Nanomaterials

2530 KiB

Open AccessArticle

Development of Poly(lactic acid)/Chitosan Fibers Loaded with Essential Oil for Antimicrobial Applications

by Yaowen Liu, Shuyao Wang, Rong Zhang, Wenting Lan and Wen Qin

Nanomaterials 2017, 7(7), 194; https://doi.org/10.3390/nano7070194 - 24 Jul 2017

Cited by 68 | Viewed by 8182

Cinnamon essential oil (CEO) was successfully encapsulated into chitosan (CS) nanoparticles at different loading amounts (1%, 1.5%, 2%, and 2.5% v/v) using oil-in-water (o/w) emulsion and ionic-gelation methods. In order to form active packaging, poly(lactic acid) (PLA) was used to [...] Read more.

Cinnamon essential oil (CEO) was successfully encapsulated into chitosan (CS) nanoparticles at different loading amounts (1%, 1.5%, 2%, and 2.5% v/v) using oil-in-water (o/w) emulsion and ionic-gelation methods. In order to form active packaging, poly(lactic acid) (PLA) was used to fabricate PLA/CS-CEO composite fibers using a simple electrospinning method. The shape, size, zeta potential, and encapsulation efficacy of the CS-CEO nanoparticles were investigated. The composition, morphology, and release behavior of the composite fibers were investigated. PLA/CS-CEO-1.5 showed good stability and favorable sustained release of CEO, resulting in improved antimicrobial activity compared to the other blends. The PLA/CS-CEO fibers showed high long-term inactivation rates against Escherichia coli and Staphylococcus aureus due to the sustained release of CEO, indicating that the developed PLA/CS-CEO fibers have great potential for active food packaging applications. Full article

► Show Figures

Figure 1

3257 KiB

Open AccessArticle

Optimization of the Silver Nanoparticles PEALD Process on the Surface of 1-D Titania Coatings

by Aleksandra Radtke, Tomasz Jędrzejewski, Wiesław Kozak, Beata Sadowska, Marzena Więckowska-Szakiel, Ewa Talik, Maarit Mäkelä, Markku Leskelä and Piotr Piszczek

Nanomaterials 2017, 7(7), 193; https://doi.org/10.3390/nano7070193 - 24 Jul 2017

Cited by 27 | Viewed by 5973

Abstract

Plasma enhanced atomic layer deposition (PEALD) of silver nanoparticles on the surface of 1-D titania coatings, such as nanotubes (TNT) and nanoneedles (TNN), has been carried out. The formation of TNT and TNN layers enriched with dispersed silver particles of strictly defined sizes [...] Read more.

Plasma enhanced atomic layer deposition (PEALD) of silver nanoparticles on the surface of 1-D titania coatings, such as nanotubes (TNT) and nanoneedles (TNN), has been carried out. The formation of TNT and TNN layers enriched with dispersed silver particles of strictly defined sizes and the estimation of their bioactivity was the aim of our investigations. The structure and the morphology of produced materials were determined using X-ray photoelectron spectroscopy (XPS) and scanning electron miscroscopy (SEM). Their bioactivity and potential usefulness in the modification of implants surface have been estimated on the basis of the fibroblasts adhesion and proliferation assays, and on the basis of the determination of their antibacterial activity. The cumulative silver release profiles have been checked with the use of inductively coupled plasma-mass spectrometry (ICPMS), in order to exclude potential cytotoxicity of silver decorated systems. Among the studied nanocomposite samples, TNT coatings, prepared at 3, 10, 12 V and enriched with silver nanoparticles produced during 25 cycles of PEALD, revealed suitable biointegration properties and may actively counteract the formation of bacterial biofilm. Full article

(This article belongs to the Special Issue Nanoengineered Interfaces, Coatings and Structures by Plasma Techniques)

► Show Figures

Graphical abstract

1783 KiB

Open AccessCommunication

A Simple and Highly Sensitive Thymine Sensor for Mercury Ion Detection Based on Surface Enhanced Raman Spectroscopy and the Mechanism Study

by Hao Yang, Sui-Bo Ye, Yu Fu, Weihong Zhang, Fangyan Xie, Li Gong, Ping-Ping Fang, Jian Chen and Yexiang Tong

Nanomaterials 2017, 7(7), 192; https://doi.org/10.3390/nano7070192 - 24 Jul 2017

Cited by 16 | Viewed by 5172

Abstract

Mercury ion (Hg²⁺) is recognized as one of the most toxic metal ions for the environment and for human health. Techniques utilized in the detection of Hg²⁺ are an important factor. Herein, a simple thymine was successfully employed as the [...] Read more.

Mercury ion (Hg²⁺) is recognized as one of the most toxic metal ions for the environment and for human health. Techniques utilized in the detection of Hg²⁺ are an important factor. Herein, a simple thymine was successfully employed as the surface enhanced Raman spectroscopy sensor for Hg²⁺ ion detection. The limit of detection (LOD) of the developed sensor is better than 0.1 nM (0.02 ppb). This sensor can also selectively distinguish Hg²⁺ ions over 7 types of alkali, heavy metal and transition-metal ions. Moreover, the LOD of the sensor can even achieve 1 ppb in practical application in the nature system, which is half the maximum allowable level (10 nM, 2 ppb) stipulated in the US Environmental Protection Agency standard. Further investigation of the thymine-Hg²⁺-thymine coordination mechanism provides a possible means of detecting other metal ions by replacing the metal ion-specific ligands. This work paves the way for the detection of toxic metal ions and environmental problems. Full article

(This article belongs to the Special Issue Nanomaterials for SERS Applications)

► Show Figures

Graphical abstract

3466 KiB

Open AccessArticle

Highly Efficient Near Infrared Photothermal Conversion Properties of Reduced Tungsten Oxide/Polyurethane Nanocomposites

by Tolesa Fita Chala, Chang-Mou Wu, Min-Hui Chou, Molla Bahiru Gebeyehu and Kuo-Bing Cheng

Nanomaterials 2017, 7(7), 191; https://doi.org/10.3390/nano7070191 - 22 Jul 2017

Cited by 52 | Viewed by 10235

Abstract

In this work, novel WO_3-x/polyurethane (PU) nanocomposites were prepared by ball milling followed by stirring using a planetary mixer/de-aerator. The effects of phase transformation (WO₃ → WO_2.8 → WO_2.72) and different weight fractions of tungsten oxide [...] Read more.

In this work, novel WO_3-x/polyurethane (PU) nanocomposites were prepared by ball milling followed by stirring using a planetary mixer/de-aerator. The effects of phase transformation (WO₃ → WO_2.8 → WO_2.72) and different weight fractions of tungsten oxide on the optical performance, photothermal conversion, and thermal properties of the prepared nanocomposites were examined. It was found that the nanocomposites exhibited strong photoabsorption in the entire near-infrared (NIR) region of 780–2500 nm and excellent photothermal conversion properties. This is because the particle size of WO_3-x was greatly reduced by ball milling and they were well-dispersed in the polyurethane matrix. The higher concentration of oxygen vacancies in WO_3-x contribute to the efficient absorption of NIR light and its conversion into thermal energy. In particular, WO_2.72/PU nanocomposites showed strong NIR light absorption of ca. 92%, high photothermal conversion, and better thermal conductivity and absorptivity than other WO₃/PU nanocomposites. Furthermore, when the nanocomposite with 7 wt % concentration of WO_2.72 nanoparticles was irradiated with infrared light, the temperature of the nanocomposite increased rapidly and stabilized at 120 °C after 5 min. This temperature is 52 °C higher than that achieved by pure PU. These nanocomposites are suitable functional materials for solar collectors, smart coatings, and energy-saving applications. Full article

(This article belongs to the Special Issue Polymer Nanocomposites)

► Show Figures

Graphical abstract

2003 KiB

Open AccessArticle

Magnetic Nanoemulsions: Comparison between Nanoemulsions Formed by Ultrasonication and by Spontaneous Emulsification

by Nathalia Rodríguez-Burneo, Maria Antònia Busquets and Joan Estelrich

Nanomaterials 2017, 7(7), 190; https://doi.org/10.3390/nano7070190 - 22 Jul 2017

Cited by 34 | Viewed by 5973

Abstract

Nanoemulsions are particularly suitable as a platform in the development of delivery systems. The type of nanoemulsion with a higher stability will offer an advantage in the preparation of a delivery system for lipophilic drugs. Nanoemulsions can be fabricated by different processing methods, [...] Read more.

Nanoemulsions are particularly suitable as a platform in the development of delivery systems. The type of nanoemulsion with a higher stability will offer an advantage in the preparation of a delivery system for lipophilic drugs. Nanoemulsions can be fabricated by different processing methods, which are usually categorized as either high- or low-energy methods. In this study, a comparison between two methods of preparing magnetic oil-in-water (O/W) nanoemulsions is described. The nanoemulsions were formed by sonication (the high-energy method) or by spontaneous emulsification (the low-energy method). In both cases, the oil phase was olive oil, and a phospholipid and a pegylated phospholipid were used as emulsifiers. To favor the comparison, the amounts of the components were the same in both kinds of nanoemulsions. Moreover, nanoemulsions were loaded with hydrophobic superparamagnetic nanoparticles and indomethacin. In vitro, releases studies indicated a short drug burst period followed by a prolonged phase of dissolutive drug release. The Korsmeyer-Peppas model can fit the associated kinetics. The results showed that such nanoemulsions are suitable as a platform in the development of delivering systems for lipophilic drugs. The long-term stability was also examined at different temperatures, as well as the interaction with plasma proteins. Nanoemulsion obtained by the low-energy method showed a great stability at 4 °C and at ambient temperature. Its size and polydispersity did not change over more than two months. The spontaneous emulsification method therefore has great potential for forming nanoemulsion-based delivery systems. Full article

► Show Figures

Figure 1

3194 KiB

Open AccessReview

Mesoporous Silica Nanoparticles as Drug Delivery Vehicles in Cancer

by Anna Watermann and Juergen Brieger

Nanomaterials 2017, 7(7), 189; https://doi.org/10.3390/nano7070189 - 22 Jul 2017

Cited by 347 | Viewed by 17821

Abstract

Even though cancer treatment has improved over the recent decades, still more specific and effective treatment concepts are mandatory. Surgical removal is not always possible, metastases are challenging and chemo- and radiotherapy can not only have severe side-effects but also resistances may occur. [...] Read more.

Even though cancer treatment has improved over the recent decades, still more specific and effective treatment concepts are mandatory. Surgical removal is not always possible, metastases are challenging and chemo- and radiotherapy can not only have severe side-effects but also resistances may occur. To cope with these challenges more efficient therapies with fewer side-effects are required. One promising approach is the use of drug delivery vehicles. Here, mesoporous silica nanoparticles (MSN) are discussed as biodegradable drug carrier to improve efficacy and reduce side-effects. MSN excellently fulfill the criteria for nanoparticulate carriers: their distinct structure allows high loading capacity and a plethora of surface modifications. MSN synthesis permits fine-tuning of particle and pore sizes. Moreover, drug release can be tailored through various gatekeeper systems which are for example pH-sensitive or redox-sensitive. Furthermore, MSN can either enter tumors passively by the enhanced permeability and retention effect or can be actively targeted by various ligands. PEGylation prolongs circulation time and availability. A huge advantage of MSN is their explicitly low toxic profile in vivo. Yet, clinical translation remains challenging. Overall, mesoporous silica nanoparticles are a promising tool for innovative, more efficient and safer cancer therapies. Full article

(This article belongs to the Special Issue Frontiers in Toxicity and Functionalization of Nanomaterials)

► Show Figures

Figure 1

4041 KiB

Open AccessArticle

Growth Mechanism Studies of ZnO Nanowires: Experimental Observations and Short-Circuit Diffusion Analysis

by Po-Hsun Shih and Sheng Yun Wu

Nanomaterials 2017, 7(7), 188; https://doi.org/10.3390/nano7070188 - 21 Jul 2017

Cited by 23 | Viewed by 6981

Abstract

Plenty of studies have been performed to probe the diverse properties of ZnO nanowires, but only a few have focused on the physical properties of a single nanowire since analyzing the growth mechanism along a single nanowire is difficult. In this study, a [...] Read more.

Plenty of studies have been performed to probe the diverse properties of ZnO nanowires, but only a few have focused on the physical properties of a single nanowire since analyzing the growth mechanism along a single nanowire is difficult. In this study, a single ZnO nanowire was synthesized using a Ti-assisted chemical vapor deposition (CVD) method to avoid the appearance of catalytic contamination. Two-dimensional energy dispersive spectroscopy (EDS) mapping with a diffusion model was used to obtain the diffusion length and the activation energy ratio. The ratio value is close to 0.3, revealing that the growth of ZnO nanowires was attributed to the short-circuit diffusion. Full article

(This article belongs to the Special Issue ZnO and TiO₂ Based Nanostructures)

► Show Figures

Graphical abstract

8830 KiB

Open AccessArticle

Properties of Cement Mortar and Ultra-High Strength Concrete Incorporating Graphene Oxide Nanosheets

by Liulei Lu and Dong Ouyang

Nanomaterials 2017, 7(7), 187; https://doi.org/10.3390/nano7070187 - 20 Jul 2017

Cited by 124 | Viewed by 9554

Abstract

In this work, the effect of graphene oxide nanosheet (GONS) additives on the properties of cement mortar and ultra-high strength concrete (UHSC) is reported. The resulting GONS-cement composites were easy to prepare and exhibited excellent mechanical properties. However, their fluidity decreased with increasing [...] Read more.

In this work, the effect of graphene oxide nanosheet (GONS) additives on the properties of cement mortar and ultra-high strength concrete (UHSC) is reported. The resulting GONS-cement composites were easy to prepare and exhibited excellent mechanical properties. However, their fluidity decreased with increasing GONS content. The UHSC specimens were prepared with various amounts of GONSs (0–0.03% by weight of cement). Results indicated that using 0.01% by weight of cement GONSs caused a 7.82% in compressive strength after 28 days of curing. Moreover, adding GONSs improved the flexural strength and deformation ability, with the increase in flexural strength more than that of compressive strength. Furthermore, field-emission scanning electron microscopy (FE-SEM) was used to observe the morphology of the hardened cement paste and UHSC samples. FE-SEM observations showed that the GONSs were well dispersed in the matrix and the bonding of the GONSs and the surrounding cement matrix was strong. Furthermore, FE-SEM observation indicated that the GONSs probably affected the shape of the cement hydration products. However, the growth space for hydrates also had an important effect on the morphology of hydrates. The true hydration mechanism of cement composites with GONSs needs further study. Full article

► Show Figures

Figure 1

4015 KiB

Open AccessReview

Application of Carbon Nanotubes in Chiral and Achiral Separations of Pharmaceuticals, Biologics and Chemicals

by Ayman L. Hemasa, Nenad Naumovski, William A. Maher and Ashraf Ghanem

Nanomaterials 2017, 7(7), 186; https://doi.org/10.3390/nano7070186 - 18 Jul 2017

Cited by 36 | Viewed by 8374

Abstract

Carbon nanotubes (CNTs) possess unique mechanical, physical, electrical and absorbability properties coupled with their nanometer dimensional scale that renders them extremely valuable for applications in many fields including nanotechnology and chromatographic separation. The aim of this review is to provide an updated overview [...] Read more.

Carbon nanotubes (CNTs) possess unique mechanical, physical, electrical and absorbability properties coupled with their nanometer dimensional scale that renders them extremely valuable for applications in many fields including nanotechnology and chromatographic separation. The aim of this review is to provide an updated overview about the applications of CNTs in chiral and achiral separations of pharmaceuticals, biologics and chemicals. Chiral single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) have been directly applied for the enantioseparation of pharmaceuticals and biologicals by using them as stationary or pseudostationary phases in chromatographic separation techniques such as high-performance liquid chromatography (HPLC), capillary electrophoresis (CE) and gas chromatography (GC). Achiral MWCNTs have been used for achiral separations as efficient sorbent objects in solid-phase extraction techniques of biochemicals and drugs. Achiral SWCNTs have been applied in achiral separation of biological samples. Achiral SWCNTs and MWCNTs have been also successfully used to separate achiral mixtures of pharmaceuticals and chemicals. Collectively, functionalized CNTs have been indirectly applied in separation science by enhancing the enantioseparation of different chiral selectors whereas non-functionalized CNTs have shown efficient capabilities for chiral separations by using techniques such as encapsulation or immobilization in polymer monolithic columns. Full article

(This article belongs to the Special Issue Frontiers in Chiral Nanomaterials)

► Show Figures

Figure 1

5446 KiB

Open AccessArticle

Effect of Alkali Metal Atoms Doping on Structural and Nonlinear Optical Properties of the Gold-Germanium Bimetallic Clusters

by Xiaojun Li, Shuna Li, Hongjiang Ren, Juxiang Yang and Yongqiang Tang

Nanomaterials 2017, 7(7), 184; https://doi.org/10.3390/nano7070184 - 17 Jul 2017

Cited by 14 | Viewed by 5880

Abstract

A new series of alkali-based complexes, AM@Ge_nAu (AM = Li, Na, and K), have been theoretically designed and investigated by means of the density functional theory calculations. The geometric structures and electronic properties of the species are systematically analyzed. The adsorption [...] Read more.

A new series of alkali-based complexes, AM@Ge_nAu (AM = Li, Na, and K), have been theoretically designed and investigated by means of the density functional theory calculations. The geometric structures and electronic properties of the species are systematically analyzed. The adsorption of alkali metals maintains the structural framework of the gold-germanium bimetallic clusters, and the alkali metals prefer energetically to be attached on clusters’ surfaces or edges. The high chemical stability of Li@Ge₁₂Au is revealed by the spherical aromaticity, the hybridization between the Ge atoms and Au-4d states, and delocalized multi-center bonds, as well as large binding energies. The static first hyperpolarizability (β_tot) is related to the cluster size and geometric structure, and the AM@Ge_nAu (AM = Na and K) clusters exhibit the much larger β_tot values up to 13050 a.u., which are considerable to establish their strong nonlinear optical (NLO) behaviors. We hope that this study will promote further application of alkali metals-adsorbed germanium-based semiconductor materials, serving for the design of remarkable and tunable NLO materials. Full article

(This article belongs to the Special Issue Semiconductor Core/Shell Nanocrystals for Optoelectronic Applications)

► Show Figures

Graphical abstract

3406 KiB

Open AccessArticle

Nano-Silica Sol-Gel and Carbon Nanotube Coupling Effect on the Performance of Cement-Based Materials

by Weiwen Li, Weiming Ji, Forood Torabian Isfahani, Yaocheng Wang, Gengying Li, Yi Liu and Feng Xing

Nanomaterials 2017, 7(7), 185; https://doi.org/10.3390/nano7070185 - 14 Jul 2017

Cited by 44 | Viewed by 5908

Abstract

Carbon nanotubes (CNTs) have shown promise for improving the mechanical performance of cement composites through crack-bridging and frictional pull-out. The interactive behaviors between CNTs and cement matrix act are crucial in optimizing the reinforcement of CNTs in cement composites. This study investigates the [...] Read more.

Carbon nanotubes (CNTs) have shown promise for improving the mechanical performance of cement composites through crack-bridging and frictional pull-out. The interactive behaviors between CNTs and cement matrix act are crucial in optimizing the reinforcement of CNTs in cement composites. This study investigates the effects of nano-silica (NS) sol-gel on the interactive behaviors of CNTs and the cement matrix through a series of experiments and analyses. UV-visible spectrometer results show that CNTs are well-dispersed in suspension and the addition of NS has a negligible effect on the stability of CNT dispersion. Calorimetry tests and dynamic mechanical analysis demonstrate the nucleation and frictional performance of CNTs in cement matrix, respectively. The paper shows that the physical adsorption of NS on the CNT surface could result in the acceleration of cement hydration. Morphology observation confirms that a denser interface between CNTs and cement hydrates is formed. Finally, the improved interaction between CNTs and cement hydrates leads to a substantial increase in friction between CNTs and the cement matrix under periodic loading. NS may act as an ideal admixture for improving both the interactive behaviors between CNTs and cement matrix and the damping properties of cement composite. Full article

► Show Figures

Figure 1

5961 KiB

Open AccessArticle

Comparison of Erosion Behavior and Particle Contamination in Mass-Production CF₄/O₂ Plasma Chambers Using Y₂O₃ and YF₃ Protective Coatings

by Tzu-Ken Lin, Wei-Kai Wang, Shih-Yung Huang, Chi-Tsung Tasi and Dong-Sing Wuu

Nanomaterials 2017, 7(7), 183; https://doi.org/10.3390/nano7070183 - 14 Jul 2017

Cited by 59 | Viewed by 9425

Abstract

Yttrium fluoride (YF₃) and yttrium oxide (Y₂O₃) protective coatings prepared using an atmospheric plasma spraying technique were used to investigate the relationship between surface erosion behaviors and their nanoparticle generation under high-density plasma (10¹²–10¹³ [...] Read more.

Yttrium fluoride (YF₃) and yttrium oxide (Y₂O₃) protective coatings prepared using an atmospheric plasma spraying technique were used to investigate the relationship between surface erosion behaviors and their nanoparticle generation under high-density plasma (10¹²–10¹³ cm⁻³) etching. As examined by transmission electron microscopy, the Y₂O₃ and YF₃ coatings become oxyfluorinated after exposure to the plasma, wherein the yttrium oxyfluoride film formation was observed on the surface with a thickness of 5.2 and 6.8 nm, respectively. The difference in the oxyfluorination of Y₂O₃ and YF₃ coatings could be attributed to Y–F and Y–O bonding energies. X-ray photoelectron spectroscopy analyses revealed that a strongly fluorinated bonding (Y–F bond) was obtained on the etched surface of the YF₃ coating. Scanning electron microscopy and energy dispersive X-ray diffraction analysis revealed that the nanoparticles on the 12-inch wafer are composed of etchant gases and Y₂O₃. These results indicate that the YF₃ coating is a more erosion-resistant material, resulting in fewer contamination particles compared with the Y₂O₃ coating. Full article

(This article belongs to the Special Issue Nanoengineered Interfaces, Coatings and Structures by Plasma Techniques)

► Show Figures

Graphical abstract

6596 KiB

Open AccessArticle

Oil Palm Waste-Based Precursors as a Renewable and Economical Carbon Sources for the Preparation of Reduced Graphene Oxide from Graphene Oxide

by Salisu Nasir, Mohd Zobir Hussein, Nor Azah Yusof and Zulkarnain Zainal

Nanomaterials 2017, 7(7), 182; https://doi.org/10.3390/nano7070182 - 13 Jul 2017

Cited by 72 | Viewed by 9153

Abstract

Herein, a new approach was proposed to produce reduced graphene oxide (rGO) from graphene oxide (GO) using various oil palm wastes: oil palm leaves (OPL), palm kernel shells (PKS) and empty fruit bunches (EFB). The effect of heating temperature on the formation of [...] Read more.

Herein, a new approach was proposed to produce reduced graphene oxide (rGO) from graphene oxide (GO) using various oil palm wastes: oil palm leaves (OPL), palm kernel shells (PKS) and empty fruit bunches (EFB). The effect of heating temperature on the formation of graphitic carbon and the yield was examined prior to the GO and rGO synthesis. Carbonization of the starting materials was conducted in a furnace under nitrogen gas for 3 h at temperatures ranging from 400 to 900 °C and a constant heating rate of 10 °C/min. The GO was further synthesized from the as-carbonized materials using the ‘improved synthesis of graphene oxide’ method. Subsequently, the GO was reduced by low-temperature annealing reduction at 300 °C in a furnace under nitrogen gas for 1 h. The I_G/I_D ratio calculated from the Raman study increases with the increasing of the degree of the graphitization in the order of rGO from oil palm leaves (rGOOPL) < rGO palm kernel shells (rGOPKS) < rGO commercial graphite (rGOCG) < rGO empty fruit bunches (rGOEFB) with the I_G/I_Dvalues of 1.06, 1.14, 1.16 and 1.20, respectively. The surface area and pore volume analyses of the as-prepared materials were performed using the Brunauer Emmett Teller-Nitrogen (BET-N₂) adsorption-desorption isotherms method. The lower BET surface area of 8 and 15 m²g⁻¹ observed for rGOCG and rGOOPL, respectively could be due to partial restacking of GO layers and locally-blocked pores. Relatively, this lower BET surface area is inconsequential when compared to rGOPKS and rGOEFB, which have a surface area of 114 and 117 m² g⁻¹, respectively. Full article

► Show Figures

Figure 1

2603 KiB

Open AccessCommunication

Dissolution-Induced Nanowire Synthesis on Hot-Dip Galvanized Surface in Supercritical Carbon Dioxide

by Aaretti Kaleva, Ville Saarimaa, Saara Heinonen, Juha-Pekka Nikkanen, Antti Markkula, Pasi Väisänen and Erkki Levänen

Nanomaterials 2017, 7(7), 181; https://doi.org/10.3390/nano7070181 - 11 Jul 2017

Cited by 13 | Viewed by 4124

Abstract

In this study, we demonstrate a rapid treatment method for producing a needle-like nanowire structure on a hot-dip galvanized sheet at a temperature of 50 °C. The processing method involved only supercritical carbon dioxide and water to induce a reaction on the zinc [...] Read more.

In this study, we demonstrate a rapid treatment method for producing a needle-like nanowire structure on a hot-dip galvanized sheet at a temperature of 50 °C. The processing method involved only supercritical carbon dioxide and water to induce a reaction on the zinc surface, which resulted in growth of zinc hydroxycarbonate nanowires into flower-like shapes. This artificial patina nanostructure predicts high surface area and offers interesting opportunities for its use in industrial high-end applications. The nanowires can significantly improve paint adhesion and promote electrochemical stability for organic coatings, or be converted to ZnO nanostructures by calcining to be used in various semiconductor applications. Full article

► Show Figures

Figure 1

2314 KiB

Open AccessArticle

Nanoporous Structure Formation in GaSb, InSb, and Ge by Ion Beam Irradiation under Controlled Point Defect Creation Conditions

by Yusuke Yanagida, Tomoya Oishi, Takashi Miyaji, Chiaki Watanabe and Noriko Nitta

Nanomaterials 2017, 7(7), 180; https://doi.org/10.3390/nano7070180 - 11 Jul 2017

Cited by 16 | Viewed by 4583

Abstract

Ion beam irradiation-induced nanoporous structure formation was investigated on GaSb, InSb, and Ge surfaces via controlled point defect creation using a focused ion beam (FIB). ‎This paper compares the nanoporous structure formation under the same extent of point defect creation while changing the [...] Read more.

Ion beam irradiation-induced nanoporous structure formation was investigated on GaSb, InSb, and Ge surfaces via controlled point defect creation using a focused ion beam (FIB). ‎This paper compares the nanoporous structure formation under the same extent of point defect creation while changing the accelerating voltage and ion dose. Although the same number of point defects were created in each case, different structures were formed on the different surfaces. The depth direction density of the point defects was an important factor in this trend. The number of point defects required for nanoporous structure formation was 4 × 10²² vacancies/m² at a depth of 18 nm under the surface, based on a comparison of similar nanoporous structure features in GaSb. The nanoporous structure formation by ion beam irradiation on GaSb, InSb, and Ge surfaces was controlled by the number and areal distribution of the created point defects. Full article

► Show Figures

Figure 1

6912 KiB

Open AccessArticle

Eco-Friendly Acaricidal Effects of Nylon 66 Nanofibers via Grafted Clove Bud Oil-Loaded Capsules on House Dust Mites

by Joo Ran Kim and Seong Hun Kim

Nanomaterials 2017, 7(7), 179; https://doi.org/10.3390/nano7070179 - 10 Jul 2017

Cited by 14 | Viewed by 6416

Abstract

Acaricidal nylon 66 fabrics (AN66Fs) grafted with clove oil-loaded microcapsules (COMCs) were developed against Dermatophagoides farina (D. gallinae). The average diameter was about 2.9 µm with a range of 100 nm–8.5 µm. COMCs carried clove oil loading of about 65 vol [...] Read more.

Acaricidal nylon 66 fabrics (AN66Fs) grafted with clove oil-loaded microcapsules (COMCs) were developed against Dermatophagoides farina (D. gallinae). The average diameter was about 2.9 µm with a range of 100 nm–8.5 µm. COMCs carried clove oil loading of about 65 vol %. COMCs were chemically grafted to electrospun nylon nanofibers by the chemical reactions between –OH groups of COMCs and –COOH end groups of nylon fabrics to form ester linkages. AN66Fs had an effect on D. farinae depending on COMCs loadings. The increase in COMCs loading of AN66Fs from 5 to 15 wt % increased from 22% to 93% mortality against D. farinae within 72 h. However, AN66Fs containing over 20 wt % COMCs were more effective, showing up to 100% mortality within 24 h because the large amount of monoterpene alcohol, eugenol. This research suggests the use of clove oil and its major constituent eugenol as eco-friendly bioactive agents that can serve as a replacement for synthetic acaricides in controlling the population of D. farinae. Full article

(This article belongs to the Special Issue Antibacterial Activity of Nanomaterials)

► Show Figures

Figure 1

4428 KiB

Open AccessArticle

The Effect of Silver Nanoparticles Size, Produced Using Plant Extract from Arbutus unedo, on Their Antibacterial Efficacy

by Nicholas Skandalis, Anastasia Dimopoulou, Anthie Georgopoulou, Nikolaos Gallios, Dimitrios Papadopoulos, Dimitrios Tsipas, Ioannis Theologidis, Nikolaos Michailidis and Maria Chatzinikolaidou

Nanomaterials 2017, 7(7), 178; https://doi.org/10.3390/nano7070178 - 10 Jul 2017

Cited by 89 | Viewed by 7123

Abstract

Silver nanoparticles (AgNPs) have been demonstrated to restrain bacterial growth, while maintaining minimal risk in development of bacterial resistance and human cell toxicity that conventional silver compounds exhibit. Several physical and chemical methods have been reported to synthesize AgNPs. However, these methods are [...] Read more.

Silver nanoparticles (AgNPs) have been demonstrated to restrain bacterial growth, while maintaining minimal risk in development of bacterial resistance and human cell toxicity that conventional silver compounds exhibit. Several physical and chemical methods have been reported to synthesize AgNPs. However, these methods are expensive and involve heavy chemical reduction agents. An alternative approach to produce AgNPs in a cost-effective and environmentally friendly way employs a biological pathway using various plant extracts to reduce metal ions. The size control issue, and the stability of nanoparticles, remain some of the latest challenges in such methods. In this study, we used two different concentrations of fresh leaf extract of the plant Arbutus unedo (LEA) as a reducing and stabilizing agent to produce two size variations of AgNPs. UV-Vis spectroscopy, Dynamic Light Scattering, Transmission Electron Microscopy, and zeta potential were applied for the characterization of AgNPs. Both AgNP variations were evaluated for their antibacterial efficacy against the gram-negative species Escherichia coli and Pseudomonas aeruginosa, as well as the gram-positive species Bacillus subtilis and Staphylococcus epidermidis. Although significant differences have been achieved in the nanoparticles’ size by varying the plant extract concentration during synthesis, the antibacterial effect was almost the same. Full article

► Show Figures

Graphical abstract

5299 KiB

Open AccessArticle

Use of Polycaprolactone Electrospun Nanofibers as a Coating for Poly(methyl methacrylate) Bone Cement

by Morshed Khandaker, Shahram Riahinezhad, Harsha G. Jamadagni, Tracy L. Morris, Alexis V. Coles and Melville B. Vaughan

Nanomaterials 2017, 7(7), 175; https://doi.org/10.3390/nano7070175 - 10 Jul 2017

Cited by 16 | Viewed by 5752

Abstract

Poly(methyl methacrylate) (PMMA) bone cement has limited biocompatibility. Polycaprolactone (PCL) electrospun nanofiber (ENF) has many applications in the biomedical field due to its excellent biocompatibility and degradability. The effect of coating PCL ENF on the surface topography, biocompatibility, and mechanical strength of PMMA [...] Read more.

Poly(methyl methacrylate) (PMMA) bone cement has limited biocompatibility. Polycaprolactone (PCL) electrospun nanofiber (ENF) has many applications in the biomedical field due to its excellent biocompatibility and degradability. The effect of coating PCL ENF on the surface topography, biocompatibility, and mechanical strength of PMMA bone cement is not currently known. This study is based on the hypothesis that the PCL ENF coating on PMMA will increase PMMA roughness leading to increased biocompatibility without influencing its mechanical properties. This study prepared PMMA samples without and with the PCL ENF coating, which were named the control and ENF coated samples. This study determined the effects on the surface topography and cytocompatibility (osteoblast cell adhesion, proliferation, mineralization, and protein adsorption) properties of each group of PMMA samples. This study also determined the bending properties (strength, modulus, and maximum deflection at fracture) of each group of PMMA samples from an American Society of Testing Metal (ASTM) standard three-point bend test. This study found that the ENF coating on PMMA significantly improved the surface roughness and cytocompatibility properties of PMMA (p < 0.05). This study also found that the bending properties of ENF-coated PMMA samples were not significantly different when compared to those values of the control PMMA samples (p > 0.05). Therefore, the PCL ENF coating technique should be further investigated for its potential in clinical applications. Full article

► Show Figures

Figure 1

2017 KiB

Open AccessArticle

Selective Dielectric Metasurfaces Based on Directional Conditions of Silicon Nanopillars

by José Francisco Algorri, Braulio García-Cámara, Alexander Cuadrado, José Manuel Sánchez-Pena and Ricardo Vergaz

Nanomaterials 2017, 7(7), 177; https://doi.org/10.3390/nano7070177 - 7 Jul 2017

Cited by 23 | Viewed by 5117

Abstract

Dielectric metasurfaces based on high refractive index materials have been proposed recently. This type of structure has several advantages over their metallic counterparts. In this work, we demonstrate that dielectric metasurfaces can be theoretically designed satisfying Kerker’s zero-forward condition. This is the first [...] Read more.

Dielectric metasurfaces based on high refractive index materials have been proposed recently. This type of structure has several advantages over their metallic counterparts. In this work, we demonstrate that dielectric metasurfaces can be theoretically designed satisfying Kerker’s zero-forward condition. This is the first time that a dielectric metasurface based on this principle has been designed. A selective dielectric metasurface of silicon nanopillars is designed to work at 632.8 nm. This structure could work both as a dielectric mirror and a reject band filter. Furthermore, by scaling up the structure, it could be possible to manufacture a terahertz (THz) dielectric mirror. Full article

► Show Figures

Figure 1

5159 KiB

Open AccessArticle

Cultivating Fluorescent Flowers with Highly Luminescent Carbon Dots Fabricated by a Double Passivation Method

by Shuai Han, Tao Chang, Haiping Zhao, Huanhuan Du, Shan Liu, Baoshuang Wu and Shenjun Qin

Nanomaterials 2017, 7(7), 176; https://doi.org/10.3390/nano7070176 - 7 Jul 2017

Cited by 14 | Viewed by 7395

Abstract

In this work, we present the fabrication of highly luminescent carbon dots (CDs) by a double passivation method with the assistance of Ca(OH)₂. In the reaction process, Ca²⁺ protects the active functional groups from overconsumption during dehydration and carbonization, and [...] Read more.

In this work, we present the fabrication of highly luminescent carbon dots (CDs) by a double passivation method with the assistance of Ca(OH)₂. In the reaction process, Ca²⁺ protects the active functional groups from overconsumption during dehydration and carbonization, and the electron-withdrawing groups on the CD surface are converted to electron-donating groups by the hydroxyl ions. As a result, the fluorescence quantum yield of the CDs was found to increase with increasing Ca(OH)₂ content in the reaction process. A blue-shift optical spectrum of the CDs was also found with increasing Ca(OH)₂ content, which could be attributed to the increasing of the energy gaps for the CDs. The highly photoluminescent CDs obtained (quantum yield: 86%) were used to cultivate fluorescent carnations by a water culture method, while the results of fluorescence microscopy analysis indicated that the CDs had entered the plant tissue structure. Full article

► Show Figures

Figure 1

8197 KiB

Open AccessArticle

Non-Noble Metal Oxide Catalysts for Methane Catalytic Combustion: Sonochemical Synthesis and Characterisation

by Przemysław J. Jodłowski, Roman J. Jędrzejczyk, Damian K. Chlebda, Anna Dziedzicka, Łukasz Kuterasiński, Anna Gancarczyk and Maciej Sitarz

Nanomaterials 2017, 7(7), 174; https://doi.org/10.3390/nano7070174 - 7 Jul 2017

Cited by 22 | Viewed by 7670

Abstract

The aim of this study was to obtain nanocrystalline mixed metal-oxide–ZrO₂ catalysts via a sonochemically-induced preparation method. The effect of a stabiliser’s addition on the catalyst parameters was investigated by several characterisation methods including X-ray Diffraction (XRD), nitrogen adsorption, X-ray fluorescence (XRF), [...] Read more.

The aim of this study was to obtain nanocrystalline mixed metal-oxide–ZrO₂ catalysts via a sonochemically-induced preparation method. The effect of a stabiliser’s addition on the catalyst parameters was investigated by several characterisation methods including X-ray Diffraction (XRD), nitrogen adsorption, X-ray fluorescence (XRF), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and µRaman. The sonochemical preparation method allowed us to manufacture the catalysts with uniformly dispersed metal-oxide nanoparticles at the support surface. The catalytic activity was tested in a methane combustion reaction. The activity of the catalysts prepared by the sonochemical method was higher than that of the reference catalysts prepared by the incipient wetness method without ultrasonic irradiation. The cobalt and chromium mixed zirconia catalysts revealed their high activities, which are comparable with those presented in the literature. Full article

(This article belongs to the Special Issue Preparation and Application of Hybrid Nanomaterials)

► Show Figures

Graphical abstract

27085 KiB

Open AccessArticle

The Influence of Copolymer Composition on PLGA/nHA Scaffolds’ Cytotoxicity and In Vitro Degradation

by Esperanza Díaz, Igor Puerto, Silvie Ribeiro, Senentxu Lanceros-Mendez and José Manuel Barandiarán

Nanomaterials 2017, 7(7), 173; https://doi.org/10.3390/nano7070173 - 6 Jul 2017

Cited by 43 | Viewed by 5562

Abstract

The influence of copolymer composition on Poly(Lactide-co-Glycolide)/nanohydroxyapatite (PLGA/nHA) composite scaffolds is studied in the context of bone tissue engineering and regenerative medicine. The composite scaffolds are fabricated by thermally-induced phase separation and the effect of bioactive nanoparticles on their in vitro [...] Read more.

The influence of copolymer composition on Poly(Lactide-co-Glycolide)/nanohydroxyapatite (PLGA/nHA) composite scaffolds is studied in the context of bone tissue engineering and regenerative medicine. The composite scaffolds are fabricated by thermally-induced phase separation and the effect of bioactive nanoparticles on their in vitro degradation in phosphate-buffered solution at 37 °C is analyzed over eight weeks. The indirect cytotoxicity evaluation of the samples followed an adaptation of the ISO 10993-5 standard test method. Based on the measurement of their molecular weight, molar mass, pH, water absorption and dimensions, the porous scaffolds of PLGA with a lower lactide/glycolide (LA/GA) molar ratio degraded faster due to their higher hydrophilicity. All of the samples without and with HA are not cytotoxic, demonstrating their potential for tissue engineering applications. Full article

(This article belongs to the Special Issue Nanofibrous Scaffolds for Biomedical Application)

► Show Figures

Figure 1

6617 KiB

Open AccessArticle

High Ultraviolet Absorption in Colloidal Gallium Nanoparticles Prepared from Thermal Evaporation

by Flavio Nucciarelli, Iria Bravo, Sergio Catalan-Gomez, Luis Vázquez, Encarnación Lorenzo and Jose Luis Pau

Nanomaterials 2017, 7(7), 172; https://doi.org/10.3390/nano7070172 - 6 Jul 2017

Cited by 22 | Viewed by 7004

Abstract

New methods for the production of colloidal Ga nanoparticles (GaNPs) are introduced based on the evaporation of gallium on expendable aluminum zinc oxide (AZO) layer. The nanoparticles can be prepared in aqueous or organic solvents such as tetrahydrofuran in order to be used [...] Read more.

New methods for the production of colloidal Ga nanoparticles (GaNPs) are introduced based on the evaporation of gallium on expendable aluminum zinc oxide (AZO) layer. The nanoparticles can be prepared in aqueous or organic solvents such as tetrahydrofuran in order to be used in different sensing applications. The particles had a quasi mono-modal distribution with diameters ranging from 10 nm to 80 nm, and their aggregation status depended on the solvent nature. Compared to common chemical synthesis, our method assures higher yield with the possibility of tailoring particles size by adjusting the deposition time. The GaNPs have been studied by spectrophotometry to obtain the absorption spectra. The colloidal solutions exhibit strong plasmonic absorption in the ultra violet (UV) region around 280 nm, whose width and intensity mainly depend on the nanoparticles dimensions and their aggregation state. With regard to the colloidal GaNPs flocculate behavior, the water solvent case has been investigated for different pH values, showing UV-visible absorption because of the formation of NPs clusters. Using discrete dipole approximation (DDA) method simulations, a close connection between the UV absorption and NPs with a diameter smaller than ~40 nm was observed. Full article

(This article belongs to the Special Issue Nanocolloids for Nanomedicine and Drug Delivery)

► Show Figures

Figure 1

1803 KiB

Open AccessReview

Recent Advances in Magnetic Microfluidic Biosensors

by Ioanna Giouroudi and Georgios Kokkinis

Nanomaterials 2017, 7(7), 171; https://doi.org/10.3390/nano7070171 - 6 Jul 2017

Cited by 53 | Viewed by 7498

Abstract

The development of portable biosening devices for the detection of biological entities such as biomolecules, pathogens, and cells has become extremely significant over the past years. Scientific research, driven by the promise for miniaturization and integration of complex laboratory equipment on inexpensive, reliable, [...] Read more.

The development of portable biosening devices for the detection of biological entities such as biomolecules, pathogens, and cells has become extremely significant over the past years. Scientific research, driven by the promise for miniaturization and integration of complex laboratory equipment on inexpensive, reliable, and accurate devices, has successfully shifted several analytical and diagnostic methods to the submillimeter scale. The miniaturization process was made possible with the birth of microfluidics, a technology that could confine, manipulate, and mix very small volumes of liquids on devices integrated on standard silicon technology chips. Such devices are then directly translating the presence of these entities into an electronic signal that can be read out with a portable instrumentation. For the aforementioned tasks, the use of magnetic markers (magnetic particles—MPs—functionalized with ligands) in combination with the application of magnetic fields is being strongly investigated by research groups worldwide. The greatest merits of using magnetic fields are that they can be applied either externally or from integrated microconductors and they can be well-tuned by adjusting the applied current on the microconductors. Moreover, the magnetic markers can be manipulated inside microfluidic channels by high gradient magnetic fields that can in turn be detected by magnetic sensors. All the above make this technology an ideal candidate for the development of such microfluidic biosensors. In this review, focus is given only to very recent advances in biosensors that use microfluidics in combination with magnetic sensors and magnetic markers/nanoparticles. Full article

(This article belongs to the Special Issue Functional Magnetic Nanoparticles in Nanomedicine)

► Show Figures

Figure 1

4536 KiB

Open AccessArticle

Effect of Precursor on Antifouling Efficacy of Vertically-Oriented Graphene Nanosheets

by Karthika Prasad, Chaturanga D. Bandara, Shailesh Kumar, Gurinder Pal Singh, Bastian Brockhoff, Kateryna Bazaka and Kostya (Ken) Ostrikov

Nanomaterials 2017, 7(7), 170; https://doi.org/10.3390/nano7070170 - 4 Jul 2017

Cited by 18 | Viewed by 5588

Abstract

Antifouling efficacy of graphene nanowalls, i.e., substrate-bound vertically-oriented graphene nanosheets, has been demonstrated against biofilm-forming Gram-positive and Gram-negative bacteria. Where graphene nanowalls are typically prepared using costly high-temperature synthesis from high-purity carbon precursors, large-scale applications demand efficient, low-cost processes. The advancement of plasma [...] Read more.

Antifouling efficacy of graphene nanowalls, i.e., substrate-bound vertically-oriented graphene nanosheets, has been demonstrated against biofilm-forming Gram-positive and Gram-negative bacteria. Where graphene nanowalls are typically prepared using costly high-temperature synthesis from high-purity carbon precursors, large-scale applications demand efficient, low-cost processes. The advancement of plasma enabled synthesis techniques in the production of nanomaterials has opened a novel and effective method for converting low-cost natural waste resources to produce nanomaterials with a wide range of applications. Through this work, we report the rapid reforming of sugarcane bagasse, a low-value by-product from sugarcane industry, into high-quality vertically-oriented graphene nanosheets at a relatively low temperature of 400 °C. Electron microscopy showed that graphene nanowalls fabricated from methane were significantly more effective at preventing surface attachment of Gram-negative rod-shaped Escherichia coli compared to bagasse-derived graphene, with both surfaces showing antifouling efficacy comparable to copper. Attachment of Gram-positive coccal Staphylococcus aureus was lower on the surfaces of both types of graphene compared to that on copper, with bagasse-derived graphene being particularly effective. Toxicity to planktonic bacteria estimated as a reduction in colony-forming units as a result of sample exposure showed that both graphenes effectively retarded cell replication. Full article

(This article belongs to the Special Issue Nanoengineered Interfaces, Coatings and Structures by Plasma Techniques)

► Show Figures

Figure 1

5900 KiB

Open AccessArticle

Synthesis and Self-Assembled Behavior of pH-Responsive Chiral Liquid Crystal Amphiphilic Copolymers Based on Diosgenyl-Functionalized Aliphatic Polycarbonate

by Zhi-Hao Guo, Xiao-Feng Liu, Jian-She Hu, Li-Qun Yang and Zhang-Pei Chen

Nanomaterials 2017, 7(7), 169; https://doi.org/10.3390/nano7070169 - 4 Jul 2017

Cited by 19 | Viewed by 5209

Abstract

The morphological control of polymer micellar aggregates is an important issue in applications such as nanomedicine and material science. Stimuli responsive soft materials have attracted significant attention for their well-controlled morphologies. However, despite extensive studies, it is still a challenge to prepare nanoscale [...] Read more.

The morphological control of polymer micellar aggregates is an important issue in applications such as nanomedicine and material science. Stimuli responsive soft materials have attracted significant attention for their well-controlled morphologies. However, despite extensive studies, it is still a challenge to prepare nanoscale assemblies with responsive behaviors. Herein, a new chiral liquid crystal (LC) aliphatic polycarbonate with side chain bearing diosgenyl mesogen, named mPEG₄₃-PMCC₂₅-P(MCC-DHO)₁₅, was synthesized through the ring-opening polymerization and coupling reaction. The self-assembled behavior of the LC copolymer was explored. In aqueous solution, the functionalized copolymer could self-organize into different nanostructures with changing pH value, such as nanospheres and nanofibers. This would offer new possibilities in the design of nanostructured organic materials. Full article

(This article belongs to the Special Issue Frontiers in Chiral Nanomaterials)

► Show Figures

Graphical abstract

3823 KiB

Open AccessArticle

Reduced Graphene Oxides: Influence of the Reduction Method on the Electrocatalytic Effect towards Nucleic Acid Oxidation

by Daniela F. Báez, Helena Pardo, Ignacio Laborda, José F. Marco, Claudia Yáñez and Soledad Bollo

Nanomaterials 2017, 7(7), 168; https://doi.org/10.3390/nano7070168 - 4 Jul 2017

Cited by 50 | Viewed by 5812

Abstract

For the first time a critical analysis of the influence that four different graphene oxide reduction methods have on the electrochemical properties of the resulting reduced graphene oxides (RGOs) is reported. Starting from the same graphene oxide, chemical (CRGO), hydrothermal (hTRGO), electrochemical (ERGO), [...] Read more.

For the first time a critical analysis of the influence that four different graphene oxide reduction methods have on the electrochemical properties of the resulting reduced graphene oxides (RGOs) is reported. Starting from the same graphene oxide, chemical (CRGO), hydrothermal (hTRGO), electrochemical (ERGO), and thermal (TRGO) reduced graphene oxide were produced. The materials were fully characterized and the topography and electroactivity of the resulting glassy carbon modified electrodes were also evaluated. An oligonucleotide molecule was used as a model of DNA electrochemical biosensing. The results allow for the conclusion that TRGO produced the RGOs with the best electrochemical performance for oligonucleotide electroanalysis. A clear shift in the guanine oxidation peak potential to lower values (~0.100 V) and an almost two-fold increase in the current intensity were observed compared with the other RGOs. The electrocatalytic effect has a multifactorial explanation because the TRGO was the material that presented a higher polydispersity and lower sheet size, thus exposing a larger quantity of defects to the electrode surface, which produces larger physical and electrochemical areas. Full article

(This article belongs to the Special Issue Nanomaterials for Sensing Applications)

► Show Figures

Graphical abstract

8086 KiB

Open AccessReview

Chiral Nanotubes

by Andrea Nitti, Aurora Pacini and Dario Pasini

Nanomaterials 2017, 7(7), 167; https://doi.org/10.3390/nano7070167 - 4 Jul 2017

Cited by 27 | Viewed by 6425

Abstract

Organic nanotubes, as assembled nanospaces, in which to carry out host–guest chemistry, reversible binding of smaller species for transport, sensing, storage or chemical transformation purposes, are currently attracting substantial interest, both as biological ion channel mimics, or for addressing tailored material properties. Nature’s [...] Read more.

Organic nanotubes, as assembled nanospaces, in which to carry out host–guest chemistry, reversible binding of smaller species for transport, sensing, storage or chemical transformation purposes, are currently attracting substantial interest, both as biological ion channel mimics, or for addressing tailored material properties. Nature’s materials and machinery are universally asymmetric, and, for chemical entities, controlled asymmetry comes from chirality. Together with carbon nanotubes, conformationally stable molecular building blocks and macrocycles have been used for the realization of organic nanotubes, by means of their assembly in the third dimension. In both cases, chiral properties have started to be fully exploited to date. In this paper, we review recent exciting developments in the synthesis and assembly of chiral nanotubes, and of their functional properties. This review will include examples of either molecule-based or macrocycle-based systems, and will try and rationalize the supramolecular interactions at play for the three-dimensional (3D) assembly of the nanoscale architectures. Full article

(This article belongs to the Special Issue Frontiers in Chiral Nanomaterials)

► Show Figures

Graphical abstract

20723 KiB

Open AccessArticle

Overcoming the Intrinsic Difference between Hydrophilic CH₃NH₃PbI₃ and Hydrophobic C₆₀ Thin Films to Improve the Photovoltaic Performance

by Lung-Chien Chen, Yu-Shiang Lin, Zong-Liang Tseng, Chiale Wu, Feng-Sheng Kao and Sheng-Hui Chen

Nanomaterials 2017, 7(7), 166; https://doi.org/10.3390/nano7070166 - 3 Jul 2017

Cited by 7 | Viewed by 5249

Abstract

Dimethylformamide/dimethyl sulfoxide solvent mixtures were used as the CH₃NH₃PbI₃ (MAPbI₃) precursor solvent in a one-step spin coating method to fabricate smooth and hydrophilic crystalline MAPbI₃ thin films on top of hydrophobic carbon-60 (C₆₀) [...] Read more.

Dimethylformamide/dimethyl sulfoxide solvent mixtures were used as the CH₃NH₃PbI₃ (MAPbI₃) precursor solvent in a one-step spin coating method to fabricate smooth and hydrophilic crystalline MAPbI₃ thin films on top of hydrophobic carbon-60 (C₆₀) thin film for highly efficient photovoltaics. The structural, optical, and excitonic characteristics of the resultant MAPbI₃ thin films were analyzed using X-ray diffraction (XRD), atomic-force microscopy, absorbance spectroscopy, photoluminescence (PL) spectrometry, and nanosecond time-resolved PL. There was a trade-off between the crystallinity and surface roughness of the MAPbI₃ thin films, which strongly influenced the device performance of MAPbI₃-based photovoltaics. The high power conversion efficiency (PCE) of 17.55% was achieved by improving the wettability of MAPbI₃ precursor solutions on top of the C₆₀ thin films. In addition, it was predicted that the fill factor and PCE could be further improved by increasing the crystallinity of the MAPbI₃ thin film while keeping it smooth. Full article

► Show Figures

Figure 1

3159 KiB

Open AccessArticle

Interleukin-10 Conjugation to Carboxylated PVP-Coated Silver Nanoparticles for Improved Stability and Therapeutic Efficacy

by Dieudonné R. Baganizi, Elijah Nyairo, Skyla A. Duncan, Shree R. Singh and Vida A. Dennis

Nanomaterials 2017, 7(7), 165; https://doi.org/10.3390/nano7070165 - 2 Jul 2017

Cited by 73 | Viewed by 7859

Abstract

Interleukin-10 (IL-10) is a key anti-inflammatory and immunosuppressive cytokine and therefore represents a potential therapeutic agent especially in inflammatory diseases. However, despite its proven therapeutic efficacy, its short half-life and proteolytic degradation in vivo combined with its low storage stability have limited its [...] Read more.

Interleukin-10 (IL-10) is a key anti-inflammatory and immunosuppressive cytokine and therefore represents a potential therapeutic agent especially in inflammatory diseases. However, despite its proven therapeutic efficacy, its short half-life and proteolytic degradation in vivo combined with its low storage stability have limited its therapeutic use. Strategies have been developed to overcome most of these shortcomings, including in particular bioconjugation with stabilizing agents such as polyethylene glycol (PEG) and poly (vinylpyrolidone) (PVP), but so far these have had limited success. In this paper, we present an alternative method consisting of bioconjugating IL-10 to PVP-coated silver nanoparticles (Ag-PVPs) in order to achieve its storage stability by preventing denaturation and to improve its anti-inflammatory efficacy. Silver nanoparticles capped with a carboxylated PVP were produced and further covalently conjugated with IL-10 protein by carbodiimide crosslinker chemistry. The IL-10 conjugated Ag-PVPs exhibited increased stability and anti-inflammatory effectiveness in vitro. This study therefore provides a novel approach to bioconjugating PVP-coated silver nanoparticles with therapeutic proteins, which could be useful in drug delivery and anti-inflammatory therapies. Full article

(This article belongs to the Special Issue Nanoparticles in Immunology)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Nanomaterials, Volume 7, Issue 7 (July 2017) – 44 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI