Nanomaterials

856 KiB

Open AccessArticle

Layer-by-Layer Self-Assembling Gold Nanorods and Glucose Oxidase onto Carbon Nanotubes Functionalized Sol-Gel Matrix for an Amperometric Glucose Biosensor

by Baoyan Wu, Shihua Hou, Zhiying Miao, Cong Zhang and Yanhong Ji

Nanomaterials 2015, 5(3), 1544-1555; https://doi.org/10.3390/nano5031544 - 18 Sep 2015

Cited by 26 | Viewed by 6667

Abstract

A novel amperometric glucose biosensor was fabricated by layer-by-layer self-assembly of gold nanorods (AuNRs) and glucose oxidase (GOD) onto single-walled carbon nanotubes (SWCNTs)-functionalized three-dimensional sol-gel matrix. A thiolated aqueous silica sol containing SWCNTs was first assembled on the surface of a cleaned Au [...] Read more.

A novel amperometric glucose biosensor was fabricated by layer-by-layer self-assembly of gold nanorods (AuNRs) and glucose oxidase (GOD) onto single-walled carbon nanotubes (SWCNTs)-functionalized three-dimensional sol-gel matrix. A thiolated aqueous silica sol containing SWCNTs was first assembled on the surface of a cleaned Au electrode, and then the alternate self-assembly of AuNRs and GOD were repeated to assemble multilayer films of AuNRs-GOD onto SWCNTs-functionalized silica gel for optimizing the biosensor. Among the resulting glucose biosensors, the four layers of AuNRs-GOD-modified electrode showed the best performance. The sol-SWCNTs-(AuNRs- GOD)₄/Au biosensor exhibited a good linear range of 0.01–8 mM glucose, high sensitivity of 1.08 μA/mM, and fast amperometric response within 4 s. The good performance of the proposed glucose biosensor could be mainly attributed to the advantages of the three-dimensional sol-gel matrix and stereo self-assembly films, and the natural features of one-dimensional nanostructure SWCNTs and AuNRs. This study may provide a new facile way to fabricate the enzyme-based biosensor with high performance. Full article

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

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1678 KiB

Open AccessArticle

Surface Evolution of Nano-Textured 4H–SiC Homoepitaxial Layers after High Temperature Treatments: Morphology Characterization and Graphene Growth

by Xingfang Liu, Yu Chen, Changzheng Sun, Min Guan, Yang Zhang, Feng Zhang, Guosheng Sun and Yiping Zeng

Nanomaterials 2015, 5(3), 1532-1543; https://doi.org/10.3390/nano5031532 - 18 Sep 2015

Cited by 4 | Viewed by 5054

Abstract

Nano-textured 4H–SiC homoepitaxial layers (NSiCLs) were grown on 4H–SiC(0001) substrates using a low pressure chemical vapor deposition technique (LPCVD), and subsequently were subjected to high temperature treatments (HTTs) for investigation of their surface morphology evolution and graphene growth. It was found that continuously [...] Read more.

Nano-textured 4H–SiC homoepitaxial layers (NSiCLs) were grown on 4H–SiC(0001) substrates using a low pressure chemical vapor deposition technique (LPCVD), and subsequently were subjected to high temperature treatments (HTTs) for investigation of their surface morphology evolution and graphene growth. It was found that continuously distributed nano-scale patterns formed on NSiCLs which were about submicrons in-plane and about 100 nanometers out-of-plane in size. After HTTs under vacuum, pattern sizes reduced, and the sizes of the remains were inversely proportional to the treatment time. Referring to Raman spectra, the establishment of multi-layer graphene (MLG) on NSiCL surfaces was observed. MLG with sp² disorders was obtained from NSiCLs after a high temperature treatment under vacuum at 1700 K for two hours, while MLG without sp² disorders was obtained under Ar atmosphere at 1900 K. Full article

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5541 KiB

Open AccessReview

Textile-Based Electronic Components for Energy Applications: Principles, Problems, and Perspective

by Vishakha Kaushik, Jaehong Lee, Juree Hong, Seulah Lee, Sanggeun Lee, Jungmok Seo, Chandreswar Mahata and Taeyoon Lee

Nanomaterials 2015, 5(3), 1493-1531; https://doi.org/10.3390/nano5031493 - 7 Sep 2015

Cited by 84 | Viewed by 15883

Abstract

Textile-based electronic components have gained interest in the fields of science and technology. Recent developments in nanotechnology have enabled the integration of electronic components into textiles while retaining desirable characteristics such as flexibility, strength, and conductivity. Various materials were investigated in detail to [...] Read more.

Textile-based electronic components have gained interest in the fields of science and technology. Recent developments in nanotechnology have enabled the integration of electronic components into textiles while retaining desirable characteristics such as flexibility, strength, and conductivity. Various materials were investigated in detail to obtain current conductive textile technology, and the integration of electronic components into these textiles shows great promise for common everyday applications. The harvest and storage of energy in textile electronics is a challenge that requires further attention in order to enable complete adoption of this technology in practical implementations. This review focuses on the various conductive textiles, their methods of preparation, and textile-based electronic components. We also focus on fabrication and the function of textile-based energy harvesting and storage devices, discuss their fundamental limitations, and suggest new areas of study. Full article

(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)

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1763 KiB

Open AccessArticle

Graphene/Sulfur/Carbon Nanocomposite for High Performance Lithium-Sulfur Batteries

by Kangke Jin, Xufeng Zhou and Zhaoping Liu

Nanomaterials 2015, 5(3), 1481-1492; https://doi.org/10.3390/nano5031481 - 1 Sep 2015

Cited by 20 | Viewed by 9320

Abstract

Here, we report a two-step synthesis of graphene/sulfur/carbon ternary composite with a multilayer structure. In this composite, ultrathin S layers are uniformly deposited on graphene nanosheets and covered by a thin layer of amorphous carbon derived from β-cyclodextrin on the surface. Such a [...] Read more.

