Nanomaterials

Research

Jump to: Review

17 pages, 2208 KiB

Open AccessArticle

Combined Effect of Ultrasound Stimulations and Autoclaving on the Enhancement of Antibacterial Activity of ZnO and SiO₂/ZnO Nanoparticles

by Hajer Rokbani¹, France Daigle²

and Abdellah Ajji^1,*

¹ 3SPack, CREPEC, Department of Chemical Engineering, Polytechnique Montréal, P.O. Box 6079, Station Centre-Ville, Montreal, QC H3C 3A7, Canada

² Department of Microbiology, Infectiology and Immunology, Pavillon Roger-Gaudry, Université de Montréal, P.O. Box 6128, Station Centre-ville, Montréal, QC H3C 3J7, Canada

Nanomaterials 2018, 8(3), 129; https://doi.org/10.3390/nano8030129 - 25 Feb 2018

Cited by 38 | Viewed by 6457

Abstract

This study investigates the antibacterial activity (ABA) of suspensions of pure ZnO nanoparticles (ZnO-NPs) and mesoporous silica doped with ZnO (ZnO-UVM7), as well as electrospun nanofibers containing those nanoparticles. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of these two materials [...] Read more.

This study investigates the antibacterial activity (ABA) of suspensions of pure ZnO nanoparticles (ZnO-NPs) and mesoporous silica doped with ZnO (ZnO-UVM7), as well as electrospun nanofibers containing those nanoparticles. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of these two materials were also determined under the same conditions. The results showed a concentration-dependent effect of antibacterial nanoparticles on the viability of Escherichia coli (E. coli). Moreover, the combination of the stimulations and sterilization considerably enhanced the antimicrobial activity (AMA) of the ZnO suspensions. Poly (lactic acid) (PLA) solutions in 2,2,2-trifluoroethanol (TFE) were mixed with different contents of nanoparticles and spun into nonwoven mats by the electrospinning process. The morphology of the mats was analyzed by scanning electron microscopy (SEM). The amount of nanoparticles contained in the mats was determined by thermogravimetric analysis (TGA). The obtained PLA-based mats showed a fibrous morphology, with an average diameter ranging from 350 to 450 nm, a porosity above 85%, but with the nanoparticles agglomeration on their surface. TGA analysis showed that the loss of ZnO-NPs increased with the increase of ZnO-NPs content in the PLA solutions and reached 79% for 1 wt % of ZnO-NPs, which was mainly due to the aggregation of nanoparticles in solution. The ABA of the obtained PLA mats was evaluated by the dynamic method according to the ASTM standard E2149. The results showed that, above an optimal concentration, the nanoparticle agglomeration reduced the antimicrobial efficiency of PLA mats. These mats have potential features for use as antimicrobial food packaging material. Full article

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

▼ Show Figures

Figure 1

19 pages, 8862 KiB

Open AccessArticle

The Effect of Weak Confinement on the Orientation of Nanorods under Shear Flows

by Saman Monjezi, James D. Jones, Alyssa K. Nelson and Joontaek Park^*

The Department of Chemical & Biochemical Engineering, Missouri University of Science & Technology, Rolla, MO 65409, USA

Nanomaterials 2018, 8(3), 130; https://doi.org/10.3390/nano8030130 - 26 Feb 2018

Cited by 11 | Viewed by 4375

Abstract

We performed a numerical analysis to study the orientation distribution of a dilute suspension of thin, rigid, rod-like nanoparticles under shearing flow near a solid boundary of weak confinement. Brownian dynamics simulation of a rod was performed under various ratios of shear rate [...] Read more.

We performed a numerical analysis to study the orientation distribution of a dilute suspension of thin, rigid, rod-like nanoparticles under shearing flow near a solid boundary of weak confinement. Brownian dynamics simulation of a rod was performed under various ratios of shear rate and rod diffusivity (Peclet number), as well as the center-of-mass position (wall confinement). We discuss the effects of Peclet number and wall confinement on the angle distributions, Jeffery orbit distribution and average orientation moments. The average orientation moments, obtained as a function of Peclet number and wall confinement, can be used to improve a previous shear-induced migration model. We demonstrate that the improved model can give excellent prediction of the orientation moment distributions in a microchannel flow. Full article

▼ Show Figures

Graphical abstract

11 pages, 5449 KiB

Open AccessArticle

Enhanced Delivery of Therapeutic siRNA into Glioblastoma Cells Using Dendrimer-Entrapped Gold Nanoparticles Conjugated with β-Cyclodextrin

by Jieru Qiu^1,2, Lingdan Kong², Xueyan Cao², Aijun Li², Ping Wei², Lu Wang², Serge Mignani^3,4,*, Anne-Marie Caminade^5,6

, Jean-Pierre Majoral^5,6,* and Xiangyang Shi^1,2,4,*

¹ Department of Radiology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai 200072, China

² College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China

³ Université Paris Descartes, PRES Sorbonne Paris Cité, CNRS UMR 860, Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologique, 45, rue des Saints Peres, 75006 Paris, France

⁴ CQM—Centro de Química da Madeira, MMRG, Universidade da Madeira, Campus da Penteada, 9020-105 Funchal, Portugal

⁵ Laboratoire de Chimie de Coordination du CNRS, 205 Route de Narbonne, BP 44099, 31077 Toulouse CEDEX 4, France

⁶ Université de Toulouse, UPS, INPT, 31077 Toulouse CEDEX 4, France

Nanomaterials 2018, 8(3), 131; https://doi.org/10.3390/nano8030131 - 27 Feb 2018

Cited by 85 | Viewed by 6862

Abstract

We describe a safe and highly effective non-viral vector system based on β-cyclodextrin (β-CD)-modified dendrimer-entrapped gold nanoparticles (Au DENPs) for improved delivery small interfering RNA (siRNA) to glioblastoma cells. In our approach, we utilized amine-terminated generation 5 poly(amidoamine) dendrimers partially grafted with β-CD [...] Read more.

We describe a safe and highly effective non-viral vector system based on β-cyclodextrin (β-CD)-modified dendrimer-entrapped gold nanoparticles (Au DENPs) for improved delivery small interfering RNA (siRNA) to glioblastoma cells. In our approach, we utilized amine-terminated generation 5 poly(amidoamine) dendrimers partially grafted with β-CD as a nanoreactor to entrap Au NPs. The acquired β-CD-modified Au DENPs (Au DENPs-β-CD) were complexed with two different types of therapeutic siRNA (B-cell lymphoma/leukemia-2 (Bcl-2) siRNA and vascular endothelial growth factor (VEGF) siRNA). The siRNA compression ability of the Au DENPs-β-CD was evaluated by various methods. The cytocompatibility of the vector/siRNA polyplexes was assessed by viability assay of cells. The siRNA transfection capability of the formed Au DENPs-β-CD vector was evaluated by flow cytometric assay of the cellular uptake of the polyplexes and Western blot assays of the Bcl-2 and VEGF protein expression. Our data reveals that the formed Au DENPs-β-CD carrier enables efficiently delivery of siRNA to glioma cells, has good cytocompatibility once complexed with the siRNA, and enables enhanced gene silencing to inhibit the expression of Bcl-2 and VEGF proteins. The developed Au DENPs-β-CD vector may be used for efficient siRNA delivery to different biosystems for therapeutic purposes. Full article

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

▼ Show Figures

Figure 1

11 pages, 5919 KiB

Open AccessArticle

Carbon Nitride Decorated Ball-Flower like Co₃O₄ Hybrid Composite: Hydrothermal Synthesis and Ethanol Gas Sensing Application

by Yuxiao Gong¹, Yan Wang^2,3,*

, Guang Sun^1,*, Tiekun Jia⁴, Lei Jia¹, Fengmei Zhang¹, Long Lin¹, Baoqing Zhang¹, Jianliang Cao^1,*

and Zhanying Zhang¹

¹ School of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo 454000, China

² The Collaboration Innovation Center of Coal Safety Production of Henan Province, Jiaozuo 454000, China

³ State Key Laboratory Cultivation Bases Gas Geology and Gas Control (Henan Polytechnic University), Jiaozuo 454000, China

⁴ Department of Materials Science and Engineering, Luoyang Institute of Science and Technology, Luoyang 471023, China

Nanomaterials 2018, 8(3), 132; https://doi.org/10.3390/nano8030132 - 27 Feb 2018

Cited by 63 | Viewed by 6642

Abstract

Recently, semiconducting metal oxide (SMO) gas sensors have attracted the attention of researchers for high conductivity, labile features by environment, low cost, easy preparation, etc. However, traditional SMOs have some defects such as higher operating temperature and lower response value, which greatly limit [...] Read more.

Recently, semiconducting metal oxide (SMO) gas sensors have attracted the attention of researchers for high conductivity, labile features by environment, low cost, easy preparation, etc. However, traditional SMOs have some defects such as higher operating temperature and lower response value, which greatly limit their application in the field of gas sensor. In this work, the carbon nitride decorated ball-flower like Co₃O₄ composite was successfully synthesized via a facile hydrothermal method, the composition and morphology of the as-synthesized samples were studied by the techniques of X-ray powder diffraction (XRD), Field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FT-IR) and N₂-sorption. As a consequence, the pure Co₃O₄ and the carbon nitride decorated Co₃O₄ both possess ball-flower like structure, and the as-synthesized carbon nitride decorated Co₃O₄ composite exhibits significant sensing properties to ethanol which is 1.6 times higher than that of pure Co₃O₄, furthermore, the composite possesses high selectivity and stability towards ethanol detection. Full article

(This article belongs to the Special Issue Graphitic Carbon Nitride Nanostructures: Catalysis and Beyond)

▼ Show Figures

Figure 1

13 pages, 8814 KiB

Open AccessArticle

Electrospun CuO-Nanoparticles-Modified Polycaprolactone @Polypyrrole Fibers: An Application to Sensing Glucose in Saliva

by Ting Xu, Wen Jin, Zhenzhen Wang, Haiyan Cheng, Xinhua Huang, Xiaoyu Guo, Ye Ying, Yiping Wu, Feng Wang, Ying Wen^* and Haifeng Yang^*

The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Municipal Education Committee Key Laboratory of Molecular Imaging Probes and Sensors and Department of Chemistry, Shanghai Normal University, Shanghai 200234, China

Nanomaterials 2018, 8(3), 133; https://doi.org/10.3390/nano8030133 - 27 Feb 2018

Cited by 41 | Viewed by 6334

Abstract

A non-invasive method for detecting glucose is pursued by millions of diabetic patients to improve their personal management of blood glucose. In this work, a novel CuO nanoparticles (NPs) decorated polycaprolactone@polypyrrole fibers modified indium-tin oxide (denoted as CuO/PCL@PPy/ITO) electrode has been fabricated by [...] Read more.

A non-invasive method for detecting glucose is pursued by millions of diabetic patients to improve their personal management of blood glucose. In this work, a novel CuO nanoparticles (NPs) decorated polycaprolactone@polypyrrole fibers modified indium-tin oxide (denoted as CuO/PCL@PPy/ITO) electrode has been fabricated by electrospinning combined with the electrodeposition method for non-enzymatic detection of glucose in saliva fluid. The electrospun composite fibers exhibit high sensitivity for the glucose detection. The synergistic effect between CuO and PPy together with the unique three-dimensional net structure contributes the reliable selectivity, good test repeatability, large-scale production reproducibility in massive way, the reasonable stability and a high catalytic surface area to the sensor. Quantitative detection of glucose is determined in the linear range from 2 μM to 6 mM and the lowest detection limit is 0.8 μM. The CuO/PCL@PPy/ITO electrode shows potential for the non-invasive detection of salivary glucose. Full article

(This article belongs to the Special Issue The Fabrication and Application of Nanofibers)

▼ Show Figures

Graphical abstract

19 pages, 1840 KiB

Open AccessArticle

Nanotransition Materials (NTMs): Photocatalysis, Validated High Effective Sorbent Models Study for Organic Dye Degradation and Precise Mathematical Data’s at Standardized Level

by Farheen Khan^1,*, Rizwan Wahab^2,3,*

, Mohamed Hagar^1,4

, Rua Alnoman¹, Lutfullah⁵ and Mohd Rashid⁶

¹ Chemistry Department, Faculty of Science, Taibah University, Yanbu 00000, Saudi Arabia

² Zoology Department, College of Science King Saud University, Riyadh 11451, Saudi Arabia

³ Al-Jeraisy, Chair for DNA Research, Department of Zoology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia

⁴ Chemistry Department, Faculty of Science, Alexandria University, Alexandria 21321, Egypt

⁵ Department of Chemistry, Aligarh Muslim University, Aligarh UP 202002, India

⁶ Saraswati Devi Post Graduate College, Khadda Bazar, Kushinagar UP 274802, India

Nanomaterials 2018, 8(3), 134; https://doi.org/10.3390/nano8030134 - 27 Feb 2018

Cited by 14 | Viewed by 4823

Abstract

The present work describes the synthesis of copper oxide nanoparticles (CuONPs) via a solution process with the aim of applying the nano-adsorbent for the reduction of methylene blue (MB) dye in alkaline media. These NPs were characterized via Field emission scanning electron microscopy [...] Read more.

