Journal of Nanomaterials The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Green Nanobiotechnology: Factors Affecting Synthesis and Characterization Techniques Wed, 17 Dec 2014 12:05:45 +0000 Nanobiotechnology is gaining tremendous impetus in this era owing to its ability to modulate metals into their nanosize, which efficiently changes their chemical, physical, and optical properties. Accordingly, considerable attention is being given to the development of novel strategies for the synthesis of different kinds of nanoparticles of specific composition and size using biological sources. However, most of the currently available techniques are expensive, environmentally harmful, and inefficient with respect to materials and energy use. Several factors such as the method used for synthesis, pH, temperature, pressure, time, particle size, pore size, environment, and proximity greatly influence the quality and quantity of the synthesized nanoparticles and their characterization and applications. Additionally, characterization of the synthesized nanoparticles is essential to their potential use in various drug delivery and biomedical applications. The present review highlights various parameters affecting the synthesis of nanoparticles by green nanobiotechnology and different techniques used for characterizing the nanoparticles for their potential use in biomedical and environmental applications. Jayanta Kumar Patra and Kwang-Hyun Baek Copyright © 2014 Jayanta Kumar Patra and Kwang-Hyun Baek. All rights reserved. Synthesis, Characterization, and DNA Binding Studies of Nanoplumbagin Wed, 17 Dec 2014 00:10:54 +0000 The traditional anticancer medicine plumbagin (PLN) was prepared as nanostructured material (nanoplumbagin, NPn1) from its commercial counterparts, simultaneously coencapsulating with cetyltrimethylammonium bromide or cyclodextrin as stabilizers using ultrasonication technique. Surface morphology of NPn analysed from atomic force microscopy (AFM) indicates that NPn has tunable size between 75 nm and 100 nm with narrow particle size distribution. Its binding efficiency with herring sperm DNA was studied using spectral and electrochemical techniques and its efficiency was found to be more compared to the commercial microcrystalline plumbagin (PLN). DNA cleavage was also studied by gel electrophoresis. The observed results indicate that NPn1 has better solubility in aqueous medium and hence showed better bioavailability compared to its commercial counterparts. Sheik Dawood Shahida Parveen, Abdullah Affrose, Basuvaraj Suresh Kumar, Jamespandi Annaraj, and Kasi Pitchumani Copyright © 2014 Sheik Dawood Shahida Parveen et al. All rights reserved. Young’s Modulus of Polycrystalline Titania Microspheres Determined by In Situ Nanoindentation and Finite Element Modeling Mon, 15 Dec 2014 13:05:16 +0000 In situ nanoindentation was employed to probe the mechanical properties of individual polycrystalline titania (TiO2) microspheres. The force-displacement curves captured by a hybrid scanning electron microscope/scanning probe microscope (SEM/SPM) system were analyzed based on Hertz’s theory of contact mechanics. However, the deformation mechanisms of the nano/microspheres in the nanoindentation tests are not very clear. Finite element simulation was employed to investigate the deformation of spheres at the nanoscale under the pressure of an AFM tip. Then a revised method for the calculation of Young’s modulus of the microspheres was presented based on the deformation mechanisms of the spheres and Hertz’s theory. Meanwhile, a new force-displacement curve was reproduced by finite element simulation with the new calculation, and it was compared with the curve obtained by the nanoindentation experiment. The results of the comparison show that utilization of this revised model produces more accurate results. The calculated results showed that Young’s modulus of a polycrystalline TiO2 microsphere was approximately 30% larger than that of the bulk counterpart. Peida Hao, Yanping Liu, Yuanming Du, and Yuefei Zhang Copyright © 2014 Peida Hao et al. All rights reserved. Recent Advances in IR and UV/VIS Spectroscopic Characterization of the C76 and C84 Isomers of D2 Symmetry Mon, 15 Dec 2014 07:53:34 +0000 The stable isomers of the higher fullerenes C76 and C84 with D2 symmetry as well as the basic fullerenes C60 and C70 were isolated from carbon soot and characterized by the new and advanced methods, techniques, and processes. The validity of several semiempirical, ab initio, and DFT theoretical calculations in predicting the general pattern of IR absorption and the vibrational frequencies, as well as the molecular electronic structure of the C76 and C84 isomers of D2 symmetry, is confirmed, based on recent experimental results. An excellent correlation was found between the previously reported theoretical data and the recently obtained experimental results for these