Here, we report a two-step synthesis of graphene/sulfur/carbon ternary composite with a multilayer structure. In this composite, ultrathin S layers are uniformly deposited on graphene nanosheets and covered by a thin layer of amorphous carbon derived from β-cyclodextrin on the surface. Such a unique microstructure, not only improves the electrical conductivity of sulfur, but also effectively inhibits the dissolution of polysulfides during charging/discharging processes. As a result, this ternary nanocomposite exhibits excellent electrochemical performance. It can deliver a high initial discharge and charge capacity of 1410 mAh·g⁻¹ and 1370 mAh·g⁻¹, respectively, and a capacity retention of 63.8% can be achieved after 100 cycles at 0.1 C (1 C = 1675 mA·g⁻¹). A relatively high specific capacity of 450 mAh·g⁻¹ can still be retained after 200 cycles at a high rate of 2 C. The synthesis process introduced here is simple and broadly applicable to the modification of sulfur cathode for better electrochemical performance. Full article

(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)

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1855 KiB

Open AccessArticle

High Performance Li₄Ti₅O₁₂/Si Composite Anodes for Li-Ion Batteries

by Chunhui Chen, Richa Agrawal and Chunlei Wang

Nanomaterials 2015, 5(3), 1469-1480; https://doi.org/10.3390/nano5031469 - 28 Aug 2015

Cited by 32 | Viewed by 8582

Abstract

Improving the energy capacity of spinel Li₄Ti₅O₁₂ (LTO) is very important to utilize it as a high-performance Li-ion battery (LIB) electrode. In this work, LTO/Si composites with different weight ratios were prepared and tested as anodes. The anodic [...] Read more.

Improving the energy capacity of spinel Li₄Ti₅O₁₂ (LTO) is very important to utilize it as a high-performance Li-ion battery (LIB) electrode. In this work, LTO/Si composites with different weight ratios were prepared and tested as anodes. The anodic and cathodic peaks from both LTO and silicon were apparent in the composites, indicating that each component was active upon Li⁺ insertion and extraction. The composites with higher Si contents (LTO:Si = 35:35) exhibited superior specific capacity (1004 mAh·g⁻¹) at lower current densities (0.22 A·g⁻¹) but the capacity deteriorated at higher current densities. On the other hand, the electrodes with moderate Si contents (LTO:Si = 50:20) were able to deliver stable capacity (100 mAh·g⁻¹) with good cycling performance, even at a very high current density of 7 A·g⁻¹. The improvement in specific capacity and rate performance was a direct result of the synergy between LTO and Si; the former can alleviate the stresses from volumetric changes in Si upon cycling, while Si can add to the capacity of the composite. Therefore, it has been demonstrated that the addition of Si and concentration optimization is an easy yet an effective way to produce high performance LTO-based electrodes for lithium-ion batteries. Full article

(This article belongs to the Special Issue Nanostructured Materials for Li-Ion Batteries and Beyond)

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1238 KiB

Open AccessArticle

Synthesis of Water-Based Dispersions of Polymer/TiO₂ Hybrid Nanospheres

by Lu Jin, Hua Wu and Massimo Morbidelli

Nanomaterials 2015, 5(3), 1454-1468; https://doi.org/10.3390/nano5031454 - 28 Aug 2015

Cited by 18 | Viewed by 6868

Abstract

We develop a strategy for preparing water-based dispersions of polymer/TiO₂ nanospheres that can be used to form composite materials applicable in various fields. The formed hybrid nanospheres are monodisperse and possess a hierarchical structure. It starts with the primary TiO₂ nanoparticles [...] Read more.

We develop a strategy for preparing water-based dispersions of polymer/TiO₂ nanospheres that can be used to form composite materials applicable in various fields. The formed hybrid nanospheres are monodisperse and possess a hierarchical structure. It starts with the primary TiO₂ nanoparticles of about 5 nm, which first assemble to nanoclusters of about 30 nm and then are integrated into monomer droplets. After emulsion polymerization, one obtains the water-based dispersions of polymer/TiO₂ nanospheres. To achieve universal size, it is necessary to have treatments with intense turbulent shear generated in a microchannel device at different stages. In addition, a procedure combining synergistic actions of steric and anionic surfactants has been designed to warrant the colloidal stability of the process. Since the formed polymer/TiO₂ nanospheres are stable aqueous dispersions, they can be easily mixed with TiO₂-free polymeric nanoparticle dispersions to form new dispersions, where TiO₂-containing nanospheres are homogeneously distributed in the dispersions at the nanoscale, thus leading to various applications. As an example, the proposed strategy has been applied to generate polystyrene/TiO₂ nanospheres of about 100 nm in diameter. Full article

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Open AccessArticle

Surface Wettability Modification of Cyclic Olefin Polymer by Direct Femtosecond Laser Irradiation

by Bing Wang, Xincai Wang, Hongyu Zheng and Yee Cheong Lam

Nanomaterials 2015, 5(3), 1442-1453; https://doi.org/10.3390/nano5031442 - 28 Aug 2015

Cited by 48 | Viewed by 7609

Abstract

The effect of laser irradiation on surface wettability of cyclic olefin polymer (COP) was investigated. Under different laser parameters, a superhydrophilic or a superhydrophobic COP surface with a water contact angle (WCA) of almost 0° or 163°, respectively, could be achieved by direct [...] Read more.

