Nanomaterials

21 pages, 9037 KiB

Open AccessReview

Review of the Functions of Archimedes’ Spiral Metallic Nanostructures

by Zhongyi Guo^*

, Zixiang Li, Jingran Zhang, Kai Guo, Fei Shen, Qingfeng Zhou and Hongping Zhou^*

School of Computer and Information, Hefei University of Technology, Hefei 230009, China

Nanomaterials 2017, 7(11), 405; https://doi.org/10.3390/nano7110405 - 22 Nov 2017

Cited by 24 | Viewed by 7838

Abstract

Here, we have reviewed some typical plasmonic structures based on Archimedes’ spiral (AS) architectures, which can produce polarization-sensitive focusing phenomenon and generate plasmonic vortices (PVs) carrying controllable orbital angular momentum (OAM) because of the relation between the incident polarized states and the chiralities [...] Read more.

Here, we have reviewed some typical plasmonic structures based on Archimedes’ spiral (AS) architectures, which can produce polarization-sensitive focusing phenomenon and generate plasmonic vortices (PVs) carrying controllable orbital angular momentum (OAM) because of the relation between the incident polarized states and the chiralities of the spiral structures. These features can be used to analyze different circular polarization states, which has been one of the rapidly developing researching topics in nanophotonics in recent years. Many investigations demonstrate that the multifunctional spiral-based plasmonic structures are excellent choices for chiral selection and generating the transmitted field with well-defined OAM. The circular polarization extinction ratio, as an evaluation criterion for the polarization selectivity of a designed structure, could be effectively improved by properly modulating the parameters of spiral structures. Such functional spiral plasmonic nanostructures are promising for applications in analyzing circular polarization light, full Stokes vector polarimetric sensors, near-field imaging, and so on. Full article

(This article belongs to the Special Issue Multifunctional Metallic Nanomaterials)

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10 pages, 6204 KiB

Open AccessArticle

Enhanced Oxygen Reduction Reaction by In Situ Anchoring Fe₂N Nanoparticles on Nitrogen-Doped Pomelo Peel-Derived Carbon

by Yiqing Wang¹, Mingyuan Zhu¹, Gang Wang^1,2,3, Bin Dai¹, Feng Yu^1,*

, Zhiqun Tian^4,* and Xuhong Guo^1,5,*

¹ Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China

² Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Production and Construction Corps, Shihezi 832003, China

³ Key Laboratory of Materials-Oriented Chemical Engineering of Xinjiang Uygur Autonomous Region, Shihezi 832003, China

⁴ Collaborative Innovation Center of Renewable Energy Materials, Guangxi University, Nanning 530004, China

⁵ State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China

Nanomaterials 2017, 7(11), 404; https://doi.org/10.3390/nano7110404 - 22 Nov 2017

Cited by 43 | Viewed by 6964

Abstract

The development of effective oxygen electrode catalysts for renewable energy technologies such as metal-air batteries and fuel cells remains challenging. Here, we prepared a novel high-performance oxygen reduction reaction (ORR) catalyst comprised of Fe₂N nanoparticles (NPs) in situ decorated over an [...] Read more.

The development of effective oxygen electrode catalysts for renewable energy technologies such as metal-air batteries and fuel cells remains challenging. Here, we prepared a novel high-performance oxygen reduction reaction (ORR) catalyst comprised of Fe₂N nanoparticles (NPs) in situ decorated over an N-doped porous carbon derived from pomelo peel (i.e., Fe₂N/N-PPC). The decorated Fe₂N NPs provided large quantities of Fe-N-C bonding catalytic sites. The as-obtained Fe₂N/N-PPC showed superior onset and half-wave potentials (0.966 and 0.891 V, respectively) in alkaline media (0.1 M KOH) compared to commercial Pt/C through a direct four-electron reaction pathway. Fe₂N/N-PPC also showed better stability and methanol tolerance than commercial Pt/C. The outstanding ORR performance of Fe₂N/N-PPC was attributed to its high specific surface area and the synergistic effects of Fe₂N NPs. The utilization of agricultural wastes as a precursor makes Fe₂N/N-PPC an ideal non-precious metal catalyst for ORR applications. Full article

(This article belongs to the Special Issue Nanomaterials Based Fuel Cells and Supercapacitors)

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17 pages, 3148 KiB

Open AccessArticle

Comparison of Anionic, Cationic and Nonionic Surfactants as Dispersing Agents for Graphene Based on the Fluorescence of Riboflavin

by Rocío Mateos¹, Soledad Vera¹

, Mercedes Valiente^1,2

, Ana María Díez-Pascual^1,2,*

and María Paz San Andrés^1,*

¹ Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Biology, Environmental Sciences and Chemistry, Alcalá University, Alcalá de Henares, 28871 Madrid, Spain

² Institute of Chemistry Research “Andrés M. del Río” (IQAR), University of Alcalá, Ctra, Madrid-Barcelona, Km. 33.6, Alcalá de Henares, 28871 Madrid, Spain

Nanomaterials 2017, 7(11), 403; https://doi.org/10.3390/nano7110403 - 22 Nov 2017

Cited by 29 | Viewed by 6378

Abstract

Fluorescence quenching is a valuable tool to gain insight about dynamic changes of fluorophores in complex systems. Graphene (G), a single-layered 2D nanomaterial with unique properties, was dispersed in surfactant aqueous solutions of different nature: non-ionic polyoxyethylene-23-lauryl ether (Brij L23), anionic sodium dodecylsulphate [...] Read more.

Fluorescence quenching is a valuable tool to gain insight about dynamic changes of fluorophores in complex systems. Graphene (G), a single-layered 2D nanomaterial with unique properties, was dispersed in surfactant aqueous solutions of different nature: non-ionic polyoxyethylene-23-lauryl ether (Brij L23), anionic sodium dodecylsulphate (SDS), and cationic hexadecyltrimethylammonium bromide (CTAB) and dodecyltrimethylammonium bromide (DTAB). The influence of the surfactant type, chain length and concentration, G total concentration and G/surfactant weight ratio on the fluorescence intensity of vitamin B₂ (riboflavin) was investigated. The quality of the different G dispersions was assessed by scanning and transmission electron microscopies (SEM and TEM). A quenching phenomenon of the fluorescence of riboflavin was found for G dispersions in all the surfactants, which generally becomes stronger with increasing G/surfactant weight ratio. For dispersions in the ionic surfactants, the quenching is more pronounced as the surfactant concentration raises, whilst the non-ionic one remains merely unchanged for the different G/Brij L23 weight ratios. More importantly, results indicate that DTAB solutions are the optimum media for dispersing G sheets, leading to an up to 16-fold drop in the fluorescence intensity. Understanding the mechanism in fluorescence quenching of G dispersions in surfactants could be useful for several optical applications. Full article

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10 pages, 2198 KiB

Open AccessArticle

Biomass-Derived Oxygen and Nitrogen Co-Doped Porous Carbon with Hierarchical Architecture as Sulfur Hosts for High-Performance Lithium/Sulfur Batteries

by Yan Zhao¹, Li Wang⁴, Lanyan Huang^1,4, Maxim. Yu. Maximov³

, Mingliang Jin^1,4, Yongguang Zhang^1,2,*, Xin Wang^1,4,*

and Guofu Zhou^1,4

¹ International Academy of Optoelectronics at Zhaoqing, South China Normal University, Zhaoqing 526060; China

² Synergy Innovation Institute of GDUT, Heyuan 517000, China

³ Peter the Great Saint-Petersburg Polytechnic University, Saint-Petersburg 195221, Russia

⁴ Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510631, China

Nanomaterials 2017, 7(11), 402; https://doi.org/10.3390/nano7110402 - 21 Nov 2017

Cited by 48 | Viewed by 6323

Abstract

In this work, a facile strategy to synthesize oxygen and nitrogen co-doped porous carbon (ONPC) is reported by one-step pyrolysis of waste coffee grounds. As-prepared ONPC possesses highly rich micro/mesopores as well as abundant oxygen and nitrogen co-doping, which is applied to sulfur [...] Read more.

In this work, a facile strategy to synthesize oxygen and nitrogen co-doped porous carbon (ONPC) is reported by one-step pyrolysis of waste coffee grounds. As-prepared ONPC possesses highly rich micro/mesopores as well as abundant oxygen and nitrogen co-doping, which is applied to sulfur hosts as lithium/sulfur batteries’ appropriate cathodes. In battery testing, the sulfur/oxygen and nitrogen co-doped porous carbon (S/ONPC) composite materials reveal a high initial capacity of 1150 mAh·g⁻¹ as well as a reversible capacity of 613 mAh·g⁻¹ after the 100th cycle at 0.2 C. Furthermore, when current density increases to 1 C, a discharge capacity of 331 mAh·g⁻¹ is still attainable. Due to the hierarchical porous framework and oxygen/nitrogen co-doping, the S/ONPC composite exhibits a high utilization of sulfur and good electrochemical performance via the immobilization of the polysulfides through strong chemical binding. Full article

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18 pages, 3652 KiB

Open AccessArticle

An In Vitro Study of the Photodynamic Effectiveness of GO-Ag Nanocomposites against Human Breast Cancer Cells

by Fozia Shaheen¹, Muhammad Hammad Aziz^2,*, Muhammad Fakhar-e-Alam^3,4, Muhammad Atif^5,6, Mahvish Fatima⁷, Riaz Ahmad^8,*, Atif Hanif⁹, Saqib Anwar¹⁰

, Fatima Zafar¹¹, Ghazanfar Abbas², Syed Mansoor Ali⁵ and Mukhtar Ahmed²

¹ Department of Physics, Government College (GC) University, Lahore 54000, Pakistan

² Department of Physics, COMSATS Institute of Information and Technology, Lahore 54000, Pakistan

³ Department of Physics, Government College (GC) University, Faisalabad 38000, Pakistan

⁴ Institute of Fundamental and Frontier Science, University of Electronic Science and Technology of China, Chengdu 610054, China

⁵ Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia

⁶ National Institute of Laser and Optronics, Nilore 45650, Islamabad

⁷ Department of Physics, University of Lahore, Lahore 54000, Pakistan

⁸ The Centre for Advanced Studies in Physics (CASP), Government College (GC) University, Church Road, Lahore 54000, Pakistan

⁹ Botany and Microbiology Department, Faculty of Science, King Saud University, Riyadh 11451, Saudi Arabia

¹⁰ Industrial Engineering Department, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia

¹¹ Department of Chemistry, GC University, Lahore 54000, Pakistan

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Nanomaterials 2017, 7(11), 401; https://doi.org/10.3390/nano7110401 - 21 Nov 2017

Cited by 23 | Viewed by 8287

Abstract

Graphene-based materials have garnered significant attention because of their versatile bioapplications and extraordinary properties. Graphene oxide (GO) is an extremely oxidized form of graphene accompanied by the functional groups of oxygen on its surface. GO is an outstanding platform on which to pacify [...] Read more.

Graphene-based materials have garnered significant attention because of their versatile bioapplications and extraordinary properties. Graphene oxide (GO) is an extremely oxidized form of graphene accompanied by the functional groups of oxygen on its surface. GO is an outstanding platform on which to pacify silver nanoparticles (Ag NPs), which gives rise to the graphene oxide-silver nanoparticle (GO-Ag) nanocomposite. In this experimental study, the toxicity of graphene oxide-silver (GO-Ag) nanocomposites was assessed in an in vitro human breast cancer model to optimize the parameters of photodynamic therapy. GO-Ag was prepared using the hydrothermal method, and characterization was done by X-ray diffraction, field-emission scanning electron microscope (FE-SEM), transmission Electron Microscopy (TEM), energy dispersive X-rays Analysis (EDAX), atomic force microscopy and ultraviolet-visible spectroscopy. The experiments were done both with laser exposure, as well as in darkness, to examine the phototoxicity and cytotoxicity of the nanocomposites. The cytotoxicity of the GO-Ag was confirmed via a methyl-thiazole-tetrazolium (MTT) assay and intracellular reactive oxygen species production analysis. The phototoxic effect explored the dose-dependent decrease in the cell viability, as well as provoked cell death via apoptosis. An enormously significant escalation of ¹O₂ in the samples when exposed to daylight was perceived. Statistical analysis was performed on the experimental results to confirm the worth and clarity of the results, with p-values < 0.05 selected as significant. These outcomes suggest that GO-Ag nanocomposites could serve as potential candidates for targeted breast cancer therapy. Full article

(This article belongs to the Special Issue Graphene and Nanotube Based Devices)

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11 pages, 4659 KiB

Open AccessArticle

Self-Assembled InAs Nanowires as Optical Reflectors

by Francesco Floris¹

, Lucia Fornasari¹, Andrea Marini², Vittorio Bellani¹

, Francesco Banfi³

, Stefano Roddaro⁴, Daniele Ercolani⁴

, Mirko Rocci⁴

, Fabio Beltram⁴, Marco Cecchini⁴, Lucia Sorba⁴

and Francesco Rossella^4,*

¹ Dipartimento di Fisica, Università di Pavia, via Bassi 6, 27100 Pavia, Italy

² ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain

³ Interdisciplinary Laboratories for Advanced Materials Physics (I-LAMP) and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Via Musei 41, 25121 Brescia, Italy

⁴ National Enterprise for Nanoscience and Nanotechnology (NEST), Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza S. Silvestro 12, 56127 Pisa, Italy

Nanomaterials 2017, 7(11), 400; https://doi.org/10.3390/nano7110400 - 21 Nov 2017

Cited by 25 | Viewed by 5749

Abstract

Subwavelength nanostructured surfaces are realized with self-assembled vertically-aligned InAs nanowires, and their functionalities as optical reflectors are investigated. In our system, polarization-resolved specular reflectance displays strong modulations as a function of incident photon energy and angle. An effective-medium model allows one to rationalize [...] Read more.

Subwavelength nanostructured surfaces are realized with self-assembled vertically-aligned InAs nanowires, and their functionalities as optical reflectors are investigated. In our system, polarization-resolved specular reflectance displays strong modulations as a function of incident photon energy and angle. An effective-medium model allows one to rationalize the experimental findings in the long wavelength regime, whereas numerical simulations fully reproduce the experimental outcomes in the entire frequency range. The impact of the refractive index of the medium surrounding the nanostructure assembly on the reflectance was estimated. In view of the present results, sensing schemes compatible with microfluidic technologies and routes to innovative nanowire-based optical elements are discussed. Full article

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13 pages, 4200 KiB

Open AccessArticle

Synthesis and Swelling Behavior of pH-Sensitive Semi-IPN Superabsorbent Hydrogels Based on Poly(acrylic acid) Reinforced with Cellulose Nanocrystals

by Lim Sze Lim¹, Noor Afizah Rosli¹, Ishak Ahmad^1,*, Azwan Mat Lazim¹ and Mohd Cairul Iqbal Mohd Amin²

¹ Polymer Research Centre (PORCE), School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi Selangor 43600, Malaysia

² Faculty of Pharmacy, University Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia

Nanomaterials 2017, 7(11), 399; https://doi.org/10.3390/nano7110399 - 20 Nov 2017

Cited by 91 | Viewed by 9013

Abstract

pH-sensitive poly(acrylic acid) (PAA) hydrogel reinforced with cellulose nanocrystals (CNC) was prepared. Acrylic acid (AA) was subjected to chemical cross-linking using the cross-linking agent MBA (N,N-methylenebisacrylamide) with CNC entrapped in the PAA matrix. The quantity of CNC was varied [...] Read more.

pH-sensitive poly(acrylic acid) (PAA) hydrogel reinforced with cellulose nanocrystals (CNC) was prepared. Acrylic acid (AA) was subjected to chemical cross-linking using the cross-linking agent MBA (N,N-methylenebisacrylamide) with CNC entrapped in the PAA matrix. The quantity of CNC was varied between 0, 5, 10, 15, 20, and 25 wt %. X-ray diffraction (XRD) data showed an increase in crystallinity with the addition of CNC, while rheology tests demonstrated a significant increase in the storage modulus of the hydrogel with an increase in CNC content. It was found that the hydrogel reached maximum swelling at pH 7. The potential of the resulting hydrogels to act as drug carriers was then evaluated by means of the drug encapsulation efficiency test using theophylline as a model drug. It was observed that 15% CNC/PAA hydrogel showed the potential to be used as drug carrier system. Full article

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27 pages, 7171 KiB

Open AccessReview

Fabrication of Semiconductor ZnO Nanostructures for Versatile SERS Application

by Lili Yang^1,2, Yong Yang^1,*

, Yunfeng Ma^1,2, Shuai Li^1,2, Yuquan Wei^1,2, Zhengren Huang¹ and Nguyen Viet Long³

¹ State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, China

² Graduate University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Beijing 100049, China

³ Ceramics and Biomaterials Research Group, Ton Duc Thang University, Ho Chi Minh City 800010, Vietnam

Nanomaterials 2017, 7(11), 398; https://doi.org/10.3390/nano7110398 - 19 Nov 2017

Cited by 83 | Viewed by 12067

Abstract

Since the initial discovery of surface-enhanced Raman scattering (SERS) in the 1970s, it has exhibited a huge potential application in many fields due to its outstanding advantages. Since the ultra-sensitive noble metallic nanostructures have increasingly exposed themselves as having some problems during application, [...] Read more.

Since the initial discovery of surface-enhanced Raman scattering (SERS) in the 1970s, it has exhibited a huge potential application in many fields due to its outstanding advantages. Since the ultra-sensitive noble metallic nanostructures have increasingly exposed themselves as having some problems during application, semiconductors have been gradually exploited as one of the critical SERS substrate materials due to their distinctive advantages when compared with noble metals. ZnO is one of the most representative metallic oxide semiconductors with an abundant reserve, various and cost-effective fabrication techniques, as well as special physical and chemical properties. Thanks to the varied morphologies, size-dependent exciton, good chemical stability, a tunable band gap, carrier concentration, and stoichiometry, ZnO nanostructures have the potential to be exploited as SERS substrates. Moreover, other distinctive properties possessed by ZnO such as biocompatibility, photocatcalysis and self-cleaning, and gas- and chemo-sensitivity can be synergistically integrated and exerted with SERS activity to realize the multifunctional potential of ZnO substrates. In this review, we discuss the inevitable development trend of exploiting the potential semiconductor ZnO as a SERS substrate. After clarifying the root cause of the great disparity between the enhancement factor (EF) of noble metals and that of ZnO nanostructures, two specific methods are put forward to improve the SERS activity of ZnO, namely: elemental doping and combination of ZnO with noble metals. Then, we introduce a distinctive advantage of ZnO as SERS substrate and illustrate the necessity of reporting a meaningful average EF. We also summarize some fabrication methods for ZnO nanostructures with varied dimensions (0–3 dimensions). Finally, we present an overview of ZnO nanostructures for the versatile SERS application. Full article

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

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11 pages, 2297 KiB

Open AccessArticle

Plasmonic Spectral Splitting in Ring/Rod Metasurface

by Naseer Muhammad^1,2,3, Adnan Daud Khan⁴, Zi-Lan Deng^5,6, Karim Khan^1,2,3, Ashish Yadav^1,2,3, Qiang Liu^1,2,3 and Zhengbiao Ouyang^1,2,3,*

¹ THz Technical Research Center of Shenzhen University, Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology, Shenzhen 518060, China

² Key Laboratory of Optoelectronics Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen 518060, China

³ College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, China

⁴ Department of Electrical Engineering, Sarhad University of Science and Information Technology, Peshawar 25000, Pakistan

⁵ Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Guangzhou 510632, China

⁶ Institute of Photonics Technology, Jinan University, Guangzhou 510632, China

Nanomaterials 2017, 7(11), 397; https://doi.org/10.3390/nano7110397 - 19 Nov 2017

Cited by 30 | Viewed by 5291

Abstract

We report spectral splitting behaviors based on Fano resonances in a novel simple planar metasurface composed of gold nanobars and nanorings. Multiple plasmonic modes and sharp Fano effects are achieved in a broadband transmittance spectrum by exploiting the rotational symmetry of the metasurface. [...] Read more.

We report spectral splitting behaviors based on Fano resonances in a novel simple planar metasurface composed of gold nanobars and nanorings. Multiple plasmonic modes and sharp Fano effects are achieved in a broadband transmittance spectrum by exploiting the rotational symmetry of the metasurface. The transmission properties are effectively modified and tuned by modulating the structural parameters. The highest single side Q-factor and FoM which reaches 196 and 105 are observed at Fano resonances. Our proposed design is relatively simple and can be applied for various applications such as multi-wavelength highly sensitive plasmonic sensors, switching, and slow light devices. Full article

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42 pages, 11347 KiB

Open AccessReview

Nanostructured MnO₂ as Electrode Materials for Energy Storage

by Christian M. Julien^*

and Alain Mauger

Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Unité Mixte de Recherche 7590, Sorbonne Universités, 75005 Paris, France

Nanomaterials 2017, 7(11), 396; https://doi.org/10.3390/nano7110396 - 17 Nov 2017

Cited by 230 | Viewed by 16936

Abstract

Manganese dioxides, inorganic materials which have been used in industry for more than a century, now find great renewal of interest for storage and conversion of energy applications. In this review article, we report the properties of MnO₂ nanomaterials with different morphologies. [...] Read more.

Manganese dioxides, inorganic materials which have been used in industry for more than a century, now find great renewal of interest for storage and conversion of energy applications. In this review article, we report the properties of MnO₂ nanomaterials with different morphologies. Techniques used for the synthesis, structural, physical properties, and electrochemical performances of periodic and aperiodic frameworks are discussed. The effect of the morphology of nanosized MnO₂ particles on their fundamental features is evidenced. Applications as electrodes in lithium batteries and supercapacitors are examined. Full article

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15 pages, 9377 KiB

Open AccessArticle

Preparation of Solution Blown Polyamic Acid Nanofibers and Their Imidization into Polyimide Nanofiber Mats

by Jing Li, Guocheng Song, Junrong Yu^*, Yan Wang, Jing Zhu and Zuming Hu

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials, Science and Engineering, Donghua University, Shanghai 201620, China

Nanomaterials 2017, 7(11), 395; https://doi.org/10.3390/nano7110395 - 17 Nov 2017

Cited by 36 | Viewed by 6759

Abstract

Solution blow spinning (SBS) is an innovative process for spinning micro/nanofibers. In this paper, polyamic acid (PAA) nanofibers were fabricated via a SBS apparatus and then imidized into polyimide (PI) nanofibers via thermal process. The morphology and diameter distributions of PAA nanofibers were [...] Read more.

Solution blow spinning (SBS) is an innovative process for spinning micro/nanofibers. In this paper, polyamic acid (PAA) nanofibers were fabricated via a SBS apparatus and then imidized into polyimide (PI) nanofibers via thermal process. The morphology and diameter distributions of PAA nanofibers were determined by scanning electron microscope (SEM) and Image Tool software, the processing parameters, including PAA concentration, solution feeding rate, gas pressure, nozzle size, and receiving distance were investigated in details. The fourier transform infrared spectroscopy (FTIR) was used to characterize the chemical changes in the nanofibers after thermal imidization. The results showed that the solution concentration exhibited a notable correlation with spinnability, and the formation of bead defects in PAA nanofibers. Solution feeding rate, gas pressure, nozzle size, and receiving distance affected nanofiber production efficiency and diameter distribution. The average diameters of fibers produced ranged from 129.6 to 197.7 nm by varying SBS parameters. Precisely, PAA nanofibers with good morphology were obtained and the average diameter of nanofibers was 178.2 nm with optimum process parameter. After thermal imidization, the PI nanofibers exhibited obvious adhesion morphology among interconnected fibers, with an increased average diameter of 209.1 nm. The tensile strength of resultant PI nanofiber mat was 12.95 MPa. Full article

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26 pages, 13435 KiB

Open AccessArticle

Mechanical, Corrosion and Biological Properties of Room-Temperature Sputtered Aluminum Nitride Films with Dissimilar Nanostructure

by Cristina Besleaga¹, Viorel Dumitru¹, Liliana Marinela Trinca¹

, Adrian-Claudiu Popa^1,2, Constantin-Catalin Negrila¹, Łukasz Kołodziejczyk³

, Catalin-Romeo Luculescu⁴

, Gabriela-Cristina Ionescu⁵, Razvan-George Ripeanu⁵, Alina Vladescu⁶

and George E. Stan^1,*

¹ National Institute of Materials Physics, RO-077125 Magurele, Romania

² Army Centre for Medical Research, RO-010195 Bucharest, Romania

³ Institute of Materials Science and Engineering, Lodz University of Technology, 90-924 Lodz, Poland

⁴ National Institute for Lasers, Plasma and Radiation Physics, RO-077125 Magurele, Romania

⁵ Petroleum-Gas University of Ploiesti, RO-100680 Ploiesti, Romania

⁶ National Institute for Optoelectronics, RO-077125 Magurele, Romania

Nanomaterials 2017, 7(11), 394; https://doi.org/10.3390/nano7110394 - 17 Nov 2017

Cited by 37 | Viewed by 6026

Abstract

Aluminum Nitride (AlN) has been long time being regarded as highly interesting material for developing sensing applications (including biosensors and implantable sensors). AlN, due to its appealing electronic properties, is envisaged lately to serve as a multi-functional biosensing platform. Although generally exploited for [...] Read more.

Aluminum Nitride (AlN) has been long time being regarded as highly interesting material for developing sensing applications (including biosensors and implantable sensors). AlN, due to its appealing electronic properties, is envisaged lately to serve as a multi-functional biosensing platform. Although generally exploited for its intrinsic piezoelectricity, its surface morphology and mechanical performance (elastic modulus, hardness, wear, scratch and tensile resistance to delamination, adherence to the substrate), corrosion resistance and cytocompatibility are also essential features for high performance sustainable biosensor devices. However, information about AlN suitability for such applications is rather scarce or at best scattered and incomplete. Here, we aim to deliver a comprehensive evaluation of the morpho-structural, compositional, mechanical, electrochemical and biological properties of reactive radio-frequency magnetron sputtered AlN nanostructured thin films with various degrees of c-axis texturing, deposited at a low temperature (~50 °C) on Si (100) substrates. The inter-conditionality elicited between the base pressure level attained in the reactor chamber and crystalline quality of AlN films is highlighted. The potential suitability of nanostructured AlN (in form of thin films) for the realization of various type of sensors (with emphasis on bio-sensors) is thoroughly probed, thus unveiling its advantages and limitations, as well as suggesting paths to safely exploit the remarkable prospects of this type of materials. Full article

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12 pages, 1692 KiB

Open AccessFeature PaperArticle

Evaluation of Different Single-Walled Carbon Nanotube Surface Coatings for Single-Particle Tracking Applications in Biological Environments

by Zhenghong Gao^1,2,†, Noémie Danné^1,2,†, Antoine Guillaume Godin^1,2, Brahim Lounis^1,2 and Laurent Cognet^1,2,*

¹ Laboratoire Photonique Numérique et Nanosciences, University of Bordeaux, UMR 5298, F-33400 Talence, France

² Institut d’Optique & CNRS, LP2N UMR 5298, F-33400 Talence, France

^† These authors contributed equally to this work.

Nanomaterials 2017, 7(11), 393; https://doi.org/10.3390/nano7110393 - 16 Nov 2017

Cited by 25 | Viewed by 4802

Abstract

Fluorescence imaging of biological systems down to the single-molecule level has generated many advances in cellular biology. For applications within intact tissue, single-walled carbon nanotubes (SWCNTs) are emerging as distinctive single-molecule nanoprobes, due to their near-infrared photoluminescence properties. For this, SWCNT surfaces must [...] Read more.

Fluorescence imaging of biological systems down to the single-molecule level has generated many advances in cellular biology. For applications within intact tissue, single-walled carbon nanotubes (SWCNTs) are emerging as distinctive single-molecule nanoprobes, due to their near-infrared photoluminescence properties. For this, SWCNT surfaces must be coated using adequate molecular moieties. Yet, the choice of the suspension agent is critical since it influences both the chemical and emission properties of the SWCNTs within their environment. Here, we compare the most commonly used surface coatings for encapsulating photoluminescent SWCNTs in the context of bio-imaging applications. To be applied as single-molecule nanoprobes, encapsulated nanotubes should display low cytotoxicity, and minimal unspecific interactions with cells while still being highly luminescent so as to be imaged and tracked down to the single nanotube level for long periods of time. We tested the cell proliferation and cellular viability of each surface coating and evaluated the impact of the biocompatible surface coatings on nanotube photoluminescence brightness. Our study establishes that phospholipid-polyethylene glycol-coated carbon nanotube is the best current choice for single nanotube tracking experiments in live biological samples. Full article

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

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8 pages, 11110 KiB

Open AccessArticle

Templated Sphere Phase Liquid Crystals for Tunable Random Lasing

by Ziping Chen¹, Dechun Hu¹, Xingwu Chen², Deren Zeng², Yungjui Lee², Xiaoxian Chen² and Jiangang Lu^1,*

¹ National Engineering Lab for TFT-LCD Materials and Technologies, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

² Shenzhen China Star Optoelectronics Technology Co., Ltd., Shenzhen 518132, China

Nanomaterials 2017, 7(11), 392; https://doi.org/10.3390/nano7110392 - 15 Nov 2017

Cited by 14 | Viewed by 4577

Abstract

A sphere phase liquid crystal (SPLC) composed of three-dimensional twist structures with disclinations among them exists between isotropic phase and blue phase in a very narrow temperature range, about several degrees centigrade. A low concentration polymer template is applied to improve the thermal [...] Read more.

A sphere phase liquid crystal (SPLC) composed of three-dimensional twist structures with disclinations among them exists between isotropic phase and blue phase in a very narrow temperature range, about several degrees centigrade. A low concentration polymer template is applied to improve the thermal stability of SPLCs and broadens the temperature range to more than 448 K. By template processing, a wavelength tunable random lasing is demonstrated with dye doped SPLC. With different polymer concentrations, the reconstructed SPLC random lasing may achieve more than 40 nm wavelength continuous shifting by electric field modulation. Full article

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

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15 pages, 3477 KiB

Open AccessArticle

Synergistic Effect of Fluorinated and N Doped TiO₂ Nanoparticles Leading to Different Microstructure and Enhanced Photocatalytic Bacterial Inactivation

by Irena Milosevic^1,*

, Amarnath Jayaprakash¹

, Brigitte Greenwood¹, Birgit Van Driel^1,†

, Sami Rtimi^1,2

and Paul Bowen¹

¹ Ecole Polytechnique Fédérale de Lausanne, EPFL-STI-IMX-LTP, Station 12, CH-1015 Lausanne, Switzerland

² Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-GPAO, Station 6, CH-1015 Lausanne, Switzerland

^† Current address: Materials for Arts and Archeology, 3ME, TU Delft, Mekelweg 2, 2628 CD Delft, The Netherlands.

Nanomaterials 2017, 7(11), 391; https://doi.org/10.3390/nano7110391 - 15 Nov 2017

Cited by 51 | Viewed by 6828

Abstract

This work focuses on the development of a facile and scalable wet milling method followed by heat treatment to prepare fluorinated and/or N-doped TiO₂ nanopowders with improved photocatalytic properties under visible light. The structural and electronic properties of doped particles were investigated [...] Read more.

This work focuses on the development of a facile and scalable wet milling method followed by heat treatment to prepare fluorinated and/or N-doped TiO₂ nanopowders with improved photocatalytic properties under visible light. The structural and electronic properties of doped particles were investigated by various techniques. The successful doping of TiO₂ was confirmed by X-ray photoelectron spectroscopy (XPS), and the atoms appeared to be mainly located in interstitial positions for N whereas the fluorination is located at the TiO₂ surface. The formation of intragap states was found to be responsible for the band gap narrowing leading to the faster bacterial inactivation dynamics observed for the fluorinated and N doped TiO₂ particles compared to N-doped TiO₂. This was attributed to a synergistic effect. The results presented in this study confirmed the suitability of the preparation approach for the large-scale production of cost-efficient doped TiO₂ for effective bacterial inactivation. Full article

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

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16 pages, 8169 KiB

Open AccessFeature PaperArticle

Free-Standing and Self-Crosslinkable Hybrid Films by Core–Shell Particle Design and Processing

by Steffen Vowinkel¹, Stephen Paul², Torsten Gutmann²

and Markus Gallei^1,*

¹ Ernst-Berl-Institute for Chemical Engineering and Macromolecular Science, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, D-64287 Darmstadt, Germany

² Eduard-Zintl Institute for Inorganic and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, D-64287 Darmstadt, Germany

Nanomaterials 2017, 7(11), 390; https://doi.org/10.3390/nano7110390 - 15 Nov 2017

Cited by 11 | Viewed by 5414

Abstract

The utilization and preparation of functional hybrid films for optical sensing applications and membranes is of utmost importance. In this work, we report the convenient and scalable preparation of self-crosslinking particle-based films derived by directed self-assembly of alkoxysilane-based cross-linkers as part of a [...] Read more.

The utilization and preparation of functional hybrid films for optical sensing applications and membranes is of utmost importance. In this work, we report the convenient and scalable preparation of self-crosslinking particle-based films derived by directed self-assembly of alkoxysilane-based cross-linkers as part of a core-shell particle architecture. The synthesis of well-designed monodisperse core-shell particles by emulsion polymerization is the basic prerequisite for subsequent particle processing via the melt-shear organization technique. In more detail, the core particles consist of polystyrene (PS) or poly(methyl methacrylate) (PMMA), while the comparably soft particle shell consists of poly(ethyl acrylate) (PEA) and different alkoxysilane-based poly(methacrylate)s. For hybrid film formation and convenient self-cross-linking, different alkyl groups at the siloxane moieties were investigated in detail by solid-state Magic-Angle Spinning Nuclear Magnetic Resonance (MAS, NMR) spectroscopy revealing different crosslinking capabilities, which strongly influence the properties of the core or shell particle films with respect to transparency and iridescent reflection colors. Furthermore, solid-state NMR spectroscopy and investigation of the thermal properties by differential scanning calorimetry (DSC) measurements allow for insights into the cross-linking capabilities prior to and after synthesis, as well as after the thermally and pressure-induced processing steps. Subsequently, free-standing and self-crosslinked particle-based films featuring excellent particle order are obtained by application of the melt-shear organization technique, as shown by microscopy (TEM, SEM). Full article

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19 pages, 5326 KiB

Open AccessArticle

Bioactive Molecules Release and Cellular Responses of Alginate-Tricalcium Phosphate Particles Hybrid Gel

by Dipankar Das^1,2

, Sumi Bang¹, Shengmin Zhang³ and Insup Noh^1,2,*

¹ Convergence Institute of Biomedical Engineering and Biomaterials, Seoul National University of Science of Technology, 232 Gongneung-ro, Nowon-gu, Seoul 01811, Korea

² Department of Chemical and Biomolecular Engineering, Seoul National University of Science of Technology, 232 Gongneung-ro, Nowon-gu, Seoul 01811, Korea

³ Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074, China

Nanomaterials 2017, 7(11), 389; https://doi.org/10.3390/nano7110389 - 14 Nov 2017

Cited by 24 | Viewed by 6725

Abstract

In this article, a hybrid gel has been developed using sodium alginate (Alg) and α-tricalcium phosphate (α-TCP) particles through ionic crosslinking process for the application in bone tissue engineering. The effects of pH and composition of the gel on osteoblast cells (MC3T3) response [...] Read more.

In this article, a hybrid gel has been developed using sodium alginate (Alg) and α-tricalcium phosphate (α-TCP) particles through ionic crosslinking process for the application in bone tissue engineering. The effects of pH and composition of the gel on osteoblast cells (MC3T3) response and bioactive molecules release have been evaluated. At first, a slurry of Alg and α-TCP has been prepared using an ultrasonicator for the homogeneous distribution of α-TCP particles in the Alg network and to achieve adequate interfacial interaction between them. After that, CaCl2 solution has been added to the slurry so that ionic crosslinked gel (Alg-α-TCP) is formed. The developed hybrid gel has been physico-chemically characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and a swelling study. The SEM analysis depicted the presence of α-TCP micro-particles on the surface of the hybrid gel, while cross-section images signified that the α-TCP particles are fully embedded in the porous gel network. Different % swelling ratio at pH 4, 7 and 7.4 confirmed the pH responsiveness of the Alg-α-TCP gel. The hybrid gel having lower % α-TCP particles showed higher % swelling at pH 7.4. The hybrid gel demonstrated a faster release rate of bovine serum albumin (BSA), tetracycline (TCN) and dimethyloxalylglycine (DMOG) at pH 7.4 and for the grade having lower % α-TCP particles. The MC3T3 cells are viable inside the hybrid gel, while the rate of cell proliferation is higher at pH 7.4 compared to pH 7. The in vitro cytotoxicity analysis using thiazolyl blue tetrazolium bromide (MTT), bromodeoxyuridine (BrdU) and neutral red assays ascertained that the hybrid gel is non-toxic for MC3T3 cells. The experimental results implied that the non-toxic and biocompatible Alg-α-TCP hybrid gel could be used as scaffold in bone tissue engineering. Full article

(This article belongs to the Special Issue Multifunctional Nanocomposites in 3D Printing Technologies)

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24 pages, 9674 KiB

Open AccessArticle

Intratumoral Delivery of Doxorubicin on Folate-Conjugated Graphene Oxide by In-Situ Forming Thermo-Sensitive Hydrogel for Breast Cancer Therapy

by Yi Teng Fong^1,2,†, Chih-Hao Chen^2,† and Jyh-Ping Chen^1,2,3,4,*

¹ Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan 33302, Taiwan

² Department of Plastic and Reconstructive Surgery and Craniofacial Research Center, Chang Gung Memorial Hospital, Linkou, Kwei-San, Taoyuan 33305, Taiwan

³ Research Center for Chinese Herbal Medicine and Research Center for Food and Cosmetic Safety, College of Human Ecology, Chang Gung University of Science and Technology, Kwei-San, Taoyuan 33302, Taiwan

⁴ Department of Materials Engineering, Ming Chi University of Technology, Tai-Shan, New Taipei City 24301, Taiwan

^† These authors contributed equally to this paper.

Nanomaterials 2017, 7(11), 388; https://doi.org/10.3390/nano7110388 - 14 Nov 2017

Cited by 113 | Viewed by 8391

Abstract

By taking advantage of the pH-sensitive drug release property of graphene oxide (GO) after intracellular uptake, we prepared folic acid (FA)-conjugated GO (GOFA) for targeted delivery of the chemotherapeutic drug doxorubicin (DOX). GOFA-DOX was further encapsulated in an injectable in-situ forming thermo-sensitive hyaluronic [...] Read more.

By taking advantage of the pH-sensitive drug release property of graphene oxide (GO) after intracellular uptake, we prepared folic acid (FA)-conjugated GO (GOFA) for targeted delivery of the chemotherapeutic drug doxorubicin (DOX). GOFA-DOX was further encapsulated in an injectable in-situ forming thermo-sensitive hyaluronic acid-chitosan-g-poly(N-isopropylacrylamide) (HACPN) hydrogel for intratumoral delivery of DOX. As the degradation time of HACPN could be extended up to 3 weeks, intratumoral delivery of GOFA-DOX/HACPN could provide controlled and targeted delivery of DOX through slow degradation HACPN and subsequent cellular uptake of released GOFA-DOX by tumor cells through interactions of GOFA with folate receptors on the tumor cell’s surface. GOFA nano-carrier and HACPN hydrogel were first characterized for the physico-chemical properties. The drug loading experiments indicated the best preparation condition of GOFA-DOX was by reacting 0.1 mg GOFA with 2 mg DOX. GOFA-DOX showed pH-responsive drug release with ~5 times more DOX released at pH 5.5 than at pH 7.4 while only limited DOX was released from GOFA-DOX/HACPN at pH 7.4. Intracellular uptake of GOFA by endocytosis and release of DOX from GOFA-DOX in vitro could be confirmed from transmission electron microscopic and confocal laser scanning microscopic analysis with MCF-7 breast cancer cells. The targeting effect of FA was revealed when intracellular uptake of GOFA was blocked by excess FA. This resulted in enhanced in vitro cytotoxicity as revealed from the lower half maximal inhibitory concentration (IC50) value of GOFA-DOX (7.3 μg/mL) compared with that of DOX (32.5 μg/mL) and GO-DOX (10 μg/mL). The flow cytometry analysis indicated higher apoptosis rates for cells treated with GOFA-DOX (30%) compared with DOX (8%) and GO-DOX (11%). Animal studies were carried out with subcutaneously implanted MCF-7 cells in BALB/c nude mice and subject to intratumoral administration of drugs. The relative tumor volumes of control (saline) and GOFA-DOX/HACPN groups at day 21 were 2.17 and 1.79 times that at day 0 with no significant difference. In comparison, the relative tumor volumes of treatment groups at the same time were significantly different at 1.02, 0.67 and 0.48 times for DOX, GOFA-DOX and GOFA-DOX/HACPN groups, respectively. The anti-tumor efficacy was also supported by images from an in vivo imaging system (IVIS) using MCF-7 cells transfected with luciferase (MCF-7/Luc). Furthermore, tissue biopsy examination and blood analysis indicated that intratumoral delivery of DOX using GOFA-DOX/HACPN did not elicit acute toxicity. Taken together, GOFA-DOX/HACPN could be deemed as a safe and efficient intratumoral drug delivery system for breast cancer therapy. Full article

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

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10 pages, 4239 KiB

Open AccessArticle

Constructing Asymmetric Polyion Complex Vesicles via Template Assembling Strategy: Formulation Control and Tunable Permeability

by Junbo Li^1,*

, Lijuan Liang¹, Ju Liang¹, Wenlan Wu², Huiyun Zhou¹ and Jinwu Guo¹

¹ School of Chemical Engineering & Pharmaceutics, Henan University of Science & Technology, 263# Kaiyuan Road, Luoyang 471023, China

² School of Medicine, Henan University of Science & Technology, 263# Kaiyuan Road, Luoyang 471023, China

Nanomaterials 2017, 7(11), 387; https://doi.org/10.3390/nano7110387 - 13 Nov 2017

Cited by 6 | Viewed by 4677

Abstract

A strategy for constructing polyion complex vesicles (PICsomes) with asymmetric structure is described. Poly(methylacrylic acid)-block-poly(N-isopropylacrylamide) modified gold nanoparticles (PMAA-b-PNIPAm-@-Au NPs) were prepared and then assembled with poly(ethylene glycol)-block-poly[1-methyl-3-(2-methacryloyloxy propylimidazolium bromine)] (PEG-b-PMMPImB) via polyion [...] Read more.

A strategy for constructing polyion complex vesicles (PICsomes) with asymmetric structure is described. Poly(methylacrylic acid)-block-poly(N-isopropylacrylamide) modified gold nanoparticles (PMAA-b-PNIPAm-@-Au NPs) were prepared and then assembled with poly(ethylene glycol)-block-poly[1-methyl-3-(2-methacryloyloxy propylimidazolium bromine)] (PEG-b-PMMPImB) via polyion complex of PMMA and PMMPImB. After removing the Au NPs template, asymmetric PICsomes composed of a PNIPAm inner-shell, PIC wall, and PEG outer-corona were obtained. These PICsomes have low protein absorption and thermally tunable permeability, provided by the PEG outer-corona and the PNIPAm inner-shell, respectively. Moreover, PICsome size can be tailored by using templates of predetermined sizes. This novel strategy for constructing asymmetric PICsomes with well-defined properties and controllable size is valuable for applications such as drug delivery, catalysis and monitoring of chemical reactions, and biomimetics. Full article

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

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14 pages, 2469 KiB

Open AccessFeature PaperArticle

Carbon Nanotubes’ Effect on Mitochondrial Oxygen Flux Dynamics: Polarography Experimental Study and Machine Learning Models using Star Graph Trace Invariants of Raman Spectra

by Michael González-Durruthy¹

, Jose M. Monserrat^1,*

, Bakhtiyor Rasulev²

, Gerardo M. Casañola-Martín³

, José María Barreiro Sorrivas⁴, Sergio Paraíso-Medina⁵

, Víctor Maojo⁵, Humberto González-Díaz^6,7, Alejandro Pazos^8,9

and Cristian R. Munteanu^8,9,*

¹ Institute of Biological Science (ICB), Federal University of Rio Grande, Rio Grande, RS 96270-900, Brazil

² Department of Coatings and Polymeric Materials, North Dakota State University (NDSU), Fargo, ND 58102, USA

³ Department of Systems and Computer Engineering, Carleton University, Ottawa, ON K1S 5B6, Canada

⁴ Computer Science School (ETSIINF), Polytechnic University of Madrid (UPM), Calle de losCiruelos, Boadilla del Monte, 28660 Madrid, Spain

⁵ Biomedical Informatics Group, Artificial Intelligence Department, Polytechnic University of Madrid, Calle de los Ciruelos, Boadilla del Monte, 28660 Madrid, Spain

⁶ Department of Organic Chemistry II, University of the Basque Country UPV/EHU, 48940 Leioa, Biscay, Spain

⁷ IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Biscay, Spain

⁸ INIBIC Institute of Biomedical Research, CHUAC, UDC, 15006 Coruña, Spain

⁹ RNASA-IMEDIR, Computer Sciences Faculty, University of Coruña, 15071 Coruña, Spain

Nanomaterials 2017, 7(11), 386; https://doi.org/10.3390/nano7110386 - 11 Nov 2017

Cited by 15 | Viewed by 5537

Abstract

This study presents the impact of carbon nanotubes (CNTs) on mitochondrial oxygen mass flux (J_m) under three experimental conditions. New experimental results and a new methodology are reported for the first time and they are based on CNT Raman spectra [...] Read more.

This study presents the impact of carbon nanotubes (CNTs) on mitochondrial oxygen mass flux (J_m) under three experimental conditions. New experimental results and a new methodology are reported for the first time and they are based on CNT Raman spectra star graph transform (spectral moments) and perturbation theory. The experimental measures of J_m showed that no tested CNT family can inhibit the oxygen consumption profiles of mitochondria. The best model for the prediction of J_m for other CNTs was provided by random forest using eight features, obtaining test R-squared (R²) of 0.863 and test root-mean-square error (RMSE) of 0.0461. The results demonstrate the capability of encoding CNT information into spectral moments of the Raman star graphs (SG) transform with a potential applicability as predictive tools in nanotechnology and material risk assessments. Full article

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

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12 pages, 2963 KiB

Open AccessArticle

Data Retention Characterization of Gate-Injected Gold-Nanoparticle Non-Volatile Memory with Low-Damage CF₄-Plasma-Treated Blocking Oxide Layer

by Yu-Hua Liu^1,†, Chyuan-Haur Kao^1,2,3,†, Tsung-Chin Cheng⁴, Chih-I Wu^4,5,6 and Jer-Chyi Wang^1,2,7,*

¹ Department of Electronic Engineering, Chang Gung University, Guishan Dist., Taoyuan 33302, Taiwan

² Department of Electronic Engineering, Ming Chi University of Technology, Taishan Dist., New Taipei City 24301, Taiwan

³ Kidney Research Center, Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Guishan Dist., Taoyuan 33305, Taiwan

⁴ Graduated Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan

⁵ Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan

⁶ Electronic and Optoelectronic System Research Laboratories, Industrial Technology Research Institute, Chutung, Hsinchu 31057, Taiwan

⁷ Department of Neurosurgery, Chang Gung Memorial Hospital, Linkou, Guishan Dist., Taoyuan 33305, Taiwan

^† These authors contributed equally to this work.

Nanomaterials 2017, 7(11), 385; https://doi.org/10.3390/nano7110385 - 10 Nov 2017

Cited by 2 | Viewed by 4126

Abstract

Gold-nanoparticle (Au-NP) non-volatile memories (NVMs) with low-damage CF₄ plasma treatment on the blocking oxide (BO) layer have been investigated to present the gate injection of the holes. These holes, injected from the Al gate with the positive gate bias, were explained by [...] Read more.

Gold-nanoparticle (Au-NP) non-volatile memories (NVMs) with low-damage CF₄ plasma treatment on the blocking oxide (BO) layer have been investigated to present the gate injection of the holes. These holes, injected from the Al gate with the positive gate bias, were explained by the bandgap engineering of the gradually-fluorinated BO layer and the effective work function modulation of the Al gate. The Si–F complex in the BO layer was analyzed by X-ray photoelectron spectroscopy (XPS), while the depth of fluorine incorporation was verified using a secondary ion mass spectrometer (SIMS). In addition, the valence band modification of the fluorinated BO layer was examined by ultraviolet photoelectron spectroscopy (UPS) to support the bandgap engineering. The reactive power of the CF₄ plasma treatment on the BO layer was modified to increase the electric field of the BO layer and raise the effective work function of the Al gate, leading to the hole-injection from the gate. The injected holes are trapped at the interface between the gold-nanoparticles (Au-NPs) and the tunneling oxide (TO) layer, resulting in superior data retention properties such as an extremely low charge loss of 5.7% at 10⁴ s and a nearly negligible increase in charge loss at 85 °C of the CF₄-plasma-treated Au-NP NVMs, which can be applied in highly reliable consumer electronics. Full article

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15 pages, 7224 KiB

Open AccessArticle

H₂S Sensing by Hybrids Based on Nanocrystalline SnO₂ Functionalized with Cu(II) Organometallic Complexes: The Role of the Ligand Platform

by Marina Rumyantseva^1,*

, Ekaterina Makeeva¹, Alexander Gaskov¹, Nikolay Shepel², Svetlana Peregudova², Andrey Khoroshutin¹, Sergey Tokarev¹ and Olga Fedorova^1,2

¹ Faculty of Chemistry, Moscow State University, 119991 Moscow, Russia

² A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, 119991 Moscow, Russia

Nanomaterials 2017, 7(11), 384; https://doi.org/10.3390/nano7110384 - 9 Nov 2017

Cited by 8 | Viewed by 4520

Abstract

This paper deals with the functionalization of nanocrystalline SnO₂ with Cu(II) complexes with organic ligands, aimed at the improvement of sensor selectivity towards gas molecules. For the synthesis of metalorganic/SnO₂ hybrid material complexes of Cu(II) with phthalocyanine, porphyrinines, bipyridine and azadithiacrown [...] Read more.

This paper deals with the functionalization of nanocrystalline SnO₂ with Cu(II) complexes with organic ligands, aimed at the improvement of sensor selectivity towards gas molecules. For the synthesis of metalorganic/SnO₂ hybrid material complexes of Cu(II) with phthalocyanine, porphyrinines, bipyridine and azadithiacrown etherwere used. The analysis of gas sensor properties showed the possibility of increasing the sensitivity and selectivity of hybrid materials in H₂S detection due to the electron transfer from SnO₂ to an adsorbed organic molecule, which changes during the interaction between H₂S and Cu(II) ions. Full article

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

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32 pages, 5946 KiB

Open AccessReview

The Electrospun Ceramic Hollow Nanofibers

by Shahin Homaeigohar^1,*

, Yalda Davoudpour², Youssef Habibi³ and Mady Elbahri^1,4,*

¹ Nanochemistry and Nanoengineering, School of Chemical Engineering, Department of Chemistry and Materials Science, Aalto University, Kemistintie 1, 00076 Aalto, Finland

² The Institute of Mineralogy, Crystallography and Material Science, Faculty of Chemistry and Mineralogy, University of Leipzig, 04109 Leipzig, Germany

³ Department of Materials Research and Technology (MRT), Luxembourg Institute of Science and Technology (LIST), L-4362 Esch-sur-Alzette, Luxembourg

⁴ Nanochemistry and Nanoengineering, Institute for Materials Science, Faculty of Engineering, Christian-Albrechts-Universität zu Kiel, Kaiserstrasse 2, 24143 Kiel, Germany

Nanomaterials 2017, 7(11), 383; https://doi.org/10.3390/nano7110383 - 9 Nov 2017

Cited by 57 | Viewed by 9356

Abstract

Hollow nanofibers are largely gaining interest from the scientific community for diverse applications in the fields of sensing, energy, health, and environment. The main reasons are: their extensive surface area that increases the possibilities of engineering, their larger accessible active area, their porosity, [...] Read more.

Hollow nanofibers are largely gaining interest from the scientific community for diverse applications in the fields of sensing, energy, health, and environment. The main reasons are: their extensive surface area that increases the possibilities of engineering, their larger accessible active area, their porosity, and their sensitivity. In particular, semiconductor ceramic hollow nanofibers show greater space charge modulation depth, higher electronic transport properties, and shorter ion or electron diffusion length (e.g., for an enhanced charging–discharging rate). In this review, we discuss and introduce the latest developments of ceramic hollow nanofiber materials in terms of synthesis approaches. Particularly, electrospinning derivatives will be highlighted. The electrospun ceramic hollow nanofibers will be reviewed with respect to their most widely studied components, i.e., metal oxides. These nanostructures have been mainly suggested for energy and environmental remediation. Despite the various advantages of such one dimensional (1D) nanostructures, their fabrication strategies need to be improved to increase their practical use. The domain of nanofabrication is still advancing, and its predictable shortcomings and bottlenecks must be identified and addressed. Inconsistency of the hollow nanostructure with regard to their composition and dimensions could be one of such challenges. Moreover, their poor scalability hinders their wide applicability for commercialization and industrial use. Full article

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30 pages, 7306 KiB

Open AccessReview

Engineering the Surface/Interface Structures of Titanium Dioxide Micro and Nano Architectures towards Environmental and Electrochemical Applications

by Xiaoliang Wang¹, Yanyan Zhao², Kristian Mølhave^3,* and Hongyu Sun^3,*

¹ College of Science, Hebei University of Science and Technology, Shijiazhuang 050018, China

² Department of Chemistry Boston College Merkert Chemistry Center, 2609 Beacon St., Chestnut Hill, MA 02467, USA

³ Department of Micro- and Nanotechnology, Technical University of Denmark, Kongens Lyngby 2800, Denmark

Nanomaterials 2017, 7(11), 382; https://doi.org/10.3390/nano7110382 - 9 Nov 2017

Cited by 43 | Viewed by 8864

Abstract

Titanium dioxide (TiO₂) materials have been intensively studied in the past years because of many varied applications. This mini review article focuses on TiO₂ micro and nano architectures with the prevalent crystal structures (anatase, rutile, brookite, and TiO₂(B)), [...] Read more.

Titanium dioxide (TiO₂) materials have been intensively studied in the past years because of many varied applications. This mini review article focuses on TiO₂ micro and nano architectures with the prevalent crystal structures (anatase, rutile, brookite, and TiO₂(B)), and summarizes the major advances in the surface and interface engineering and applications in environmental and electrochemical applications. We analyze the advantages of surface/interface engineered TiO₂ micro and nano structures, and present the principles and growth mechanisms of TiO₂ nanostructures via different strategies, with an emphasis on rational control of the surface and interface structures. We further discuss the applications of TiO₂ micro and nano architectures in photocatalysis, lithium/sodium ion batteries, and Li–S batteries. Throughout the discussion, the relationship between the device performance and the surface/interface structures of TiO₂ micro and nano structures will be highlighted. Then, we discuss the phase transitions of TiO₂ nanostructures and possible strategies of improving the phase stability. The review concludes with a perspective on the current challenges and future research directions. Full article

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

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13 pages, 2346 KiB

Open AccessReview

ZnO Nanowire Application in Chemoresistive Sensing: A Review

by Simas Rackauskas^*, Nadia Barbero, Claudia Barolo and Guido Viscardi

Department of Chemistry, NIS Interdepartmental Centre and INSTM Reference Centre, University of Turin, Via Pietro Giuria 7, 10125 Turin, Italy

Nanomaterials 2017, 7(11), 381; https://doi.org/10.3390/nano7110381 - 9 Nov 2017

Cited by 73 | Viewed by 7859

Abstract

This article provides an overview of the recent development of ZnO nanowires (NWs) for chemoresistive sensing. Working mechanisms of chemoresistive sensors are unified for gas, ultraviolet (UV) and bio sensor types: single nanowire and nanowire junction sensors are described, giving the overview for [...] Read more.

This article provides an overview of the recent development of ZnO nanowires (NWs) for chemoresistive sensing. Working mechanisms of chemoresistive sensors are unified for gas, ultraviolet (UV) and bio sensor types: single nanowire and nanowire junction sensors are described, giving the overview for a simple sensor manufacture by multiple nanowire junctions. ZnO NW surface functionalization is discussed, and how this effects the sensing is explained. Further, novel approaches for sensing, using ZnO NW functionalization with other materials such as metal nanoparticles or heterojunctions, are explained, and limiting factors and possible improvements are discussed. The review concludes with the insights and recommendations for the future improvement of the ZnO NW chemoresistive sensing. Full article

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

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13 pages, 4998 KiB

Open AccessArticle

Rationally Controlled Synthesis of CdSe_xTe_1−x Alloy Nanocrystals and Their Application in Efficient Graded Bandgap Solar Cells

by Shiya Wen^1,†, Miaozi Li^1,†, Junyu Yang², Xianglin Mei¹, Bin Wu¹, Xiaolin Liu¹, Jingxuan Heng¹, Donghuan Qin^1,3,*

, Lintao Hou^2,*, Wei Xu^1,3 and Dan Wang^1,3

¹ School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China

² Siyuan Laboratory, Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Department of Physics, Jinan University, Guangzhou 510632, China

³ Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology, Guangzhou 510640, China

^† These authors contributed equally to this work.

Nanomaterials 2017, 7(11), 380; https://doi.org/10.3390/nano7110380 - 8 Nov 2017

Cited by 30 | Viewed by 4838

Abstract

CdSe_xTe_1−x semiconductor nanocrystals (NCs), being rod-shaped/irregular dot-shaped in morphology, have been fabricated via a simple hot-injection method. The NCs composition is well controlled through varying molar ratios of Se to Te precursors. Through changing the composition of the CdSe_x [...] Read more.

CdSe_xTe_1−x semiconductor nanocrystals (NCs), being rod-shaped/irregular dot-shaped in morphology, have been fabricated via a simple hot-injection method. The NCs composition is well controlled through varying molar ratios of Se to Te precursors. Through changing the composition of the CdSe_xTe_1−x NCs, the spectral absorption of the NC thin film between 570–800 nm is proved to be tunable. It is shown that the bandgap of homogeneously alloyed CdSe_xTe_1−x active thin film is nonlinearly correlated with the different compositions, which is perceived as optical bowing. The solar cell devices based on CdSe_xTe_1−x NCs with the structure of ITO/ZnO/CdSe/CdSe_xTe_1−x/MoO_x/Au and the graded bandgap ITO/ZnO/CdSe(w/o)/CdSe_x_Te_1−x/CdTe/MoO_x/Au are systematically evaluated. It was found that the performance of solar cells degrades almost linearly with the increase of alloy NC film thickness with respect to ITO/ZnO/CdSe/CdSe_0.2Te_0.8/MoO_x/Au. From another perspective, in terms of the graded bandgap structure of ITO/ZnO/CdSe/CdSe_xTe_1−x/CdTe/MoO_x/Au, the performance is improved in contrast with its single-junction analogues. The graded bandgap structure is proved to be efficient when absorbing spectrum and the solar cells fabricated under the structure of ITO/ZnO/CdSe_0.8Te_0.2/CdSe_0.2Te_0.8/CdTe/MoO_x/Au indicate power conversion efficiency (PCE) of 6.37%, a value among the highest for solution-processed inversely-structured CdSe_xTe_1−x NC solar cells. As the NC solar cells are solution-processed under environmental conditions, they are promising for fabricating solar cells at low cost, roll by roll and in large area. Full article

(This article belongs to the Special Issue Nanomaterials for Renewable and Sustainable Energy)

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17 pages, 18385 KiB

Open AccessArticle

Increased Loading, Efficacy and Sustained Release of Silibinin, a Poorly Soluble Drug Using Hydrophobically-Modified Chitosan Nanoparticles for Enhanced Delivery of Anticancer Drug Delivery Systems

by Cha Yee Kuen^1,2

, Sharida Fakurazi³, Siti Sarah Othman¹

and Mas Jaffri Masarudin^1,2,*

¹ Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia

² Cancer Research Laboratory, Institute of Biosciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia

³ Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia

Nanomaterials 2017, 7(11), 379; https://doi.org/10.3390/nano7110379 - 8 Nov 2017

Cited by 40 | Viewed by 6855

Abstract

Conventional delivery of anticancer drugs is less effective due to pharmacological drawbacks such as lack of aqueous solubility and poor cellular accumulation. This study reports the increased drug loading, therapeutic delivery, and cellular accumulation of silibinin (SLB), a poorly water-soluble phenolic compound using [...] Read more.

Conventional delivery of anticancer drugs is less effective due to pharmacological drawbacks such as lack of aqueous solubility and poor cellular accumulation. This study reports the increased drug loading, therapeutic delivery, and cellular accumulation of silibinin (SLB), a poorly water-soluble phenolic compound using a hydrophobically-modified chitosan nanoparticle (pCNP) system. In this study, chitosan nanoparticles were hydrophobically-modified to confer a palmitoyl group as confirmed by 2,4,6-Trinitrobenzenesulfonic acid (TNBS) assay. Physicochemical features of the nanoparticles were studied using the TNBS assay, and Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analyses. The FTIR profile and electron microscopy correlated the successful formation of pCNP and pCNP-SLB as nano-sized particles, while Dynamic Light Scattering (DLS) and Field Emission-Scanning Electron Microscopy (FESEM) results exhibited an expansion in size between pCNP and pCNP-SLB to accommodate the drug within its particle core. To evaluate the cytotoxicity of the nanoparticles, a Methylthiazolyldiphenyl-tetrazolium bromide (MTT) cytotoxicity assay was subsequently performed using the A549 lung cancer cell line. Cytotoxicity assays exhibited an enhanced efficacy of SLB when delivered by CNP and pCNP. Interestingly, controlled release delivery of SLB was achieved using the pCNP-SLB system, conferring higher cytotoxic effects and lower IC₅₀ values in 72-h treatments compared to CNP-SLB, which was attributed to the hydrophobic modification of the CNP system. Full article

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

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8 pages, 1624 KiB

Open AccessArticle

ZnO Nanoparticles Protect RNA from Degradation Better than DNA

by Jayden McCall¹

, Joshua J. Smith², Kelsey N. Marquardt², Katelin R. Knight², Hunter Bane², Alice Barber² and Robert K. DeLong^1,*

¹ Nanotechnology Innovation Center Kansas State (NICKS), Department of Anatomy and Physiology, College of Veterinary Medicine, Manhattan, KS 66506, USA

² Department of Biomedical Sciences, College of Health and Human Services, Missouri State University, Springfield, MO 65897, USA

Nanomaterials 2017, 7(11), 378; https://doi.org/10.3390/nano7110378 - 8 Nov 2017

Cited by 21 | Viewed by 6808

Abstract

Gene therapy and RNA delivery require a nanoparticle (NP) to stabilize these nucleic acids when administered in vivo. The presence of degradative hydrolytic enzymes within these environments limits the nucleic acids’ pharmacologic activity. This study compared the effects of nanoscale ZnO and MgO [...] Read more.

Gene therapy and RNA delivery require a nanoparticle (NP) to stabilize these nucleic acids when administered in vivo. The presence of degradative hydrolytic enzymes within these environments limits the nucleic acids’ pharmacologic activity. This study compared the effects of nanoscale ZnO and MgO in the protection afforded to DNA and RNA from degradation by DNase, serum or tumor homogenate. For double-stranded plasmid DNA degradation by DNase, our results suggest that the presence of MgO NP can protect DNA from DNase digestion at an elevated temperature (65 °C), a biochemical activity not present in ZnO NP-containing samples at any temperature. In this case, intact DNA was remarkably present for MgO NP after ethidium bromide staining and agarose gel electrophoresis where these same stained DNA bands were notably absent for ZnO NP. Anticancer RNA, polyinosinic-polycytidylic acid (poly I:C) is now considered an anti-metastatic RNA targeting agent and as such there is great interest in its delivery by NP. For it to function, the NP must protect it from degradation in serum and the tumor environment. Surprisingly, ZnO NP protected the RNA from degradation in either serum-containing media or melanoma tumor homogenate after gel electrophoretic analysis, whereas the band was much more diminished in the presence of MgO. For both MgO and ZnO NP, buffer-dependent rescue from degradation occurred. These data suggest a fundamental difference in the ability of MgO and ZnO NP to stabilize nucleic acids with implications for DNA and RNA delivery and therapy. Full article

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

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9 pages, 2049 KiB

Open AccessArticle

Magnetic Nanoparticle-Assisted Tunable Optical Patterns from Spherical Cholesteric Liquid Crystal Bragg Reflectors

by Yali Lin^1,2, Yujie Yang^1,2, Yuwei Shan^1,2, Lingli Gong^1,2, Jingzhi Chen¹, Sensen Li^1,2 and Lujian Chen^1,2,*

¹ Department of Electronic Engineering, Xiamen University, Xiamen 361005, China

² Shenzhen Research Institute of Xiamen University, Shenzhen 518057, China

Nanomaterials 2017, 7(11), 376; https://doi.org/10.3390/nano7110376 - 8 Nov 2017

Cited by 26 | Viewed by 6099

Abstract

Cholesteric liquid crystals (CLCs) exhibit selective Bragg reflections of circularly polarized (CP) light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC) structures. To endow these [...] Read more.

Cholesteric liquid crystals (CLCs) exhibit selective Bragg reflections of circularly polarized (CP) light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC) structures. To endow these optical patterns with tunability, we fabricated spherical CLC Bragg reflectors in the shape of microshells by glass-capillary microfluidics. Water-soluble magnetofluid with Fe₃O₄ nanoparticles incorporated in the inner aqueous core of CLC shells is responsible for the non-invasive transportable capability. With the aid of an external magnetic field, the reflection interactions between neighboring microshells and microdroplets were identified by varying the mutual distance in a group of magnetically transportable and unmovable spherical CLC structures. The temperature-dependent optical reflection patterns were investigated in close-packed hexagonal arrangements of seven CLC microdroplets and microshells with inverse helicity handedness. Moreover, we demonstrated that the magnetic field-assisted assembly of microshells array into geometric figures of uppercase English letters “L” and “C” was successfully achieved. We hope that these findings can provide good application prospects for security pattern designs. Full article

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

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14 pages, 2467 KiB

Open AccessArticle

ZnO Interactions with Biomatrices: Effect of Particle Size on ZnO-Protein Corona

by Jin Yu, Hyeon-Jin Kim, Mi-Ran Go, Song-Hwa Bae and Soo-Jin Choi^*

Department of Applied Food System, Major of Food Science & Technology, Seoul Women’s University, Seoul 01797, Korea

Nanomaterials 2017, 7(11), 377; https://doi.org/10.3390/nano7110377 - 6 Nov 2017

Cited by 52 | Viewed by 5740

Abstract

Zinc oxide (ZnO) nanoparticles (NPs) have been widely used for food fortification, because zinc is essential for many enzyme and hormone activities and cellular functions, but public concern about their potential toxicity is increasing. Interactions between ZnO and biomatrices might affect the oral [...] Read more.

Zinc oxide (ZnO) nanoparticles (NPs) have been widely used for food fortification, because zinc is essential for many enzyme and hormone activities and cellular functions, but public concern about their potential toxicity is increasing. Interactions between ZnO and biomatrices might affect the oral absorption, distribution, and toxicity of ZnO, which may be influenced by particle size. In this study, ZnO interactions with biomatrices were investigated by examining the physicochemical properties, solubility, protein fluorescence quenching, particle–protein corona, and intestinal transport with respect to the particle size (bulk vs. nano) in simulated gastrointestinal (GI) and plasma fluids and in rat-extracted fluids. The results demonstrate that the hydrodynamic radii and zeta potentials of bulk ZnO and nano ZnO in biofluids changed in different ways, and that nano ZnO induced higher protein fluorescence quenching than bulk ZnO. However, ZnO solubility and its intestinal transport mechanism were unaffected by particle size. Proteomic analysis revealed that albumin, fibrinogen, and fibronectin play roles in particle–plasma protein corona, regardless of particle size. Furthermore, nano ZnO was found to interact more strongly with plasma proteins. These observations show that bulk ZnO and nano ZnO interact with biomatrices in different ways and highlight the need for further study of their long-term toxicity. Full article

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

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Nanomaterials, Volume 7, Issue 11 (November 2017) – 60 articles

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