapacitors are examined. Full article
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Open AccessArticle Preparation of Solution Blown Polyamic Acid Nanofibers and Their Imidization into Polyimide Nanofiber Mats
Nanomaterials 2017, 7(11), 395; https://doi.org/10.3390/nano7110395
Received: 6 October 2017 / Revised: 6 November 2017 / Accepted: 14 November 2017 / Published: 17 November 2017
Cited by 1 | PDF Full-text (9377 KB) | HTML Full-text | XML Full-text
Abstract
Solution blow spinning (SBS) is an innovative process for spinning micro/nanofibers. In this paper, polyamic acid (PAA) nanofibers were fabricated via a SBS apparatus and then imidized into polyimide (PI) nanofibers via thermal process. The morphology and diameter distributions of PAA nanofibers were
[...] Read more.
Solution blow spinning (SBS) is an innovative process for spinning micro/nanofibers. In this paper, polyamic acid (PAA) nanofibers were fabricated via a SBS apparatus and then imidized into polyimide (PI) nanofibers via thermal process. The morphology and diameter distributions of PAA nanofibers were determined by scanning electron microscope (SEM) and Image Tool software, the processing parameters, including PAA concentration, solution feeding rate, gas pressure, nozzle size, and receiving distance were investigated in details. The fourier transform infrared spectroscopy (FTIR) was used to characterize the chemical changes in the nanofibers after thermal imidization. The results showed that the solution concentration exhibited a notable correlation with spinnability, and the formation of bead defects in PAA nanofibers. Solution feeding rate, gas pressure, nozzle size, and receiving distance affected nanofiber production efficiency and diameter distribution. The average diameters of fibers produced ranged from 129.6 to 197.7 nm by varying SBS parameters. Precisely, PAA nanofibers with good morphology were obtained and the average diameter of nanofibers was 178.2 nm with optimum process parameter. After thermal imidization, the PI nanofibers exhibited obvious adhesion morphology among interconnected fibers, with an increased average diameter of 209.1 nm. The tensile strength of resultant PI nanofiber mat was 12.95 MPa. Full article
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Open AccessArticle Mechanical, Corrosion and Biological Properties of Room-Temperature Sputtered Aluminum Nitride Films with Dissimilar Nanostructure
Nanomaterials 2017, 7(11), 394; https://doi.org/10.3390/nano7110394
Received: 7 September 2017 / Revised: 13 November 2017 / Accepted: 14 November 2017 / Published: 17 November 2017
Cited by 1 | PDF Full-text (13435 KB) | HTML Full-text | XML Full-text
Abstract
Aluminum Nitride (AlN) has been long time being regarded as highly interesting material for developing sensing applications (including biosensors and implantable sensors). AlN, due to its appealing electronic properties, is envisaged lately to serve as a multi-functional biosensing platform. Although generally exploited for
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Aluminum Nitride (AlN) has been long time being regarded as highly interesting material for developing sensing applications (including biosensors and implantable sensors). AlN, due to its appealing electronic properties, is envisaged lately to serve as a multi-functional biosensing platform. Although generally exploited for its intrinsic piezoelectricity, its surface morphology and mechanical performance (elastic modulus, hardness, wear, scratch and tensile resistance to delamination, adherence to the substrate), corrosion resistance and cytocompatibility are also essential features for high performance sustainable biosensor devices. However, information about AlN suitability for such applications is rather scarce or at best scattered and incomplete. Here, we aim to deliver a comprehensive evaluation of the morpho-structural, compositional, mechanical, electrochemical and biological properties of reactive radio-frequency magnetron sputtered AlN nanostructured thin films with various degrees of c-axis texturing, deposited at a low temperature (~50 °C) on Si (100) substrates. The inter-conditionality elicited between the base pressure level attained in the reactor chamber and crystalline quality of AlN films is highlighted. The potential suitability of nanostructured AlN (in form of thin films) for the realization of various type of sensors (with emphasis on bio-sensors) is thoroughly probed, thus unveiling its advantages and limitations, as well as suggesting paths to safely exploit the remarkable prospects of this type of materials. Full article
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Open AccessFeature PaperArticle Evaluation of Different Single-Walled Carbon Nanotube Surface Coatings for Single-Particle Tracking Applications in Biological Environments
Nanomaterials 2017, 7(11), 393; https://doi.org/10.3390/nano7110393
Received: 10 October 2017 / Revised: 7 November 2017 / Accepted: 13 November 2017 / Published: 16 November 2017
Cited by 4 | PDF Full-text (1692 KB) | HTML Full-text | XML Full-text
Abstract
Fluorescence imaging of biological systems down to the single-molecule level has generated many advances in cellular biology. For applications within intact tissue, single-walled carbon nanotubes (SWCNTs) are emerging as distinctive single-molecule nanoprobes, due to their near-infrared photoluminescence properties. For this, SWCNT surfaces must
[...] Read more.
Fluorescence imaging of biological systems down to the single-molecule level has generated many advances in cellular biology. For applications within intact tissue, single-walled carbon nanotubes (SWCNTs) are emerging as distinctive single-molecule nanoprobes, due to their near-infrared photoluminescence properties. For this, SWCNT surfaces must be coated using adequate molecular moieties. Yet, the choice of the suspension agent is critical since it influences both the chemical and emission properties of the SWCNTs within their environment. Here, we compare the most commonly used surface coatings for encapsulating photoluminescent SWCNTs in the context of bio-imaging applications. To be applied as single-molecule nanoprobes, encapsulated nanotubes should display low cytotoxicity, and minimal unspecific interactions with cells while still being highly luminescent so as to be imaged and tracked down to the single nanotube level for long periods of time. We tested the cell proliferation and cellular viability of each surface coating and evaluated the impact of the biocompatible surface coatings on nanotube photoluminescence brightness. Our study establishes that phospholipid-polyethylene glycol-coated carbon nanotube is the best current choice for single nanotube tracking experiments in live biological samples. Full article
(This article belongs to the Special Issue Nanomaterials with Functional Polymer Elements)
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Open AccessArticle Templated Sphere Phase Liquid Crystals for Tunable Random Lasing
Nanomaterials 2017, 7(11), 392; https://doi.org/10.3390/nano7110392
Received: 30 September 2017 / Revised: 3 November 2017 / Accepted: 7 November 2017 / Published: 15 November 2017
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Abstract
A sphere phase liquid crystal (SPLC) composed of three-dimensional twist structures with disclinations among them exists between isotropic phase and blue phase in a very narrow temperature range, about several degrees centigrade. A low concentration polymer template is applied to improve the thermal
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A sphere phase liquid crystal (SPLC) composed of three-dimensional twist structures with disclinations among them exists between isotropic phase and blue phase in a very narrow temperature range, about several degrees centigrade. A low concentration polymer template is applied to improve the thermal stability of SPLCs and broadens the temperature range to more than 448 K. By template processing, a wavelength tunable random lasing is demonstrated with dye doped SPLC. With different polymer concentrations, the reconstructed SPLC random lasing may achieve more than 40 nm wavelength continuous shifting by electric field modulation. Full article
(This article belongs to the Special Issue Nanomaterials in Liquid Crystals)
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Open AccessArticle Synergistic Effect of Fluorinated and N Doped TiO2 Nanoparticles Leading to Different Microstructure and Enhanced Photocatalytic Bacterial Inactivation
Nanomaterials 2017, 7(11), 391; https://doi.org/10.3390/nano7110391
Received: 9 October 2017 / Revised: 9 November 2017 / Accepted: 10 November 2017 / Published: 15 November 2017
Cited by 5 | PDF Full-text (3477 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
This work focuses on the development of a facile and scalable wet milling method followed by heat treatment to prepare fluorinated and/or N-doped TiO2 nanopowders with improved photocatalytic properties under visible light. The structural and electronic properties of doped particles were investigated
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This work focuses on the development of a facile and scalable wet milling method followed by heat treatment to prepare fluorinated and/or N-doped TiO2 nanopowders with improved photocatalytic properties under visible light. The structural and electronic properties of doped particles were investigated by various techniques. The successful doping of TiO2 was confirmed by X-ray photoelectron spectroscopy (XPS), and the atoms appeared to be mainly located in interstitial positions for N whereas the fluorination is located at the TiO2 surface. The formation of intragap states was found to be responsible for the band gap narrowing leading to the faster bacterial inactivation dynamics observed for the fluorinated and N doped TiO2 particles compared to N-doped TiO2. This was attributed to a synergistic effect. The results presented in this study confirmed the suitability of the preparation approach for the large-scale production of cost-efficient doped TiO2 for effective bacterial inactivation. Full article
(This article belongs to the Special Issue Antibacterial Activity of Nanomaterials)
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Open AccessFeature PaperArticle Free-Standing and Self-Crosslinkable Hybrid Films by Core–Shell Particle Design and Processing
Nanomaterials 2017, 7(11), 390; https://doi.org/10.3390/nano7110390
Received: 29 October 2017 / Revised: 10 November 2017 / Accepted: 13 November 2017 / Published: 15 November 2017
Cited by 1 | PDF Full-text (8169 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The utilization and preparation of functional hybrid films for optical sensing applications and membranes is of utmost importance. In this work, we report the convenient and scalable preparation of self-crosslinking particle-based films derived by directed self-assembly of alkoxysilane-based cross-linkers as part of a