The effect of laser irradiation on surface wettability of cyclic olefin polymer (COP) was investigated. Under different laser parameters, a superhydrophilic or a superhydrophobic COP surface with a water contact angle (WCA) of almost 0° or 163°, respectively, could be achieved by direct femtosecond laser irradiation. The laser power deposition rate (PDR) was found to be a key factor on the wettability of the laser-treated COP surface. The surface roughness and surface chemistry of the laser-irradiated samples were characterized by surface profilometer and X-ray photoelectron spectroscopy, respectively; they were found to be responsible for the changes of the laser-induced surface wettability. The mechanisms involved in the laser surface wettability modification process were discussed. Full article

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

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Open AccessArticle

Synthesis of Mesoporous Metal Oxides by Structure Replication: Thermal Analysis of Metal Nitrates in Porous Carbon Matrices

by Christian Weinberger, Jan Roggenbuck, Jan Hanss and Michael Tiemann

Nanomaterials 2015, 5(3), 1431-1441; https://doi.org/10.3390/nano5031431 - 28 Aug 2015

Cited by 9 | Viewed by 6924

Abstract

A variety of metal nitrates were filled into the pores of an ordered mesoporous CMK-3 carbon matrix by solution-based impregnation. Thermal conversion of the metal nitrates into the respective metal oxides, and subsequent removal of the carbon matrix by thermal combustion, provides a [...] Read more.

A variety of metal nitrates were filled into the pores of an ordered mesoporous CMK-3 carbon matrix by solution-based impregnation. Thermal conversion of the metal nitrates into the respective metal oxides, and subsequent removal of the carbon matrix by thermal combustion, provides a versatile means to prepare mesoporous metal oxides (so-called nanocasting). This study aims to monitor the thermally induced processes by thermogravimetric analysis (TGA), coupled with mass ion detection (MS). The highly dispersed metal nitrates in the pores of the carbon matrix tend to react to the respective metal oxides at lower temperature than reported in the literature for pure, i.e., carbon-free, metal nitrates. The subsequent thermal combustion of the CMK-3 carbon matrix also occurs at lower temperature, which is explained by a catalytic effect of the metal oxides present in the pores. This catalytic effect is particularly strong for oxides of redox active metals, such as transition group VII and VIII metals (Mn, Fe, Co, Ni), Cu, and Ce. Full article

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

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982 KiB

Open AccessArticle

Comparison of the in Vitro Uptake and Toxicity of Collagen- and Synthetic Polymer-Coated Gold Nanoparticles

by Oana T. Marisca, Karsten Kantner, Christian Pfeiffer, Qian Zhang, Beatriz Pelaz, Nicolae Leopold, Wolfgang J. Parak and Joanna Rejman

Nanomaterials 2015, 5(3), 1418-1430; https://doi.org/10.3390/nano5031418 - 27 Aug 2015

Cited by 38 | Viewed by 7070

Abstract

We studied the physico-chemical properties (size, shape, zeta-potential), cellular internalization and toxicity of gold nanoparticles (NPs) stabilized with the most abundant mammalian protein, collagen. The properties of these gold NPs were compared to the same sized gold NPs coated with synthetic poly(isobutylene-alt-maleic anhydride) [...] Read more.

We studied the physico-chemical properties (size, shape, zeta-potential), cellular internalization and toxicity of gold nanoparticles (NPs) stabilized with the most abundant mammalian protein, collagen. The properties of these gold NPs were compared to the same sized gold NPs coated with synthetic poly(isobutylene-alt-maleic anhydride) (PMA). Intracellular uptake and cytotoxicity were assessed in two cell lines (cervical carcinoma and lung adenocarcinoma cells) by employing inductively-coupled plasma-mass spectrometry (ICP-MS) analysis and a cell viability assay based on 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), respectively. We found that the collagen-coated gold NPs exhibit lower cytotoxicity, but higher uptake levels than PMA-coated gold NPs. These results demonstrate that the surface coating of Au NPs plays a decisive role in their biocompatibility. Full article

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

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3921 KiB

Open AccessArticle

Preparation and Photocatalytic Activity of Potassium- Incorporated Titanium Oxide Nanostructures Produced by the Wet Corrosion Process Using Various Titanium Alloys

by So Yoon Lee, Choong Hyun Lee, Do Yun Kim, Jean-Pierre Locquet and Jin Won Seo

Nanomaterials 2015, 5(3), 1397-1417; https://doi.org/10.3390/nano5031397 - 21 Aug 2015

Cited by 23 | Viewed by 6769

Abstract

Nanostructured potassium-incorporated Ti-based oxides have attracted much attention because the incorporated potassium can influence their structural and physico-chemical properties. With the aim of tuning the structural and physical properties, we have demonstrated the wet corrosion process (WCP) as a simple method for nanostructure [...] Read more.

Nanostructured potassium-incorporated Ti-based oxides have attracted much attention because the incorporated potassium can influence their structural and physico-chemical properties. With the aim of tuning the structural and physical properties, we have demonstrated the wet corrosion process (WCP) as a simple method for nanostructure fabrication using various Ti-based materials, namely Ti–6Al–4V alloy (TAV), Ti–Ni (TN) alloy and pure Ti, which have 90%, 50% and 100% initial Ti content, respectively. We have systematically investigated the relationship between the Ti content in the initial metal and the precise condition of WCP to control the structural and physical properties of the resulting nanostructures. The WCP treatment involved various concentrations of KOH solutions. The precise conditions for producing K-incorporated nanostructured titanium oxide films (nTOFs) were strongly dependent on the Ti content of the initial metal. Ti and TAV yielded one-dimensional nanowires of K-incorporated nTOFs after treatment with 10 mol/L-KOH solution, whereas TN required a higher concentration (20 mol/L-KOH solution) to produce comparable nanostructures. The obtained nanostructures revealed a blue-shift in UV absorption spectra due to the quantum confinement effects. A significant enhancement of the photocatalytic activity was observed via the chromomeric change and the intermediate formation of methylene blue molecules under UV irradiation. This study demonstrates the WCP as a simple, versatile and scalable method for the production of nanostructured K-incorporated nTOFs to be used as high-performance photocatalysts for environmental and energy applications. Full article

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3184 KiB

Open AccessArticle

Hyaluronic Acid-Chitosan Nanoparticles to Deliver Gd-DTPA for MR Cancer Imaging

by Li Zhang, Tingxian Liu, Yanan Xiao, Dexin Yu and Na Zhang

Nanomaterials 2015, 5(3), 1379-1396; https://doi.org/10.3390/nano5031379 - 20 Aug 2015

Cited by 26 | Viewed by 8035

Abstract

Molecular imaging is essential to increase the sensitivity and selectivity of cancer diagnosis especially at the early stage of tumors. Recently, polyionic nanocomplexes (PICs), which are composed of polyanions and opposite polycations, have been demonstrated to be a promising strategy for biomedical applications. [...] Read more.