The present work describes the synthesis of copper oxide nanoparticles (CuONPs) via a solution process with the aim of applying the nano-adsorbent for the reduction of methylene blue (MB) dye in alkaline media. These NPs were characterized via Field emission scanning electron microscopy (FE-SEM), X-ray diffraction, high-resolution Transmission electron microscopy (TEM), and ultra violet UV-visible spectroscopy to confirm their morphology and crystalline and optical properties in order to design an adsorption-degradation process. The photocatalytic CuONPs exhibited dynamic properties, great adsorption affinity during the chemisorption process, and operated at various modes with a strong interaction between the adsorbent and the adsorptive species, and equilibrium isotherm, kinetic isotherm, and thermodynamic activities in the presence of UV light. All basic quantities, such as concentration, pH, adsorbent dose, time, and temperature, were determined by an optimization process. The best-fitted adsorption Langmuir model (R² = 0.9988) and performance, including adsorption capacity (350.87 mg/g), photocatalytic efficiency (90.74%), and degradation rate constant (Ks = 2.23 ×10⁻² min⁻¹), illustrate good feasibility with respect to sorption-reduction reactions but followed a pseudo-second-order kinetic on the adsorbent surface, reaching an equilibrium point in 80 min. The thermodynamic analysis suggests that the adsorption reaction is spontaneous and endothermic in nature. The thermodynamic parameters such as enthalpy (∆H°), entropy (∆S°), and Gibbs free energy (∆G°) give effective results to support a chemical reduction reaction at 303 K temperature. The equilibrium isotherm and kinetic and thermodynamic models with error function analysis explore the potential, acceptability, accuracy, access to adsorbents, and novelty of an unrivaled-sorption system. Full article

(This article belongs to the Special Issue Hybrid Nanomaterials for Future Technologies)

▼ Show Figures

Figure 1

9 pages, 5492 KiB

Open AccessArticle

Three-Dimensional SnS Decorated Carbon Nano-Networks as Anode Materials for Lithium and Sodium Ion Batteries

by Yanli Zhou, Qi Wang, Xiaotao Zhu and Fuyi Jiang^*

School of Environmental and Materials Engineering, Yantai University, Yantai 264005, China

Nanomaterials 2018, 8(3), 135; https://doi.org/10.3390/nano8030135 - 28 Feb 2018

Cited by 31 | Viewed by 6213

Abstract

The three-dimensional (3D) SnS decorated carbon nano-networks (SnS@C) were synthesized via a facile two-step method of freeze-drying combined with post-heat treatment. The lithium and sodium storage performances of above composites acting as anode materials were investigated. As anode materials for lithium ion batteries, [...] Read more.

The three-dimensional (3D) SnS decorated carbon nano-networks (SnS@C) were synthesized via a facile two-step method of freeze-drying combined with post-heat treatment. The lithium and sodium storage performances of above composites acting as anode materials were investigated. As anode materials for lithium ion batteries, a high reversible capacity of 780 mAh·g⁻¹ for SnS@C composites can be obtained at 100 mA·g⁻¹ after 100 cycles. Even cycled at a high current density of 2 A·g⁻¹, the reversible capacity of this composite can be maintained at 610 mAh·g⁻¹ after 1000 cycles. The initial charge capacity for sodium ion batteries can reach 333 mAh·g⁻¹, and it retains a reversible capacity of 186 mAh·g⁻¹ at 100 mA·g⁻¹ after 100 cycles. The good lithium or sodium storage performances are likely attributed to the synergistic effects of the conductive carbon nano-networks and small SnS nanoparticles. Full article

(This article belongs to the Special Issue Three-dimensional Nanomaterials for Energy Storage and Conversions)

▼ Show Figures

Graphical abstract

19 pages, 12549 KiB

Open AccessArticle

Morphology-Variable Aggregates Prepared from Cholesterol-Containing Amphiphilic Glycopolymers: Their Protein Recognition/Adsorption and Drug Delivery Applications

by Zhao Wang^1,2, Ting Luo², Amin Cao^2,*, Jingjing Sun², Lin Jia^1,2,* and Ruilong Sheng^2,3,*

¹ Department of Polymer Materials, Shanghai University, 99 Shangda Road, Mailbox 152, Shanghai 200444, China

² CAS Key Laboratory of Synthetic and Self-assembly Chemistry for Organic Functional Molecules, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China

³ CQM—Centro de Química da Madeira, Universidade da Madeira, Campus da Penteada, 9000-390 Funchal, Portugal

Nanomaterials 2018, 8(3), 136; https://doi.org/10.3390/nano8030136 - 28 Feb 2018

Cited by 27 | Viewed by 5117

Abstract

In this study, a series of diblock glycopolymers, poly(6-O-methacryloyl-d-galactopyranose)-b-poly(6-cholesteryloxyhexyl methacrylate) (PMAgala-b-PMAChols), with cholesterol/galactose grafts were prepared through a sequential reversible addition-fragmentation chain transfer (RAFT) polymerization and deprotection process. The glycopolymers could self-assemble into aggregates with [...] Read more.

In this study, a series of diblock glycopolymers, poly(6-O-methacryloyl-d-galactopyranose)-b-poly(6-cholesteryloxyhexyl methacrylate) (PMAgala-b-PMAChols), with cholesterol/galactose grafts were prepared through a sequential reversible addition-fragmentation chain transfer (RAFT) polymerization and deprotection process. The glycopolymers could self-assemble into aggregates with various morphologies depending on cholesterol/galactose-containing block weight ratios, as determined by transmission electronic microscopy (TEM) and dynamic laser light scattering (DLS). In addition, the lectin (Ricinus communis agglutinin II, RCA₁₂₀) recognition and bovine serum albumin (BSA) adsorption of the PMAgala-b-PMAChol aggregates were evaluated. The SK-Hep-1 tumor cell inhibition properties of the PMAgala-b-PMAChol/doxorubicin (DOX) complex aggregates were further examined in vitro. Results indicate that the PMAgala-b-PMAChol aggregates with various morphologies showed different interaction/recognition features with RCA₁₂₀ and BSA. Spherical aggregates (d ≈ 92 nm) possessed the highest RCA₁₂₀ recognition ability and lowest BSA protein adsorption. In addition, the DOX-loaded spherical complex aggregates exhibited a better tumor cell inhibition property than those of nanofibrous complex aggregates. The morphology-variable aggregates derived from the amphiphilic glycopolymers may serve as multifunctional biomaterials with biomolecular recognition and drug delivery features. Full article

▼ Show Figures

Graphical abstract

11 pages, 2861 KiB

Open AccessArticle

Epoxidation of Carbon Nanocapsules: Decoration of Single-Walled Carbon Nanotubes Filled with Metal Halides

by Lucia D’Accolti¹

, Agnieszka Gajewska², Magdalena Kierkowicz³, Markus Martincic³, Angelo Nacci¹

, Stefania Sandoval³

, Belén Ballesteros⁴

, Gerard Tobias^3,*

, Tatiana Da Ros^2,*

and Caterina Fusco^5,*

¹ Department of Chemistry, University of Bari “A. Moro”, Via Orabona, 4, 70126 Bari, Italy

² INSTM Unit of Trieste, Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy

³ Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Bellaterra, 08193 Barcelona, Spain

⁴ Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain

⁵ CNR-ICCOM, Department of Chemistry, University of Bari, Via Orabona, 4, 70126 Bari, Italy

Nanomaterials 2018, 8(3), 137; https://doi.org/10.3390/nano8030137 - 28 Feb 2018

Cited by 9 | Viewed by 4372

Abstract

Methyl(trifluoromethyl)dioxirane (TFDO) can be used for the oxyfunctionalization of SWCNTs filled with NaI and LuCl₃ under mild conditions. The chosen metal halides are of interest for theranostics, both for imaging and therapy when in their radioactive form. The applied functionalization methodology does [...] Read more.

Methyl(trifluoromethyl)dioxirane (TFDO) can be used for the oxyfunctionalization of SWCNTs filled with NaI and LuCl₃ under mild conditions. The chosen metal halides are of interest for theranostics, both for imaging and therapy when in their radioactive form. The applied functionalization methodology does not require metal catalyst, preserves the integrity of the nanotubes during treatment, avoiding the release of the filling material. In this way, epoxidation can be considered as an efficient methodology for the functionalization of carbon nanocapsules, where the traditional harsh oxidation conditions by acids are not applicable. Full article

(This article belongs to the Special Issue Applications of Carbon Nanotubes)

▼ Show Figures

Graphical abstract

13 pages, 12211 KiB

Open AccessCommunication

MOF-Derived Cu@Cu₂O Nanocatalyst for Oxygen Reduction Reaction and Cycloaddition Reaction

by Aram Kim¹, Nallal Muthuchamy¹

, Chohye Yoon¹, Sang Hoon Joo² and Kang Hyun Park^1,*

¹ Department of Chemistry, Pusan National University, Busan 46241, Korea

² School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Korea

Nanomaterials 2018, 8(3), 138; https://doi.org/10.3390/nano8030138 - 28 Feb 2018

Cited by 79 | Viewed by 8995

Abstract

Research on the synthesis of nanomaterials using metal-organic frameworks (MOFs), which are characterized by multi-functionality and porosity, as precursors have been accomplished through various synthetic approaches. In this study, copper and copper oxide nanoparticles were fabricated within 30 min by a simple and [...] Read more.

Research on the synthesis of nanomaterials using metal-organic frameworks (MOFs), which are characterized by multi-functionality and porosity, as precursors have been accomplished through various synthetic approaches. In this study, copper and copper oxide nanoparticles were fabricated within 30 min by a simple and rapid method involving the reduction of a copper(II)-containing MOF with sodium borohydride solution at room temperature. The obtained nanoparticles consist of a copper core and a copper oxide shell exhibited catalytic activity in the oxygen reduction reaction. The as-synthesized Cu@Cu₂O core-shell nanocatalyst exhibited an enhanced limit current density as well as onset potential in the electrocatalytic oxygen reduction reaction (ORR). Moreover, the nanoparticles exhibited good catalytic activity in the Huisgen cycloaddition of various substituted azides and alkynes under mild reaction conditions. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

▼ Show Figures

Graphical abstract

11 pages, 1749 KiB

Open AccessArticle

Antimicrobial Membranes of Bio-Based PA 11 and HNTs Filled with Lysozyme Obtained by an Electrospinning Process

by Valeria Bugatti, Luigi Vertuccio, Gianluca Viscusi and Giuliana Gorrasi^*

Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy

Nanomaterials 2018, 8(3), 139; https://doi.org/10.3390/nano8030139 - 1 Mar 2018

Cited by 43 | Viewed by 5114

Abstract

Bio-based membranes were obtained using Polyamide 11 (PA11) from renewable sources and a nano-hybrid composed of halloysite nanotubes (HNTs) filled with lysozyme (50 wt % of lysozyme), as a natural antimicrobial molecule. Composites were prepared using an electrospinning process, varying the nano-hybrid loading [...] Read more.

Bio-based membranes were obtained using Polyamide 11 (PA11) from renewable sources and a nano-hybrid composed of halloysite nanotubes (HNTs) filled with lysozyme (50 wt % of lysozyme), as a natural antimicrobial molecule. Composites were prepared using an electrospinning process, varying the nano-hybrid loading (i.e., 1.0, 2.5, 5.0 wt %). The morphology of the membranes was investigated through SEM analysis and there was found to be a narrow average fiber diameter (0.3–0.5 μm). The mechanical properties were analyzed and correlated to the nano-hybrid content. Controlled release of lysozyme was followed using UV spectrophotometry and the release kinetics were found to be dependent on HNTs–lysozyme loading. The experimental results were analyzed by a modified Gallagher–Corrigan model. The application of the produced membranes, as bio-based pads, for extending the shelf life of chicken slices has been tested and evaluated. Full article

(This article belongs to the Special Issue Food Packaging Based on Nanomaterials)

▼ Show Figures

Graphical abstract

13 pages, 2670 KiB

Open AccessArticle

Inhibition of E. coli Growth by Nanodiamond and Graphene Oxide Enhanced by Luria-Bertani Medium

by Jaroslav Jira^1,2,*, Bohuslav Rezek², Vitezslav Kriha², Anna Artemenko¹, Iva Matolínová³

, Viera Skakalova⁴, Pavla Stenclova¹ and Alexander Kromka¹

¹ Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Prague 6, Czech Republic

² Faculty of Electrical Engineering, Czech Technical University, Technická 2, 166 27 Prague 6, Czech Republic

³ Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 181 00 Prague 8, Czech Republic

⁴ Danubia NanoTech, s.r.o., Ilkovicova 3, 841 04 Bratislava, Slovakia

Nanomaterials 2018, 8(3), 140; https://doi.org/10.3390/nano8030140 - 1 Mar 2018

Cited by 44 | Viewed by 7804

Abstract

Nanodiamonds (NDs) and graphene oxide (GO) are modern carbon-based nanomaterials with promising features for the inhibition of microorganism growth ability. Here we compare the effects of nanodiamond and graphene oxide in both annealed (oxidized) and reduced (hydrogenated) forms in two types of cultivation [...] Read more.

Nanodiamonds (NDs) and graphene oxide (GO) are modern carbon-based nanomaterials with promising features for the inhibition of microorganism growth ability. Here we compare the effects of nanodiamond and graphene oxide in both annealed (oxidized) and reduced (hydrogenated) forms in two types of cultivation media—Luria-Bertani (LB) and Mueller-Hinton (MH) broths. The comparison shows that the number of colony forming unit (CFU) of Escherichia coli is significantly lowered (45%) by all the nanomaterials in LB medium for at least 24 h against control. On the contrary, a significant long-term inhibition of E. coli growth (by 45%) in the MH medium is provided only by hydrogenated NDs terminated with C-H_X groups. The use of salty agars did not enhance the inhibition effects of nanomaterials used, i.e. disruption of bacterial membrane or differences in ionic concentrations do not play any role in bactericidal effects of nanomaterials used. The specific role of the ND and GO on the enhancement of the oxidative stress of bacteria or possible wrapping bacteria by GO nanosheets, therefore isolating them from both the environment and nutrition was suggested. Analyses by infrared spectroscopy, photoelectron spectroscopy, scanning electron microscopy and dynamic light scattering corroborate these conclusions. Full article

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

▼ Show Figures

Figure 1

13 pages, 3337 KiB

Open AccessArticle

Palladium Supported on Titanium Carbide: A Highly Efficient, Durable, and Recyclable Bifunctional Catalyst for the Transformation of 4-Chlorophenol and 4-Nitrophenol

by Guangyin Fan^1,*, Xiaojing Li¹, Caili Xu¹, Weidong Jiang², Yun Zhang^1,*, Daojiang Gao¹, Jian Bi¹ and Yi Wang¹

¹ College of Chemistry and Materials Science, Sichuan Normal University, Chengdu 610068, China

² School of Chemical and Environmental Engineering, Sichuan University of Science & Engineering, Zigong 643000, China

Nanomaterials 2018, 8(3), 141; https://doi.org/10.3390/nano8030141 - 2 Mar 2018

Cited by 32 | Viewed by 6451

Abstract

Developing highly efficient and recyclable catalysts for the transformation of toxic organic contaminates still remains a challenge. Herein, Titanium Carbide (Ti₃C₂) MXene modified by alkali treatment process was selected as a support (designated as alk-Ti₃C₂X [...] Read more.

Developing highly efficient and recyclable catalysts for the transformation of toxic organic contaminates still remains a challenge. Herein, Titanium Carbide (Ti₃C₂) MXene modified by alkali treatment process was selected as a support (designated as alk-Ti₃C₂X₂, where X represents the surface terminations) for the synthesis of Pd/alk-Ti₃C₂X₂. Results show that the alkali treatment leads to the increase of surface area and surface oxygen-containing groups of Ti₃C₂X₂, thereby facilitating the dispersion and stabilization of Pd species on the surface of alk-Ti₃C₂X₂. The Pd/alk-Ti₃C₂X₂ catalyst shows excellent catalytic activity for the hydrodechlorination of 4-chlorophenol and the hydrogenation of 4-nitrophenol in aqueous solution at 25 °C and hydrogen balloon pressure. High initial reaction rates of 216.6 and 126.3 min⁻¹·

g_{pd}^{- 1}

are observed for the hydrodechlorination of 4-chlorophenol and hydrogenation of 4-nitrophenol, respectively. Most importantly, Pd/alk-Ti₃C₂X₂ exhibits excellent stability and recyclability in both reactions without any promoters. The superior property of Pd/alk-Ti₃C₂X₂ makes it as a potential material for practical applications. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

▼ Show Figures

Graphical abstract

13 pages, 2409 KiB

Open AccessFeature PaperArticle

Immobilization of Polyoxometalates on Tailored Polymeric Surfaces

by Saioa Aguado-Ureta¹, Juan Rodríguez-Hernández², Adolfo Del Campo³, Leyre Perez-Álvarez^4,5, Leire Ruiz-Rubio^4,5

, José Luis Vilas^4,5,*

, Beñat Artetxe¹

, Santiago Reinoso¹

and Juan M. Gutiérrez-Zorrilla^1,5,*

¹ Departamento de Química Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, P.O. Box 644, 48080 Bilbao, Spain

² Departamento de Química y Propiedades de Materiales Poliméricos, Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain

³ Departamento de Electrocerámica, Instituto de Cerámica y Vidrio (ICV-CSIC), C/Kelsen 5, 28049 Madrid, Spain

⁴ Grupo de Química Macromolecular (LABQUIMAC), Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, P.O. Box 644, 48080 Bilbao, Spain

⁵ BCMaterials, Basque Center for Materials, Applications and Nanostructures, UPV/EHU Science Park, 48940 Leioa, Spain

Nanomaterials 2018, 8(3), 142; https://doi.org/10.3390/nano8030142 - 2 Mar 2018

Cited by 6 | Viewed by 5102

Abstract

Herein we describe the preparation of hybrid polymer–inorganic interfaces by the immobilization of polyoxometalate nanoclusters on functionalized polymer surfaces. The polymeric surfaces were made of polystyrene-b-poly(acrylic acid)/polystyrene (PS-b-PAA/PS) blends by spin coating on a silicon wafer. The functionalization of [...] Read more.

Herein we describe the preparation of hybrid polymer–inorganic interfaces by the immobilization of polyoxometalate nanoclusters on functionalized polymer surfaces. The polymeric surfaces were made of polystyrene-b-poly(acrylic acid)/polystyrene (PS-b-PAA/PS) blends by spin coating on a silicon wafer. The functionalization of the polymer film was obtained by interfacial migration of the amphiphilic block copolymer toward the interface upon water vapor annealing. The carboxylic acid functional groups contained in the PAA block were then employed to anchor the [Ln^III(α-SiW₁₁O₃₉)]⁵⁻ polyoxometalates (Ln: Ce, Er). This purpose was achieved by immersing the films in aqueous solutions of the in situ-formed inorganic nanoclusters. X-ray photoelectron and confocal Raman spectroscopies, together with atomic force microscopy, confirmed the immobilization of the inorganic species at the interface. Full article

(This article belongs to the Special Issue Experimental Nanosciences, Computational Chemistry, and Data Analysis)

▼ Show Figures

Graphical abstract

15 pages, 4245 KiB

Open AccessFeature PaperArticle

Lipid-Coated Zinc Oxide Nanoparticles as Innovative ROS-Generators for Photodynamic Therapy in Cancer Cells

by Andrea Ancona¹, Bianca Dumontel¹, Nadia Garino^1,2, Benjamin Demarco³, Dimitra Chatzitheodoridou³, Walter Fazzini¹, Hanna Engelke^3,*

and Valentina Cauda^1,2,*

¹ Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy

² Center for Sustainable Future Technologies—CSFT@POLITO, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Turin, Italy

³ Department of Chemistry, Ludwig-Maximilians-University of Munich, Butenandtstrasse 11E, 81377 Munich, Germany

Nanomaterials 2018, 8(3), 143; https://doi.org/10.3390/nano8030143 - 2 Mar 2018

Cited by 117 | Viewed by 10955

Abstract

In the present paper, we use zinc oxide nanoparticles under the excitation of ultraviolet (UV) light for the generation of Reactive Oxygen Species (ROS), with the aim of further using these species for fighting cancer cells in vitro. Owing to the difficulties in [...] Read more.

In the present paper, we use zinc oxide nanoparticles under the excitation of ultraviolet (UV) light for the generation of Reactive Oxygen Species (ROS), with the aim of further using these species for fighting cancer cells in vitro. Owing to the difficulties in obtaining highly dispersed nanoparticles (NPs) in biological media, we propose their coating with a double-lipidic layer and we evaluate their colloidal stability in comparison to the pristine zinc oxide NPs. Then, using Electron Paramagnetic Resonance (EPR) coupled with the spin-trapping technique, we demonstrate and characterize the ability of bare and lipid-coated ZnO NPs to generate ROS in water only when remotely actuated via UV light irradiation. Interestingly, our results reveal that the surface chemistry of the NPs greatly influences the type of photo-generated ROS. Finally, we show that lipid-coated ZnO NPs are effectively internalized inside human epithelial carcinoma cells (HeLa) via a lysosomal pathway and that they can generate ROS inside cancer cells, leading to enhanced cell death. The results are promising for the development of ZnO-based therapeutic systems. Full article

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

▼ Show Figures

Graphical abstract

12 pages, 3339 KiB

Open AccessArticle

A Rapid and Semi-Quantitative Gold Nanoparticles Based Strip Sensor for Polymyxin B Sulfate Residues

by Yue Li^1,2,3, Liqiang Liu^1,2,3, Shanshan Song^1,2,3, Hua Kuang^1,2,3,* and Chuanlai Xu^1,2,3,*

¹ State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China

² International Joint Research Laboratory for Biointerface and Biodetection, and School of Food Science and Technology, Jiangnan University, Wuxi 214122, China

³ Collaborative Innovationcenter of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi 214122, China

Nanomaterials 2018, 8(3), 144; https://doi.org/10.3390/nano8030144 - 5 Mar 2018

Cited by 38 | Viewed by 5417

Abstract

Increasing attention is now being directed to the utilization of polymyxin B (PMB) as a last-line treatment for life-threatening infections caused by multidrug resistant Gram-negative bacteria. Unfortunately, polymyxins resistance is also increasingly reported, leaving a serious threat to human health. Therefore, the establishment [...] Read more.

Increasing attention is now being directed to the utilization of polymyxin B (PMB) as a last-line treatment for life-threatening infections caused by multidrug resistant Gram-negative bacteria. Unfortunately, polymyxins resistance is also increasingly reported, leaving a serious threat to human health. Therefore, the establishment of rapid detection methods for PMB residues is highly essential to ensure public health. In this study, two monoclonal antibodies (mAb; 2A2 and 3C6) were obtained using PMB-bovine serum albumin as the immunogen and PMB-ovalbumin as the coating antigen, which were prepared with N-(γ-maleimidobutyryloxy) succinimide ester and glutaraldehyde as cross-linking agents, respectively. Through an indirect competitive enzyme-linked immunosorbent assay, resultant two mAbs were compared and the results indicated that 3C6 showed higher sensitivity with a half maximum inhibition concentration of 13.13 ng/mL. Based on 3C6, a gold nanoparticles (AuNPs)-based immunochromatographic test (ICT) strip was then established, the mechanism of which is that free PMB competes with the fixed coating antigen to combine with mAb labeled by AuNPs. Using ICT strip to detect milk and animal feed samples revealed the visible detection limits were 25 ng/mL and 500 μg/kg, respectively and the cutoff limits were 100 ng/mL and 1000 μg/kg, respectively. The ICT strip provides results within 15 min, facilitating rapid and semi-quantitative analysis of PMB residues in milk and animal feed. Full article

(This article belongs to the Special Issue Supramolecular Nano-architectures)

▼ Show Figures

Figure 1

12 pages, 5524 KiB

Open AccessArticle

Tunable Electronic and Topological Properties of Germanene by Functional Group Modification

by Ceng-Ceng Ren, Shu-Feng Zhang, Wei-Xiao Ji, Chang-Wen Zhang, Ping Li and Pei-Ji Wang^*

School of Physics, University of Jinan, Jinan 250022, China

Nanomaterials 2018, 8(3), 145; https://doi.org/10.3390/nano8030145 - 6 Mar 2018

Cited by 21 | Viewed by 4754

Abstract

Electronic and topological properties of two-dimensional germanene modified by functional group X (X = H, F, OH, CH₃) at full coverage are studied with first-principles calculation. Without considering the effect of spin-orbit coupling (SOC), all functionalized configurations become semiconductors, removing the [...] Read more.

Electronic and topological properties of two-dimensional germanene modified by functional group X (X = H, F, OH, CH₃) at full coverage are studied with first-principles calculation. Without considering the effect of spin-orbit coupling (SOC), all functionalized configurations become semiconductors, removing the Dirac cone at K point in pristine germanene. We also find that their band gaps can be especially well tuned by an external strain. When the SOC is switched on, GeX (X = H, CH₃) is a normal insulator and strain leads to a phase transition to a topological insulator (TI) phase. However, GeX (X = F, OH) becomes a TI with a large gap of 0.19 eV for X = F and 0.24 eV for X = OH, even without external strains. More interestingly, when all these functionalized monolayers form a bilayer structure, semiconductor-metal states are observed. All these results suggest a possible route of modulating the electronic properties of germanene and promote applications in nanoelectronics. Full article

▼ Show Figures

Graphical abstract

11 pages, 3134 KiB

Open AccessArticle

Phase Transition-Driven Nanoparticle Assembly in Liquid Crystal Droplets

by Charles N. Melton¹, Sheida T. Riahinasab¹, Amir Keshavarz², Benjamin J. Stokes² and Linda S. Hirst^1,*

¹ Department of Physics, School of Natural Sciences, University of California, 5200 North Lake Rd., Merced, CA 95343, USA

² Chemistry and Chemical Biology Unit, School of Natural Sciences, University of California, 5200 North Lake Rd., Merced, CA 95343, USA

Nanomaterials 2018, 8(3), 146; https://doi.org/10.3390/nano8030146 - 7 Mar 2018

Cited by 13 | Viewed by 7625

Abstract

When nanoparticle self-assembly takes place in an anisotropic liquid crystal environment, fascinating new effects can arise. The presence of elastic anisotropy and topological defects can direct spatial organization. An important goal in nanoscience is to direct the assembly of nanoparticles over large length [...] Read more.

When nanoparticle self-assembly takes place in an anisotropic liquid crystal environment, fascinating new effects can arise. The presence of elastic anisotropy and topological defects can direct spatial organization. An important goal in nanoscience is to direct the assembly of nanoparticles over large length scales to produce macroscopic composite materials; however, limitations on spatial ordering exist due to the inherent disorder of fluid-based methods. In this paper we demonstrate the formation of quantum dot clusters and spherical capsules suspended within spherical liquid crystal droplets as a method to position nanoparticle clusters at defined locations. Our experiments demonstrate that particle sorting at the isotropic–nematic phase front can dominate over topological defect-based assembly. Notably, we find that assembly at the nematic phase front can force nanoparticle clustering at energetically unfavorable locations in the droplets to form stable hollow capsules and fractal clusters at the droplet centers. Full article

(This article belongs to the Special Issue Nanomaterials in Liquid Crystals)

▼ Show Figures

Figure 1

17 pages, 4479 KiB

Open AccessArticle

Modifying Thermal Switchability of Liquid Crystalline Nanoparticles by Alkyl Ligands Variation

by Jan Grzelak

, Maciej Żuk, Martyna Tupikowska and Wiktor Lewandowski^*

Faculty of Chemistry, University of Warsaw, 00-927 Warsaw, Poland

Nanomaterials 2018, 8(3), 147; https://doi.org/10.3390/nano8030147 - 7 Mar 2018

Cited by 8 | Viewed by 10290

Abstract

By coating plasmonic nanoparticles (NPs) with thermally responsive liquid crystals (LCs) it is possible to prepare reversibly reconfigurable plasmonic nanomaterials with prospective applications in optoelectronic devices. However, simple and versatile methods to precisely tailor properties of liquid-crystalline nanoparticles (LC NPs) are still required. [...] Read more.

By coating plasmonic nanoparticles (NPs) with thermally responsive liquid crystals (LCs) it is possible to prepare reversibly reconfigurable plasmonic nanomaterials with prospective applications in optoelectronic devices. However, simple and versatile methods to precisely tailor properties of liquid-crystalline nanoparticles (LC NPs) are still required. Here, we report a new method for tuning structural properties of assemblies of nanoparticles grafted with a mixture of promesogenic and alkyl thiols, by varying design of the latter. As a model system, we used Ag and Au nanoparticles that were coated with three-ring promesogenic molecules and dodecanethiol ligand. These LC NPs self-assemble into switchable lamellar (Ag NPs) or tetragonal (Au NPs) aggregates, as determined with small angle X-ray diffraction and transmission electron microscopy. Reconfigurable assemblies of Au NPs with different unit cell symmetry (orthorombic) are formed if hexadecanethiol and 1H,1H,2H,2H-perfluorodecanethiol were used in the place of dodecanethiol; in the case of Ag NPs the use of 11-hydroxyundecanethiol promotes formation of a lamellar structure as in the reference system, although with substantially broader range of thermal stability (140 vs. 90 °C). Our results underline the importance of alkyl ligand functionalities in determining structural properties of liquid-crystalline nanoparticles, and, more generally, broaden the scope of synthetic tools available for tailoring properties of reversibly reconfigurable plasmonic nanomaterials. Full article

(This article belongs to the Special Issue Nanomaterials in Liquid Crystals)

▼ Show Figures

Figure 1

19 pages, 3987 KiB

Open AccessFeature PaperArticle

Biocompatible Materials Based on Self-Assembling Peptides on Ti25Nb10Zr Alloy: Molecular Structure and Organization Investigated by Synchrotron Radiation Induced Techniques

by Valeria Secchi¹

, Stefano Franchi^1,*,†, Marta Santi¹

, Alina Vladescu²

, Mariana Braic², Tomáš Skála³

, Jaroslava Nováková³, Monica Dettin⁴

, Annj Zamuner⁴, Giovanna Iucci¹

and Chiara Battocchio^1,*

¹ Department of Science, Roma Tre University of Rome, Via della Vasca Navale 79, 00146 Rome, Italy

² National Institute for Optoelectronics, 409 Atomistilor St., 077125 Magurele, Romania

³ Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 18000 Prague, Czech Republic

⁴ Department of Industrial Engineering, University of Padua, Via Marzolo, 9, Padua 35131, Italy

^† Present Address: Elettra-Sincrotrone Trieste S.C.p.A. di interesse nazionale, Strada Statale 14-km 163,5 in AREA Science Park, 34149 Basovizza, Trieste, Italy.