molecules over the relevant spectral range for the identification of fullerenes. These results indicate that there are no errors in the calculations in the significant spectral regions, the assumptions that were based on previous comparisons with partial experimental results. Isolated fullerenes are important for their applications in electronic and optical devices, solar cells, optical limiting, sensors, polymers, nanophotonic materials, diagnostic and therapeutic agents, health and environment protection, and so forth. Tamara Jovanović, Đuro Koruga, and Branimir Jovančićević Copyright © 2014 Tamara Jovanović et al. All rights reserved. Continuum Fracture Analysis and Molecular Dynamic Study on Crack Initiation and Propagation in Nanofilms Sun, 14 Dec 2014 00:11:08 +0000 Crack initiation and propagation in a nanostructured nickel film were studied by molecular dynamic simulation as well as an interatomic-potential-based continuum approach. In the molecular dynamic simulation, the interatomic potential was described by using Embedded Atom Method (EAM), and a reduced 2D plane model was employed to simulate the mechanical behavior of nanofilms. Atomistic simulation shows that the reduced plane model in this paper can not only reveal the physical nature of crack initiation clearly but also give the critical time of crack initiation accurately as the continuum fracture analysis does. The normal stress and average atom energy at the crack tip which resulted from atomistic simulation at the time of crack initiation agree well with the analytical results. On the other hand, the crack propagation in nanofilms was studied by interatomic-potential-based continuum fracture mechanics analysis based on Griffith criterion. The coupled continuum-atomic analysis can predict the crack initiation and atomic stress accurately. Continuum analysis with material property parameters determined by interatomic potential is proved to be another promising way of solving failure problem on nanoscale. Dan Huang, Mengwei Wang, and Guangda Lu Copyright © 2014 Dan Huang et al. All rights reserved. Highly Branched Sn-Doped ZnO Nanostructures for Sunlight Driven Photocatalytic Reactions Thu, 11 Dec 2014 10:50:02 +0000 Ultralong, highly branched Sn-doped zinc oxide (ZnO) nanostructures were fabricated using a simple substrate-free chemical vapor deposition (CVD) method. The nanostructures exhibited efficient photocatalytic activities in degradation of methylene blue (MB) under natural sunlight. 100% of MB with the concentration of 10 mg/L could be completely removed within 36 minutes. Possible reasons for the enhanced photocatalytic effect were analyzed. Yangyang Liu, Xiaodong Chen, Ying Xu, Quanhua Zhang, and Xianying Wang Copyright © 2014 Yangyang Liu et al. All rights reserved. Influence of Sonication on the Stability and Thermal Properties of Al2O3 Nanofluids Thu, 11 Dec 2014 06:13:53 +0000 Nanofluids containing Al2O3 nanoparticles (either 11 or 30 nm in size) dispersed in distilled water at low concentrations (0.125–0.5 wt%) were prepared using two different ultrasonic devices (a probe and a bath sonicator) as the dispersant. The effect of the ultrasonic system on the stability and thermal diffusivity of the nanofluids was investigated. Thermal diffusivity measurements were conducted using a photopyroelectric technique. The dispersion characteristics and morphology of the nanoparticles, as well as the optical absorption properties of the nanofluids, were studied using photon cross correlation spectroscopy with a Nanophox analyzer, transmission electron microscopy, and ultraviolet-visible spectroscopy. At higher particle concentration, there was greater enhancement of the thermal diffusivity of the nanofluids resulting from sonication. Moreover, greater stability and enhancement of thermal diffusivity were obtained by sonicating the nanofluids with the higher power probe sonicator prior to measurement. Monir Noroozi, Shahidan Radiman, and Azmi Zakaria Copyright © 2014 Monir Noroozi et al. All rights reserved. Improved Sensitization of Zinc Oxide Nanorods by Cadmium Telluride Quantum Dots through Charge Induced Hydrophilic Surface Generation Wed, 10 Dec 2014 00:11:00 +0000 This paper reports on UV-mediated enhancement in the sensitization of semiconductor quantum dots (QDs) on zinc oxide (ZnO) nanorods, improving the charge transfer efficiency across the QD-ZnO interface. The improvement was primarily due to the reduction in the interfacial resistance achieved via the incorporation of UV light induced surface defects on zinc oxide nanorods. The photoinduced defects were characterized by XPS, FTIR, and water contact angle measurements, which demonstrated an increase in the surface defects (oxygen vacancies) in the ZnO crystal, leading to an increase in the active sites available for the QD attachment. As a proof of concept, a model cadmium telluride (CdTe) QD solar cell was fabricated using the defect engineered ZnO photoelectrodes, which showed ∼10% increase in photovoltage and ∼66% improvement in the photocurrent compared to the defect-free photoelectrodes. The improvement in the photocurrent was mainly attributed to the enhancement in the charge transfer efficiency across the defect rich QD-ZnO interface, which was indicated by the higher quenching of the CdTe QD photoluminescence upon sensitization. Karthik Laxman, Tanujjal Bora, Salim H. Al-Harthi, and Joydeep Dutta Copyright © 2014 Karthik Laxman et al. All rights reserved. Construction of 3D Arrays of Cylindrically Hierarchical Structures with ZnO Nanorods Hydrothermally Synthesized on Optical Fiber Cores Tue, 09 Dec 2014 06:12:57 +0000 With ZnO nanorods hydrothermally synthesized on manually assembled arrays of optical fiber cores, 3D arrays of ZnO nanorod-based cylindrically hierarchical structures with nominal pitch 250 μm or 375 μm were constructed. Based on micrographs of scanning electron microscopy and image processing operators of MATLAB software, the 3D arrays of cylindrically hierarchical structures were quantitatively characterized. The values of the actual diameters, the actual pitches, and the parallelism errors suggest that the process capability of the manual assembling is sufficient and the quality of the 3D arrays of cylindrically hierarchical structures is acceptable. The values of the characteristic parameters such as roughness, skewness, kurtosis, correlation length, and power spectrum density show that the surface morphologies of the cylindrically hierarchical structures not only were affected significantly by Zn2+ concentration of the growth solution but also were anisotropic due to different curvature radii of the optical fiber core at side and front view. Weixuan Jing, Han Qi, Jiafan Shi, Zhuangde Jiang, Fan Zhou, and Yanyan Cheng Copyright © 2014 Weixuan Jing et al. All rights reserved. Field-Induced Electron Emission from Nanoporous Carbons Sun, 07 Dec 2014 07:30:21 +0000 Influence of fabrication technology on field electron emission properties of nanoporous carbon (NPC) was investigated. Samples of NPC derived from different carbides via chlorination at different temperatures demonstrated similar low-field emission ability with threshold electric field 2-3 V/m. This property correlated with presence of nanopores with characteristic size 0.5–1.2 nm, determining high values of specific surface area (>800 m2/g) of the material. In most cases, current characteristics of emission were approximately linear in Fowler-Nordheim coordinates (excluding a low-current part near the emission threshold), but the plots’ slope angles were in notable disagreement with the known material morphology and electronic properties, unexplainable within the frames of the classical emission theory. We suggest that the actual emission mechanism for NPC involves generation of hot electrons at internal boundaries and that emission centers may be associated with relatively large (20–100 nm) onion-like particles observed in many microscopic images. Such particles can serve two functions: to provide additional “internal” enhancement of the electric field and to inhibit relaxation of hot charge carriers due to the “phonon bottleneck” effect. Alexander Arkhipov, Sergey Davydov, Pavel Gabdullin, Nikolay Gnuchev, Alexandr Kravchik, and Svyatoslav Krel Copyright © 2014 Alexander Arkhipov et al. All rights reserved. Study of Optical and Structural Characteristics of Ceria Nanoparticles Doped with Negative and Positive Association Lanthanide Elements Sun, 30 Nov 2014 17:31:40 +0000 This paper studies the effect of adding lanthanides with negative association energy, such as holmium and erbium, to ceria nanoparticles doped with positive association energy lanthanides, such as neodymium and samarium. That is what we called mixed doped ceria nanoparticles (MDC NPs). In MDC NPs of grain size range around 6 nm, it is proved qualitatively that the conversion rate from Ce4+ to Ce3+ is reduced, compared to ceria doped only with positive association energy lanthanides. There are many pieces of evidence which confirm the obtained conclusion. These indications are an increase in the allowed direct band gap which is calculated from the absorbance dispersion measurements, a decrease in the emitted fluorescence intensity, and an increase in the size of nanoparticles, which is measured using both techniques: transmission electron microscope (TEM) and X-ray diffractometer (XRD). That gives a novel conclusion that there are some trivalent dopants, such as holmium and erbium, which can suppress Ce3+ ionization states in ceria and consequently act as scavengers for active O-vacancies in MDC. This promising concept can develop applications which depend on the defects in ceria such as biomedicine, electronic devices, and gas sensors. N. Shehata, K. Meehan, M. Hudait, N. Jain, and S. Gaballah Copyright © 2014 