Journal of Nanomaterials The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Peptide Self-Assembled Nanostructures for Drug Delivery Applications Mon, 24 Apr 2017 06:13:25 +0000 Peptide self-assembled nanostructures are very popular in many biomedical applications. Drug delivery is one of the most promising applications among them. The tremendous advantages for peptide self-assembled nanostructures include good biocompatibility, low cost, tunable bioactivity, high drug loading capacities, chemical diversity, specific targeting, and stimuli responsive drug delivery at disease sites. Peptide self-assembled nanostructures such as nanoparticles, nanotubes, nanofibers, and hydrogels have been investigated by many researchers for drug delivery applications. In this review, the underlying mechanisms for the self-assembled nanostructures based on peptides with different types and structures are introduced and discussed. Peptide self-assembled nanostructures associated promising drug delivery applications such as anticancer drug and gene drug delivery are highlighted. Furthermore, peptide self-assembled nanostructures for targeted and stimuli responsive drug delivery applications are also reviewed and discussed. Taotao Fan, Xiaoyan Yu, Bing Shen, and Leming Sun Copyright © 2017 Taotao Fan et al. All rights reserved. Influence of Film Thickness and Heat Treatment on the Physical Properties of Mn Doped Sb2Se3 Nanocrystalline Thin Films Sun, 23 Apr 2017 06:17:50 +0000 Nanocrystalline thin films of Sb37.07Mn1.95Se60.98 with different thickness (7, 20, 40, and 80 nm) were successfully prepared via inert gas condensation technique. As-deposited films showed amorphous structure by grazing incident in-plane X-ray diffraction (GIIXD) technique. All films of different thicknesses were heat treated at 433 K for 90 min. The GIIXD pattern of annealed films showed nanocrystalline orthorhombic structure. The effect of thickness of annealed films on the structure and optical properties was studied. Calculated particle sizes are 20.67 and 24.15 for 40 and 80 nm thickness of heat treated film. High resolution transmission electron microscope HRTEM images and their diffraction patterns proved that 40 nm film thickness annealed at different temperature has nanocrystalline nature with observed (high) crystallinity that increases with annealing temperature. Blue shift of optical energy gap was observed from 1.68 to 2 eV with decreasing film thickness from 80 to 7 nm. Film thickness of 40 nm was exposed to different heat treated temperatures from 353 to 473 K to detect its effect on structure and optical and electrical properties. Blue shift from 1.73 to 1.9 eV was observed in its optical band gap due to direct transition as heat treatment temperature decreasing from 473 to 353 K. Electrical conductivity was studied for different heat treated films of thickness 40 nm, and intrinsic conduction mechanism is dominant. The activation energy was affected by heat treatment process. I. K. El Zawawi, Manal A. Mahdy, and E. A. El-Sayad Copyright © 2017 I. K. El Zawawi et al. All rights reserved. Optical and Structural Properties of Solvent Free Synthesized Starch/Chitosan-ZnO Nanocomposites Thu, 20 Apr 2017 00:00:00 +0000 The objective of this work is to develop an environmentally friendly method for preparation of ZnO nanocomposites. ZnO nanocomposites were prepared by three natural fibers such as coir, sawdust, and chitosan using aqueous solution of zinc chloride and sodium hydroxide. The functional groups of ZnO, C=O for polysaccharide, and N-H bending vibration of amine were confirmed by FTIR spectroscopy. A new high intensity absorption band has been observed at 424 cm−1 which corresponds to the E2 mode of hexagonal ZnO. The crystallinity and phase formation of coir, chitosan, and sawdust combined ZnO nanocomposites were confirmed by X-ray diffraction patterns. XRD patterns revealed the polycrystalline nature of ZnO composites belonging to the hexagonal phase with (101) preferential lattice orientation. The microstructural parameters were calculated for coir, chitosan, and saw wood combined ZnO composites. Also texture coefficients were estimated for all the diffraction lines of ZnO based nanocomposites. SEM and TEM analyses confirmed evenly distributed nanosized grains in the ZnO composites. The UV-Vis absorption spectra were observed where the blue shift absorption peak was at 334 nm. The optical band gap values were estimated in the range of 3.18–3.26 eV. The emission peak was observed at ~388 nm and ~463 nm by photoluminescence spectroscopy. Anandhavelu Sanmugam, Dhanasekaran Vikraman, Sethuraman Venkatesan, and Hui Joon Park Copyright © 2017 Anandhavelu Sanmugam et al. All