Nanomaterials 2018, 8(3), 148; https://doi.org/10.3390/nano8030148 - 7 Mar 2018

Cited by 14 | Viewed by 4836

Abstract

In this work, we applied advanced Synchrotron Radiation (SR) induced techniques to the study of the chemisorption of the Self Assembling Peptide EAbuK16, i.e., H-Abu-Glu-Abu-Glu-Abu-Lys-Abu-Lys-Abu-Glu-Abu-Glu-Abu-Lys-Abu-Lys-NH₂ that is able to spontaneously aggregate in anti-parallel β-sheet conformation, onto annealed Ti25Nb10Zr alloy surfaces. This synthetic [...] Read more.

In this work, we applied advanced Synchrotron Radiation (SR) induced techniques to the study of the chemisorption of the Self Assembling Peptide EAbuK16, i.e., H-Abu-Glu-Abu-Glu-Abu-Lys-Abu-Lys-Abu-Glu-Abu-Glu-Abu-Lys-Abu-Lys-NH₂ that is able to spontaneously aggregate in anti-parallel β-sheet conformation, onto annealed Ti25Nb10Zr alloy surfaces. This synthetic amphiphilic oligopeptide is a good candidate to mimic extracellular matrix for bone prosthesis, since its β-sheets stack onto each other in a multilayer oriented nanostructure with internal pores of 5–200 nm size. To prepare the biomimetic material, Ti25Nb10Zr discs were treated with aqueous solutions of EAbuK16 at different pH values. Here we present the results achieved by performing SR-induced X-ray Photoelectron Spectroscopy (SR-XPS), angle-dependent Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy, FESEM and AFM imaging on Ti25Nb10Zr discs after incubation with self-assembling peptide solution at five different pH values, selected deliberately to investigate the best conditions for peptide immobilization. Full article

(This article belongs to the Special Issue Advanced Synchrotron Radiation Techniques for Nanostructured Materials)

▼ Show Figures

Graphical abstract

16 pages, 14478 KiB

Open AccessArticle

Electrospun Zein Fibers Incorporating Poly(glycerol sebacate) for Soft Tissue Engineering

by Lena Vogt¹, Liliana Liverani^1,*

, Judith A. Roether² and Aldo R. Boccaccini^1,*

¹ Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstr. 6, 91058 Erlangen, Germany

² Institute of Polymer Materials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen, Germany

Nanomaterials 2018, 8(3), 150; https://doi.org/10.3390/nano8030150 - 8 Mar 2018

Cited by 78 | Viewed by 7690

Abstract

For biomedical applications such as soft tissue engineering, plant proteins are becoming increasingly attractive. Zein, a class of prolamine proteins found in corn, offers excellent properties for application in the human body, but has inferior mechanical properties and lacks aqueous stability. In this [...] Read more.

For biomedical applications such as soft tissue engineering, plant proteins are becoming increasingly attractive. Zein, a class of prolamine proteins found in corn, offers excellent properties for application in the human body, but has inferior mechanical properties and lacks aqueous stability. In this study, electrospun scaffolds from neat zein and zein blended with prepolymer and mildly cross-linked poly(glycerol sebacate) (PGS) were fabricated. Less toxic solvents like acetic acid and ethanol were used. The morphological, physiochemical and degradation properties of the as-spun fiber mats were determined. Neat zein and zein-PGS fiber mats with high zein concentration (24 wt % and 27 wt %) showed defect-free microstructures. The average fiber diameter decreased with increasing PGS amount from 0.7 ± 0.2 µm to 0.09 ± 0.03 µm. The addition of PGS to zein resulted in a seven-fold increase in ultimate tensile strength and a four-fold increase in failure strain, whereas the Young’s Modulus did not change significantly. Degradation tests in phosphate buffered saline revealed the morphological instability of zein containing fiber mats in contact with aqueous media. Therefore, the fibers were in situ cross-linked with N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide (EDC)/N-Hydroxysuccinimide (NHS), which led to improved morphological stability in aqueous environment. The novel fibers have suitable properties for application in soft tissue engineering. Full article

(This article belongs to the Special Issue The Fabrication and Application of Nanofibers)

▼ Show Figures

Figure 1

10 pages, 2550 KiB

Open AccessArticle

Transport and Field Emission Properties of MoS₂ Bilayers

by Francesca Urban^1,2

, Maurizio Passacantando³

, Filippo Giubileo²

, Laura Iemmo^1,2

and Antonio Di Bartolomeo^1,2,*

¹ Department of Physics “E.R. Caianiello”, University of Salerno, 84084 Fisciano, Italy

² CNR-SPIN Salerno, 84084 Fisciano, Italy

³ Department of Physical and Chemical Sciences, University of L’Aquila, and CNR-SPIN L’Aquila, 67100 L’Aquila, Italy

Nanomaterials 2018, 8(3), 151; https://doi.org/10.3390/nano8030151 - 8 Mar 2018

Cited by 77 | Viewed by 7239

Abstract

We report the electrical characterization and field emission properties of

{MoS}_{2}

bilayers deposited on a

{SiO}_{2} / Si

substrate. Current–voltage characteristics are measured in the back-gate transistor configuration, with

Ti

contacts patterned by electron beam lithography. We confirm the n-type character [...] Read more.

We report the electrical characterization and field emission properties of

{MoS}_{2}

bilayers deposited on a

{SiO}_{2} / Si

substrate. Current–voltage characteristics are measured in the back-gate transistor configuration, with

Ti

contacts patterned by electron beam lithography. We confirm the n-type character of as-grown

{MoS}_{2}

and we report normally-on field-effect transistors. Local characterization of field emission is performed inside a scanning electron microscope chamber with piezo-controlled tungsten tips working as the anode and the cathode. We demonstrate that an electric field of

~ 200 V / μ m

is able to extract current from the flat part of

{MoS}_{2}

bilayers, which can therefore be conveniently exploited for field emission applications even in low field enhancement configurations. We show that a Fowler–Nordheim model, modified to account for electron confinement in two-dimensional (2D) materials, fully describes the emission process. Full article

(This article belongs to the Special Issue Synthesis, Structure and Applications of 2D Nanomaterials)

▼ Show Figures

Graphical abstract

12 pages, 3406 KiB

Open AccessArticle

Ultra-Fine Bubble Distributions in a Plant Factory Observed by Transmission Electron Microscope with a Freeze-Fracture Replica Technique

by Tsutomu Uchida^1,*

, Hitoshi Nishikawa², Nobuki Sakurai², Masashi Asano³ and Naoki Noda²

¹ Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan

² Minamata Research Center, JNC Co., Minamata, Kumamoto 867-8501, Japan

³ Business Promotion Office, JNC Co., Chiyoda-ku, Tokyo 100-8105, Japan

Nanomaterials 2018, 8(3), 152; https://doi.org/10.3390/nano8030152 - 8 Mar 2018

Cited by 14 | Viewed by 5996

Abstract

Water containing ultra-fine bubbles (UFB) may promote plant growth. But, as UFBs are too small to distinguish from other impurities in a nutrient solution, it is not known if UFBs survive transport from the water source to the rhizosphere. Here we use the [...] Read more.

Water containing ultra-fine bubbles (UFB) may promote plant growth. But, as UFBs are too small to distinguish from other impurities in a nutrient solution, it is not known if UFBs survive transport from the water source to the rhizosphere. Here we use the freeze-fracture replica method and a transmission electron microscope (TEM) to observe UFBs in the nutrient solutions used in a crop-growing system known as a plant factory. In this factory, TEM images taken from various points in the supply line indicate that the concentration of UFBs in the nutrient solution is conserved, starting from their addition to the nutrient solution in the buffer tank, through the peat-moss layer, all the way to the rhizosphere. Measurements also show that a thin film formed on the surface of UFBs in the nutrient solution, with greater film thickness at the rhizosphere. This film is considered to be made from the accumulation of impurities coming from solute and the peat-moss layer. Full article

▼ Show Figures

Figure 1

14 pages, 14612 KiB

Open AccessArticle

Aqueous-Phase Hydrogenolysis of Glycerol over Re Promoted Ru Catalysts Encapuslated in Porous Silica Nanoparticles

by Kuo-Tseng Li^* and Ruey-Hsiang Yen

Department of Chemical Engineering, Tunghai University, 40704 Taichung, Taiwan

Nanomaterials 2018, 8(3), 153; https://doi.org/10.3390/nano8030153 - 9 Mar 2018

Cited by 16 | Viewed by 5838

Abstract

Activity improvement of Ru-based catalysts is needed for efficient production of valuable chemicals from glycerol hydrogenolysis. In this work, a series of Re promoted Ru catalysts encapuslated in porous silica nanoparticles (denoted as Re-Ru@SiO₂) were prepared by coating silica onto the [...] Read more.

Activity improvement of Ru-based catalysts is needed for efficient production of valuable chemicals from glycerol hydrogenolysis. In this work, a series of Re promoted Ru catalysts encapuslated in porous silica nanoparticles (denoted as Re-Ru@SiO₂) were prepared by coating silica onto the surface of chemically reduced Ru-polyvinylpyrrolidone colloids, and were used to catalyze the conversion of glycerol to diols and alcohols in water. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) were used to characterize these nanoparticles. Effects of Ru/Si atomic ratio, Re addition, glycerol and catalyst concentrations, reaction time, temperature, and hydrogen pressure were investigated. Re addition retarded the reduction of ruthenium oxide, but increased the catalyst reactivity for glycerol hydrogenolysis. Due to its greater Ru content, Re-Ru@ SiO₂ showed much better activity (reacted at much lower temperature) and more yields of 1,2-propanediol and overall liquid-phase products than Re-Ru/SiO₂ (prepared by conventional impregnation method) reported before. The rate of glycerol disappearance exhibited first-order dependence on glycerol concentration and hydrogen pressure, with an activation energy of 107.8 kJ/mol. The rate constant increased linearly with increasing Ru/Si atomic ratio and catalyst amount. The yield of overall liquid-phase products correlated well with glycerol conversion. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

▼ Show Figures

Figure 1

14 pages, 6046 KiB

Open AccessArticle

Chemical Synthesis of High-Stable Amorphous FeCo Nanoalloys with Good Magnetic Properties

by Bai Yang^*, Yue Wu, Xiaopan Li and Ronghai Yu

Key Laboratory of Aerospace Advanced Materials and Performance, Ministry of Education, School of Materials Science and Engineering, Beihang University, Beijing 100191, China

Nanomaterials 2018, 8(3), 154; https://doi.org/10.3390/nano8030154 - 9 Mar 2018

Cited by 30 | Viewed by 6352

Abstract

It is difficult to fabricate high-purity amorphous FeCo alloys by traditional physical methods due to their weak glass forming ability. In this work, the fully amorphous FeCo nanoalloys with high purity and good stability have been prepared by a direct chemical reduction of [...] Read more.

It is difficult to fabricate high-purity amorphous FeCo alloys by traditional physical methods due to their weak glass forming ability. In this work, the fully amorphous FeCo nanoalloys with high purity and good stability have been prepared by a direct chemical reduction of Fe²⁺ and Co²⁺ ions with NaBH₄ as the reducing agent and polyvinylpyrrolidone (PVP) as the surfactant. The morphologies, surface compositions and particle sizes with their distribution of these amorphous samples can be effectively tuned by the suitable PVP additions. High crystallization temperature up to 468 °C, high saturation magnetization of 196.2 A·m²·kg⁻¹ and low coercivity of 83.3 Oe are obtained in amorphous FeCo nanoalloys due to their uniform distribution, weak surface oxidation and low surface B concentration. Good frequency-dependent magnetic properties can be also achieved in the fully compacted amorphous sample with a high density of 7.20 g/cm³. The simple chemical method, high stability and good magnetic properties for these amorphous FeCo nanoalloys promise their significant potential applications in high-power magnetic devices. Full article

▼ Show Figures

Graphical abstract

13 pages, 978 KiB

Open AccessArticle

Microglial Immune Response to Low Concentrations of Combustion-Generated Nanoparticles: An In Vitro Model of Brain Health

by Cayla M. Duffy^1,2, Jacob Swanson^3,4, William Northrop⁴, Joshua P. Nixon^1,2 and Tammy A. Butterick^1,2,*

¹ Minneapolis Veterans Affairs Health Care System, Minneapolis, MN 55417, USA

² Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108, USA

³ Department of Integrated Engineering, Minnesota State University, Mankato, MN 56001, USA

⁴ Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA

Nanomaterials 2018, 8(3), 155; https://doi.org/10.3390/nano8030155 - 9 Mar 2018

Cited by 13 | Viewed by 4947

Abstract

The brain is the central regulator for integration and control of responses to environmental cues. Previous studies suggest that air pollution may directly impact brain health by triggering the onset of chronic neuroinflammation. We hypothesize that nanoparticle components of combustion-generated air pollution may [...] Read more.