N. Shehata et al. All rights reserved. Graphene: One Material, Many Possibilities—Application Difficulties in Biological Systems Sun, 30 Nov 2014 06:31:18 +0000 Energetic technologies, nanoelectronics, biomedicine including gene therapy, cell imaging or tissue engineering are only few from all possible applications for graphene, the thinnest known carbon configuration and a basic element for other more complicated, better discovered and widely used nanostructures such as graphite, fullerenes and carbon nanotubes. The number of researches concerning graphene applications is rising every day which proves the great interest in its unique structure and properties. Ideal pristine graphene sheet presents a flat membrane of unlimited size with no imperfections while in practice we get different flakes with irregular edges and structural defects which influence the reactivity. Nanomaterials from graphene family differ in size, shape, layer number, lateral dimension, surface chemistry and defect density causing the existence of graphene samples with various influence on biological systems. Whether graphene induces cellular stress and activates apoptosis, or on the contrary facilitates growth and differentiation of the cells depends on its structure, chemical modifications and the growth process. A certain number of in vitro studies has indicated cytotoxic effects of graphene while the other show that it is safe. The diversity of the samples and methods of the production make it impossible to establish clearly the biological impact of graphene. Marta Skoda, Ilona Dudek, Anna Jarosz, and Dariusz Szukiewicz Copyright © 2014 Marta Skoda et al. All rights reserved. Interlamellar Space Configuration under Variable Environmental Conditions in the Case of Ni-Exchanged Montmorillonite: Quantitative XRD Analysis Thu, 27 Nov 2014 08:25:58 +0000 Interlamellar space organization of low-charge montmorillonite was studied by modeling of X-ray diffraction (XRD) patterns recorded under controlled relative humidity (RH) conditions on Ni saturated specimens. The quantitative XRD investigation, based on an indirect method consisting of the comparison of experimental reflections with the other calculated from structural models, is used to characterize eventual nanostructural changes along axis of Ni-exchanged montmorillonite. This method allowed us to determine, respectively, the relative layer types contribution, the layer thickness, nanoconfiguration of the interlamellar space, and position, amount, and organization of water molecules and exchangeable cations. Obtained theoretical models exhibit heterogeneous hydration state which is the dominating character detected all over studied cycles. Along RH cycle a modification in the main structure of the host materials is performed and the presence of a mixed layer structure (MLS) is noted. The hydration hysteresis at the low and the high RH range can be explained by fluctuations in the water retention mechanism and hydration heterogeneities created within the smectite crystallite. Marwa Ammar, Walid Oueslati, Nejmeddine Chorfi, and Hafsia Ben Rhaiem Copyright © 2014 Marwa Ammar et al. All rights reserved. Equilibrium and Nonequilibrium Nanoscale Ordering of Polystyrene-b-poly(N,N′-diethylaminoethyl methacrylate), a Block Copolymer Carrying Tertiary Amine Functional Groups Thu, 27 Nov 2014 07:26:15 +0000 Poly(styrene)-b-poly(N,N′-diethylaminoethyl methacrylate) (PS-b-PDEAEM) block copolymer was synthesized by RAFT free-radical polymerization using a trithiocarbonate type of chain transfer agent (CTA). Several block copolymer compositions were achieved maintaining low polydispersities by using PS as macro-CTA in the first step. Thin films of PS60%-b-PDEAEM40% were deposited over mica substrate, and its equilibrium and nonequilibrium nanostructures were studied. Lamellar (equilibrium), bicontinuous (nonequilibrium) and detached nanoflakes (nonequilibrium), were obtained by using different annealing methods. Mixing nanocomposites of gold nanoparticles/PDEAEM in the block copolymer resulted in the formation of toroidal nanostructures confining gold nanoparticles to the core of those nanostructures. The same toroidal nanostructure was achieved by different annealing methods, including irradiation with UV light for 15 min. Electron micrographs show clearly this different type of arrays. Pedro Navarro-Vega, Arturo Zizumbo-López, Angel Licea-Claverie, Alejandro Vega-Rios, and Francisco Paraguay-Delgado Copyright © 2014 Pedro Navarro-Vega et al. All rights reserved. Bioinspired Functional Materials Tue, 25 Nov 2014 11:48:01 +0000 Yongmei Zheng, Jingxia Wang, Yongping Hou, Hao Bai, and Michael Z. Hu Copyright © 2014 Yongmei Zheng et al. All rights reserved. Biosynthesis of Silver Nanoparticles Using Chenopodium ambrosioides Tue, 25 Nov 2014 00:00:00 +0000 Biosynthesis of silver nanoparticles (AgNPs) was achieved using extract of Chenopodium