Molecular imaging is essential to increase the sensitivity and selectivity of cancer diagnosis especially at the early stage of tumors. Recently, polyionic nanocomplexes (PICs), which are composed of polyanions and opposite polycations, have been demonstrated to be a promising strategy for biomedical applications. In this work, chitosan-hyaluronic acid nanoparticles (GCHN) were developed to deliver Gd-DTPA as MRI contrast agents for tumor diagnosis. The Gd-labeled conjugates (CS-DTPA-Gd) were successfully synthesized by carbodiimide reaction, and then GCHN were prepared by ionic gelation using the obtained CS-DTPA-Gd and hyaluronic acid. The morphology of GCHN was spherical or ellipsoidal, which is observed by transmission electronic microscopy (TEM). The mean particle size and zeta potential of GCHN were 213.8 ± 2.6 nm and 19.92 ± 1.69 mV, respectively. The significant enhancement of signal intensity induced by GCHN was observed both in vitro and in vivo. Also, compared with Magnevist, GCHN was witnessed for a prolonged imaging time in the B16 tumor-bearing mice model. Furthermore, GCHN were verified as below toxic both in vitro and in vivo. These results indicated that GCHN could potentially be an alternative to current MRI contrast agents for tumor diagnosis. Full article

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

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Open AccessArticle

Carbon Nanotube/Alumina/Polyethersulfone Hybrid Hollow Fiber Membranes with Enhanced Mechanical and Anti-Fouling Properties

by Yi Feng, Kun Wang, Chris H. J. Davies and Huanting Wang

Nanomaterials 2015, 5(3), 1366-1378; https://doi.org/10.3390/nano5031366 - 20 Aug 2015

Cited by 31 | Viewed by 6350

Abstract

Carbon nanotubes (CNTs) were incorporated into alumina/polyethersulfone hollow fibre membranes to enhance the mechanical property and the efficiency of water treatment. Results show that the incorporation of CNTs can greatly limit the formation of large surface pores, decrease the void size in support [...] Read more.

Carbon nanotubes (CNTs) were incorporated into alumina/polyethersulfone hollow fibre membranes to enhance the mechanical property and the efficiency of water treatment. Results show that the incorporation of CNTs can greatly limit the formation of large surface pores, decrease the void size in support layers and improve the porosity and pore connectivity of alumina/polyethersulfone membranes. As a result of such morphology change and pore size change, both improved flux and rejection were achieved in such CNTs/alumina/polyethersulfone membranes. Moreover, the CNTs/alumina/PES membranes show higher antifouling ability and the flux recoveries after being fouled by bovine serum albumin (BSA) and humic acid were improved by 84.1% and 53.2% compared to the samples without CNT incorporation. Besides the improvement in water treatment performance, the incorporation of CNTs enhanced the tensile properties of inorganic/polymer membranes. Therefore, such CNTs/alumina/PES hollow fiber membranes are very promising candidates for good filter media in industry, considering their high efficiency and high mechanical properties. Full article

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652 KiB

Open AccessReview

Role of Physicochemical Properties in Nanoparticle Toxicity

by Seung Won Shin, In Hyun Song and Soong Ho Um

Nanomaterials 2015, 5(3), 1351-1365; https://doi.org/10.3390/nano5031351 - 19 Aug 2015

Cited by 253 | Viewed by 14150

Abstract

With the recent rapid growth of technological comprehension in nanoscience, researchers have aimed to adapt this knowledge to various research fields within engineering and applied science. Dramatic advances in nanomaterials marked a new epoch in biomedical engineering with the expectation that they would [...] Read more.

With the recent rapid growth of technological comprehension in nanoscience, researchers have aimed to adapt this knowledge to various research fields within engineering and applied science. Dramatic advances in nanomaterials marked a new epoch in biomedical engineering with the expectation that they would have huge contributions to healthcare. However, several questions regarding their safety and toxicity have arisen due to numerous novel properties. Here, recent studies of nanomaterial toxicology will be reviewed from several physiochemical perspectives. A variety of physiochemical properties such as size distribution, electrostatics, surface area, general morphology and aggregation may significantly affect physiological interactions between nanomaterials and target biological areas. Accordingly, it is very important to finely tune these properties in order to safely fulfill a bio-user’s purpose. Full article

(This article belongs to the Special Issue Advancements in Nanotoxicology)

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Open AccessArticle

Impact of Carbon Nano-Onions on Hydra vulgaris as a Model Organism for Nanoecotoxicology

by Valentina Marchesano, Alfredo Ambrosone, Juergen Bartelmess, Federica Strisciante, Angela Tino, Luis Echegoyen, Claudia Tortiglione and Silvia Giordani

Nanomaterials 2015, 5(3), 1331-1350; https://doi.org/10.3390/nano5031331 - 13 Aug 2015

Cited by 50 | Viewed by 15406

Abstract

The toxicological effects of pristine and chemically modified carbon nano-onions (CNOs) on the development of the freshwater polyp Hydra vulgaris were investigated in order to elucidate the ecotoxicological effects of CNOs. Chemical modifications of the CNOs were accomplished by surface functionalization with benzoic [...] Read more.