The brain is the central regulator for integration and control of responses to environmental cues. Previous studies suggest that air pollution may directly impact brain health by triggering the onset of chronic neuroinflammation. We hypothesize that nanoparticle components of combustion-generated air pollution may underlie these effects. To test this association, a microglial in vitro biological sensor model was used for testing neuroinflammatory response caused by low-dose nanoparticle exposure. The model was first validated using 20 nm silver nanoparticles (AgNP). Next, neuroinflammatory response was tested after exposure to size-selected 20 nm combustion-generated nanoparticles (CGNP) collected from a modern diesel engine. We show that low concentrations of CGNPs promote low-grade inflammatory response indicated by increased pro-inflammatory cytokine release (tumor necrosis factor-α), similar to that observed after AgNP exposure. We also demonstrate increased production of reactive oxygen species and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65 phosphorylation in microglia after CGNP stimulation. Finally, we show conditioned media from CGNP-stimulated microglia significantly reduced hypothalamic neuronal survival in vitro. To our knowledge, this data show for the first time that exposure to AgNP and CGNP elicits microglial neuroinflammatory response through the activation of NF-κB. Full article

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

▼ Show Figures

Graphical abstract

20 pages, 5191 KiB

Open AccessArticle

Preparation and Characterization of WS₂@SiO₂ and WS₂@PANI Core-Shell Nanocomposites

by Hagit Sade and Jean-Paul Lellouche^*

Institute of Nanotechnology and Advanced Materials & Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel

Nanomaterials 2018, 8(3), 156; https://doi.org/10.3390/nano8030156 - 10 Mar 2018

Cited by 21 | Viewed by 7613

Abstract

Two tungsten disulfide (WS₂)-based core-shell nanocomposites were fabricated using readily available reagents and simple procedures. The surface was pre-treated with a surfactant couple in a layer-by-layer approach, enabling good dispersion of the WS₂ nanostructures in aqueous media and providing a [...] Read more.

Two tungsten disulfide (WS₂)-based core-shell nanocomposites were fabricated using readily available reagents and simple procedures. The surface was pre-treated with a surfactant couple in a layer-by-layer approach, enabling good dispersion of the WS₂ nanostructures in aqueous media and providing a template for the polymerization of a silica (SiO₂) shell. After a Stöber-like reaction, a conformal silica coating was achieved. Inspired by the resulting nanocomposite, a second one was prepared by reacting the surfactant-modified WS₂ nanostructures with aniline and an oxidizing agent in an aqueous medium. Here too, a conformal coating of polyaniline (PANI) was obtained, giving a WS₂@PANI nanocomposite. Both nanocomposites were analyzed by electron microscopy, energy dispersive X-ray spectroscopy (EDS) and FTIR, verifying the core-shell structure and the character of shells. The silica shell was amorphous and mesoporous and the surface area of the composite increases with shell thickness. Polyaniline shells slightly differ in their morphologies dependent on the acid used in the polymerization process and are amorphous like the silica shell. Electron paramagnetic resonance (EPR) spectroscopy of the WS₂@PANI nanocomposite showed variation between bulk PANI and the PANI shell. These two nanocomposites have great potential to expand the use of transition metals dichalcogenides (TMDCs) for new applications in different fields. Full article

(This article belongs to the Special Issue Nanomaterials with Functional Polymer Elements)

▼ Show Figures

Graphical abstract

10 pages, 2348 KiB

Open AccessArticle

Influence of InAlN Nanospiral Structures on the Behavior of Reflected Light Polarization

by Yu-Hung Kuo, Roger Magnusson, Elena Alexandra Serban

, Per Sandström, Lars Hultman, Kenneth Järrendahl

, Jens Birch

and Ching-Lien Hsiao^*

Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden

Nanomaterials 2018, 8(3), 157; https://doi.org/10.3390/nano8030157 - 12 Mar 2018

Cited by 3 | Viewed by 4479

Abstract

The influence of structural configurations of indium aluminum nitride (InAlN) nanospirals, grown by reactive magnetron sputter epitaxy, on the transformation of light polarization are investigated in terms of varying structural chirality, growth temperatures, titanium nitride (TiN) seed (buffer) layer thickness, nanospiral thickness, and [...] Read more.

The influence of structural configurations of indium aluminum nitride (InAlN) nanospirals, grown by reactive magnetron sputter epitaxy, on the transformation of light polarization are investigated in terms of varying structural chirality, growth temperatures, titanium nitride (TiN) seed (buffer) layer thickness, nanospiral thickness, and pitch. The handedness of reflected circularly polarized light in the ultraviolet–visible region corresponding to the chirality of nanospirals is demonstrated. A high degree of circular polarization (P_c) value of 0.75 is obtained from a sample consisting of 1.2 μm InAlN nanospirals grown at 650 °C. A film-like structure is formed at temperatures lower than 450 °C. At growth temperatures higher than 750 °C, less than 0.1 In-content is incorporated into the InAlN nanospirals. Both cases reveal very low P_c. A red shift of wavelength at P_c peak is found with increasing nanospiral pitch in the range of 200–300 nm. The P_c decreases to 0.37 for two-turn nanospirals with total length of 0.7 μm, attributed to insufficient constructive interference. A branch-like structure appears on the surface when the nanospirals are grown longer than 1.2 μm, which yields a low P_c around 0.5, caused by the excessive scattering of incident light. Full article

(This article belongs to the Special Issue Design and Development of Nanostructured Thin Films)

▼ Show Figures

Figure 1

13 pages, 3398 KiB

Open AccessArticle

A Comparison of the Effects of Packaging Containing Nano ZnO or Polylysine on the Microbial Purity and Texture of Cod (Gadus morhua) Fillets

by Małgorzata Mizielińska^*

, Urszula Kowalska, Michał Jarosz and Patrycja Sumińska

Center of Bioimmobilisation and Innovative Packaging Materials, Faculty of Food Sciences and Fisheries, West Pomeranian University of Technology Szczecin, Janickiego 35, 71-270 Szczecin, Poland

Nanomaterials 2018, 8(3), 158; https://doi.org/10.3390/nano8030158 - 12 Mar 2018

Cited by 43 | Viewed by 5370

Abstract

Portions of fresh Baltic cod fillets were packed into cellulose boxes (control samples), which were covered with Methyl Hydroxypropyl Celluloses (MHPC) coating with 2% polylysine. The cellulose boxes had square PE films and were enclosed in MHPC coating containing ZnO nanoparticles. The cod [...] Read more.

Portions of fresh Baltic cod fillets were packed into cellulose boxes (control samples), which were covered with Methyl Hydroxypropyl Celluloses (MHPC) coating with 2% polylysine. The cellulose boxes had square PE films and were enclosed in MHPC coating containing ZnO nanoparticles. The cod fillets were stored at 5 °C and examined after 72 h and 144 h storage times. Results obtained in this study showed that the textural parameters of the cod fillets increased, with both Springiness and Cohesiveness found greater after 144 h of storage for all analysed packaging materials. The Gumminess of fillets increased after storage, but the lowest increase was noted in cod samples that were stored in boxes containing PE films with ZnO nanoparticles. It was found that water loss from the cod fillets in these boxes was also lowest. The Adhesiveness of the fish samples stored in boxes devoid of active coatings also increased. In contrast to the packaging material devoid of active coatings, the storage of fillets in active coating boxes resulted in a decrease of adhesiveness. Microbial analysis showed that packaging material containing nano-ZnO was found to be more active against mesophilic and psychotropic bacterial cells than the coatings with polylysine after 72 h and 144 h of storage. Full article

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

▼ Show Figures

Graphical abstract

13 pages, 6258 KiB

Open AccessArticle

Sustained Cytotoxicity of Wogonin on Breast Cancer Cells by Encapsulation in Solid Lipid Nanoparticles

by Jong-Suep Baek, Young-Guk Na

and Cheong-Weon Cho^*

College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea

Nanomaterials 2018, 8(3), 159; https://doi.org/10.3390/nano8030159 - 13 Mar 2018

Cited by 55 | Viewed by 6089

Abstract

While wogonin has been known to have cytotoxicity against various cancer cells, its bioavailability and cytotoxicity are low due to its low water solubility. Therefore, wogonin-loaded solid lipid nanoparticles were fabricated using a hot-melted evaporation technique. The highest solubility of wogonin was observed [...] Read more.

While wogonin has been known to have cytotoxicity against various cancer cells, its bioavailability and cytotoxicity are low due to its low water solubility. Therefore, wogonin-loaded solid lipid nanoparticles were fabricated using a hot-melted evaporation technique. The highest solubility of wogonin was observed in stearic acid. Hence, wogonin-loaded solid lipid nanoparticles were composed of stearic acid as the lipid matrix. The physicochemical properties of the wogonin-loaded solid lipid nanoparticles were evaluated by dynamic laser scattering and scanning electron microscopy. The wogonin-loaded solid lipid nanoparticles exhibited sustained and controlled release up to 72 h. In addition, it was observed that the wogonin-loaded solid lipid nanoparticles exhibited enhanced cytotoxicity and inhibited poly (ADP-ribose) polymerase in MCF-7 breast cancer cells. Overall, the results indicate that wogonin-loaded solid lipid nanoparticles could be an efficient delivery system for the treatment of breast cancer. Full article

▼ Show Figures

Figure 1

29 pages, 1506 KiB

Open AccessArticle

In Vitro and In Vivo Short-Term Pulmonary Toxicity of Differently Sized Colloidal Amorphous SiO₂

by Martin Wiemann^1,*, Ursula G. Sauer², Antje Vennemann¹, Sandra Bäcker³, Johannes-Georg Keller⁴

, Lan Ma-Hock⁵, Wendel Wohlleben⁴

and Robert Landsiedel⁵

¹ IBR R&D gGmbH Institute for Lung Health, Mendelstr. 11, 48149 Münster, Germany

² Scientific Consultancy—Animal Welfare, 85579 Neubiberg, Germany

³ BASF SE, Human Biomonitoring and Industrial Hygiene, 67056 Ludwigshafen, Germany

⁴ BASF SE, Advanced Materials Research, 67056 Ludwigshafen, Germany

⁵ BASF SE, Experimental Toxicology and Ecology, 67056 Ludwigshafen, Germany

Nanomaterials 2018, 8(3), 160; https://doi.org/10.3390/nano8030160 - 13 Mar 2018

Cited by 25 | Viewed by 6270

Abstract

In vitro prediction of inflammatory lung effects of well-dispersed nanomaterials is challenging. Here, the in vitro effects of four colloidal amorphous SiO₂ nanomaterials that differed only by their primary particle size (9, 15, 30, and 55 nm) were analyzed using the rat [...] Read more.

In vitro prediction of inflammatory lung effects of well-dispersed nanomaterials is challenging. Here, the in vitro effects of four colloidal amorphous SiO₂ nanomaterials that differed only by their primary particle size (9, 15, 30, and 55 nm) were analyzed using the rat NR8383 alveolar macrophage (AM) assay. Data were compared to effects of single doses of 15 nm and 55 nm SiO₂ intratracheally instilled in rat lungs. In vitro, all four elicited the release of concentration-dependent lactate dehydrogenase, β-glucuronidase, and tumor necrosis factor alpha, and the two smaller materials also released H₂O₂. All effects were size-dependent. Since the colloidal SiO₂ remained well-dispersed in serum-free in vitro conditions, effective particle concentrations reaching the cells were estimated using different models. Evaluating the effective concentration–based in vitro effects using the Decision-making framework for the grouping and testing of nanomaterials, all four nanomaterials were assigned as “active.” This assignment and the size dependency of effects were consistent with the outcomes of intratracheal instillation studies and available short-term rat inhalation data for 15 nm SiO₂. The study confirms the applicability of the NR8383 AM assay to assessing colloidal SiO₂ but underlines the need to estimate and consider the effective concentration of such well-dispersed test materials. Full article

▼ Show Figures

Graphical abstract

15 pages, 24924 KiB

Open AccessArticle

Understanding the Effects of NaCl, NaBr and Their Mixtures on Silver Nanowire Nucleation and Growth in Terms of the Distribution of Electron Traps in Silver Halide Crystals

by Yunjun Rui^1,2,*, Weiliang Zhao¹, Dewei Zhu², Hengyu Wang¹, Guangliang Song³, Mark T. Swihart^2,*, Neng Wan⁴, Dawei Gu¹, Xiaobing Tang¹, Ying Yang¹ and Tianyou Zhang¹

¹ Department of Applied Physics, Nanjing Tech University, Nanjing 210009, China

² Department of Chemical and Biological Engineering, University at Buffalo (SUNY), Buffalo, New York, NY 14260, USA

³ College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 210009, China

⁴ School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China

Nanomaterials 2018, 8(3), 161; https://doi.org/10.3390/nano8030161 - 14 Mar 2018

Cited by 30 | Viewed by 9167

Abstract

In recent years, many research groups have synthesized ultra-thin silver nanowires (AgNWs) with diameters below 30 nm by employing Cl⁻ and Br⁻ simultaneously in the polyol process. However, the yield of AgNWs in this method was low, due to the production [...] Read more.

In recent years, many research groups have synthesized ultra-thin silver nanowires (AgNWs) with diameters below 30 nm by employing Cl⁻ and Br⁻ simultaneously in the polyol process. However, the yield of AgNWs in this method was low, due to the production of Ag nanoparticles (AgNPs) as an unwanted byproduct, especially in the case of high Br⁻ concentration. Here, we investigated the roles of Cl⁻ and Br⁻ in the preparation of AgNWs and then synthesized high aspect ratio (up to 2100) AgNWs in high yield (>85% AgNWs) using a Cl⁻ and Br⁻ co-mediated method. We found that multiply-twinned particles (MTPs) with different critical sizes were formed and grew into AgNWs, accompanied by a small and large amount of AgNPs for the NaCl and NaBr additives, respectively. For the first time, we propose that the growth of AgNWs of different diameters and yields can be understood based on the electron trap distribution (ETD) of the silver halide crystals. For the case of Cl⁻ and Br⁻ co-additives, a mixed silver halide crystal of AgBr_1−xCl_x was formed, rather than the AgBr/AgCl mixture reported previously. In this type of crystal, the ETD is uniform, which is beneficial for the synthesis of AgNWs with small diameter (30~40 nm) and high aspect ratio. AgNW transparent electrodes were prepared in air by rod coating. A sheet resistance of 48 Ω/sq and transmittance of 95% at 550 nm were obtained without any post-treatment. Full article

(This article belongs to the Special Issue Synthesis and Characterization of Nanowires)

▼ Show Figures

Figure 1

16 pages, 5781 KiB

Open AccessArticle

One-Step Fabrication of Dual Responsive Lignin Coated Fe₃O₄ Nanoparticles for Efficient Removal of Cationic and Anionic Dyes

by Xingang Li^1,2,3, Youyi He^1,2, Hong Sui^1,2,3 and Lin He^1,2,*

¹ School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China

² National Engineering Research Centre for Distillation Technology, Tianjin 300072, China

³ Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China

Nanomaterials 2018, 8(3), 162; https://doi.org/10.3390/nano8030162 - 14 Mar 2018

Cited by 77 | Viewed by 7755

Abstract

A new, simple one-step approach has been developed to synthesize lignin and lignin amine coated Fe₃O₄ nanoparticles. These nanoparticles (lignin magnetic nanoparticles (LMNPs) and lignin amine magnetic nanoparticles (LAMNPs)) are found to possess not only magnetic response but also pH-dependent [...] Read more.

A new, simple one-step approach has been developed to synthesize lignin and lignin amine coated Fe₃O₄ nanoparticles. These nanoparticles (lignin magnetic nanoparticles (LMNPs) and lignin amine magnetic nanoparticles (LAMNPs)) are found to possess not only magnetic response but also pH-dependent adsorption behavior. Results show that the combination of lignin with nanoparticles increased the adsorption capacities 2–5 times higher than other traditional single lignin based adsorbents (211.42 mg/g for methylene blue (MB) by LMNPs and 176.49 mg/g for acid scarlet GR (AS-GR) by LAMNPs). Meanwhile, by simply adjusting the pH, the dye-loaded adsorbents can be regenerated to recycle both adsorbents and dyes with a desorption efficiency up to 90%. Mechanistic study shows that dye structure and surface charges of adsorbents play the most important part in adsorption where dyes interact with the adsorbent surface via π–π stacking and electrostatic attraction interactions. The efficient fabrication method, eco-friendly reactant, quick magnetic separation, high adsorption and desorption efficiency suggest this novel type of nano-adsorbents to be promising materials for efficient dye pollutant removal and recovery. Full article

▼ Show Figures

Graphical abstract

15 pages, 6257 KiB

Open AccessArticle

The Preparation of Graphene Oxide-Silver Nanocomposites: The Effect of Silver Loads on Gram-Positive and Gram-Negative Antibacterial Activities

by Truong Thi Tuong Vi¹, Selvaraj Rajesh Kumar¹

, Bishakh Rout², Chi-Hsien Liu²

, Chak-Bor Wong³, Chia-Wei Chang³, Chien-Hao Chen³, Dave W. Chen^3,* and Shingjiang Jessie Lue^1,4,5,*

¹ Department of Chemical and Materials Engineering and Green Technology Research Center, Chang Gung University, Taoyuan City 333, Taiwan

² Department of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan City 333, Taiwan

³ Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Keelung City 204, Taiwan

⁴ Department of Safety, Health and Environment Engineering, Ming-Chi University of Technology, New Taipei City 243, Taiwan

⁵ Department of Radiation Oncology, Chang Gung Memorial Hospital, Taoyuan City 333, Taiwan

Nanomaterials 2018, 8(3), 163; https://doi.org/10.3390/nano8030163 - 14 Mar 2018

Cited by 77 | Viewed by 9663

Abstract

In this work, silver nanoparticles (Ag NPs) were decorated on thiol (–SH) grafted graphene oxide (GO) layers to investigate the antibacterial activities in Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Pseudomonas aeruginosa). The quasi-spherical, nano-sized Ag NPs were attached [...] Read more.

In this work, silver nanoparticles (Ag NPs) were decorated on thiol (–SH) grafted graphene oxide (GO) layers to investigate the antibacterial activities in Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Pseudomonas aeruginosa). The quasi-spherical, nano-sized Ag NPs were attached to the GO surface layers, as confirmed by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. The average size of GO-Ag nanocomposites was significantly reduced (327 nm) from those of pristine GO (962 nm) while the average size of loaded Ag NPs was significantly smaller than the Ag NPs without GO. Various concentrations of AgNO₃ solutions (0.1, 0.2, and 0.25 M) were loaded into GO nanosheets and resulted in the Ag contents of 31, 43, and 65%, respectively, with 1–2 nm sizes of Ag NPs anchored on the GO layers. These GO-Ag samples have negative surface charges but the GO-Ag 0.2 M sample (43% Ag) demonstrated the highest antibacterial efficiency. At 10 ppm load of GO-Ag suspension, only a GO-Ag 0.2 M sample yielded slight bacterial inhibition (5.79–7.82%). As the GO-Ag content was doubled to 20 ppm, the GO-Ag 0.2 M composite exhibited ~49% inhibition. When the GO-Ag 0.2 M composite level was raised to 100 ppm, almost 100% inhibition efficiencies were found on both Staphylococcus aureus (S.A.) and Pseudomonas aeruginosa (P.A.), which were significantly higher than using pristine GO (27% and 33% for S.A. and P.A.). The combined effect of GO and Ag nanoparticles demonstrate efficient antibacterial activities. Full article

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

▼ Show Figures

Graphical abstract

11 pages, 3025 KiB

Open AccessArticle

Enhancing the Microparticle Deposition Stability and Homogeneity on Planer for Synthesis of Self-Assembly Monolayer

by An-Ci Shih, Chi-Jui Han, Tsung-Cheng Kuo and Yun-Chien Cheng^*

Department of Mechanical Engineering, National Chiao Tung University, Hsinchu 300, Taiwan

Nanomaterials 2018, 8(3), 164; https://doi.org/10.3390/nano8030164 - 14 Mar 2018

Cited by 3 | Viewed by 4037

Abstract

The deposition stability and homogeneity of microparticles improved with mask, lengthened nozzle and flow rate adjustment. The microparticles can be used to encapsulate monomers, before the monomers in the microparticles can be deposited onto a substrate for nanoscale self-assembly. For the uniformity of [...] Read more.

The deposition stability and homogeneity of microparticles improved with mask, lengthened nozzle and flow rate adjustment. The microparticles can be used to encapsulate monomers, before the monomers in the microparticles can be deposited onto a substrate for nanoscale self-assembly. For the uniformity of the synthesized nanofilm, the homogeneity of the deposited microparticles becomes an important issue. Based on the ANSYS simulation results, the effects of secondary flow were minimized with a lengthened nozzle. The ANSYS simulation was also used to investigate the ring-vortex generation and why the ring vortex can be eliminated by adding a mask with an aperture between the nozzle and deposition substrate. The experimental results also showed that particle deposition with a lengthened nozzle was more stable, while adding the mask stabilized deposition and diminished the ring-vortex contamination. The effects of flow rate and pressure were also investigated. Hence, the deposition stability and homogeneity of microparticles was improved. Full article

(This article belongs to the Special Issue Design and Development of Nanostructured Thin Films)

▼ Show Figures

Figure 1

17 pages, 6612 KiB

Open AccessArticle

The Effect of Laminin Surface Modification of Electrospun Silica Nanofiber Substrate on Neuronal Tissue Engineering

by Wen Shuo Chen¹, Ling Yu Guo¹, Chia Chun Tang¹, Cheng Kang Tsai¹, Hui Hua Huang¹, Ting Yu Chin², Mong-Lin Yang^3,*

and Yui Whei Chen-Yang^1,*

¹ Center for Nanotechnology, Center for Biomedical Technology, Department of Chemistry, Chung Yuan Christian University, Taoyuan 32023, Taiwan

² Department of Bioscience Technology, Chung Yuan Christian University, Taoyuan 32023, Taiwan

³ Department of Science, Concordia University Saint Paul, Saint Paul, MN 55104, USA

Nanomaterials 2018, 8(3), 165; https://doi.org/10.3390/nano8030165 - 14 Mar 2018

Cited by 31 | Viewed by 7077

Abstract

In this study, we first synthesized a slow-degrading silica nanofiber (SNF2) through an electrospun solution with an optimized tetraethyl orthosilicate (TEOS) to polyvinyl pyrrolidone (PVP) ratio. Then, laminin-modified SNF2, namely SNF2-AP-S-L, was obtained through a series of chemical reactions to attach the extracellular [...] Read more.

In this study, we first synthesized a slow-degrading silica nanofiber (SNF2) through an electrospun solution with an optimized tetraethyl orthosilicate (TEOS) to polyvinyl pyrrolidone (PVP) ratio. Then, laminin-modified SNF2, namely SNF2-AP-S-L, was obtained through a series of chemical reactions to attach the extracellular matrix protein, laminin, to its surface. The SNF2-AP-S-L substrate was characterized by a combination of scanning electron microscopy (SEM), Fourier transform–infrared (FTIR) spectroscopy, nitrogen adsorption/desorption isotherms, and contact angle measurements. The results of further functional assays show that this substrate is a biocompatible, bioactive and biodegradable scaffold with good structural integrity that persisted beyond 18 days. Moreover, a synergistic effect of sustained structure support and prolonged biochemical stimulation for cell differentiation on SNF2-AP-S-L was found when neuron-like PC12 cells were seeded onto its surface. Specifically, neurite extensions on the covalently modified SNF2-AP-S-L were significantly longer than those observed on unmodified SNF and SNF subjected to physical adsorption of laminin. Together, these results indicate that the SNF2-AP-S-L substrate prepared in this study is a promising 3D biocompatible substrate capable of sustaining longer neuronal growth for tissue-engineering applications. Full article

(This article belongs to the Special Issue Functional Nanomaterials by Electrospinning)

▼ Show Figures

Graphical abstract

16 pages, 9528 KiB

Open AccessArticle

The Hydrolytic Stability and Degradation Mechanism of a Hierarchically Porous Metal Alkylphosphonate Framework

by Kai Lv^*, Chu-Ting Yang, Yi Liu, Sheng Hu and Xiao-Lin Wang

Radiochemistry Lab, Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, P.O. Box 919, Mianyang 621900, Sichuan, China

Nanomaterials 2018, 8(3), 166; https://doi.org/10.3390/nano8030166 - 14 Mar 2018

Cited by 8 | Viewed by 4631

Abstract

To aid the design of a hierarchically porous unconventional metal-phosphonate framework (HP-UMPF) for practical radioanalytical separation, a systematic investigation of the hydrolytic stability of bulk phase against acidic corrosion has been carried out for an archetypical HP-UMPF. Bulk dissolution results suggest that aqueous [...] Read more.

To aid the design of a hierarchically porous unconventional metal-phosphonate framework (HP-UMPF) for practical radioanalytical separation, a systematic investigation of the hydrolytic stability of bulk phase against acidic corrosion has been carried out for an archetypical HP-UMPF. Bulk dissolution results suggest that aqueous acidity has a more paramount effect on incongruent leaching than the temperature, and the kinetic stability reaches equilibrium by way of an accumulation of a partial leached species on the corrosion conduits. A variation of particle morphology, hierarchical porosity and backbone composition upon corrosion reveals that they are hydrolytically resilient without suffering any great degradation of porous texture, although large aggregates crack into sporadic fractures while the nucleophilic attack of inorganic layers cause the leaching of tin and phosphorus. The remaining selectivity of these HP-UMPFs is dictated by a balance between the elimination of free phosphonate and the exposure of confined phosphonates, thus allowing a real-time tailor of radionuclide sequestration. Moreover, a plausible degradation mechanism has been proposed for the triple progressive dissolution of three-level hierarchical porous structures to elucidate resultant reactivity. These HP-UMPFs are compared with benchmark metal-organic frameworks (MOFs) to obtain a rough grading of hydrolytic stability and two feasible approaches are suggested for enhancing their hydrolytic stability that are intended for real-life separation protocols. Full article

▼ Show Figures

Graphical abstract

18 pages, 19004 KiB

Open AccessArticle

A Modular Coassembly Approach to All-In-One Multifunctional Nanoplatform for Synergistic Codelivery of Doxorubicin and Curcumin

by Muyang Yang^1,2,3, Lixia Yu^1,2, Ruiwei Guo^1,2, Anjie Dong^1,2, Cunguo Lin³ and Jianhua Zhang^1,4,*

¹ Department of Polymer Science and Technology, Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China

² Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China

³ State Key Laboratory for Marine Corrosion and Protection, Luoyang Ship Material Research Institute (LSMRI), Qingdao 266101, China

⁴ Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072, China

Nanomaterials 2018, 8(3), 167; https://doi.org/10.3390/nano8030167 - 15 Mar 2018

Cited by 30 | Viewed by 6009

Abstract

Synergistic combination therapy by integrating chemotherapeutics and chemosensitizers into nanoparticles has demonstrated great potential to reduce side effects, overcome multidrug resistance (MDR), and thus improve therapeutic efficacy. However, with regard to the nanocarriers for multidrug codelivery, it remains a strong challenge to maintain [...] Read more.

Synergistic combination therapy by integrating chemotherapeutics and chemosensitizers into nanoparticles has demonstrated great potential to reduce side effects, overcome multidrug resistance (MDR), and thus improve therapeutic efficacy. However, with regard to the nanocarriers for multidrug codelivery, it remains a strong challenge to maintain design simplicity, while incorporating the desirable multifunctionalities, such as coloaded high payloads, targeted delivery, hemodynamic stability, and also to ensure low drug leakage before reaching the tumor site, but simultaneously the corelease of drugs in the same cancer cell. Herein, we developed a facile modular coassembly approach to construct an all-in-one multifunctional multidrug delivery system for the synergistic codelivery of doxorubicin (DOX, chemotherapeutic agent) and curcumin (CUR, MDR modulator). The acid-cleavable PEGylated polymeric prodrug (DOX-h-PCEC), tumor cell-specific targeting peptide (CRGDK-PEG-PCL), and natural chemosensitizer (CUR) were ratiometrically assembled into in one single nanocarrier (CUR/DOX-h-PCEC@CRGDK NPs). The resulting CUR/DOX-h-PCEC@CRGDK NPs exhibited several desirable characteristics, such as efficient and ratiometric drug loading, high hemodynamic stability and low drug leakage, tumor intracellular acid-triggered cleavage, and subsequent intracellular simultaneous drug corelease, which are expected to maximize a synergistic effect of chemotherapy and chemosensitization. Collectively, the multifunctional nanocarrier is feasible for the creation of a robust nanoplatform for targeted multidrug codelivery and efficient MDR modulation. Full article

(This article belongs to the Special Issue Self-Assembled Bio-Nanomaterials: Synthesis, Characterization, and Applications)

▼ Show Figures

Figure 1

19 pages, 7291 KiB

Open AccessArticle

Supramolecular Control over the Interparticle Distance in Gold Nanoparticle Arrays by Cyclodextrin Polyrotaxanes

by Joao Paulo Coelho¹, José Osío Barcina², Elena Junquera¹

, Emilio Aicart¹, Gloria Tardajos¹, Sergio Gómez-Graña³

, Pablo Cruz-Gil², Cástor Salgado², Pablo Díaz-Núñez⁴, Ovidio Peña-Rodríguez⁴

and Andrés Guerrero-Martínez^1,*

¹ Departamento de Química Física, Universidad Complutense de Madrid, Avenida Complutense s/n, 28040 Madrid, Spain

² Departamento de Química Orgánica, Universidad Complutense de Madrid, Avenida Complutense s/n, 28040 Madrid, Spain

³ Departamento de Química en Ciencias Farmacéuticas, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain

⁴ Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, 28006 Madrid, Spain

Nanomaterials 2018, 8(3), 168; https://doi.org/10.3390/nano8030168 - 16 Mar 2018

Cited by 9 | Viewed by 6639

Abstract

Amphiphilic nonionic ligands, synthesized with a fixed hydrophobic moiety formed by a thiolated alkyl chain and an aromatic ring, and with a hydrophilic tail composed of a variable number of oxyethylene units, were used to functionalize spherical gold nanoparticles (AuNPs) in water. Steady-state [...] Read more.

Amphiphilic nonionic ligands, synthesized with a fixed hydrophobic moiety formed by a thiolated alkyl chain and an aromatic ring, and with a hydrophilic tail composed of a variable number of oxyethylene units, were used to functionalize spherical gold nanoparticles (AuNPs) in water. Steady-state and time-resolved fluorescence measurements of the AuNPs in the presence of α-cyclodextrin (α-CD) revealed the formation of supramolecular complexes between the ligand and macrocycle at the surface of the nanocrystals. The addition of α-CD induced the formation of inclusion complexes with a high apparent binding constant that decreased with the increasing oxyethylene chain length. The formation of polyrotaxanes at the surface of AuNPs, in which many α-CDs are trapped as hosts on the long and linear ligands, was demonstrated by the formation of large and homogeneous arrays of self-assembled AuNPs with hexagonal close packing, where the interparticle distance increased with the length of the oxyethylene chain. The estimated number of α-CDs per polyrotaxane suggests a high rigidization of the ligand upon complexation, allowing for nearly perfect control of the interparticle distance in the arrays. This degree of supramolecular control was extended to arrays formed by AuNPs stabilized with polyethylene glycol and even to binary arrays. Electromagnetic simulations showed that the enhancement and distribution of the electric field can be finely controlled in these plasmonic arrays. Full article

(This article belongs to the Special Issue Supramolecular Nano-architectures)

▼ Show Figures

Graphical abstract

10 pages, 1580 KiB

Open AccessArticle

Strongly Iridescent Hybrid Photonic Sensors Based on Self-Assembled Nanoparticles for Hazardous Solvent Detection

by Ayaka Sato, Yuya Ikeda, Koichi Yamaguchi and Varun Vohra^*

Department of Engineering Science, the University of Electro-communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan

Nanomaterials 2018, 8(3), 169; https://doi.org/10.3390/nano8030169 - 16 Mar 2018

Cited by 10 | Viewed by 5278

Abstract

Facile detection and the identification of hazardous organic solvents are essential for ensuring global safety and avoiding harm to the environment caused by industrial wastes. Here, we present a simple method for the fabrication of silver-coated monodisperse polystyrene nanoparticle photonic structures that are [...] Read more.

Facile detection and the identification of hazardous organic solvents are essential for ensuring global safety and avoiding harm to the environment caused by industrial wastes. Here, we present a simple method for the fabrication of silver-coated monodisperse polystyrene nanoparticle photonic structures that are embedded into a polydimethylsiloxane (PDMS) matrix. These hybrid materials exhibit a strong green iridescence with a reflectance peak at 550 nm that originates from the close-packed arrangement of the nanoparticles. This reflectance peak measured under Wulff-Bragg conditions displays a 20 to 50 nm red shift when the photonic sensors are exposed to five commonly employed and highly hazardous organic solvents. These red-shifts correlate well with PDMS swelling ratios using the various solvents, which suggests that the observable color variations result from an increase in the photonic crystal lattice parameter with a similar mechanism to the color modulation of the chameleon skin. Dynamic reflectance measurements enable the possibility of clearly identifying each of the tested solvents. Furthermore, as small amounts of hazardous solvents such as tetrahydrofuran can be detected even when mixed with water, the nanostructured solvent sensors we introduce here could have a major impact on global safety measures as innovative photonic technology for easily visualizing and identifying the presence of contaminants in water. Full article

(This article belongs to the Special Issue Design and Development of Nanostructured Thin Films)

▼ Show Figures

Graphical abstract

17 pages, 10059 KiB

Open AccessArticle

Cyclodextrin-Based Magnetic Nanoparticles for Cancer Therapy

by Radosław Mrówczyński^1,*

, Artur Jędrzak^1,2, Kosma Szutkowski^1,*

, Bartosz F. Grześkowiak¹, Emerson Coy¹

, Roksana Markiewicz¹

, Teofil Jesionowski²

and Stefan Jurga¹

¹ NanoBioMedical Centre, Adam Mickiewicz University in Poznan, Umultowska 85, PL-61614 Poznan, Poland

² Faculty of Chemical Technology, Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, PL-60965 Poznan, Poland

Nanomaterials 2018, 8(3), 170; https://doi.org/10.3390/nano8030170 - 16 Mar 2018

Cited by 70 | Viewed by 7932

Abstract

Polydopamine (PDA)-coated magnetic nanoparticles functionalized with mono-6-thio-β-cyclodextrin (SH-βCD) were obtained and characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Nuclear and Magnetic Resonance Imaging (NMR and MRI), and doxorubicin (DOXO)-loading experiments. The liver cancer cellular internalization [...] Read more.

Polydopamine (PDA)-coated magnetic nanoparticles functionalized with mono-6-thio-β-cyclodextrin (SH-βCD) were obtained and characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Nuclear and Magnetic Resonance Imaging (NMR and MRI), and doxorubicin (DOXO)-loading experiments. The liver cancer cellular internalization of DOXO-loaded nanoparticles was investigated by confocal imaging microscopy. Synthesized nanomaterials bearing a chemotherapeutic drug and a layer of polydopamine capable of absorbing near-infrared light show high performance in the combined chemo- and photothermal therapy (CT-PTT) of liver cancer due to the synergistic effect of both modalities as demonstrated in vitro. Moreover, our material exhibits improved T₂ contrast properties, which have been verified using Carr-Purcell-Meiboom-Gill pulse sequence and MRI Spin-Echo imaging of the nanoparticles dispersed in the agarose gel phantoms. Therefore, the presented results cast new light on the preparation of polydopamine-based magnetic theranostic nanomaterials, as well as on the proper methodology for investigation of magnetic nanoparticles in high field MRI experiments. The prepared material is a robust theranostic nanoasystem with great potential in nanomedicine. Full article

▼ Show Figures

Graphical abstract

8 pages, 1386 KiB

Open AccessArticle

Investigation on the Stability of Derivative Melam from Melamine Pyrolysis under High Pressure

by Xiaohong Yuan¹, Kun Luo^1,2

, Yingju Wu¹, Julong He¹, Zhisheng Zhao^1,*

and Dongli Yu^1,*

¹ State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China

² Hebei Key Laboratory of Microstructural Material Physics, School of Science, Yanshan University, Qinhuangdao 066004, China

Nanomaterials 2018, 8(3), 172; https://doi.org/10.3390/nano8030172 - 18 Mar 2018

Cited by 26 | Viewed by 6804

Abstract

Although various kinds of carbon nitride precursors have been proposed, s-triazine-based structures are hardly reported because of their unfavorable energy, higher than that of heptazine-based ones. In this study, we investigate the thermal stability of s-triazine-based melam processed at a high pressure of [...] Read more.

Although various kinds of carbon nitride precursors have been proposed, s-triazine-based structures are hardly reported because of their unfavorable energy, higher than that of heptazine-based ones. In this study, we investigate the thermal stability of s-triazine-based melam processed at a high pressure of 5 GPa and a temperature of 400–700 °C and complete the analyses of the composition and structure of the treated samples through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and elemental analyses (EA). Results show that melam can stably exist up to 600 °C at 5 GPa. XRD and FTIR analyses reveal that residual melamine can be pyrolyzed into melam as temperature increases from 400 °C to 600 °C at a high pressure, suggesting that melam may be purified through high-pressure pyrolysis. Further melam polymerization at a higher pressure is a promising strategy for the preparation of s-triazine-based carbon nitride precursors used for bulk carbon nitride synthesis. Full article

(This article belongs to the Special Issue Graphitic Carbon Nitride Nanostructures: Catalysis and Beyond)

▼ Show Figures

Figure 1

13 pages, 3214 KiB

Open AccessArticle

The Adsorption of Dextranase onto Mg/Fe-Layered Double Hydroxide: Insight into the Immobilization

by Yi Ding^1,2,3, Le Liu^1,2,3, Yaowei Fang^1,2,3, Xu Zhang⁴, Mingsheng Lyu^1,2,3,* and Shujun Wang^1,2,3,*

¹ College of Marine Life and Fisheries, Huaihai Institute of Technology, Lianyungang 222005, China

² Jiangsu Institute of Marine Resources Development, Huaihai Institute of Technology, Lianyungang 222005, China

³ Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Huaihai Institute of Technology, Lianyungang 222005, China

⁴ Verschuren Centre for Sustainability in Energy & the Environment, Cape Breton University, Sydney, NS B1P 6L2, Canada

Nanomaterials 2018, 8(3), 173; https://doi.org/10.3390/nano8030173 - 19 Mar 2018

Cited by 19 | Viewed by 5325

Abstract

We report the adsorption of dextranase on a Mg/Fe-layered double hydroxide (Mg/Fe-LDH). We focused the effects of different buffers, pH, and amino acids. The Mg/Fe-LDH was synthesized, and adsorption experiments were performed to investigate the effects. The maximum adsorption occurred in pH 7.0 [...] Read more.

We report the adsorption of dextranase on a Mg/Fe-layered double hydroxide (Mg/Fe-LDH). We focused the effects of different buffers, pH, and amino acids. The Mg/Fe-LDH was synthesized, and adsorption experiments were performed to investigate the effects. The maximum adsorption occurred in pH 7.0 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer, and the maximum dextranase adsorption uptake was 1.38 mg/g (416.67 U/mg); histidine and phenylalanine could affect the adsorption. A histidine tag could be added to the protein to increase the adsorption significantly. The performance features and mechanism were investigated with X-ray diffraction patterns (XRD) and Fourier transform infrared spectra (FTIR). The protein could affect the crystal structure of LDH, and the enzyme was adsorbed on the LDH surface. The main interactions between the protein and LDH were electrostatic and hydrophobic. Histidine and phenylalanine could significantly affect the adsorption. The hexagonal morphology of LDH was not affected after adsorption. Full article

(This article belongs to the Special Issue Layered Double Hydroxide-Based Nanomaterials – From Fundamentals to Applications)

▼ Show Figures

Figure 1

15 pages, 4653 KiB

Open AccessArticle

Synthesis of Gold Nanoparticles Using Leaf Extract of Ziziphus zizyphus and their Antimicrobial Activity

by Alaa A. A. Aljabali^1,*

, Yazan Akkam¹, Mazhar Salim Al Zoubi²

, Khalid M. Al-Batayneh³

, Bahaa Al-Trad³

, Osama Abo Alrob¹, Alaaldin M. Alkilany⁴, Mourad Benamara⁵ and David J. Evans⁶

¹ Faculty of Pharmacy, Yarmouk University, P.O.BOX 566, Irbid 21163, Jordan

² Department of Basic Medical Sciences, Faculty of Medicine, Yarmouk University, Irbid 21163, Jordan

³ Department of Biological Science, Yarmouk University, P.O.BOX 566, Irbid 21163, Jordan

⁴ School of Pharmacy, University of Jordan, Aljubeiha, Amman, Jordan 11942, Jordan

⁵ Institute for Nanoscience, University of Arkansas, Fayetteville, AR 72701, USA

⁶ John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK

Nanomaterials 2018, 8(3), 174; https://doi.org/10.3390/nano8030174 - 19 Mar 2018

Cited by 296 | Viewed by 14488

Abstract

(1) Background: There is a growing need for the development of new methods for the synthesis of nanoparticles. The interest in such particles has raised concerns about the environmental safety of their production methods; (2) Objectives: The current methods of nanoparticle production are [...] Read more.

(1) Background: There is a growing need for the development of new methods for the synthesis of nanoparticles. The interest in such particles has raised concerns about the environmental safety of their production methods; (2) Objectives: The current methods of nanoparticle production are often expensive and employ chemicals that are potentially harmful to the environment, which calls for the development of “greener” protocols. Herein we describe the synthesis of gold nanoparticles (AuNPs) using plant extracts, which offers an alternative, efficient, inexpensive, and environmentally friendly method to produce well-defined geometries of nanoparticles; (3) Methods: The phytochemicals present in the aqueous leaf extract acted as an effective reducing agent. The generated AuNPs were characterized by Transmission electron microscopy (TEM), Scanning electron microscope (SEM), and Atomic Force microscopy (AFM), X-ray diffraction (XRD), UV-visible spectroscopy, energy dispersive X-ray (EDX), and thermogravimetric analyses (TGA); (4) Results and Conclusions: The prepared nanoparticles were found to be biocompatible and exhibited no antimicrobial or antifungal effect, deeming the particles safe for various applications in nanomedicine. TGA analysis revealed that biomolecules, which were present in the plant extract, capped the nanoparticles and acted as stabilizing agents. Full article

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

▼ Show Figures

Graphical abstract

8 pages, 2551 KiB

Open AccessArticle

Plasmonic Absorption Enhancement in Elliptical Graphene Arrays

by Jiajia Chen^1,2, Yu Zeng^1,2, Xibin Xu³, Xifang Chen^1,2, Zigang Zhou^1,2, Pengcheng Shi^1,2, Zao Yi^1,2,*

, Xin Ye^3,*, Shuyuan Xiao^4,*

and Yougen Yi⁵

¹ School of Science, Southwest University of Science and Technology, Mianyang 621010, China

² Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, Mianyang 621010, China

³ Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China

⁴ Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China

⁵ College of Physics and Electronics, Central South University, Changsha 410083, China

Nanomaterials 2018, 8(3), 175; https://doi.org/10.3390/nano8030175 - 19 Mar 2018

Cited by 49 | Viewed by 5836

Abstract

In this paper, we come up with a wavelength tunable absorber which is made up of periodically elliptical graphene arrays in the far-infrared and terahertz regions. Through simulation, we find that we can increase the length of long axis of the ellipse, raise [...] Read more.

In this paper, we come up with a wavelength tunable absorber which is made up of periodically elliptical graphene arrays in the far-infrared and terahertz regions. Through simulation, we find that we can increase the length of long axis of the ellipse, raise the incidence angles of TM- and TE-polarization (TM- and TE-polarization indicate the direction of the incident electric field along the direction of the x and the y axis, respectively.) within certain limits, and increase the chemical potential of graphene, so as to enhance the absorption of light in the elliptical graphene arrays. We also compare the absorption spectra of the original structure and the complementary structure, and find that the absorption of the original structure is higher than that of the complementary structure. In the end, we study the changes in the absorption rate of the double layer structure of the elliptical array with the increase in the thickness of SiO₂. The elliptical array structure can be applied to tunable spectral detectors, filters and sensors at far-infrared and terahertz wavelengths. Full article

▼ Show Figures

Graphical abstract

14 pages, 7522 KiB

Open AccessFeature PaperArticle

Comparison of Branched and Linear Perfluoropolyether Chains Functionalization on Hydrophobic, Morphological and Conductive Properties of Multi-Walled Carbon Nanotubes

by Maurizio Sansotera^1,2,*, Sadaf Talaeemashhadi¹, Cristian Gambarotti^1,2, Carlo Pirola^3,4

, Mariangela Longhi³

, Marco A. Ortenzi³

, Walter Navarrini^1,2 and Claudia L. Bianchi^3,4,*

¹ Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, via Mancinelli 7, I-20131 Milano, Italy

² Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (UdR-PoliMi), via G. Giusti, 9, 50121 Firenze, Italy

³ Dipartimento di Chimica, Università degli Studi di Milano, via Golgi 19, I-20133 Milano, Italy

⁴ Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (UdR-UniMi), via G. Giusti, 9, 50121 Firenze, Italy

Nanomaterials 2018, 8(3), 176; https://doi.org/10.3390/nano8030176 - 19 Mar 2018

Cited by 5 | Viewed by 5279

Abstract

The functionalization of multi-walled carbon nanotubes (MW-CNTs) was obtained by generating reactive perfluoropolyether (PFPE) radicals that can covalently bond to MW-CNTs’ surface. Branched and linear PFPE peroxides with equivalent molecular weights of 1275 and 1200 amu, respectively, have been thermally decomposed for the [...] Read more.

The functionalization of multi-walled carbon nanotubes (MW-CNTs) was obtained by generating reactive perfluoropolyether (PFPE) radicals that can covalently bond to MW-CNTs’ surface. Branched and linear PFPE peroxides with equivalent molecular weights of 1275 and 1200 amu, respectively, have been thermally decomposed for the production of PFPE radicals. The functionalization with PFPE chains has changed the wettability of MW-CNTs, which switched their behavior from hydrophilic to super-hydrophobic. The low surface energy properties of PFPEs have been transferred to MW-CNTs surface and branched units with trifluoromethyl groups, CF₃, have conferred higher hydrophobicity than linear units. Porosimetry discriminated the effects of PFPE functionalization on meso-porosity and macro-porosity. It has been observed that reactive sites located in MW-CNTs mesopores have been intensively functionalized by branched PFPE peroxide due to its low average molecular weight. Conductivity measurements at different applied pressures have showed that the covalent linkage of PFPE chains, branched as well as linear, weakly modified the electrical conductivity of MW-CNTs. The decomposed portions of PFPE residues, the PFPE chains bonded on carbon nanotubes, and the PFPE fluids obtained by homo-coupling side-reactions were evaluated by mass balances. PFPE-modified MW-CNTs have been characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), static contact angle (SCA), surface area, and porosity measurements. Full article

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

▼ Show Figures

Graphical abstract

26 pages, 6387 KiB

Open AccessFeature PaperArticle

TiO₂-SiO₂ Coatings with a Low Content of AuNPs for Producing Self-Cleaning Building Materials

by Manuel Luna¹

, Juan J. Delgado²

, M. L. Almoraima Gil¹ and María J. Mosquera^1,*

¹ TEP-243 Nanomaterials Group, Department of Physical-Chemistry, Faculty of Sciences, University of Cadiz, 11510 Puerto Real, Spain

² Department of Inorganic Chemistry, CASEM, University of Cadiz, 11510 Puerto Real, Spain

Nanomaterials 2018, 8(3), 177; https://doi.org/10.3390/nano8030177 - 20 Mar 2018

Cited by 37 | Viewed by 6546

Abstract

The high pollution levels in our cities are producing a significant increase of dust on buildings. An application of photoactive coatings on building materials can produce buildings with self-cleaning surfaces. In this study, we have developed a simple sol-gel route for producing Au-TiO [...] Read more.

The high pollution levels in our cities are producing a significant increase of dust on buildings. An application of photoactive coatings on building materials can produce buildings with self-cleaning surfaces. In this study, we have developed a simple sol-gel route for producing Au-TiO₂/SiO₂ photocatalysts with application on buildings. The gold nanoparticles (AuNPs) improved the TiO₂ photoactivity under solar radiation because they promoted absorption in the visible range. We varied the content of AuNPs in the sols under study, in order to investigate their effect on self-cleaning properties. The sols obtained were sprayed on a common building stone, producing coatings which adhere firmly to the stone and preserve their aesthetic qualities. We studied the decolourization efficiency of the photocatalysts under study against methylene blue and against soot (a real staining agent for buildings). Finally, we established that the coating with an intermediate Au content presented the best self-cleaning performance, due to the role played by its structure and texture on its photoactivity. Full article

▼ Show Figures

Graphical abstract

10 pages, 1719 KiB

Open AccessArticle

Transferrin Functionalized Liposomes Loading Dopamine HCl: Development and Permeability Studies across an In Vitro Model of Human Blood–Brain Barrier

by Antonio Lopalco¹, Annalisa Cutrignelli^1,*, Nunzio Denora^1,2, Angela Lopedota¹, Massimo Franco¹ and Valentino Laquintana¹

¹ Department of Pharmacy–Drug Sciences, University of Bari “Aldo Moro”, 4 E. Orabona st, 70125 Bari, Italy

² Institute for Physical and Chemical Processes (IPCF)-CNR, SS Bari, 4 E. Orabona st, 70125 Bari, Italy

Nanomaterials 2018, 8(3), 178; https://doi.org/10.3390/nano8030178 - 20 Mar 2018

Cited by 78 | Viewed by 7188

Abstract

The transport of dopamine across the blood brain barrier represents a challenge for the management of Parkinson’s disease. The employment of central nervous system targeted ligands functionalized nanocarriers could be a valid tactic to overcome this obstacle and avoid undesirable side effects. In [...] Read more.

The transport of dopamine across the blood brain barrier represents a challenge for the management of Parkinson’s disease. The employment of central nervous system targeted ligands functionalized nanocarriers could be a valid tactic to overcome this obstacle and avoid undesirable side effects. In this work, transferrin functionalized dopamine-loaded liposomes were made by a modified dehydration–rehydration technique from hydrogenated soy phosphatidylcoline, cholesterol and 1,2-stearoyl-sn-glycero-3-phosphoethanolamine-N-[carboxy(poly(ethylene glycol)-2000)]. The physical features of the prepared liposomes were established with successive determination of their endothelial permeability across an in vitro model of the blood-brain barrier, constituted by human cerebral microvascular endothelial cells (hCMEC/D3). Functionalized dopamine-loaded liposomes with encapsulation efficiency more than 35% were made with sizes in a range around 180 nm, polydispersity indices of 0.2, and positive zeta potential values (+7.5 mV). Their stability and drug release kinetics were also evaluated. The apparent permeability (P_e) values of encapsulated dopamine in functionalized and unfunctionalized liposomes showed that transferrin functionalized nanocarriers could represent appealing non-toxic candidates for brain delivery, thus improving benefits and decreasing complications to patients subjected to L-dopa chronical treatment. Full article

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

▼ Show Figures

Graphical abstract

25 pages, 15384 KiB

Open AccessArticle

Synthesis of the Novel Type of Bimodal Ceramic Nanowires from Polymer and Composite Fibrous Mats

by Tomasz Tański^*

and Wiktor Matysiak^*

Institute of Engineering Materials and Biomaterials, Silesian University of Technology, Konarskiego 18a, 44-100 Gliwice, Poland

Nanomaterials 2018, 8(3), 179; https://doi.org/10.3390/nano8030179 - 20 Mar 2018

Cited by 13 | Viewed by 5007

Abstract

The purpose of this paper was to produce SiO₂ and TiO₂ nanowires via the electrospinning process from a polyvinylpyrrolidone (PVP)/Tetraethyl orthosilicate (TEOS)/Titanium (IV) butoxide (TNBT)/dimethylformamide (DMF) and ethanol (EtOH) solution. The as-obtained nanofibers were calcined at temperatures ranging from 400 °C [...] Read more.

The purpose of this paper was to produce SiO₂ and TiO₂ nanowires via the electrospinning process from a polyvinylpyrrolidone (PVP)/Tetraethyl orthosilicate (TEOS)/Titanium (IV) butoxide (TNBT)/dimethylformamide (DMF) and ethanol (EtOH) solution. The as-obtained nanofibers were calcined at temperatures ranging from 400 °C to 600 °C in order to remove the organic phase. The one-dimensional ceramic nanostructures were studied using a scanning electron microscope (SEM) and a transmission electron microscope (TEM) to analyze the influence of the used temperature on the morphology and structures of the obtained ceramic nanomaterials. In order to examine the chemical structure of the nanowires, energy dispersive spectrometry (EDX) and Fourier-Transform Infrared spectroscopy (FTIR) were used. The optical property analysis was performed on the basis of UV-Vis spectra of absorbance as a function of the wavelength. Using the modified Swanepoel method, which the authors proposed and the recorded absorbance spectra allowed to determine the banded refractive index n, real n′ and imaginary k part of the refractive index as a function of the wavelength, complex dielectric permeability ε, and real and imaginary part ε_r and ε_i of the dielectric permeability as a function of the radiation energy of the produced ceramic nanowires. Full article

▼ Show Figures

Graphical abstract

Review

Jump to: Research

29 pages, 8983 KiB

Open AccessReview

Iron Oxide and Gold Based Magneto-Plasmonic Nanostructures for Medical Applications: A Review

by Thi Thuy Nguyen^1,2,*

, Fayna Mammeri^1,*

and Souad Ammar^1,*

¹ Interfaces, Traitements, Organisation et Dynamique des Systèmes, ITODYS, UMR 7086, CNRS, Université Paris Diderot, Sorbonne Paris Cité, 15 rue Jean Antoine de Baïf, 75205 Paris, France

² Department of Advanced Materials Science and Nanotechnology, University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Vietnam

Nanomaterials 2018, 8(3), 149; https://doi.org/10.3390/nano8030149 - 7 Mar 2018

Cited by 86 | Viewed by 13312

Abstract

Iron oxide and gold-based magneto-plasmonic nanostructures exhibit remarkable optical and superparamagnetic properties originating from their two different components. As a consequence, they have improved and broadened the application potential of nanomaterials in medicine. They can be used as multifunctional nanoprobes for magneto-plasmonic heating [...] Read more.

Iron oxide and gold-based magneto-plasmonic nanostructures exhibit remarkable optical and superparamagnetic properties originating from their two different components. As a consequence, they have improved and broadened the application potential of nanomaterials in medicine. They can be used as multifunctional nanoprobes for magneto-plasmonic heating as well as for magnetic and optical imaging. They can also be used for magnetically assisted optical biosensing, to detect extreme traces of targeted bioanalytes. This review introduces the previous work on magneto-plasmonic hetero-nanostructures including: (i) their synthesis from simple “one-step” to complex “multi-step” routes, including seed-mediated and non-seed-mediated methods; and (ii) the characterization of their multifunctional features, with a special emphasis on the relationships between their synthesis conditions, their structures and their properties. It also focuses on the most important progress made with regard to their use in nanomedicine, keeping in mind the same aim, the correlation between their morphology—namely spherical and non-spherical, core-satellite and core-shell, and the desired applications. Full article

(This article belongs to the Special Issue Magnetic Nanoparticles in Biological Applications)

▼ Show Figures

Graphical abstract

29 pages, 4734 KiB

Open AccessFeature PaperReview

Preparation, Modification, Characterization, and Biosensing Application of Nanoporous Gold Using Electrochemical Techniques

by Jay K. Bhattarai

, Dharmendra Neupane, Bishal Nepal, Vasilii Mikhaylov, Alexei V. Demchenko

and Keith J. Stine^*

Department of Chemistry and Biochemistry, University of Missouri, St. Louis, Saint Louis, MO 63121, USA

Nanomaterials 2018, 8(3), 171; https://doi.org/10.3390/nano8030171 - 16 Mar 2018

Cited by 72 | Viewed by 9424

Abstract

Nanoporous gold (np-Au), because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, [...] Read more.

Nanoporous gold (np-Au), because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au. Recently, researchers are focusing on easier and controlled ways to tune the pores and ligaments size of np-Au for its use in different applications. Electrochemical methods have good control over fine-tuning pore and ligament sizes. The np-Au electrodes that are prepared using electrochemical techniques are robust and are easier to handle for their use in electrochemical biosensing. Here, we review different electrochemical strategies for the preparation, post-modification, and characterization of np-Au along with the synergistic use of both electrochemistry and np-Au for applications in biosensing. Full article

(This article belongs to the Special Issue Nanoporous Gold and Other Related Materials)

▼ Show Figures

Figure 1

Journal Menu

Journal Browser

Nanomaterials, Volume 8, Issue 3 (March 2018) – 51 articles

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI