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Nanomaterials, Volume 7, Issue 5 (May 2017)

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Cover Story Highly crystalline α-MnO2 nanorods were obtained using natural extracts of apple peels and [...] Read more.
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Open AccessArticle A Large-Area Nanoplasmonic Sensor Fabricated by Rapid Thermal Annealing Treatment for Label-Free and Multi-Point Immunoglobulin Sensing
Nanomaterials 2017, 7(5), 100; doi:10.3390/nano7050100
Received: 17 February 2017 / Revised: 25 April 2017 / Accepted: 28 April 2017 / Published: 2 May 2017
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Abstract
Immunoglobulins are important biomarkers to evaluate the immune status or development of infectious diseases. To provide timely clinical treatments, it is important to continuously monitor the level of multiple immunoglobulins. Localized surface plasmon resonance (LSPR)-based nanoplasmonic sensors have been demonstrated for multiplex immunoglobulins
[...] Read more.
Immunoglobulins are important biomarkers to evaluate the immune status or development of infectious diseases. To provide timely clinical treatments, it is important to continuously monitor the level of multiple immunoglobulins. Localized surface plasmon resonance (LSPR)-based nanoplasmonic sensors have been demonstrated for multiplex immunoglobulins detection. However, the sensor fabrication process is usually slow and complicated, so it is not accessible for large-area and batch fabrication. Herein, we report a large-area (2 cm × 2 cm) nanofabrication method using physical vapor deposition followed by a rapid thermal annealing treatment. To optimize the sensor performance, we systematically characterized three fabrication conditions, including (1) the deposition thickness; (2) the maximum annealing temperature, and (3) the annealing time. The corresponding absorbance spectrum profile and surface morphology of the nanostructures were observed by a UV-VIS spectrometer and atomic force microscopy. We then tested the sensitivity of the sensor using a glucose solution at different concentrations. The results showed that the sensor with 10 nm gold deposition thickness under 5-min 900 °C rapid thermal annealing can achieve the highest sensitivity (189 nm RIU−1). Finally, we integrated this nanoplasmonic sensor with a microchannel and a motorized stage to perform a 10-spot immunoglobulin detection in 50 min. Based on its real-time, dynamic and multi-point analyte detection capability, the nanoplasmonic sensor has the potential to be applied in high-throughput or multiplex immunoassay analysis, which would be beneficial for disease diagnosis or biomedical research in a simple and cost-effective platform. Full article
(This article belongs to the Special Issue Nanomaterials for Sensing Applications)
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Open AccessCommunication CdTe Nanocrystal Hetero-Junction Solar Cells with High Open Circuit Voltage Based on Sb-doped TiO2 Electron Acceptor Materials
Nanomaterials 2017, 7(5), 101; doi:10.3390/nano7050101
Received: 13 April 2017 / Revised: 27 April 2017 / Accepted: 28 April 2017 / Published: 3 May 2017
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Abstract
We propose Sb-doped TiO2 as electron acceptor material for depleted CdTe nanocrystal (NC) hetero-junction solar cells. Novel devices with the architecture of FTO/ZnO/Sb:TiO2/CdTe/Au based on CdTe NC and TiO2 precursor are fabricated by rational ambient solution process. By introducing
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We propose Sb-doped TiO2 as electron acceptor material for depleted CdTe nanocrystal (NC) hetero-junction solar cells. Novel devices with the architecture of FTO/ZnO/Sb:TiO2/CdTe/Au based on CdTe NC and TiO2 precursor are fabricated by rational ambient solution process. By introducing TiO2 with dopant concentration, we are able to tailor the optoelectronic properties of NC solar cells. Our novel devices demonstrate a very high open circuit voltage of 0.74 V, which is the highest Voc reported for any CdTe NC based solar cells. The power conversion efficiency (PCE) of solar cells increases with the increase of Sb-doped content from 1% to 3%, then decreases almost linearly with further increase of Sb content due to the recombination effect. The champion device shows Jsc, Voc, FF, and PCE of 14.65 mA/cm2, 0.70 V, 34.44, and 3.53% respectively, which is prospective for solution processed NC solar cells with high Voc. Full article
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Open AccessArticle Effect of Nano-SiO2 on the Early Hydration of Alite-Sulphoaluminate Cement
Nanomaterials 2017, 7(5), 102; doi:10.3390/nano7050102
Received: 17 March 2017 / Revised: 26 April 2017 / Accepted: 26 April 2017 / Published: 3 May 2017
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Abstract
The impact of nano-SiO2 on the early hydration properties of alite-sulphoaluminate (AC$A) cement was investigated with a fixed water to solid ratio (w/s) of one. Nano-SiO2 was used in partial substitution of AC$A cement at zero, one
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The impact of nano-SiO2 on the early hydration properties of alite-sulphoaluminate (AC$A) cement was investigated with a fixed water to solid ratio (w/s) of one. Nano-SiO2 was used in partial substitution of AC$A cement at zero, one and three wt %. Calorimetry, X-ray diffraction (XRD), thermogravimetric/derivative thermogravimetric (TG/DTG), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) analyses were used to characterize the hydration and hydrates of the blended cement. The hydration of the AC$A cement was significantly promoted, resulting in an increase of the heat released with the addition of nano-SiO2. Phase development composition analysis showed that nano-SiO2 had no effect on the type of crystalline hydration products of the AC$A cement. Moreover, nano-SiO2 showed significant positive effects on pore refinement where the total porosity decreased by 54.09% at three days with the inclusion of 3% nano-SiO2. Finally, from the SEM observations, nano-SiO2 was conducive to producing a denser microstructure than that of the control sample. Full article