The toxicological effects of pristine and chemically modified carbon nano-onions (CNOs) on the development of the freshwater polyp Hydra vulgaris were investigated in order to elucidate the ecotoxicological effects of CNOs. Chemical modifications of the CNOs were accomplished by surface functionalization with benzoic acid, pyridine and pyridinium moieties. thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy confirmed the covalent surface functionalization of CNOs. Hydra specimens were exposed to the carbon nanomaterials by prolonged incubation within their medium. Uptake was monitored by optical microscopy, and the toxicological effects of the CNOs on Hydra behavior, morphology, as well as the long-term effects on the development and reproductive capability were examined. The obtained data revealed the absence of adverse effects of CNOs (in the range 0.05–0.1 mg/L) in vivo at the whole animal level. Together with previously performed in vitro toxicological analyses, our findings indicate the biosafety of CNOs and the feasibility of employing them as materials for biomedical applications. Full article

(This article belongs to the Special Issue Advancements in Nanotoxicology)

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1024 KiB

Open AccessArticle

An Investigation of the Cytotoxicity and Caspase-Mediated Apoptotic Effect of Green Synthesized Zinc Oxide Nanoparticles Using Eclipta prostrata on Human Liver Carcinoma Cells

by Ill-Min Chung, Abdul Abdul Rahuman, Sampath Marimuthu, Arivarasan Vishnu Kirthi, Karunanithi Anbarasan and Govindasamy Rajakumar

Nanomaterials 2015, 5(3), 1317-1330; https://doi.org/10.3390/nano5031317 - 12 Aug 2015

Cited by 70 | Viewed by 9216

Abstract

Cancer is a leading cause of death worldwide and sustained focus is on the discovery and development of newer and better tolerated anticancer drugs, especially from plants. In the present study, a simple, eco-friendly, and inexpensive approach was followed for the synthesis of [...] Read more.

Cancer is a leading cause of death worldwide and sustained focus is on the discovery and development of newer and better tolerated anticancer drugs, especially from plants. In the present study, a simple, eco-friendly, and inexpensive approach was followed for the synthesis of zinc oxide nanoparticles (ZnO NPs) using the aqueous leaf extract of Eclipta prostrata. The synthesized ZnO NPs were characterized by UV-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), High-resolution transmission electron microscopy (HRTEM), and Selected area (electron) diffraction (SAED). The HRTEM images confirmed the presence of triangle, radial, hexagonal, rod, and rectangle, shaped with an average size of 29 ± 1.3 nm. The functional groups for synthesized ZnO NPs were 3852 cm⁻¹ for H-H weak peak, 3138 cm⁻¹ for aromatic C-H extend, and 1648 cm⁻¹ for Aromatic ring stretch. The 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT), caspase and DNA fragmentation assays were carried out using various concentrations of ZnO NPs ranging from 1 to 100 mg/mL. The synthesized ZnO NPs showed dose dependent cytopathic effects in the Hep-G2 cell line. At 100 mg/mL concentration, the synthesized ZnO NPs exhibited significant cytotoxic effects and the apoptotic features were confirmed through caspase-3 activation and DNA fragmentation assays. Full article

(This article belongs to the Special Issue Advancements in Nanotoxicology)

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Open AccessArticle

Conjugation of Polymer-Coated Gold Nanoparticles with Antibodies—Synthesis and Characterization

by Gamze Tan, Karsten Kantner, Qian Zhang, Mahmoud G. Soliman, Pablo Del Pino, Wolfgang J. Parak, Mehmet A. Onur, Daniel Valdeperez, Joanna Rejman and Beatriz Pelaz

Nanomaterials 2015, 5(3), 1297-1316; https://doi.org/10.3390/nano5031297 - 7 Aug 2015

Cited by 30 | Viewed by 11734

Abstract

The synthesis of polymer-coated gold nanoparticles with high colloidal stability is described, together with appropriate characterization techniques concerning the colloidal properties of the nanoparticles. Antibodies against vascular endothelial growth factor (VEGF) are conjugated to the surface of the nanoparticles. Antibody attachment is probed [...] Read more.

The synthesis of polymer-coated gold nanoparticles with high colloidal stability is described, together with appropriate characterization techniques concerning the colloidal properties of the nanoparticles. Antibodies against vascular endothelial growth factor (VEGF) are conjugated to the surface of the nanoparticles. Antibody attachment is probed by different techniques, giving a guideline about the characterization of such conjugates. The effect of the nanoparticles on human adenocarcinoma alveolar basal epithelial cells (A549) and human umbilical vein endothelial cells (HUVECs) is probed in terms of internalization and viability assays. Full article

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

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883 KiB

Open AccessArticle

Microwave-Assisted Hydrothermal Rapid Synthesis of Calcium Phosphates: Structural Control and Application in Protein Adsorption

by Zhu-Yun Cai, Fan Peng, Yun-Peng Zi, Feng Chen and Qi-Rong Qian

Nanomaterials 2015, 5(3), 1284-1296; https://doi.org/10.3390/nano5031284 - 31 Jul 2015

Cited by 19 | Viewed by 8031

Abstract

Synthetic calcium phosphate (CaP)-based materials have attracted much attention in the biomedical field. In this study, we have investigated the effect of pH values on CaP nanostructures prepared using a microwave-assisted hydrothermal method. The hierarchical nanosheet-assembled hydroxyapatite (HAP) nanostructure was prepared under weak [...] Read more.

Synthetic calcium phosphate (CaP)-based materials have attracted much attention in the biomedical field. In this study, we have investigated the effect of pH values on CaP nanostructures prepared using a microwave-assisted hydrothermal method. The hierarchical nanosheet-assembled hydroxyapatite (HAP) nanostructure was prepared under weak acidic conditions (pH 5), while the HAP nanorod was prepared under neutral (pH 7) and weak alkali (pH 9) condition. However, when the pH value increases to 11, a mixed product of HAP nanorod and tri-calcium phosphate nanoparticle was obtained. The results indicated that the pH value of the initial reaction solution played an important role in the phase and structure of the CaP. Furthermore, the protein adsorption and release performance of the as-prepared CaP nanostructures were investigated by using hemoglobin (Hb) as a model protein. The sample that was prepared at pH = 11 and consisted of mixed morphologies of nanorods and nanoprisms showed a higher Hb protein adsorption capacity than the sample prepared at pH 5, which could be explained by its smaller size and dispersed structure. The results revealed the relatively high protein adsorption capacity of the as-prepared CaP nanostructures, which show promise for applications in various biomedical fields such as drug delivery and protein adsorption. Full article

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

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Open AccessArticle

Effects of Primary Processing Techniques and Significance of Hall-Petch Strengthening on the Mechanical Response of Magnesium Matrix Composites Containing TiO₂ Nanoparticulates

by Ganesh Kumar Meenashisundaram, Mui Hoon Nai and Manoj Gupta

Nanomaterials 2015, 5(3), 1256-1283; https://doi.org/10.3390/nano5031256 - 31 Jul 2015

Cited by 27 | Viewed by 5610

Abstract

In the present study, Mg (1.98 and 2.5) vol % TiO₂ nanocomposites are primarily synthesized utilizing solid-phase blend-press-sinter powder metallurgy (PM) technique and liquid-phase disintegrated melt deposition technique (DMD) followed by hot extrusion. Microstructural characterization of the synthesized Mg-TiO₂ nanocomposites indicated [...] Read more.

In the present study, Mg (1.98 and 2.5) vol % TiO₂ nanocomposites are primarily synthesized utilizing solid-phase blend-press-sinter powder metallurgy (PM) technique and liquid-phase disintegrated melt deposition technique (DMD) followed by hot extrusion. Microstructural characterization of the synthesized Mg-TiO₂ nanocomposites indicated significant grain refinement with DMD synthesized Mg nanocomposites exhibiting as high as ~47% for 2.5 vol % TiO₂ NPs addition. X-ray diffraction studies indicated that texture randomization of pure Mg depends not only on the critical amount of TiO₂ NPs added to the Mg matrix but also on the adopted synthesis methodology. Irrespective of the processing technique, theoretically predicted tensile yield strength of Mg-TiO₂ nanocomposites was found to be primarily governed by Hall-Petch mechanism. Among the synthesized Mg materials, solid-phase synthesized Mg 1.98 vol % TiO₂ nanocomposite exhibited a maximum tensile fracture strain of ~14.5%. Further, the liquid-phase synthesized Mg-TiO₂ nanocomposites exhibited higher tensile and compression properties than those primarily processed by solid-phase synthesis. The tensile-compression asymmetry values of the synthesized Mg-TiO₂ nanocomposite was found to be lower than that of pure Mg with solid-phase synthesized Mg 1.98 vol % TiO₂ nanocomposite exhibiting as low as 1.06. Full article

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843 KiB

Open AccessArticle

Hydrothermal Fabrication of WO₃ Hierarchical Architectures: Structure, Growth and Response

by Chuan-Sheng Wu

Nanomaterials 2015, 5(3), 1250-1255; https://doi.org/10.3390/nano5031250 - 22 Jul 2015

Cited by 18 | Viewed by 5828

Abstract

Recently hierarchical architectures, consisting of two-dimensional (2D) nanostructures, are of great interest for potential applications in energy and environmental. Here, novel rose-like WO₃ hierarchical architectures were successfully synthesized via a facile hydrothermal method. The as-prepared WO₃ hierarchical architectures were in fact [...] Read more.

Recently hierarchical architectures, consisting of two-dimensional (2D) nanostructures, are of great interest for potential applications in energy and environmental. Here, novel rose-like WO₃ hierarchical architectures were successfully synthesized via a facile hydrothermal method. The as-prepared WO₃ hierarchical architectures were in fact assembled by numerous nanosheets with an average thickness of ~30 nm. We found that the oxalic acid played a significant role in governing morphologies of WO₃ during hydrothermal process. Based on comparative studies, a possible formation mechanism was also proposed in detail. Furthermore, gas-sensing measurement showed that the well-defined 3D WO₃ hierarchical architectures exhibited the excellent gas sensing properties towards CO. Full article

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

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1937 KiB

Open AccessArticle

Modeling In Vivo Interactions of Engineered Nanoparticles in the Pulmonary Alveolar Lining Fluid

by Dwaipayan Mukherjee, Alexandra Porter, Mary Ryan, Stephan Schwander, Kian Fan Chung, Teresa Tetley, Junfeng Zhang and Panos Georgopoulos

Nanomaterials 2015, 5(3), 1223-1249; https://doi.org/10.3390/nano5031223 - 22 Jul 2015

Cited by 5 | Viewed by 7669

Abstract

Increasing use of engineered nanomaterials (ENMs) in consumer products may result in widespread human inhalation exposures. Due to their high surface area per unit mass, inhaled ENMs interact with multiple components of the pulmonary system, and these interactions affect their ultimate fate in [...] Read more.

Increasing use of engineered nanomaterials (ENMs) in consumer products may result in widespread human inhalation exposures. Due to their high surface area per unit mass, inhaled ENMs interact with multiple components of the pulmonary system, and these interactions affect their ultimate fate in the body. Modeling of ENM transport and clearance in vivo has traditionally treated tissues as well-mixed compartments, without consideration of nanoscale interaction and transformation mechanisms. ENM agglomeration, dissolution and transport, along with adsorption of biomolecules, such as surfactant lipids and proteins, cause irreversible changes to ENM morphology and surface properties. The model presented in this article quantifies ENM transformation and transport in the alveolar air to liquid interface and estimates eventual alveolar cell dosimetry. This formulation brings together established concepts from colloidal and surface science, physics, and biochemistry to provide a stochastic framework capable of capturing essential in vivo processes in the pulmonary alveolar lining layer. The model has been implemented for in vitro solutions with parameters estimated from relevant published in vitro measurements and has been extended here to in vivo systems simulating human inhalation exposures. Applications are presented for four different ENMs, and relevant kinetic rates are estimated, demonstrating an approach for improving human in vivo pulmonary dosimetry. Full article

(This article belongs to the Special Issue Advancements in Nanotoxicology)

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1605 KiB

Open AccessArticle

Facile Attachment of TAT Peptide on Gold Monolayer Protected Clusters: Synthesis and Characterization

by Ndabenhle M. Sosibo, Frankline K. Keter, Amanda Skepu, Robert T. Tshikhudo and Neerish Revaprasadu

Nanomaterials 2015, 5(3), 1211-1222; https://doi.org/10.3390/nano5031211 - 21 Jul 2015

Cited by 14 | Viewed by 6264

Abstract

High affinity thiolate-based polymeric capping ligands are known to impart stability onto nanosized gold nanoparticles. Due to the stable gold-sulfur bond, the ligand forms a protective layer around the gold core and subsequently controls the physicochemical properties of the resultant nanogold mononuclear protected [...] Read more.

High affinity thiolate-based polymeric capping ligands are known to impart stability onto nanosized gold nanoparticles. Due to the stable gold-sulfur bond, the ligand forms a protective layer around the gold core and subsequently controls the physicochemical properties of the resultant nanogold mononuclear protected clusters (AuMPCs). The choice of ligands to use as surfactants for AuMPCs largely depends on the desired degree of hydrophilicity and biocompatibility of the MPCs, normally dictated by the intended application. Subsequent surface modification of AuMPCs allows further conjugation of additional biomolecules yielding bilayer or multilayered clusters suitable for bioanalytical applications ranging from targeted drug delivery to diagnostics. In this study, we discuss our recent laboratory findings on a simple route for the introduction of Trans-Activator of Transcription (TAT) peptide onto the surface of biotin-derivatised gold MPCs via the biotin-strepavidin interaction. By changing the surface loading of biotin, controlled amounts of TAT could be attached. This bioconjugate system is very attractive as a carrier in intercellular delivery of various delivery cargoes such as antibodies, proteins and oligonucleotides. Full article

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563 KiB

Open AccessArticle

The Application of Gas Dwell Time Control for Rapid Single Wall Carbon Nanotube Forest Synthesis to Acetylene Feedstock

by Naoyuki Matsumoto, Azusa Oshima, Shunsuke Sakurai, Takeo Yamada, Motoo Yumura, Kenji Hata and Don N. Futaba

Nanomaterials 2015, 5(3), 1200-1210; https://doi.org/10.3390/nano5031200 - 17 Jul 2015

Cited by 10 | Viewed by 5325

Abstract

One aspect of carbon nanotube (CNT) synthesis that remains an obstacle to realize industrial mass production is the growth efficiency. Many approaches have been reported to improve the efficiency, either by lengthening the catalyst lifetime or by increasing the growth rate. We investigated [...] Read more.

One aspect of carbon nanotube (CNT) synthesis that remains an obstacle to realize industrial mass production is the growth efficiency. Many approaches have been reported to improve the efficiency, either by lengthening the catalyst lifetime or by increasing the growth rate. We investigated the applicability of dwell time and carbon flux control to optimize yield, growth rate, and catalyst lifetime of water-assisted chemical vapor deposition of single-walled carbon nanotube (SWCNT) forests using acetylene as a carbon feedstock. Our results show that although acetylene is a precursor to CNT synthesis and possesses a high reactivity, the SWCNT forest growth efficiency is highly sensitive to dwell time and carbon flux similar to ethylene. Through a systematic study spanning a wide range of dwell time and carbon flux levels, the relationship of the height, growth rate, and catalyst lifetime is found. Further, for the optimum conditions for 10 min growth, SWCNT forests with ~2500 μm height, ~350 μm/min initial growth rates and extended lifetimes could be achieved by increasing the dwell time to ~5 s, demonstrating the generality of dwell time control to highly reactive gases. Full article

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2924 KiB

Open AccessReview

Neural Cell Chip Based Electrochemical Detection of Nanotoxicity

by Md. Abdul Kafi, Hyeon-Yeol Cho and Jeong Woo Choi

Nanomaterials 2015, 5(3), 1181-1199; https://doi.org/10.3390/nano5031181 - 2 Jul 2015

Cited by 11 | Viewed by 7064

Abstract

Development of a rapid, sensitive and cost-effective method for toxicity assessment of commonly used nanoparticles is urgently needed for the sustainable development of nanotechnology. A neural cell with high sensitivity and conductivity has become a potential candidate for a cell chip to investigate [...] Read more.

Development of a rapid, sensitive and cost-effective method for toxicity assessment of commonly used nanoparticles is urgently needed for the sustainable development of nanotechnology. A neural cell with high sensitivity and conductivity has become a potential candidate for a cell chip to investigate toxicity of environmental influences. A neural cell immobilized on a conductive surface has become a potential tool for the assessment of nanotoxicity based on electrochemical methods. The effective electrochemical monitoring largely depends on the adequate attachment of a neural cell on the chip surfaces. Recently, establishment of integrin receptor specific ligand molecules arginine-glycine-aspartic acid (RGD) or its several modifications RGD-Multi Armed Peptide terminated with cysteine (RGD-MAP-C), C(RGD)₄ ensure farm attachment of neural cell on the electrode surfaces either in their two dimensional (dot) or three dimensional (rod or pillar) like nano-scale arrangement. A three dimensional RGD modified electrode surface has been proven to be more suitable for cell adhesion, proliferation, differentiation as well as electrochemical measurement. This review discusses fabrication as well as electrochemical measurements of neural cell chip with particular emphasis on their use for nanotoxicity assessments sequentially since inception to date. Successful monitoring of quantum dot (QD), graphene oxide (GO) and cosmetic compound toxicity using the newly developed neural cell chip were discussed here as a case study. This review recommended that a neural cell chip established on a nanostructured ligand modified conductive surface can be a potential tool for the toxicity assessments of newly developed nanomaterials prior to their use on biology or biomedical technologies. Full article

(This article belongs to the Special Issue Advancements in Nanotoxicology)

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392 KiB

Open AccessReview

Nanotoxicity: An Interplay of Oxidative Stress, Inflammation and Cell Death

by Puja Khanna, Cynthia Ong, Boon Huat Bay and Gyeong Hun Baeg

Nanomaterials 2015, 5(3), 1163-1180; https://doi.org/10.3390/nano5031163 - 30 Jun 2015

Cited by 404 | Viewed by 19324

Abstract

Nanoparticles are emerging as a useful tool for a wide variety of biomedical, consumer and instrumental applications that include drug delivery systems, biosensors and environmental sensors. In particular, nanoparticles have been shown to offer greater specificity with enhanced bioavailability and less detrimental side [...] Read more.

Nanoparticles are emerging as a useful tool for a wide variety of biomedical, consumer and instrumental applications that include drug delivery systems, biosensors and environmental sensors. In particular, nanoparticles have been shown to offer greater specificity with enhanced bioavailability and less detrimental side effects as compared to the existing conventional therapies in nanomedicine. Hence, bionanotechnology has been receiving immense attention in recent years. However, despite the extensive use of nanoparticles today, there is still a limited understanding of nanoparticle-mediated toxicity. Both in vivo and in vitro studies have shown that nanoparticles are closely associated with toxicity by increasing intracellular reactive oxygen species (ROS) levels and/or the levels of pro-inflammatory mediators. The homeostatic redox state of the host becomes disrupted upon ROS induction by nanoparticles. Nanoparticles are also known to up-regulate the transcription of various pro-inflammatory genes, including tumor necrosis factor-α and IL (interleukins)-1, IL-6 and IL-8, by activating nuclear factor-kappa B (NF-κB) signaling. These sequential molecular and cellular events are known to cause oxidative stress, followed by severe cellular genotoxicity and then programmed cell death. However, the exact molecular mechanisms underlying nanotoxicity are not fully understood. This lack of knowledge is a significant impediment in the use of nanoparticles in vivo. In this review, we will provide an assessment of signaling pathways that are involved in the nanoparticle- induced oxidative stress and propose possible strategies to circumvent nanotoxicity. Full article

(This article belongs to the Special Issue Advancements in Nanotoxicology)

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781 KiB

Open AccessArticle

Nano-Sized Secondary Organic Aerosol of Diesel Engine Exhaust Origin Impairs Olfactory-Based Spatial Learning Performance in Preweaning Mice

by Tin-Tin Win-Shwe, Chaw Kyi-Tha-Thu, Yadanar Moe, Fumihiko Maekawa, Rie Yanagisawa, Akiko Furuyama, Shinji Tsukahara, Yuji Fujitani and Seishiro Hirano

Nanomaterials 2015, 5(3), 1147-1162; https://doi.org/10.3390/nano5031147 - 30 Jun 2015

Cited by 10 | Viewed by 6326

Abstract

The aims of our present study were to establish a novel olfactory-based spatial learning test and to examine the effects of exposure to nano-sized diesel exhaust-origin secondary organic aerosol (SOA), a model environmental pollutant, on the learning performance in preweaning mice. Pregnant BALB/c [...] Read more.

The aims of our present study were to establish a novel olfactory-based spatial learning test and to examine the effects of exposure to nano-sized diesel exhaust-origin secondary organic aerosol (SOA), a model environmental pollutant, on the learning performance in preweaning mice. Pregnant BALB/c mice were exposed to clean air, diesel exhaust (DE), or DE-origin SOA (DE-SOA) from gestational day 14 to postnatal day (PND) 10 in exposure chambers. On PND 11, the preweaning mice were examined by the olfactory-based spatial learning test. After completion of the spatial learning test, the hippocampus from each mouse was removed and examined for the expressions of neurological and immunological markers using real-time RT-PCR. In the test phase of the study, the mice exposed to DE or DE-SOA took a longer time to reach the target as compared to the control mice. The expression levels of neurological markers such as the N-methyl-d-aspartate (NMDA) receptor subunits NR1 and NR2B, and of immunological markers such as TNF-α, COX2, and Iba1 were significantly increased in the hippocampi of the DE-SOA-exposed preweaning mice as compared to the control mice. Our results indicate that DE-SOA exposure in utero and in the neonatal period may affect the olfactory-based spatial learning behavior in preweaning mice by modulating the expressions of memory function–related pathway genes and inflammatory markers in the hippocampus. Full article

(This article belongs to the Special Issue Advancements in Nanotoxicology)

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1957 KiB

Open AccessArticle

Mechanical Dispersion of Nanoparticles and Its Effect on the Specific Heat Capacity of Impure Binary Nitrate Salt Mixtures

by Mathieu Lasfargues, Qiao Geng, Hui Cao and Yulong Ding

Nanomaterials 2015, 5(3), 1136-1146; https://doi.org/10.3390/nano5031136 - 29 Jun 2015

Cited by 105 | Viewed by 9224

Abstract

In this study, the effect of nanoparticle concentration was tested for both CuO and TiO₂ in eutectic mixture of sodium and potassium nitrate. Results showed an enhancement in specific heat capacity (C_p) for both types of nanoparticles (+10.48% at [...] Read more.

In this study, the effect of nanoparticle concentration was tested for both CuO and TiO₂ in eutectic mixture of sodium and potassium nitrate. Results showed an enhancement in specific heat capacity (C_p) for both types of nanoparticles (+10.48% at 440 °C for 0.1 wt % CuO and +4.95% at 440 °C for 0.5 wt % TiO₂) but the behavior toward a rise in concentration was different with CuO displaying its highest enhancement at the lowest concentration whilst TiO₂ showed no concentration dependence for three of the four different concentrations tested. The production of cluster of nanoparticles was visible in CuO but not in TiO₂. This formation of nanostructure in molten salt might promote the enhancement in C_p. However, the size and shape of these structures will most likely impact the energy density of the molten salt. Full article

(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)

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Nanomaterials, Volume 5, Issue 3 (September 2015) – 26 articles , Pages 1136-1555

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