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The utilization and preparation of functional hybrid films for optical sensing applications and membranes is of utmost importance. In this work, we report the convenient and scalable preparation of self-crosslinking particle-based films derived by directed self-assembly of alkoxysilane-based cross-linkers as part of a core-shell particle architecture. The synthesis of well-designed monodisperse core-shell particles by emulsion polymerization is the basic prerequisite for subsequent particle processing via the melt-shear organization technique. In more detail, the core particles consist of polystyrene (PS) or poly(methyl methacrylate) (PMMA), while the comparably soft particle shell consists of poly(ethyl acrylate) (PEA) and different alkoxysilane-based poly(methacrylate)s. For hybrid film formation and convenient self-cross-linking, different alkyl groups at the siloxane moieties were investigated in detail by solid-state Magic-Angle Spinning Nuclear Magnetic Resonance (MAS, NMR) spectroscopy revealing different crosslinking capabilities, which strongly influence the properties of the core or shell particle films with respect to transparency and iridescent reflection colors. Furthermore, solid-state NMR spectroscopy and investigation of the thermal properties by differential scanning calorimetry (DSC) measurements allow for insights into the cross-linking capabilities prior to and after synthesis, as well as after the thermally and pressure-induced processing steps. Subsequently, free-standing and self-crosslinked particle-based films featuring excellent particle order are obtained by application of the melt-shear organization technique, as shown by microscopy (TEM, SEM). Full article
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Open AccessArticle Bioactive Molecules Release and Cellular Responses of Alginate-Tricalcium Phosphate Particles Hybrid Gel
Nanomaterials 2017, 7(11), 389; https://doi.org/10.3390/nano7110389
Received: 7 October 2017 / Revised: 7 November 2017 / Accepted: 13 November 2017 / Published: 14 November 2017
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Abstract
In this article, a hybrid gel has been developed using sodium alginate (Alg) and α-tricalcium phosphate (α-TCP) particles through ionic crosslinking process for the application in bone tissue engineering. The effects of pH and composition of the gel on osteoblast cells (MC3T3) response
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In this article, a hybrid gel has been developed using sodium alginate (Alg) and α-tricalcium phosphate (α-TCP) particles through ionic crosslinking process for the application in bone tissue engineering. The effects of pH and composition of the gel on osteoblast cells (MC3T3) response and bioactive molecules release have been evaluated. At first, a slurry of Alg and α-TCP has been prepared using an ultrasonicator for the homogeneous distribution of α-TCP particles in the Alg network and to achieve adequate interfacial interaction between them. After that, CaCl2 solution has been added to the slurry so that ionic crosslinked gel (Alg-α-TCP) is formed. The developed hybrid gel has been physico-chemically characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and a swelling study. The SEM analysis depicted the presence of α-TCP micro-particles on the surface of the hybrid gel, while cross-section images signified that the α-TCP particles are fully embedded in the porous gel network. Different % swelling ratio at pH 4, 7 and 7.4 confirmed the pH responsiveness of the Alg-α-TCP gel. The hybrid gel having lower % α-TCP particles showed higher % swelling at pH 7.4. The hybrid gel demonstrated a faster release rate of bovine serum albumin (BSA), tetracycline (TCN) and dimethyloxalylglycine (DMOG) at pH 7.4 and for the grade having lower % α-TCP particles. The MC3T3 cells are viable inside the hybrid gel, while the rate of cell proliferation is higher at pH 7.4 compared to pH 7. The in vitro cytotoxicity analysis using thiazolyl blue tetrazolium bromide (MTT), bromodeoxyuridine (BrdU) and neutral red assays ascertained that the hybrid gel is non-toxic for MC3T3 cells. The experimental results implied that the non-toxic and biocompatible Alg-α-TCP hybrid gel could be used as scaffold in bone tissue engineering. Full article
(This article belongs to the Special Issue Multifunctional Nanocomposites in 3D Printing Technologies)
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Open AccessArticle Intratumoral Delivery of Doxorubicin on Folate-Conjugated Graphene Oxide by In-Situ Forming Thermo-Sensitive Hydrogel for Breast Cancer Therapy
Nanomaterials 2017, 7(11), 388; https://doi.org/10.3390/nano7110388
Received: 6 October 2017 / Revised: 3 November 2017 / Accepted: 7 November 2017 / Published: 14 November 2017
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Abstract
By taking advantage of the pH-sensitive drug release property of graphene oxide (GO) after intracellular uptake, we prepared folic acid (FA)-conjugated GO (GOFA) for targeted delivery of the chemotherapeutic drug doxorubicin (DOX). GOFA-DOX was further encapsulated in an injectable in-situ forming thermo-sensitive hyaluronic
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By taking advantage of the pH-sensitive drug release property of graphene oxide (GO) after intracellular uptake, we prepared folic acid (FA)-conjugated GO (GOFA) for targeted delivery of the chemotherapeutic drug doxorubicin (DOX). GOFA-DOX was further encapsulated in an injectable in-situ forming thermo-sensitive hyaluronic acid-chitosan-g-poly(N-isopropylacrylamide) (HACPN) hydrogel for intratumoral delivery of DOX. As the degradation time of HACPN could be extended up to 3 weeks, intratumoral delivery of GOFA-DOX/HACPN could provide controlled and targeted delivery of DOX through slow degradation HACPN and subsequent cellular uptake of released GOFA-DOX by tumor cells through interactions of GOFA with folate receptors on the tumor cell’s surface. GOFA nano-carrier and HACPN hydrogel were first characterized for the physico-chemical properties. The drug loading experiments indicated the best preparation condition of GOFA-DOX was by reacting 0.1 mg GOFA with 2 mg DOX. GOFA-DOX showed pH-responsive drug release with ~5 times more DOX released at pH 5.5 than at pH 7.4 while only limited DOX was released from GOFA-DOX/HACPN at pH 7.4. Intracellular uptake of GOFA by endocytosis and release of DOX from GOFA-DOX in vitro could be confirmed from transmission electron microscopic and confocal laser scanning microscopic analysis with MCF-7 breast cancer cells. The targeting effect of FA was revealed when intracellular uptake of GOFA was blocked by excess FA. This resulted in enhanced in vitro cytotoxicity as revealed from the lower half maximal inhibitory concentration (IC50) value of GOFA-DOX (7.3 μg/mL) compared with that of DOX (32.5 μg/mL) and GO-DOX (10 μg/mL). The flow cytometry analysis indicated higher apoptosis rates for cells treated with GOFA-DOX (30%) compared with DOX (8%) and GO-DOX (11%). Animal studies were carried out with subcutaneously implanted MCF-7 cells in BALB/c nude mice and subject to intratumoral administration of drugs. The relative tumor volumes of control (saline) and GOFA-DOX/HACPN groups at day 21 were 2.17 and 1.79 times that at day 0 with no significant difference. In comparison, the relative tumor volumes of treatment groups at the same time were significantly different at 1.02, 0.67 and 0.48 times for DOX, GOFA-DOX and GOFA-DOX/HACPN groups, respectively. The anti-tumor efficacy was also supported by images from an in vivo imaging system (IVIS) using MCF-7 cells transfected with luciferase (MCF-7/Luc). Furthermore, tissue biopsy examination and blood analysis indicated that intratumoral delivery of DOX using GOFA-DOX/HACPN did not elicit acute toxicity. Taken together, GOFA-DOX/HACPN could be deemed as a safe and efficient intratumoral drug delivery system for breast cancer therapy. Full article
(This article belongs to the Special Issue Nanocolloids for Nanomedicine and Drug Delivery)
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Open AccessArticle Constructing Asymmetric Polyion Complex Vesicles via Template Assembling Strategy: Formulation Control and Tunable Permeability
Nanomaterials 2017, 7(11), 387; https://doi.org/10.3390/nano7110387
Received: 23 September 2017 / Revised: 27 October 2017 / Accepted: 8 November 2017 / Published: 13 November 2017
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Abstract
A strategy for constructing polyion complex vesicles (PICsomes) with asymmetric structure is described. Poly(methylacrylic acid)-block-poly(N-isopropylacrylamide) modified gold nanoparticles (PMAA-b-PNIPAm-@-Au NPs) were prepared and then assembled with poly(ethylene glycol)-block-poly[1-methyl-3-(2-methacryloyloxy propylimidazolium bromine)] (PEG-b-PMMPImB) via polyion
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A strategy for constructing polyion complex vesicles (PICsomes) with asymmetric structure is described. Poly(methylacrylic acid)-block-poly(N-isopropylacrylamide) modified gold nanoparticles (PMAA-b-PNIPAm-@-Au NPs) were prepared and then assembled with poly(ethylene glycol)-block-poly[1-methyl-3-(2-methacryloyloxy propylimidazolium bromine)] (PEG-b-PMMPImB) via polyion complex of PMMA and PMMPImB. After removing the Au NPs template, asymmetric PICsomes composed of a PNIPAm inner-shell, PIC wall, and PEG outer-corona were obtained. These PICsomes have low protein absorption and thermally tunable permeability, provided by the PEG outer-corona and the PNIPAm inner-shell, respectively. Moreover, PICsome size can be tailored by using templates of predetermined sizes. This novel strategy for constructing asymmetric PICsomes with well-defined properties and controllable size is valuable for applications such as drug delivery, catalysis and monitoring of chemical reactions, and biomimetics. Full article
(This article belongs to the Special Issue Nanoporous Gold and Other Related Materials)
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Open AccessFeature PaperArticle Carbon Nanotubes’ Effect on Mitochondrial Oxygen Flux Dynamics: Polarography Experimental Study and Machine Learning Models using Star Graph Trace Invariants of Raman Spectra
Nanomaterials 2017, 7(11), 386; https://doi.org/10.3390/nano7110386
Received: 7 October 2017 / Revised: 6 November 2017 / Accepted: 8 November 2017 / Published: 11 November 2017
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Abstract
This study presents the impact of carbon nanotubes (CNTs) on mitochondrial oxygen mass flux (Jm) under three experimental conditions. New experimental results and a new methodology are reported for the first time and they are based on CNT Raman spectra
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This study presents the impact of carbon nanotubes (CNTs) on mitochondrial oxygen mass flux (Jm) under three experimental conditions. New experimental results and a new methodology are reported for the first time and they are based on CNT Raman spectra star graph transform (spectral moments) and perturbation theory. The experimental measures of Jm showed that no tested CNT family can inhibit the oxygen consumption profiles of mitochondria. The best model for the prediction of Jm for other CNTs was provided by random forest using eight features, obtaining test R-squared (R2) of 0.863 and test root-mean-square error (RMSE) of 0.0461. The results demonstrate the capability of encoding CNT information into spectral moments of the Raman star graphs (SG) transform with a potential applicability as predictive tools in nanotechnology and material risk assessments. Full article
(This article belongs to the Special Issue Experimental Nanosciences, Computational Chemistry, and Data Analysis)
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Open AccessArticle Data Retention Characterization of Gate-Injected Gold-Nanoparticle Non-Volatile Memory with Low-Damage CF4-Plasma-Treated Blocking Oxide Layer
Nanomaterials 2017, 7(11), 385; https://doi.org/10.3390/nano7110385
Received: 26 September 2017 / Revised: 4 November 2017 / Accepted: 5 November 2017 / Published: 10 November 2017
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Abstract
Gold-nanoparticle (Au-NP) non-volatile memories (NVMs) with low-damage CF4 plasma treatment on the blocking oxide (BO) layer have been investigated to present the gate injection of the holes. These holes, injected from the Al gate with the positive gate bias, were explained by
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Gold-nanoparticle (Au-NP) non-volatile memories (NVMs) with low-damage CF4 plasma treatment on the blocking oxide (BO) layer have been investigated to present the gate injection of the holes. These holes, injected from the Al gate with the positive gate bias, were explained by the bandgap engineering of the gradually-fluorinated BO layer and the effective work function modulation of the Al gate. The Si–F complex in the BO layer was analyzed by X-ray photoelectron spectroscopy (XPS), while the depth of fluorine incorporation was verified using a secondary ion mass spectrometer (SIMS). In addition, the valence band modification of the fluorinated BO layer was examined by ultraviolet photoelectron spectroscopy (UPS) to support the bandgap engineering. The reactive power of the CF4 plasma treatment on the BO layer was modified to increase the electric field of the BO layer and raise the effective work function of the Al gate, leading to the hole-injection from the gate. The injected holes are trapped at the interface between the gold-nanoparticles (Au-NPs) and the tunneling oxide (TO) layer, resulting in superior data retention properties such as an extremely low charge loss of 5.7% at 104 s and a nearly negligible increase in charge loss at 85 °C of the CF4-plasma-treated Au-NP NVMs, which can be applied in highly reliable consumer electronics. Full article
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Open AccessArticle H2S Sensing by Hybrids Based on Nanocrystalline SnO2 Functionalized with Cu(II) Organometallic Complexes: The Role of the Ligand Platform
Nanomaterials 2017, 7(11), 384; https://doi.org/10.3390/nano7110384
Received: 1 October 2017 / Revised: 24 October 2017 / Accepted: 6 November 2017 / Published: 9 November 2017
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Abstract
This paper deals with the functionalization of nanocrystalline SnO2 with Cu(II) complexes with organic ligands, aimed at the improvement of sensor selectivity towards gas molecules. For the synthesis of metalorganic/SnO2 hybrid material complexes of Cu(II) with phthalocyanine, porphyrinines, bipyridine and azadithiacrown
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This paper deals with the functionalization of nanocrystalline SnO2 with Cu(II) complexes with organic ligands, aimed at the improvement of sensor selectivity towards gas molecules. For the synthesis of metalorganic/SnO2 hybrid material complexes of Cu(II) with phthalocyanine, porphyrinines, bipyridine and azadithiacrown etherwere used. The analysis of gas sensor properties showed the possibility of increasing the sensitivity and selectivity of hybrid materials in H2S detection due to the electron transfer from SnO2 to an adsorbed organic molecule, which changes during the interaction between H2S and Cu(II) ions. Full article
(This article belongs to the Special Issue Nanomaterials for Sensing Applications)
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Open AccessReview The Electrospun Ceramic Hollow Nanofibers
Nanomaterials 2017, 7(11), 383; https://doi.org/10.3390/nano7110383
Received: 28 September 2017 / Revised: 1 November 2017 / Accepted: 6 November 2017 / Published: 9 November 2017
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Abstract
Hollow nanofibers are largely gaining interest from the scientific community for diverse applications in the fields of sensing, energy, health, and environment. The main reasons are: their extensive surface area that increases the possibilities of engineering, their larger accessible active area, their porosity,
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Hollow nanofibers are largely gaining interest from the scientific community for diverse applications in the fields of sensing, energy, health, and environment. The main reasons are: their extensive surface area that increases the possibilities of engineering, their larger accessible active area, their porosity, and their sensitivity. In particular, semiconductor ceramic hollow nanofibers show greater space charge modulation depth, higher electronic transport properties, and shorter ion or electron diffusion length (e.g., for an enhanced charging–discharging rate). In this review, we discuss and introduce the latest developments of ceramic hollow nanofiber materials in terms of synthesis approaches. Particularly, electrospinning derivatives will be highlighted. The electrospun ceramic hollow nanofibers will be reviewed with respect to their most widely studied components, i.e., metal oxides. These nanostructures have been mainly suggested for energy and environmental remediation. Despite the various advantages of such one dimensional (1D) nanostructures, their fabrication strategies need to be improved to increase their practical use. The domain of nanofabrication is still advancing, and its predictable shortcomings and bottlenecks must be identified and addressed. Inconsistency of the hollow nanostructure with regard to their composition and dimensions could be one of such challenges. Moreover, their poor scalability hinders their wide applicability for commercialization and industrial use. Full article
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Open AccessReview Engineering the Surface/Interface Structures of Titanium Dioxide Micro and Nano Architectures towards Environmental and Electrochemical Applications
Nanomaterials 2017, 7(11), 382; https://doi.org/10.3390/nano7110382
Received: 30 September 2017 / Revised: 5 November 2017 / Accepted: 6 November 2017 / Published: 9 November 2017
Cited by 4 | PDF Full-text (7306 KB) | HTML Full-text | XML Full-text
Abstract
Titanium dioxide (TiO2) materials have been intensively studied in the past years because of many varied applications. This mini review article focuses on TiO2 micro and nano architectures with the prevalent crystal structures (anatase, rutile, brookite, and TiO2(B)),
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Titanium dioxide (TiO2) materials have been intensively studied in the past years because of many varied applications. This mini review article focuses on TiO2 micro and nano architectures with the prevalent crystal structures (anatase, rutile, brookite, and TiO2(B)), and summarizes the major advances in the surface and interface engineering and applications in environmental and electrochemical applications. We analyze the advantages of surface/interface engineered TiO2 micro and nano structures, and present the principles and growth mechanisms of TiO2 nanostructures via different strategies, with an emphasis on rational control of the surface and interface structures. We further discuss the applications of TiO2 micro and nano architectures in photocatalysis, lithium/sodium ion batteries, and Li–S batteries. Throughout the discussion, the relationship between the device performance and the surface/interface structures of TiO2 micro and nano structures will be highlighted. Then, we discuss the phase transitions of TiO2 nanostructures and possible strategies of improving the phase stability. The review concludes with a perspective on the current challenges and future research directions. Full article
(This article belongs to the Special Issue ZnO and TiO2 Based Nanostructures)
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Open AccessReview ZnO Nanowire Application in Chemoresistive Sensing: A Review
Nanomaterials 2017, 7(11), 381; https://doi.org/10.3390/nano7110381
Received: 30 September 2017 / Revised: 31 October 2017 / Accepted: 6 November 2017 / Published: 9 November 2017
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Abstract
This article provides an overview of the recent development of ZnO nanowires (NWs) for chemoresistive sensing. Working mechanisms of chemoresistive sensors are unified for gas, ultraviolet (UV) and bio sensor types: single nanowire and nanowire junction sensors are described, giving the overview for
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This article provides an overview of the recent development of ZnO nanowires (NWs) for chemoresistive sensing. Working mechanisms of chemoresistive sensors are unified for gas, ultraviolet (UV) and bio sensor types: single nanowire and nanowire junction sensors are described, giving the overview for a simple sensor manufacture by multiple nanowire junctions. ZnO NW surface functionalization is discussed, and how this effects the sensing is explained. Further, novel approaches for sensing, using ZnO NW functionalization with other materials such as metal nanoparticles or heterojunctions, are explained, and limiting factors and possible improvements are discussed. The review concludes with the insights and recommendations for the future improvement of the ZnO NW chemoresistive sensing. Full article
(This article belongs to the Special Issue ZnO and TiO2 Based Nanostructures)
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Open AccessArticle Rationally Controlled Synthesis of CdSexTe1−x Alloy Nanocrystals and Their Application in Efficient Graded Bandgap Solar Cells
Nanomaterials 2017, 7(11), 380; https://doi.org/10.3390/nano7110380
Received: 27 September 2017 / Revised: 1 November 2017 / Accepted: 5 November 2017 / Published: 8 November 2017
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Abstract
CdSexTe1−x semiconductor nanocrystals (NCs), being rod-shaped/irregular dot-shaped in morphology, have been fabricated via a simple hot-injection method. The NCs composition is well controlled through varying molar ratios of Se to Te precursors. Through changing the composition of the CdSex
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CdSexTe1−x semiconductor nanocrystals (NCs), being rod-shaped/irregular dot-shaped in morphology, have been fabricated via a simple hot-injection method. The NCs composition is well controlled through varying molar ratios of Se to Te precursors. Through changing the composition of the CdSexTe1−x NCs, the spectral absorption of the NC thin film between 570–800 nm is proved to be tunable. It is shown that the bandgap of homogeneously alloyed CdSexTe1−x active thin film is nonlinearly correlated with the different compositions, which is perceived as optical bowing. The solar cell devices based on CdSexTe1−x NCs with the structure of ITO/ZnO/CdSe/CdSexTe1−x/MoOx/Au and the graded bandgap ITO/ZnO/CdSe(w/o)/CdSexTe1−x/CdTe/MoOx/Au are systematically evaluated. It was found that the performance of solar cells degrades almost linearly with the increase of alloy NC film thickness with respect to ITO/ZnO/CdSe/CdSe0.2Te0.8/MoOx/Au. From another perspective, in terms of the graded bandgap structure of ITO/ZnO/CdSe/CdSexTe1−x/CdTe/MoOx/Au, the performance is improved in contrast with its single-junction analogues. The graded bandgap structure is proved to be efficient when absorbing spectrum and the solar cells fabricated under the structure of ITO/ZnO/CdSe0.8Te0.2/CdSe0.2Te0.8/CdTe/MoOx/Au indicate power conversion efficiency (PCE) of 6.37%, a value among the highest for solution-processed inversely-structured CdSexTe1−x NC solar cells. As the NC solar cells are solution-processed under environmental conditions, they are promising for fabricating solar cells at low cost, roll by roll and in large area. Full article
(This article belongs to the Special Issue Nanomaterials for Renewable and Sustainable Energy)
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Open AccessArticle Increased Loading, Efficacy and Sustained Release of Silibinin, a Poorly Soluble Drug Using Hydrophobically-Modified Chitosan Nanoparticles for Enhanced Delivery of Anticancer Drug Delivery Systems
Nanomaterials 2017, 7(11), 379; https://doi.org/10.3390/nano7110379
Received: 19 October 2017 / Revised: 28 October 2017 / Accepted: 30 October 2017 / Published: 8 November 2017
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Abstract
Conventional delivery of anticancer drugs is less effective due to pharmacological drawbacks such as lack of aqueous solubility and poor cellular accumulation. This study reports the increased drug loading, therapeutic delivery, and cellular accumulation of silibinin (SLB), a poorly water-soluble phenolic compound using
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Conventional delivery of anticancer drugs is less effective due to pharmacological drawbacks such as lack of aqueous solubility and poor cellular accumulation. This study reports the increased drug loading, therapeutic delivery, and cellular accumulation of silibinin (SLB), a poorly water-soluble phenolic compound using a hydrophobically-modified chitosan nanoparticle (pCNP) system. In this study, chitosan nanoparticles were hydrophobically-modified to confer a palmitoyl group as confirmed by 2,4,6-Trinitrobenzenesulfonic acid (TNBS) assay. Physicochemical features of the nanoparticles were studied using the TNBS assay, and Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analyses. The FTIR profile and electron microscopy correlated the successful formation of pCNP and pCNP-SLB as nano-sized particles, while Dynamic Light Scattering (DLS) and Field Emission-Scanning Electron Microscopy (FESEM) results exhibited an expansion in size between pCNP and pCNP-SLB to accommodate the drug within its particle core. To evaluate the cytotoxicity of the nanoparticles, a Methylthiazolyldiphenyl-tetrazolium bromide (MTT) cytotoxicity assay was subsequently performed using the A549 lung cancer cell line. Cytotoxicity assays exhibited an enhanced efficacy of SLB when delivered by CNP and pCNP. Interestingly, controlled release delivery of SLB was achieved using the pCNP-SLB system, conferring higher cytotoxic effects and lower IC50 values in 72-h treatments compared to CNP-SLB, which was attributed to the hydrophobic modification of the CNP system. Full article
(This article belongs to the Special Issue Nanocolloids for Nanomedicine and Drug Delivery)
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Open AccessArticle ZnO Nanoparticles Protect RNA from Degradation Better than DNA
Nanomaterials 2017, 7(11), 378; https://doi.org/10.3390/nano7110378
Received: 22 September 2017 / Revised: 23 October 2017 / Accepted: 31 October 2017 / Published: 8 November 2017
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Abstract
Gene therapy and RNA delivery require a nanoparticle (NP) to stabilize these nucleic acids when administered in vivo. The presence of degradative hydrolytic enzymes within these environments limits the nucleic acids’ pharmacologic activity. This study compared the effects of nanoscale ZnO and MgO
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Gene therapy and RNA delivery require a nanoparticle (NP) to stabilize these nucleic acids when administered in vivo. The presence of degradative hydrolytic enzymes within these environments limits the nucleic acids’ pharmacologic activity. This study compared the effects of nanoscale ZnO and MgO in the protection afforded to DNA and RNA from degradation by DNase, serum or tumor homogenate. For double-stranded plasmid DNA degradation by DNase, our results suggest that the presence of MgO NP can protect DNA from DNase digestion at an elevated temperature (65 °C), a biochemical activity not present in ZnO NP-containing samples at any temperature. In this case, intact DNA was remarkably present for MgO NP after ethidium bromide staining and agarose gel electrophoresis where these same stained DNA bands were notably absent for ZnO NP. Anticancer RNA, polyinosinic-polycytidylic acid (poly I:C) is now considered an anti-metastatic RNA targeting agent and as such there is great interest in its delivery by NP. For it to function, the NP must protect it from degradation in serum and the tumor environment. Surprisingly, ZnO NP protected the RNA from degradation in either serum-containing media or melanoma tumor homogenate after gel electrophoretic analysis, whereas the band was much more diminished in the presence of MgO. For both MgO and ZnO NP, buffer-dependent rescue from degradation occurred. These data suggest a fundamental difference in the ability of MgO and ZnO NP to stabilize nucleic acids with implications for DNA and RNA delivery and therapy. Full article
(This article belongs to the Special Issue ZnO and TiO2 Based Nanostructures)
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Open AccessArticle Magnetic Nanoparticle-Assisted Tunable Optical Patterns from Spherical Cholesteric Liquid Crystal Bragg Reflectors
Nanomaterials 2017, 7(11), 376; https://doi.org/10.3390/nano7110376
Received: 30 September 2017 / Revised: 25 October 2017 / Accepted: 2 November 2017 / Published: 8 November 2017
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Abstract
Cholesteric liquid crystals (CLCs) exhibit selective Bragg reflections of circularly polarized (CP) light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC) structures. To endow these
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Cholesteric liquid crystals (CLCs) exhibit selective Bragg reflections of circularly polarized (CP) light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC) structures. To endow these optical patterns with tunability, we fabricated spherical CLC Bragg reflectors in the shape of microshells by glass-capillary microfluidics. Water-soluble magnetofluid with Fe3O4 nanoparticles incorporated in the inner aqueous core of CLC shells is responsible for the non-invasive transportable capability. With the aid of an external magnetic field, the reflection interactions between neighboring microshells and microdroplets were identified by varying the mutual distance in a group of magnetically transportable and unmovable spherical CLC structures. The temperature-dependent optical reflection patterns were investigated in close-packed hexagonal arrangements of seven CLC microdroplets and microshells with inverse helicity handedness. Moreover, we demonstrated that the magnetic field-assisted assembly of microshells array into geometric figures of uppercase English letters “L” and “C” was successfully achieved. We hope that these findings can provide good application prospects for security pattern designs. Full article
(This article belongs to the Special Issue Nanomaterials in Liquid Crystals)
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Open AccessArticle ZnO Interactions with Biomatrices: Effect of Particle Size on ZnO-Protein Corona
Nanomaterials 2017, 7(11), 377; https://doi.org/10.3390/nano7110377
Received: 27 September 2017 / Revised: 28 October 2017 / Accepted: 2 November 2017 / Published: 6 November 2017
Cited by 5 | PDF Full-text (2467 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Zinc oxide (ZnO) nanoparticles (NPs) have been widely used for food fortification, because zinc is essential for many enzyme and hormone activities and cellular functions, but public concern about their potential toxicity is increasing. Interactions between ZnO and biomatrices might affect the oral
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Zinc oxide (ZnO) nanoparticles (NPs) have been widely used for food fortification, because zinc is essential for many enzyme and hormone activities and cellular functions, but public concern about their potential toxicity is increasing. Interactions between ZnO and biomatrices might affect the oral absorption, distribution, and toxicity of ZnO, which may be influenced by particle size. In this study, ZnO interactions with biomatrices were investigated by examining the physicochemical properties, solubility, protein fluorescence quenching, particle–protein corona, and intestinal transport with respect to the particle size (bulk vs. nano) in simulated gastrointestinal (GI) and plasma fluids and in rat-extracted fluids. The results demonstrate that the hydrodynamic radii and zeta potentials of bulk ZnO and nano ZnO in biofluids changed in different ways, and that nano ZnO induced higher protein fluorescence quenching than bulk ZnO. However, ZnO solubility and its intestinal transport mechanism were unaffected by particle size. Proteomic analysis revealed that albumin, fibrinogen, and fibronectin play roles in particle–plasma protein corona, regardless of particle size. Furthermore, nano ZnO was found to interact more strongly with plasma proteins. These observations show that bulk ZnO and nano ZnO interact with biomatrices in different ways and highlight the need for further study of their long-term toxicity. Full article
(This article belongs to the Special Issue ZnO and TiO2 Based Nanostructures)
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