ambrosioides as a reducer and coating agent at room temperature (25°C). Two molar solutions of AgNO3 (1 mM and 10 mM) and five extract volumes (0.5, 1, 2, 3, and 5 mL) were used to assess quantity, shape, and size of the particles. The UV-Vis spectra gave surface plasmon resonance at 434–436 nm of the NPs synthesized with AgNO3 10 mM and all extract volumes tested, showing a direct relationship between extract volumes and quantity of particles formed. In contrast, the concentration of silver ions was related negatively to particle size. The smallest (4.9 ± 3.4 nm) particles were obtained with 1 mL of extract in AgNO3 10 mM and the larger amount of particles were obtained with 2 mL and 5 mL of extract. TEM study indicated that the particles were polycrystalline and randomly oriented with a silver structure face centered cubic (fcc) and fourier transform infrared spectroscopy (FTIR) indicated that disappearance of the –OH group band after bioreduction evidences its role in reducing silver ions. Luis M. Carrillo-López, Hilda A. Zavaleta-Mancera, Alfredo Vilchis-Nestor, R. Marcos Soto-Hernández, Jesús Arenas-Alatorre, Libia I. Trejo-Téllez, and Fernando Gómez-Merino Copyright © 2014 Luis M. Carrillo-López et al. All rights reserved. Synthesis of ZnO-CuO Nanocomposite Aerogels by the Sol-Gel Route Sun, 23 Nov 2014 00:00:00 +0000 The epoxide addition sol-gel method has been utilized to synthesize porous zinc-copper composite aerogels in the zinc-to-copper molar ratios of 50 : 50 to 90 : 10. A two-step mixing approach has been employed to produce aerogels composed of nano- to micrometer sized particles. The aerogels were characterized by ultrahigh resolution scanning electron microscopy, transmission electron microscopy, and powder X-ray diffraction. The as-synthesized aerogels had a thin flake- or petal-like microstructure comprised of clustered flakes on two size scales; they were identified as being crystalline with the crystalline species identified as copper nitrate hydroxide, zinc hydroxide chloride hydrate, and zinc hydroxide nitrate hydrate. Annealing of the aerogel materials at a relatively low temperature (400°C) resulted in a complete phase transition of the material to give highly crystalline ZnO-CuO aerogels; the aerogels consisted of networked nanoparticles in the ~25–550 nm size range with an average crystallite size of ~3 nm and average crystallinity of 98%. ZnO-CuO aerogels are of particular interest due to their particular catalytic and sensing properties. This work emphasizes the versatility of this sol-gel route in synthesizing aerogels; this method offers a possible route for the fabrication of aerogels of different metal oxides and their composites. Rula M. Allaf and Louisa J. Hope-Weeks Copyright © 2014 Rula M. Allaf and Louisa J. Hope-Weeks. All rights reserved. Synthesis and Magnetic Properties of Hematite Particles in a “Nanomedusa” Morphology Thu, 20 Nov 2014 11:44:34 +0000 We present the synthesis, characterization, and magnetic properties of hematite particles in a peculiar “nanomedusa” morphology. The particles were prepared from an iron-silica complex by a hydrothermal process in a solution consisting of ethyl acetate and ethanol. The particles’ morphology, structure, and chemical composition were investigated by transmission electron microscopy, powder X-ray diffraction, and scanning electron microscope equipped with an energy-dispersive X-ray spectrometer. The “hairy” particles consist of a spherical-like core of about 100 nm diameter and fibrous exterior composed of thin “legs” of 5 nm diameter grown along one preferential direction. The particles’ cores are crystalline and undergo a magnetic phase transition to a weakly ferromagnetic state at a temperature of 930 K that matches reasonably the Néel temperature of bulk hematite. However, unlike bulk hematite that undergoes Morin transition to an antiferromagnetic state around room temperature and small hematite nanoparticles that are superparamagnetic, the “nanomedusa” particles remain weakly ferromagnetic down to the lowest investigated temperature of 2 K. Each particle thus represents a nanodimensional “hairy” ferromagnet in a very broad temperature interval, extending much above the room temperature. Such high-temperature ferromagnetic nanoparticles are not frequently found among the nanomaterials. Jin Bae Lee, Hae Jin Kim, Janez Lužnik, Andreja Jelen, Damir Pajić, Magdalena Wencka, Zvonko Jagličić, Anton Meden, and Janez Dolinšek Copyright © 2014 Jin Bae Lee et al. All rights reserved. Influence of the Hydrothermal Method Growth Parameters on the Zinc Oxide Nanowires Deposited on Several Substrates Tue, 18 Nov 2014 11:24:43 +0000 We report the synthesis of ZnO nanowires grown on several substrates (PET, glass, and Si) using a two-step process: (a) preparation of the seed layer on the substrate by spin coating, from solutions of zinc acetate dihydrate and 1-propanol, and (b) growth of the ZnO nanostructures by dipping the substrate in an equimolar solution of zinc nitrate hexahydrate and hexamethylenetetramine. Subsequently, films were thermally treated with a commercial microwave oven (350 and 700 W) for 5, 20, and 35 min. The ZnO nanowires obtained were characterized structurally, morphologically, and optically using XRD, SEM, and UV-VIS transmission, respectively. XRD patterns spectra revealed the presence of Zn(OH)2 on the films grown on glass and Si substrates. A preferential orientation along c-axis directions for films grown on PET substrate was observed. An analysis by SEM revealed that the growth of the ZnO nanowires on PET and glass is better than the growth on Si when the same growth parameters are used. On glass substrates, ZnO nanowires less than 50 nm in diameter and between 200 nm and 1200 nm in length were obtained. The ZnO nanowires band gap energy for the films grown on PET and glass was obtained from optical transmission spectra. Concepción Mejía-García, Elvia Díaz-Valdés, Marco Alberto Ayala-Torres, Josué Romero-Ibarra, and Máximo López-López Copyright © 2014 Concepción Mejía-García et al. All rights reserved. Comparison of Apoptotic Inducing Effect of Zerumbone and Zerumbone-Loaded Nanostructured Lipid Carrier on Human Mammary Adenocarcinoma MDA-MB-231 Cell Line Tue, 18 Nov 2014 07:59:22 +0000 This study investigated the anticancer effect of zerumbone (ZER) and zerumbone-loaded nanostructured lipid carrier (ZER-NLC) on the human mammary gland adenocarcinoma (MDA-MB-231) cell line. The effect of ZER and ZER-NLC on MDA-MB-231 cells was determined via electron and fluorescent microscopy and flow cytometry using the Annexin V, cell cycle, and Tdt-mediated dUTP nick-end labeling assays. We demonstrated that ZER and ZER-NLC significantly suppressed the proliferation of MDA-MB-231 cells with an IC50 of 5.96 ± 0.13 and 6.01 ± 0.11 μg/mL, respectively. ZER and ZER-NLC arrested MDA-MB-231 cell cycle at the G2/M phase. The induction of apoptosis by ZER and ZER-NLC was via the intrinsic pathway through the release of cytochrome c and activation of caspase-3 and caspase-9. The treatments also caused the downregulation of antiapoptotic Bcl-2, Bcl-xL proteins, and proliferating cell nuclear protein and upregulation of proapoptotic Bax protein. Therefore, loading of ZER into NLC did not compromise the anticancer effects of ZER on MDA-MB-231 cells. In conclusion, ZER-NLC, which increased the bioavailability of ZER, is an effective agent in the treatment of cancers. Mahnaz Hosseinpour, Ahmad Bustamam Abdul, Heshu Sulaiman Rahman, Abdullah Rasedee, Swee Keong Yeap, Negin Ahmadi, Hemn Hassan Othman, and Max Stanley Chartrand Copyright © 2014 Mahnaz Hosseinpour et al. All rights reserved. Combining Hyaluronic Acid with Chitosan Enhances Gene Delivery Tue, 18 Nov 2014 00:00:00 +0000 The low gene transfer efficiency of chitosan-DNA polyplexes is a consequence of their high stability and consequent slow DNA release. The incorporation of an anionic polymer is believed to loosen chitosan interactions with DNA and thus promote higher transfection efficiencies. In this work, several formulations of chitosan-DNA polyplexes incorporating hyaluronic acid were prepared and characterized for their gene transfection efficiency on both HEK293 and retinal pigment epithelial cells. The different polyplex formulations showed morphology, size, and charge compatible with a role in gene delivery. The incorporation of hyaluronic acid rendered the formulations less stable, as was the goal, but it did not affect the loading and protection of the DNA. Compared with chitosan alone, the transfection efficiency had a 4-fold improvement, which was attributed to the presence of hyaluronic acid. Overall, our hybrid chitosan-hyaluronic acid polyplexes showed a significant improvement of the efficiency of chitosan-based nonviral vectors in vitro, suggesting that this strategy can further improve the transfection efficiency of nonviral vectors. Ana V. Oliveira, Diogo B. Bitoque, and Gabriela A. Silva Copyright © 2014 Ana V. Oliveira et al. All rights reserved. A Novel Micro-Nano Structure Profile Control Agent: Graphene Oxide Dispersion Sun, 16 Nov 2014 12:02:37 +0000 Graphite oxide sheet, now referred to as graphene oxide (GO), is the product of chemical exfoliation of graphite and has been known for more than a century. A GO sheet is characterized by two abruptly different length scales; the apparent thickness of the functionalized carbon sheet is approximately 1 nm, but the lateral dimensions can range from a few nanometers to micrometers. In this paper, an improved method for the preparation of graphene oxide within a mild condition is described. We have found that cancelling the high-temperature stage and prolonging the reaction time of mid-temperature can improve the efficiency of oxidation process. We utilized FTIR, XRD, Ultraviolet-visible, TGA, Raman spectrum, and XPS measurements to characterize the successfully synthesized GO. SEM images were employed to reveal the interior microstructure of as-prepared GO dispersion. We also wondrously found that the GO dispersion could be used as profile control agent in the oilfield water-flooding. Flooding experiments showed that the GO dispersion has an ability to adjust water injection profile, reduce permeability ratio, and improve conformance factor. So the GO dispersion would have potential applications in oilfield exploitation. Zhong-Bin Ye, Yuan Xu, Hong Chen, Chen Cheng, Li-Juan Han, and Lin Xiao Copyright © 2014 Zhong-Bin Ye et al. All rights reserved. Properties of Y-Shaped PFO-DBT Nanotubes Sun, 16 Nov 2014 09:30:33 +0000 Immersion of template into solution is used to synthesize the Y-shaped poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) nanotubes. Solution annealing and different aging times (1, 24, and 72 hours) are conducted to synthesize the Y-shaped PFO-DBT nanotubes and the effects on the morphological, structural, and optical properties of Y-shaped PFO-DBT nanotubes are investigated. The dense, aligned, and elongated Y-shaped PFO-DBT nanotubes have been successfully fabricated by aging the PFO-DBT solution for 72 hours. Enhanced light absorption with less light scattering can be exhibited from the elongated Y-shaped PFO-DBT nanotubes. Partial and complete infiltration is governed by 1 hour and 72 hours of aging time, respectively. Preformed nanofibres are initiated by the process of annealing and aging of PFO-DBT solution. During the aging process, PFO-DBT nanofibres are formed to coat the pores’ wall and replicated the Y-branched nanopores for the production of Y-shaped PFO-DBT nanotubes. The effects of solution annealing and aging process are essential for the improvement on the morphological, structural, and optical properties of Y-shaped PFO-DBT nanotubes. Muhamad Saipul Fakir, Azzuliani Supangat, and Khaulah Sulaiman Copyright © 2014 Muhamad Saipul Fakir et al. All rights reserved. Novel Alginate-Gelatin Hybrid Nanoparticle for Drug Delivery and Tissue Engineering Applications Sun, 16 Nov 2014 07:37:03 +0000 Novel alginate-gelatin hybrid nanoparticles were fabricated using single oil in water (O/W) emulsification techniques. Physicochemical property of the particle was characterized using scanning electron microscopy and Fourier’s transmission infrared spectroscopy. Particle size was determined using zeta potential metastasize analyzer and was found to be in range of 400–600 nm. AGNPs were used for culturing human keratinocytes for two weeks to check biocompatibility of synthesized AGNPs. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed increased metabolic activity of cells cultured on AGNPs in comparison to two-dimensional (2D) system (control). Cellular attachment on nanoparticle was further confirmed using SEM and 4′,6-diamidino-2-phenylindole staining. The drug release profile shows possible electrostatic bond between alginate and gelatin resulting in controlled release of drug from AGNPs. For the first time alginate-gelatin hybrid nanosystem has been fabricated and all results showed it can be used as potential system for delivery of drug and therapeutical agents to cells and can also be used for regenerative medicine applications. Eun Mi Lee, Deepti Singh, Dolly Singh, Soon Mo Choi, Sun Mi Zo, Seon Joo Park, and Sung Soo Han Copyright © 2014 Eun Mi Lee et al. All rights reserved. Synthesis and Characterization of Rhodium Doped on TiO2/HCP for Enhanced Photocatalytic Performance on Pentachlorophenol Thu, 13 Nov 2014 11:35:47 +0000 Visible-light-responsive material based on Rhodium doped on titanium dispersed on dealuminated clinoptilolite (TiO2/HCP) was synthesized via a combination of the sol-gel method and photoreductive deposition technique. The photocatalyst surface characterization, structural and optical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and UV-visible spectra (UV-VIS). Doping TiO2/HCP with Rh imparts a red shifting of the absorption band into the visible light region according to UV-VIS. The prepared composite materials were evaluated for their photocatalytic activities on pentachlorophenol (PCP) degradation under sunlight irradiation. The Rhodium doped TiO2/HCP exhibited enhanced photocatalytic activity and can be considered as a potential photocatalyst in wastewater treatment. Saheed Olalekan Sanni and Omoruyi Gold Idemudia Copyright © 2014 Saheed Olalekan Sanni and Omoruyi Gold Idemudia. All rights reserved. Fabrication of Novel 2D NiO Nanosheet Branched on 1D-ZnO Nanorod Arrays for Gas Sensor Application Thu, 13 Nov 2014 09:48:53 +0000 Fabrication of 3D structures composed of 1D n-type ZnO nanorods (NRs) and 2D p-type NiO nanosheets (NSs) by a low-cost, low-temperature, and large-area scalable hydrothermal process and its use in highly sensitive NO2 gas sensors were studied. The p-n heterojunctions formed by NiO-ZnO interfaces as well as large area two-dimensional NiO NSs themselves increased the adsorption of NO2. Moreover, the charge transfer between NiO and ZnO enhanced the responsivity and sensitivity of NO2 sensing even at a concentration of 1 ppm. The 30-min NiO NS growth on ZnO NRs in the hybrid sensor showed the highest sensitivity due to the formation of optimum p-n heterojunctions between ZnO NRs and NiO NSs for gas adsorption and carrier transport. Low responsivity toward reducing gases was also observed. Le Thuy Hoa, Huynh Ngoc Tien, and Seung Hyun Hur Copyright © 2014 Le Thuy Hoa et al. All rights reserved. Effect of Process Parameters of CNT Containing Friction Powder on Flexural Properties and Friction Performance of Organic Brake Friction Materials Wed, 12 Nov 2014 11:50:08 +0000 This research is to investigate the influences of carbon nanotube (CNT) containing friction powder prepared through different process parameters on flexural properties and friction performance of organic brake friction materials. Experimental results indicate significant influence on flexural property and friction performance of organic brake friction materials when the modified CNT/friction powders are adopted. Particularly for the specimens adopted the modified CNT/friction powders prepared through 2.0 M concentration of catalyst and 30% C2H2 show the highest flexural strength, better ductility and toughness, most stable friction coefficient, and lowest weight loss. However, too many amorphous carbon clusters and CNTs aggregation derived from higher concentration of catalyst and ratio of C2H2/N2 would cause poor formation of specimens and reduction of reinforcement effectiveness. Kuo-Jung Lee, Mao-Hsiang Hsu, and Huy-Zu Cheng Copyright © 2014 Kuo-Jung Lee et al. All rights reserved. Intercalation of Aceclofenac/Sulfobutyl Ether-β-cyclodextrin Complex into Layered Double Hydroxides through Swelling/Restoration Reaction and Its Controlled-Release Properties Wed, 12 Nov 2014 00:00:00 +0000 Aceclofenac (AC)/sulfobutyl ether-β-cyclodextrin (SBE-β-CD) inclusion complex intercalated layered double hydroxides (LDHs) composite were prepared by swelling/restoration method. After swelling/restoration, the -spacing of LDHs is expanded to 2.23 nm, which clearly demonstrates the successful intercalation of AC/SBE-β-CD into LDHs layer. AC/SBE-β-CD inclusion complex in the interlayer has monolayer arrangement based on the -spacing of LDHs and torus thickness of SBE-β-CD. The AC release performances were also studied in buffer solutions with different pH values. The results show AC/SBE-β-CD intercalated LDHs not only enhance the dissolution profile of AC but also exhibit a controlled-release process, which indicates that the AC/SBE-β-CD-LDHs have a potential application in drug delivery agent. Shifeng Li, Tan Zhang, Min Xiao, Zhigang Zhang, Wenxiu Li, and Jing Bai Copyright © 2014 Shifeng Li et al. All rights reserved. ZnO Thin-Film Transistor Grown by rf Sputtering Using Carbon Dioxide and Substrate Bias Modulation Tue, 11 Nov 2014 08:23:54 +0000 ZnO thin-film transistor (TFT) grown by rf magnetron sputtering in Ar/O2 atmosphere shows inferior turn-off characteristics compared to ZnO TFT grown by other methods. We thought that reactions between Zn and O2 might produce defects responsible for the poor turn-off behavior. In order to solve this problem, we studied sputtering growth in Ar/CO2 atmosphere at 450°C. During sputtering growth, we modulated substrate dc bias to control ion supply to the substrate. After growth ZnO was annealed in CO2 and O2 gas. With these methods, our bottom-gate ZnO thin-film transistor showed 4.7 cm2/Vsec mobility, on/off ratio, and –2 V threshold voltage. Junghwan Kim, Jun Meng, Donghoon Lee, Meng Yu, Dukyean Yoo, Doo Won Kang, and Jungyol Jo Copyright © 2014 Junghwan Kim et al. All rights reserved. Antibacterial Coating for Elimination of Pseudomonas aeruginosa and Escherichia coli Tue, 11 Nov 2014 07:08:47 +0000 A polymer antibacterial surface has been successfully developed. The coating system used silane as binder and Ag particles as antibacterial agent. The silver was synthesized using precipitation method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET) tests, energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were carried out to evaluate the silver particles. Antibacterial properties of the coating system were tested against gram-negative bacteria, namely, Pseudomonas aeruginosa and Escherichia coli. Different amounts of Ag were used in the coating to optimize its usage. The Japanese International Standard, JISZ2801, was used for bacteria test and the surface developed complies with the standard being antibacterial. Zainal Abidin Ali, W. Ahliah Ismail, Cheng-Foh Le, Hassan Mahmood Jindal, Rosiyah Yahya, Shamala Devi Sekaran, and R. Puteh Copyright © 2014 Zainal Abidin Ali et al. All rights reserved.