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Open AccessArticle Electrodeposition of Rhodium Nanowires Arrays and Their Morphology-Dependent Hydrogen Evolution Activity
Nanomaterials 2017, 7(5), 103; doi:10.3390/nano7050103
Received: 22 March 2017 / Revised: 26 April 2017 / Accepted: 30 April 2017 / Published: 3 May 2017
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Abstract
This work reports on the electrodeposition of rhodium (Rh) nanowires with a controlled surface morphology synthesized using an anodic aluminum oxide (AAO) template. Vertically aligned Rh nanowires with a smooth and coarse morphology were successfully deposited by adjusting the electrode potential and the
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This work reports on the electrodeposition of rhodium (Rh) nanowires with a controlled surface morphology synthesized using an anodic aluminum oxide (AAO) template. Vertically aligned Rh nanowires with a smooth and coarse morphology were successfully deposited by adjusting the electrode potential and the concentration of precursor ions and by involving a complexing reagent in the electrolyte solution. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses were used to follow the morphological evolution of Rh nanowires. As a heterogeneous electrocatalyst for hydrogen evolution reactions (HER), the coarse Rh nanowire array exhibited an enhanced catalytic performance respect to smooth ones due to the larger surface area to mass ratio and the higher density of catalytically active defects, as evidenced by voltammetric measurements and TEM. Results suggest that the morphology of metallic nanomaterials could be readily engineered by electrodeposition. The controlled electrodeposition offers great potential for the development of an effective synthesis tool for heterogeneous catalysts with a superior performance for wide applications. Full article
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Open AccessArticle Probing Temperature- and pH-Dependent Binding between Quantum Dots and Bovine Serum Albumin by Fluorescence Correlation Spectroscopy
Nanomaterials 2017, 7(5), 93; doi:10.3390/nano7050093
Received: 13 March 2017 / Revised: 15 April 2017 / Accepted: 21 April 2017 / Published: 25 April 2017
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Abstract
Luminescent quantum dots (QDs) with unique optical properties have potential applications in bio-imaging. The interaction between QDs and bio-molecules is important to the biological effect of QDs in vivo. In this paper, we have employed fluorescence correlation spectroscopy (FCS) to probe the temperature-
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Luminescent quantum dots (QDs) with unique optical properties have potential applications in bio-imaging. The interaction between QDs and bio-molecules is important to the biological effect of QDs in vivo. In this paper, we have employed fluorescence correlation spectroscopy (FCS) to probe the temperature- and pH-dependent interactions between CdSe QDs with carboxyl (QDs-COOH) and bovine serum albumin (BSA) in buffer solutions. The results have shown that microscopic dissociation constant K′D is in the range of (1.5 ± 0.2) × 10−5 to (8.6 ± 0.1) × 10−7 M, the Hill coefficient n is from 0.4 to 2.3, and the protein corona thickness is from 3.0 to 9.4 nm. Variable-temperature measurements have shown both negative values of ∆H and ∆S for BSA adsorption on QDs-COOH, while pH has a profound effect on the adsorption. Additional, FCS measurement QDs-COOH and proteins in whole mice serum and plasma samples has also been conducted. Finally, simulation results have shown four favored QD binding sites in BSA. Full article
(This article belongs to the Special Issue Quantum Dots for Following Therapeutic Delivery)
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Open AccessArticle Improving Visible Light-Absorptivity and Photoelectric Conversion Efficiency of a TiO2 Nanotube Anode Film by Sensitization with Bi2O3 Nanoparticles
Nanomaterials 2017, 7(5), 104; doi:10.3390/nano7050104
Received: 1 March 2017 / Revised: 27 April 2017 / Accepted: 2 May 2017 / Published: 9 May 2017
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Abstract
This study presents a novel visible light-active TiO2 nanotube anode film by sensitization with Bi2O3 nanoparticles. The uniform incorporation of Bi2O3 contributes to largely enhancing the solar light absorption and photoelectric conversion efficiency of TiO2
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This study presents a novel visible light-active TiO2 nanotube anode film by sensitization with Bi2O3 nanoparticles. The uniform incorporation of Bi2O3 contributes to largely enhancing the solar light absorption and photoelectric conversion efficiency of TiO2 nanotubes. Due to the energy level difference between Bi2O3 and TiO2, the built-in electric field is suggested to be formed in the Bi2O3 sensitized TiO2 hybrid, which effectively separates the photo-generated electron-hole pairs and hence improves the photocatalytic activity. It is also found that the photoelectric conversion efficiency of Bi2O3 sensitized TiO2 nanotubes is not in direct proportion with the content of the sensitizer, Bi2O3, which should be carefully controlled to realize excellent photoelectrical properties. With a narrower energy band gap relative to TiO2, the sensitizer Bi2O3 can efficiently harvest the solar energy to generate electrons and holes, while TiO2 collects and transports the charge carriers. The new-type visible light-sensitive photocatalyst presented in this paper will shed light on sensitizing many other wide-band-gap semiconductors for improving solar photocatalysis, and on understanding the visible light-driven photocatalysis through narrow-band-gap semiconductor coupling. Full article
(This article belongs to the Special Issue Semiconductor Nanoparticles for Electric Device Applications)
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Open AccessFeature PaperArticle Direct Laser Writing of Magneto-Photonic Sub-Microstructures for Prospective Applications in Biomedical Engineering
Nanomaterials 2017, 7(5), 105; doi:10.3390/nano7050105
Received: 6 December 2016 / Revised: 2 May 2017 / Accepted: 4 May 2017 / Published: 9 May 2017
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Abstract
We report on the fabrication of desired magneto-photonic devices by a low one-photon absorption (LOPA) direct laser writing (DLW) technique on a photocurable nanocomposite consisting of magnetite (Fe3O4) nanoparticles and a commercial SU-8 photoresist. The magnetic nanocomposite was
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We report on the fabrication of desired magneto-photonic devices by a low one-photon absorption (LOPA) direct laser writing (DLW) technique on a photocurable nanocomposite consisting of magnetite ( Fe 3 O 4 ) nanoparticles and a commercial SU-8 photoresist. The magnetic nanocomposite was synthesized by mixing Fe 3 O 4 nanoparticles with different kinds of SU-8 photoresists. We demonstrated that the degree of dispersion of Fe 3 O 4 nanoparticles in the nanocomposite depended on the concentration of Fe 3 O 4 nanoparticles, the viscosity of SU-8 resist, and the mixing time. By tuning these parameters, the most homogeneous magnetic nanocomposite was obtained with a concentration of about 2 wt % of Fe 3 O 4 nanoparticles in SU-8 2005 photoresist for the mixing time of 20 days. The LOPA-based DLW technique was employed to fabricate on demand various magneto-photonic submicrometer structures, which are similar to those obtained without Fe 3 O 4 nanoparticles. The magneto-photonic 2D and 3D structures with sizes as small as 150 nm were created. We demonstrated the strong magnetic field responses of the magneto-photonic nanostructures and their use as micro-actuators when immersed in a liquid solution. Full article
(This article belongs to the Special Issue Functional Magnetic Nanoparticles in Nanomedicine)
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Open AccessArticle Improvement of Polylactide Properties through Cellulose Nanocrystals Embedded in Poly(Vinyl Alcohol) Electrospun Nanofibers
Nanomaterials 2017, 7(5), 106; doi:10.3390/nano7050106
Received: 9 January 2017 / Revised: 3 May 2017 / Accepted: 5 May 2017 / Published: 11 May 2017
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Abstract
Electrospun nanofibers of poly (vinyl alcohol) (PV) were obtained to improve dispersion of cellulose nanocrystals (CNC) within hydrophobic biopolymeric matrices, such as poly(lactic acid) (PLA). Electrospun nanofibers (PV/CNC)n were successfully obtained with a final concentration of 23% (w/w)
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Electrospun nanofibers of poly (vinyl alcohol) (PV) were obtained to improve dispersion of cellulose nanocrystals (CNC) within hydrophobic biopolymeric matrices, such as poly(lactic acid) (PLA). Electrospun nanofibers (PV/CNC)n were successfully obtained with a final concentration of 23% (w/w) of CNC. Morphological, structural and thermal properties of developed CNC and electrospun nanofibers were characterized. X-ray diffraction and thermal analysis revealed that the crystallinity of PV was reduced by the electrospinning process, and the incorporation of CNC increased the thermal stability of biodegradable nanofibers. Interactions between CNC and PV polymer also enhanced the thermal stability of CNC and improved the dispersion of CNC within the PLA matrix. PLA materials with CNC lyophilized were also casted in order to compare the properties with materials based on CNC containing nanofibers. Nanofibers and CNC were incorporated into PLA at three concentrations: 0.5%, 1% and 3% (CNC respect to polymer weight) and nanocomposites were fully characterized. Overall, nanofibers containing CNC positively modified the physical properties of PLA materials, such as the crystallinity degree of PLA which was greatly enhanced. Specifically, materials with 1% nanofiber 1PLA(PV/CNC)n presented highest improvements related to mechanical and barrier properties; elongation at break was enhanced almost four times and the permeation of oxygen was reduced by approximately 30%. Full article
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Open AccessArticle Fabrication and Properties of Micro-Nanoencapsulated Phase Change Materials for Internally-Cooled Liquid Desiccant Dehumidification
Nanomaterials 2017, 7(5), 96; doi:10.3390/nano7050096
Received: 8 February 2017 / Revised: 25 April 2017 / Accepted: 26 April 2017 / Published: 29 April 2017
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Abstract
Micro-nanoencapsulated phase change materials (M-NEPCMs) are proposed to be useful in liquid desiccant dehumidification by restraining the temperature rise in the moisture-removal process and improving the dehumidification efficiency. In this paper, the n-octadecane M-NEPCMs with desirable thermal properties for internally-cooled dehumidification were
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Micro-nanoencapsulated phase change materials (M-NEPCMs) are proposed to be useful in liquid desiccant dehumidification by restraining the temperature rise in the moisture-removal process and improving the dehumidification efficiency. In this paper, the n-octadecane M-NEPCMs with desirable thermal properties for internally-cooled dehumidification were fabricated by using compound emulsifiers through the in-situ polymerization method. Melamine-formaldehyde resin was used as the shell material. The effects of the mixing ratio, emulsification methods and amount of the compound emulsifiers on the morphology, size and thermal properties of the M-NEPCMs were investigated experimentally. The optimum weight mixing ratio of the compound emulsifiers is SDS (sodium dodecyl sulfate):Tween80 (polyoxyethylene sorbitan monooleate):Span80 (sorbitan monooleate) = 0.1:0.6:0.3, which achieves the best stability of the n-octadecane emulsion. When the compound emulsifiers are 10 wt. % of the core material, the melting enthalpy of M-NEPCMs reaches its maximum of 145.26 J/g of capsules, with an encapsulation efficiency of 62.88% and a mean diameter of 636 nm. The sub-cooling of the prepared M-NEPCMs is lower than 3 °C, with an acceptable thermal reliability after the thermal cycling test. A pre-emulsification prior to the addition of deionized water in the emulsification is beneficial to the morphology of the capsules, as the phase change enthalpy can be increased by 123.7%. Full article
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Open AccessArticle Superparamagnetic Iron Oxide Nanoparticles-Complexed Cationic Amylose for In Vivo Magnetic Resonance Imaging Tracking of Transplanted Stem Cells in Stroke
Nanomaterials 2017, 7(5), 107; doi:10.3390/nano7050107
Received: 30 March 2017 / Revised: 27 April 2017 / Accepted: 8 May 2017 / Published: 10 May 2017
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Abstract
Cell-based therapy with mesenchymal stem cells (MSCs) is a promising strategy for acute ischemic stroke. In vivo tracking of therapeutic stem cells with magnetic resonance imaging (MRI) is imperative for better understanding cellular survival and migrational dynamics over time. In this study, we
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Cell-based therapy with mesenchymal stem cells (MSCs) is a promising strategy for acute ischemic stroke. In vivo tracking of therapeutic stem cells with magnetic resonance imaging (MRI) is imperative for better understanding cellular survival and migrational dynamics over time. In this study, we develop a novel biocompatible nanocomplex (ASP-SPIONs) based on cationic amylose, by introducing spermine and the image label, ultrasmall superparamagnetic iron oxide nanoparticles (SPIONs), to label MSCs. The capacity, efficiency, and cytotoxicity of the nanocomplex in transferring SPIONs into green fluorescence protein-modified MSCs were tested; and the performance of in vivo MRI tracking of the transplanted cells in acute ischemic stroke was determined. The results demonstrated that the new class of SPIONs-complexed nanoparticles based on biodegradable amylose can serve as a highly effective and safe carrier to transfer magnetic label into stem cells. A reliable tracking of transplanted stem cells in stroke was achieved by MRI up to 6 weeks, with the desirable therapeutic benefit of stem cells on stroke retained. With the advantages of a relatively low SPIONs concentration and a short labeling period, the biocompatible complex of cationic amylose with SPIONs is highly translatable for clinical application. It holds great promise in efficient, rapid, and safe labeling of stem cells for subsequent cellular MRI tracking in regenerative medicine. Full article
(This article belongs to the Special Issue Functional Magnetic Nanoparticles in Nanomedicine)
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Open AccessArticle Synthesis of Pt@TiO2@CNTs Hierarchical Structure Catalyst by Atomic Layer Deposition and Their Photocatalytic and Photoelectrochemical Activity
Nanomaterials 2017, 7(5), 97; doi:10.3390/nano7050097
Received: 1 March 2017 / Revised: 20 April 2017 / Accepted: 26 April 2017 / Published: 29 April 2017
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Abstract
Pt@TiO2@CNTs hierarchical structures were prepared by first functionalizing carbon nanotubes (CNTs) with nitric acid at 140 °C. Coating of TiO2 particles on the CNTs at 300 °C was then conducted by atomic layer deposition (ALD). After the TiO2@CNTs structure was fabricated, Pt particles
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Pt@TiO2@CNTs hierarchical structures were prepared by first functionalizing carbon nanotubes (CNTs) with nitric acid at 140 °C. Coating of TiO2 particles on the CNTs at 300 °C was then conducted by atomic layer deposition (ALD). After the TiO2@CNTs structure was fabricated, Pt particles were deposited on the TiO2 surface as co-catalyst by plasma-enhanced ALD. The saturated deposition rates of TiO2 on a-CNTs were 1.5 Å/cycle and 0.4 Å/cycle for substrate-enhanced process and linear process, respectively. The saturated deposition rate of Pt on TiO2 was 0.39 Å/cycle. The photocatalytic activities of Pt@TiO2@CNTs hierarchical structures were higher than those without Pt co-catalyst. The particle size of Pt on TiO2@CNTs was a key factor to determine the efficiency of methylene blue (MB) degradation. The Pt@TiO2@CNTs of 2.41 ± 0.27 nm exhibited the best efficiency of MB degradation. Full article
(This article belongs to the Special Issue Noble Metal Nanoparticles in Catalysis)
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Open AccessArticle Surface Modification and Damage of MeV-Energy Heavy Ion Irradiation on Gold Nanowires
Nanomaterials 2017, 7(5), 108; doi:10.3390/nano7050108
Received: 23 January 2017 / Revised: 17 April 2017 / Accepted: 20 April 2017 / Published: 15 May 2017
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Abstract
Gold nanowires with diameters ranging from 20 to 90 nm were fabricated by the electrochemical deposition technique in etched ion track polycarbonate templates and were then irradiated by Xe and Kr ions with the energy in MeV range. The surface modification of nanowires
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Gold nanowires with diameters ranging from 20 to 90 nm were fabricated by the electrochemical deposition technique in etched ion track polycarbonate templates and were then irradiated by Xe and Kr ions with the energy in MeV range. The surface modification of nanowires was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations. Different craters with and without protrusion on the gold nanowires were analyzed, and the two corresponding formation mechanisms, i.e., plastic flow and micro-explosion, were investigated. In addition, the sputtered gold nanoparticles caused by ion irradiation were studied and it was confirmed that the surface damage produced in gold nanowires was increased as the diameter of the nanowires decreased. It was also found that heavy ion irradiation can also create stacking fault tetrahedrons (SFTs) in gold nanowires and three different SFTs were confirmed in irradiated nanowires. A statistical analysis of the size distribution of SFTs in gold nanowires proved that the average size distribution of SFT was positively related to the nuclear stopping power of incident ions, i.e., the higher nuclear stopping power of incident ions could generate SFT with a larger average size in gold nanowires. Full article
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Open AccessArticle Calcination Method Synthesis of SnO2/g-C3N4 Composites for a High-Performance Ethanol Gas Sensing Application
Nanomaterials 2017, 7(5), 98; doi:10.3390/nano7050098
Received: 7 February 2017 / Revised: 12 April 2017 / Accepted: 26 April 2017 / Published: 29 April 2017
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Abstract
The SnO2/g-C3N4 composites were synthesized via a facile calcination method by using SnCl4·5H2O and urea as the precursor. The structure and morphology of the as-synthesized composites were characterized by the techniques of X-ray diffraction
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The SnO2/g-C3N4 composites were synthesized via a facile calcination method by using SnCl4·5H2O and urea as the precursor. The structure and morphology of the as-synthesized composites were characterized by the techniques of X-ray diffraction (XRD), the field-emission scanning electron microscopy and transmission electron microscopy (FESEM and TEM), energy dispersive spectrometry (EDS), thermal gravity and differential thermal analysis (TG-DTA), and N2-sorption. The analysis results indicated that the as-synthesized samples possess the two dimensional structure. Additionally, the SnO2 nanoparticles were highly dispersed on the surface of the g-C3N4 nanosheets. The gas-sensing performance of the as-synthesized composites for different gases was tested. Moreover, the composite with 7 wt % g-C3N4 content (SnO2/g-C3N4-7) exhibits an admirable gas-sensing property to ethanol, which possesses a higher response and better selectivity than that of the pure SnO2-based sensor. The high surface area of the SnO2/g-C3N4 composite and the good electronic characteristics of the two dimensional graphitic carbon nitride are in favor of the elevated gas-sensing property. Full article
(This article belongs to the Special Issue Nanomaterials for Sensing Applications)
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Open AccessArticle Fabrication of Silicon Nanobelts and Nanopillars by Soft Lithography for Hydrophobic and Hydrophilic Photonic Surfaces
Nanomaterials 2017, 7(5), 109; doi:10.3390/nano7050109
Received: 18 January 2017 / Revised: 20 March 2017 / Accepted: 8 May 2017 / Published: 11 May 2017
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Abstract
Soft lithography allows for the simple and low-cost fabrication of nanopatterns with different shapes and sizes over large areas. However, the resolution and the aspect ratio of the nanostructures fabricated by soft lithography are limited by the depth and the physical properties of
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Soft lithography allows for the simple and low-cost fabrication of nanopatterns with different shapes and sizes over large areas. However, the resolution and the aspect ratio of the nanostructures fabricated by soft lithography are limited by the depth and the physical properties of the stamp. In this work, silicon nanobelts and nanostructures were achieved by combining soft nanolithography patterning with optimized reactive ion etching (RIE) in silicon. Using polymethylmethacrylate (PMMA) nanopatterned layers with thicknesses ranging between 14 and 50 nm, we obtained silicon nanobelts in areas of square centimeters with aspect ratios up to ~1.6 and linewidths of 225 nm. The soft lithographic process was assisted by a thin film of SiOx (less than 15 nm) used as a hard mask and RIE. This simple patterning method was also used to fabricate 2D nanostructures (nanopillars) with aspect ratios of ~2.7 and diameters of ~200 nm. We demonstrate that large areas patterned with silicon nanobelts exhibit a high reflectivity peak in the ultraviolet C (UVC) spectral region (280 nm) where some aminoacids and peptides have a strong absorption. We also demonstrated how to tailor the aspect ratio and the wettability of these photonic surfaces (contact angles ranging from 8.1 to 96.2°) by changing the RIE power applied during the fabrication process. Full article
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Open AccessArticle Magnetic Cationic Amylose Nanoparticles Used to Deliver Survivin-Small Interfering RNA for Gene Therapy of Hepatocellular Carcinoma In Vitro
Nanomaterials 2017, 7(5), 110; doi:10.3390/nano7050110
Received: 1 April 2017 / Revised: 7 May 2017 / Accepted: 9 May 2017 / Published: 11 May 2017
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Abstract
Amylose is a promising nanocarrier for gene delivery in terms of its good biocompatibility and high transfection efficiency. Small interfering RNA against survivin (survivin-siRNA) can cause tumor apoptosis by silencing a hepatocellular carcinoma (HCC)-specific gene at the messenger RNA level. In this study,
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Amylose is a promising nanocarrier for gene delivery in terms of its good biocompatibility and high transfection efficiency. Small interfering RNA against survivin (survivin-siRNA) can cause tumor apoptosis by silencing a hepatocellular carcinoma (HCC)-specific gene at the messenger RNA level. In this study, we developed a new class of folate-functionalized, superparamagnetic iron oxide (SPIO)-loaded cationic amylose nanoparticles to deliver survivin-siRNA to HCC cells. The cellular uptake of nanocomplexes, cytotoxicity, cell apoptosis, and gene suppression mediated by siRNA-complexed nanoparticles were tested. The results demonstrated that folate-functionalized, SPIO-loaded cationic amylose nanoparticles can mediate a specific and safe cellular uptake of survivin-siRNA with high transfection efficiency, resulting in a robust survivin gene downregulation in HCC cells. The biocompatible complex of cationic amylose could be used as an efficient, rapid, and safe gene delivery vector. Upon SPIO loading, it holds a great promise as a theranostic carrier for gene therapy of HCC. Full article
(This article belongs to the Special Issue Functional Magnetic Nanoparticles in Nanomedicine)
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Open AccessArticle Core-Shell Magnetic Gold Nanoparticles for Magnetic Field-Enhanced Radio-Photothermal Therapy in Cervical Cancer
Nanomaterials 2017, 7(5), 111; doi:10.3390/nano7050111
Received: 31 March 2017 / Revised: 26 April 2017 / Accepted: 8 May 2017 / Published: 11 May 2017
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Abstract
The combination of radiotherapy (RT) and photothermal therapy (PTT) has been considered an attractive strategy in cervical cancer treatment. However, it remains a challenge to simultaneously enhance the radio-sensitivity of tumor tissue, develop tumor tissue-focused radiation therapies and combine dual therapeutic modalities. In
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The combination of radiotherapy (RT) and photothermal therapy (PTT) has been considered an attractive strategy in cervical cancer treatment. However, it remains a challenge to simultaneously enhance the radio-sensitivity of tumor tissue, develop tumor tissue-focused radiation therapies and combine dual therapeutic modalities. In this study, core-shell type magnetic gold (Fe3O4@Au) nanoparticles are exploited to achieve the synergistic efficacy of radio-photothermal therapy in cervical cancer. Fe3O4@Au nanoparticles (NPs) with uniform morphology exhibited superior surface plasmon resonance properties, excellent superparamagnetic properties, good biocompatibility and high photothermal conversion efficiency. For the in vitro tests, a low concentration of Fe3O4@Au NPs after a short period of near-infrared irradiation lead to the time-dependent death of cervical cancer cells. Further, the combination of RT and PTT induced synergistic anti-cancer effects in vitro. More importantly, an external magnetic field could significantly enhance the synergistic efficacy of Fe3O4@Au NPs by improving their internalization. Hence, the reported Fe3O4@Au NPs have the potential to be good nanoagents with excellent magnetic targeting ability for cervical cancer radio-photothermal treatment. Full article
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Open AccessArticle Encapsulation of 16-Hydroxycleroda-3,13-Dine-16,15-Olide in Mesoporous Silica Nanoparticles as a Natural Dipeptidyl Peptidase-4 Inhibitor Potentiated Hypoglycemia in Diabetic Mice
Nanomaterials 2017, 7(5), 112; doi:10.3390/nano7050112
Received: 20 April 2017 / Revised: 9 May 2017 / Accepted: 9 May 2017 / Published: 12 May 2017
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Abstract
Natural supplements comprise good efficacy with less adverse effects as against diabetic therapy, but their advancement as anti-diabetic agents is unsatisfactory with regard to the delivery system. Dipeptidyl peptidase-4 (DPP4)/CD26) can degrade glucagon-like pepetide-1 (GLP-1) which renders a decrease of blood glucose levels.
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Natural supplements comprise good efficacy with less adverse effects as against diabetic therapy, but their advancement as anti-diabetic agents is unsatisfactory with regard to the delivery system. Dipeptidyl peptidase-4 (DPP4)/CD26) can degrade glucagon-like pepetide-1 (GLP-1) which renders a decrease of blood glucose levels. 16-hydroxycleroda-3,13-dine-16,15-olide (HCD) extracted from Polyalthia longifolia, exhibits numerous medicinal potentials including hypoglycemic potential. On consideration of HCD application, the bioavailability is affected by low solubility. Extended experiments of anti-diabetic efficacy confirmed HCD biocompatible with mesoporous silica nanoparticles (MSNs) encapsulation resulted in a sustained release property in delivering HCD for the inhibition of DPP4 via the activity and protein levels of DPP4 analysis. In the enzymatic activity assay, MSN-HCD directly changed DPP4 activity. Moreover, MSN-HCD nanoparticles were treated with Caco-2 cells and the protein levels of DPP4 determined within the cells. The results revealed that MSN-HCD caused reduction of DPP4 activity in a time- and dose-dependent fashion. Orally administered MSN-HCD in diet-induced diabetic mice alleviated blood glucose via an oral glucose tolerance test. In addition, administration of MSN-HCD for five weeks revealed that the biochemical cues such as pyruvate transaminase (GPT), glutamate oxaloacetate transaminase (GOT), triglycerides (TG), cholesterol (CHO), and glycated hemoglobin (HbA1c) in mice were commendable as further confirmation of MSN-HCD efficacy and less adverse effects in down-regulation of hyperglycemia. Furthermore, this formulation effectively controlled blood glucose and significantly decreased the body weight of mice, suggesting that MSN-HCD exerts natural DPP4 inhibitor as a potential clinical drug for the treatment of diabetes. Full article
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Open AccessArticle Deposition of Visible Light-Active C-Doped Titania Films via Magnetron Sputtering Using CO2 as a Source of Carbon
Nanomaterials 2017, 7(5), 113; doi:10.3390/nano7050113
Received: 8 April 2017 / Revised: 9 May 2017 / Accepted: 11 May 2017 / Published: 16 May 2017
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Abstract
Doping of titanium dioxide with p-block elements is typically described as an efficient pathway for the enhancement of photocatalytic activity. However, the properties of the doped titania films depend greatly on the production method, source of doping, type of substrate, etc. The present
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Doping of titanium dioxide with p-block elements is typically described as an efficient pathway for the enhancement of photocatalytic activity. However, the properties of the doped titania films depend greatly on the production method, source of doping, type of substrate, etc. The present work describes the use of pulsed direct current (pDC) magnetron sputtering for the deposition of carbon-doped titania coatings, using CO2 as the source of carbon; ratios of O2/CO2 were varied through variations of CO2 flow rates and oxygen flow control setpoints. Additionally, undoped Titanium dioxide (TiO2) coatings were prepared under identical deposition conditions for comparison purposes. Coatings were post-deposition annealed at 873 K and analysed with scanning electron microscopy (SEM), X-ray diffreaction (XRD), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The photocatalytic properties of the thin films were evaluated under ultraviolet (UV) and visible light irradiation using methylene blue and stearic acid decomposition tests. Photoinduced hydrophilicity was assessed through measurements of the water contact angle under UV and visible light irradiation. It was found that, though C-doping resulted in improved dye degradation compared to undoped TiO2, the UV-induced photoactivity of Carbon-doped (C-doped) photocatalysts was lower for both model pollutants used. Full article
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Open AccessArticle Resonance Rayleigh Scattering and SERS Spectral Detection of Trace Hg(II) Based on the Gold Nanocatalysis
Nanomaterials 2017, 7(5), 114; doi:10.3390/nano7050114
Received: 5 March 2017 / Revised: 6 May 2017 / Accepted: 8 May 2017 / Published: 17 May 2017
PDF Full-text (2324 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Mercury (Hg) is a heavy metal pollutant, there is an urgent need to develop simple and sensitive methods for Hg(II) in water. In this article, a simple and sensitive resonance Rayleigh scattering (RRS) method was developed for determination of 0.008–1.33 µmol/L Hg, with
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Mercury (Hg) is a heavy metal pollutant, there is an urgent need to develop simple and sensitive methods for Hg(II) in water. In this article, a simple and sensitive resonance Rayleigh scattering (RRS) method was developed for determination of 0.008–1.33 µmol/L Hg, with a detection limit of 0.003 μmol/L, based on the Hg(II) regulation of gold nanoenzyme catalysis on the HAuCl4-H2O2 to form gold nanoparticles (AuNPs) with an RRS peak at 370 nm. Upon addition of molecular probes of Victoria blue B (VBB), the surface-enhanced Raman scattering (SERS) peak linearly decreased at 1612 cm−1 with the Hg(II) concentration increasing in the range of 0.013–0.5 μmol/L. With its good selectivity and good accuracy, the RRS method is expected to be a promising candidate for determining mercury ions in water samples. Full article
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Open AccessArticle Computational Predictions for Single Chain Chalcogenide-Based One-Dimensional Materials
Nanomaterials 2017, 7(5), 115; doi:10.3390/nano7050115
Received: 9 March 2017 / Revised: 24 April 2017 / Accepted: 2 May 2017 / Published: 17 May 2017
PDF Full-text (3515 KB) | HTML Full-text | XML Full-text
Abstract
Exfoliation of multilayered materials has led to an abundance of new two-dimensional (2D) materials and to their fabrication by other means. These materials have shown exceptional promise for many applications. In a similar fashion, we can envision starting with crystalline polymeric (multichain) materials
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Exfoliation of multilayered materials has led to an abundance of new two-dimensional (2D) materials and to their fabrication by other means. These materials have shown exceptional promise for many applications. In a similar fashion, we can envision starting with crystalline polymeric (multichain) materials and exfoliate single-chain, one-dimensional (1D) materials that may also prove useful. We use electronic structure methods to elucidate the properties of such 1D materials: individual chains of chalcogens, of silicon dichalcogenides and of sulfur nitrides. The results indicate reasonable exfoliation energies in the case of polymeric three-dimensional (3D) materials. Quantum confinement effects lead to large band gaps and large exciton binding energies. The effects of strain are quantified and heterojunction band offsets are determined. Possible applications would entail 1D materials on 3D or 2D substrates. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessArticle Oriented Growth of α-MnO2 Nanorods Using Natural Extracts from Grape Stems and Apple Peels
Nanomaterials 2017, 7(5), 117; doi:10.3390/nano7050117
Received: 5 April 2017 / Revised: 10 May 2017 / Accepted: 15 May 2017 / Published: 22 May 2017
PDF Full-text (3671 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
We report on the synthesis of alpha manganese dioxide (α-MnO2) nanorods using natural extracts from Vitis vinifera grape stems and Malus domestica ‘Cortland’ apple peels. We used a two-step method to produce highly crystalline α-MnO2 nanorods: (1) reduction of KMnO
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We report on the synthesis of alpha manganese dioxide (α-MnO2) nanorods using natural extracts from Vitis vinifera grape stems and Malus domestica ‘Cortland’ apple peels. We used a two-step method to produce highly crystalline α-MnO2 nanorods: (1) reduction of KMnO4 in the presence of natural extracts to initiate the nucleation process; and (2) a thermal treatment to enable further solid-state growth of the nuclei. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) images provided direct evidence of the morphology of the nanorods and these images were used to propose nucleation and growth mechanisms. We found that the α-MnO2 nanorods synthesized using natural extracts exhibit structural and magnetic properties similar to those of nanoparticles synthesized via traditional chemical routes. Furthermore, Fourier transform infrared (FTIR) shows that the particle growth of the α-MnO2 nanorods appears to be controlled by the presence of natural capping agents during the thermal treatment. We also evaluated the catalytic activity of the nanorods in the degradation of aqueous solutions of indigo carmine dye, highlighting the potential use of these materials to clean dye-polluted water. Full article
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Review

Jump to: Research

Open AccessReview Recent Advances in Nanomaterials for Gene Delivery—A Review
Nanomaterials 2017, 7(5), 94; doi:10.3390/nano7050094
Received: 16 March 2017 / Revised: 20 April 2017 / Accepted: 24 April 2017 / Published: 28 April 2017
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Abstract
With the rapid development of nanotechnology in the recent decade, novel DNA and RNA delivery systems for gene therapy have become available that can be used instead of viral vectors. These non-viral vectors can be made of a variety of materials, including inorganic
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With the rapid development of nanotechnology in the recent decade, novel DNA and RNA delivery systems for gene therapy have become available that can be used instead of viral vectors. These non-viral vectors can be made of a variety of materials, including inorganic nanoparticles, carbon nanotubes, liposomes, protein and peptide-based nanoparticles, as well as nanoscale polymeric materials. They have as advantages over viral vectors a decreased immune response, and additionally offer flexibility in design, allowing them to be functionalized and targeted to specific sites in a biological system with low cytotoxicity. The focus of this review is to provide an overview of novel nanotechnology-based methods to deliver DNA and small interfering RNAs into biological systems. Full article
(This article belongs to the Special Issue Nanomaterials in Gene Therapy)
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Open AccessReview One-Dimensional Electron Transport Layers for Perovskite Solar Cells
Nanomaterials 2017, 7(5), 95; doi:10.3390/nano7050095
Received: 12 February 2017 / Revised: 3 April 2017 / Accepted: 24 April 2017 / Published: 29 April 2017
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Abstract
The electron diffusion length (Ln) is smaller than the hole diffusion length (Lp) in many halide perovskite semiconductors meaning that the use of ordered one-dimensional (1D) structures such as nanowires (NWs) and nanotubes (NTs) as electron transport
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The electron diffusion length (Ln) is smaller than the hole diffusion length (Lp) in many halide perovskite semiconductors meaning that the use of ordered one-dimensional (1D) structures such as nanowires (NWs) and nanotubes (NTs) as electron transport layers (ETLs) is a promising method of achieving high performance halide perovskite solar cells (HPSCs). ETLs consisting of oriented and aligned NWs and NTs offer the potential not merely for improved directional charge transport but also for the enhanced absorption of incoming light and thermodynamically efficient management of photogenerated carrier populations. The ordered architecture of NW/NT arrays affords superior infiltration of a deposited material making them ideal for use in HPSCs. Photoconversion efficiencies (PCEs) as high as 18% have been demonstrated for HPSCs using 1D ETLs. Despite the advantages of 1D ETLs, there are still challenges that need to be overcome to achieve even higher PCEs, such as better methods to eliminate or passivate surface traps, improved understanding of the hetero-interface and optimization of the morphology (i.e., length, diameter, and spacing of NWs/NTs). This review introduces the general considerations of ETLs for HPSCs, deposition techniques used, and the current research and challenges in the field of 1D ETLs for perovskite solar cells. Full article
(This article belongs to the Special Issue New Developments in Nanomaterials for Energy Storage and Conversions)
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Open AccessReview Carbon Nanotube Membranes: Synthesis, Properties, and Future Filtration Applications
Nanomaterials 2017, 7(5), 99; doi:10.3390/nano7050099
Received: 25 February 2017 / Revised: 16 April 2017 / Accepted: 24 April 2017 / Published: 1 May 2017
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Abstract
Over the course of the past decade, there has been growing interest in the development of different types of membranes composed of carbon nanotubes (CNTs), including buckypapers and composite materials, for an ever-widening range of filtration applications. This article provides an overview of
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Over the course of the past decade, there has been growing interest in the development of different types of membranes composed of carbon nanotubes (CNTs), including buckypapers and composite materials, for an ever-widening range of filtration applications. This article provides an overview of how different types of CNT membranes are prepared and the results obtained from investigations into their suitability for different applications. The latter involve the removal of small particles from air samples, the filtration of aqueous solutions containing organic compounds and/or bacteria, and the separation of individual liquids present in mixtures. A growing number of reports have demonstrated that the incorporation of CNTs into composite membranes confers an improved resistance to fouling caused by biomacromolecules and bacteria. These results are discussed, along with evidence that demonstrates it is possible to further reduce fouling by taking advantage of the inherent conductivity of composite membranes containing CNTs, as well as by using different types of electrochemical stimuli. Full article
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Open AccessReview Meta-Chirality: Fundamentals, Construction and Applications
Nanomaterials 2017, 7(5), 116; doi:10.3390/nano7050116
Received: 18 April 2017 / Revised: 9 May 2017 / Accepted: 10 May 2017 / Published: 17 May 2017
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Abstract
Chiral metamaterials represent a special type of artificial structures that cannot be superposed to their mirror images. Due to the lack of mirror symmetry, cross-coupling between electric and magnetic fields exist in chiral mediums and present unique electromagnetic characters of circular dichroism and
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Chiral metamaterials represent a special type of artificial structures that cannot be superposed to their mirror images. Due to the lack of mirror symmetry, cross-coupling between electric and magnetic fields exist in chiral mediums and present unique electromagnetic characters of circular dichroism and optical activity, which provide a new opportunity to tune polarization and realize negative refractive index. Chiral metamaterials have attracted great attentions in recent years and have given rise to a series of applications in polarization manipulation, imaging, chemical and biological detection, and nonlinear optics. Here we review the fundamental theory of chiral media and analyze the construction principles of some typical chiral metamaterials. Then, the progress in extrinsic chiral metamaterials, absorbing chiral metamaterials, and reconfigurable chiral metamaterials are summarized. In the last section, future trends in chiral metamaterials and application in nonlinear optics are introduced. Full article
(This article belongs to the Special Issue Frontiers in Chiral Nanomaterials)
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