rights reserved. Synthesis Approaches of Zinc Oxide Nanoparticles: The Dilemma of Ecotoxicity Tue, 18 Apr 2017 00:00:00 +0000 Human’s quest for innovation, finding solutions of problems, and upgrading the industrial yield with energy efficient and cost-effective materials has opened the avenues of nanotechnology. Among a variety of nanoparticles, zinc oxide nanoparticles (ZnO) have advantages because of the extraordinary physical and chemical properties. It is one of the cheap materials in cosmetic industry, nanofertilizers, and electrical devices and also a suitable agent for bioimaging and targeted drug and gene delivery and an excellent sensor for detecting ecological pollutants and environmental remediation. Despite inherent toxicity of nanoparticles, synthetic routes are making use of large amount of chemical and stringent reactions conditions that are contributing as environmental contaminants in the form of high energy consumption, heat generation, water consumption, and chemical waste. Further, it is also adding to the innate toxicity of nanoparticles (NPs) that is either entirely ignored or poorly investigated. The current review illustrates a comparison between pollutants and hazards spawned from chemical, physical, and biological methods used for the synthesis of ZnO. Further, the emphasis is on devising eco-friendly techniques for the synthesis of ZnO especially biological methods which are comparatively less hazardous and need to be optimized by controlling the reaction conditions in order to get desired yield and characteristics. Ayesha Naveed Ul Haq, Akhtar Nadhman, Ikram Ullah, Ghulam Mustafa, Masoom Yasinzai, and Imran Khan Copyright © 2017 Ayesha Naveed Ul Haq et al. All rights reserved. Graphene Oxide Modified Electrodes for Dopamine Sensing Sun, 16 Apr 2017 00:00:00 +0000 Dopamine (DA) is one of the most important catecholamine neurotransmitters that plays an important role in the central nervous, renal, hormonal, and cardiovascular systems. Since its discovery, tremendous effort has been made and various techniques have been developed for the DA detection. Recently, graphene-based materials have attracted a tremendous amount of attention due to their high sensitivity and rapid response towards effective detection of DA. This review focuses on current advances of graphene-based materials for DA detection based on recent articles published in the last five years. M. Z. H. Khan Copyright © 2017 M. Z. H. Khan. All rights reserved. Characteristics of Carbon Nanotubes/Graphene Coatings on Stainless Steel Meshes Used as Electrodes for Air-Cathode Microbial Fuel Cells Sun, 16 Apr 2017 00:00:00 +0000 Microbial fuel cells (MFCs) generate low-pollution power by feeding organic matter to bacteria; MFC applications have become crucial for energy recovery and environmental protection. The electrode materials of any MFC affect its power generation capacity. In this research, nine single-chamber MFCs with various electrode configurations were investigated and compared with each other. A fabrication process for carbon-based electrode coatings was proposed, and Escherichia coli HB101 was used in the studied MFC system. The results show that applying a coat of either graphene or carbon nanotubes (CNTs) to a stainless steel mesh electrode can improve the power density and reduce the internal resistance of an MFC system. Using the proposed surface modification method, CNTs and graphene used for anodic and cathodic modification can increase power generation by approximately 3–7 and 1.5–4.5 times, respectively. Remarkably, compared to a standard MFC with an untreated anode, the internal resistances of MFCs with CNTs- and graphene-modified anodes were reduced to 18 and 30% of standard internal resistance. Measurements of the nine systems we studied clearly presented the performance levels of CNTs and graphene applied as surface modification of stainless steel mesh electrodes. Wei-Hsuan Hsu, Hung-Yin Tsai, and Ying-Chen Huang Copyright © 2017 Wei-Hsuan Hsu et al. All rights reserved. One-Step Preparation of Graphene Oxide/Cellulose Nanofibril Hybrid Aerogel for Adsorptive Removal of Four Kinds of Antibiotics Sun, 16 Apr 2017 00:00:00 +0000 Via a one-step ultrasonication method, cellulose nanofibril/graphene oxide hybrid (GO-CNF) aerogel was successfully prepared. The as-prepared GO-CNF possessed interconnected 3D network microstructure based on GO nanosheets grown along CNF through hydrogen bonds. The aerogel exhibited superior adsorption capacity toward four kinds of antibiotics. The removal percentages () of these antibiotics were 81.5%, 79.5%, 79.1%, and 73.9% for Doxycycline (DXC), Chlortetracycline (CTC), Oxytetracycline (OTC), and tetracycline (TC), respectively. Simultaneously, the adsorption isotherms were well fitted to Langmuir model and kinetics study implied that the adsorption process was attributed to pseudo-second-order model. The maximum theoretical adsorption capacities of GO-CNF were 469.7, 396.5, 386.5, and 343.8 mg·g−1 for DXC, CTC, OTC, and TC, respectively, calculated by the Langmuir isotherm models. After five cycles, importantly, the regenerated aerogels still could be used with little degradation of adsorption property. Consequently, the as-synthesized GO-CNF was a successful application of effective removal of antibiotics. Jin Wang, Qiufang Yao, Chengmin Sheng, Chunde Jin, and Qingfeng Sun Copyright © 2017 Jin Wang et al. All rights reserved. Ultrafast Hydro-Micromechanical Synthesis of Calcium Zincate: Structural and Morphological Characterizations Tue, 11 Apr 2017 09:29:19 +0000 Calcium zincate is a compound with a large panel of application: mainly known as an advantageous replacement of zinc oxide in negative electrodes for air-zinc or nickel-zinc batteries, it is also used as precursor catalyst in biodiesel synthesis and as antifungal compound for the protection of limestone monuments. However, its synthesis is not optimized yet. In this study, it was elaborated using an ultrafast synthesis protocol: Hydro-Micromechanical Synthesis. Two other synthesis methods, Hydrochemical Synthesis and Hydrothermal Synthesis, were used for comparison. In all cases, the as-synthesized samples were analyzed by X-ray diffraction, scanning electron microscopy, and LASER diffraction particle size analysis. Rietveld method was used to refine various structural parameters and obtain an average crystallite size, on a Hydro-Micromechanical submicronic sample. X-ray single crystal structure determination was performed on a crystal obtained by Hydrochemical Synthesis. It has been shown that regardless of the synthesis protocol, the prepared samples always crystallize in the same crystal lattice, with space group and only differ from their macroscopic textural parameters. Nevertheless, only the Hydro-Micromechanical method is industrially scalable and enables a precise control of the textural parameters of the obtained calcium zincate. Vincent Caldeira, Laurent Jouffret, Julien Thiel, François R. Lacoste, Saïd Obbade, Laetitia Dubau, and Marian Chatenet Copyright © 2017 Vincent Caldeira et al. All rights reserved. Direct Synthesis of MnO2 Nanorods on Carbon Cloth as Flexible Supercapacitor Electrode Thu, 06 Apr 2017 07:45:27 +0000 MnO2 nanorod/carbon cloth (MnO2/CC) composites were prepared through in situ redox deposition as freestanding electrodes for flexible supercapacitors. The CC substrates possessing porous and interconnecting structures enable the uniform decoration of MnO2 nanorods on each fiber, thus forming conformal coaxial micro/nanocomposites. Three-dimensional CC can provide considerable specific surface area for high mass loading of MnO2, and the direct deposition process without using polymeric binders enables reliable electrical connection of MnO2 with CC. The effect of MnO2 decoration on the electrochemical performances was further investigated, indicating that the electrode prepared with 40 min deposition time shows high specific capacitance (220 F/g at a scan rate of 5 mV/s) and good cycling property (90% of the initial specific capacitance was maintained after 2500 cycles) in 1 M Na2SO4 aqueous solution. This enhanced electrochemical performance is ascribed to the synergistic effect of good conductivity of carbon substrates as well as outstanding pseudocapacitance of MnO2 nanorods. The obtained MnO2/CC compositing electrode with the advantages of low cost and easy fabrication is promising in applications of flexible supercapacitors. Shuang Xi, Yinlong Zhu, Yutu Yang, and Ying Liu Copyright © 2017 Shuang Xi et al. All rights reserved. PEDOT:PSS Overcoating Layer for Mechanically and Chemically Stable Ag Nanowire Flexible Transparent Electrode Thu, 06 Apr 2017 00:00:00 +0000 We investigated the effect of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) deposition on the chemical and mechanical stability of Ag nanowire flexible electrodes. A large number of bending cycles, up to 500,000 cycles, were imposed on the Ag nanowire electrodes with and without PEDOT:PSS overcoating layer. In situ resistance measurement during bending tests revealed that the Ag nanowire electrode with PEDOT:PSS overcoating layer was mechanically reliable, showing a 21.9% increase in resistance after 500,000 cycles of bending. Scanning electron microscope images revealed that the failure of the Ag nanowire network occurred along with cracks initiated in the PEDOT:PSS layer, which resulted in the increase in resistance under bending. Furthermore, the PEDOT:PSS deposition enhanced the chemical stability of Ag nanowire electrode, which showed no significant increase in resistance after exposure in air for 50 days. Our study underscored that PEDOT:PSS is effective in protecting the Ag nanowires, while maintaining the high mechanical stability. Byungil Hwang and Sooman Lim Copyright © 2017 Byungil Hwang and Sooman Lim. All rights reserved. Dispersion of High Concentrations of Carbon Nanofibers in Portland Cement Mortars Wed, 05 Apr 2017 06:36:14 +0000 This research focuses on creating and maintaining a stable dispersion of carbon nanofibers (CNFs) in portland cement based materials. A microfine cement is used in conjunction with an untraditional dispersion method to encourage and stabilize the dispersion of CNFs in concentrations up to 5% by mass of cement. A computational simulation was utilized to examine an effect called geometric clustering on the dispersion of CNFs among Type I/II and microfine cement grains. The geometric clustering simulation revealed a higher achievable dispersion for microfine cement than for Type I/II cement. Scanning electron microscopy (SEM) was used to quantify the dispersion of CNFs among Type I/II and microfine cement grains. SEM image analysis indicated excessive CNF clumping among Type I/II cement grains, while the dispersion of hybrid microfine cement mortar continued to improve as the concentration of CNFs increased up to 5% by mass of cement. Mortar cube elastic stiffness and mortar prism flexure tests revealed that high concentrations of CNFs had detrimental effects in hybrid Type I/II cement mortar, whereas similar concentrations of CNFs had negligible or beneficial effects in hybrid microfine cement mortar. Joshua Hogancamp and Zachary Grasley Copyright © 2017 Joshua Hogancamp and Zachary Grasley. All rights reserved. Synthesis of Gold Nanoparticles Dispersed in Palm Oil Using Laser Ablation Technique Wed, 05 Apr 2017 00:00:00 +0000 Gold nanoparticles have more applications in biology, medicine, and industry. In this study, gold nanoparticles were synthesized in pure palm oil using laser ablation technique. Gold nanoparticles were fabricated in different temperature, and the effect of the temperature on the particle size was investigated. Consequently, the tail of the carbonyl band of fatty acids was capped gold nanoparticles, and spherically shaped gold nanoparticles with size range of 8.92 to 19.73 nm were formed in palm oil. The temperature caused the agglomeration of nanoparticles while the particle size increased with an increase in the temperature. Amir Reza Sadrolhosseini, Suraya Abdul Rashid, and Azmi Zakaria Copyright © 2017 Amir Reza Sadrolhosseini et al. All rights reserved. Donor Impurity-Related Optical Absorption in GaAs Elliptic-Shaped Quantum Dots Wed, 05 Apr 2017 00:00:00 +0000 The conduction band and electron-donor impurity states in elliptic-shaped GaAs quantum dots under the effect of an externally applied electric field are calculated within the effective mass and adiabatic approximations using two different numerical approaches: a spectral scheme and the finite element method. The resulting energies and wave functions become the basic information needed to evaluate the interstate optical absorption in the system, which is reported as a function of the geometry, the electric field strength, and the temperature. M. A. Londoño, R. L. Restrepo, J. H. Ojeda, Huynh Vinh Phuc, M. E. Mora-Ramos, E. Kasapoglu, A. L. Morales, and C. A. Duque Copyright © 2017 M. A. Londoño et al. All rights reserved. Nonlinear Mechanooptical Transmittance Controlled by a Rotating TiO2 Thin Solid Film with Embedded Bimetallic Au-Pt Nanoparticles Tue, 04 Apr 2017 09:24:00 +0000 The modification in the third-order nonlinear optical behavior exhibited by a titanium dioxide thin solid film with embedded Gold-Platinum nanoparticles was induced by nanosecond optical pulses. A Nd:YAG laser system was employed for the experiments explored by a vectorial two-wave mixing method with the sample in rotation. The nanostructures were prepared by a sol-gel technique. Transmission Electron Microscopy studies and ultraviolet-optical spectroscopy measurements were undertaken. The evolution of the optical transmittance exhibited by the sample in rotation controlled by a servomechanism was observed. Potential applications for developing mechanooptical functions based on third-order optical nonlinearities were contemplated. A. J. Piña-Díaz, M. Trejo-Valdez, S. Morales-Bonilla, C. R. Torres-San Miguel, C. L. Martínez-González, and C. Torres-Torres Copyright © 2017 A. J. Piña-Díaz et al. All rights reserved. Effect of Saline Solution on the Electrical Response of Single Wall Carbon Nanotubes-Epoxy Nanocomposites Tue, 04 Apr 2017 09:08:44 +0000 The effects of saline solution on the electrical resistance of single wall carbon nanotubes-epoxy nanocomposites have been investigated experimentally. Ultrasonic assisted fabricated 1.0% and 0.5 W/W% SWCNTs epoxy nanocomposites are integrated into a Kelvin structure by smear cast the nanocomposites on a glass wafer. Four metal pads are deposited on the nanocomposites using the beam evaporator and wires are tethered using soldering. The effect of saline solution on the electrical resistance of the nanocomposites is studied by adding drop of saline solution to the surface of the fabricated nanocomposites and measuring electrical resistance. Moreover, the nanocomposites are soaked completely into 3 wt.% saline solution and real-time measurement of the electrical resistance is conducted. It is found that a drop of saline solution on the surface of the nanocomposites film increases the resistance by 50%. Furthermore, the real-time measurement reveals a 40% increase in the resistance of the nanocomposites film. More importantly, the nanocomposites are successfully reset by soaking in DI water for four hours. This study may open the door for using SWCNTs epoxy nanocomposites as scale sensors in oil and gas industry. Hammad Younes, Md. Mahfuzur Rahman, Amal Al Ghaferi, and Irfan Saadat Copyright © 2017 Hammad Younes et al. All rights reserved. Plasmonic Hybrid Thin Film for Broadband Absorption and Characterization of Its Optical and Electrical Properties Tue, 04 Apr 2017 07:24:46 +0000 We developed a simple and effective technique for fabricating a hybrid nanostructure of graphene-silver nanoparticles. The structure was prepared by stacking method with polyvinylpyrrolidone as a stabilizer. The chemical linking of G-PVP-Ag is possible through PVP-based ligand chemistry. The resulting hybrid film exhibited 87% transparency. The electrical properties under UV light increased compared with only one material. The conversion efficiency of a solar cell fabricated with the hybrid structure also increased approximately by 1.5% compared with that of solar cell fabricated without the hybrid film. Sookyoung Moon Copyright © 2017 Sookyoung Moon. All rights reserved. Rapid Biosynthesis of Silver Nanoparticles Based on Flocculation and Reduction of an Exopolysaccharide from Arthrobacter sp. B4: Its Antimicrobial Activity and Phytotoxicity Mon, 03 Apr 2017 00:00:00 +0000 Silver nanoparticles (AgNPs) were rapidly synthesized using an exopolysaccharide from Arthrobacter sp. B4 (B4-EPS). The optimum condition for AgNPs synthesis was under the concentration of 5 g/L B4-EPS and 1 mM AgNO3 at 80°C between pH 7.0 and 8.0. The resulting AgNPs displayed a face-centred-cubic structure with the size range from 9 nm to 72 nm. Further analysis showed that flocculation and reduction of B4-EPS played a pivotal role in the formation of AgNPs. Furthermore, these nanoparticles exhibited great stability, excellent antimicrobial activity, and low phytotoxicity. The aforementioned data provide a feasible and efficient approach for green synthesis of AgNPs using microbial polysaccharides with flocculation and reduction activity, which will be promising in medical filed. Li Yumei, Li Yamei, Li Qiang, and Bao Jie Copyright © 2017 Li Yumei et al. All rights reserved. Preparation of a Leaf-Like BiVO4-Reduced Graphene Oxide Composite and Its Photocatalytic Activity Mon, 03 Apr 2017 00:00:00 +0000 We prepared a unique leaf-like BiVO4-reduced graphene oxide (BiVO4-rGO) composite with prominent adsorption performance and photocatalytic ability by a single-step method. Multiple characterization results showed that the leaf-like BiVO4 with average diameter of about 5 um was well dispersed on the reduced graphene oxide sheet, which enhanced the transportation of photogenerated electrons into BiVO4, thereby leading to efficient separation of photogenerated carriers in the coupled graphene-nanocomposite system. The characterization and experiment results also indicated that the outstanding adsorption ability of such composite was closely associated with the rough surface of the leaf-like BiVO4 and doped rGO. The surface photocurrent spectroscopy and transient photocurrent density measurement results demonstrated that the doped rGO enhanced separation efficiency and transfer rate of photogenerated charges. As a result, the BiVO4-rGO exhibited higher photocatalytic capacity toward the degradation of rhodamine B dye under visible-light irradiation compared with pure BiVO4 and P25. Shimin Xiong, Tianhui Wu, Zihong Fan, Deqiang Zhao, Mao Du, and Xuan Xu Copyright © 2017 Shimin Xiong et al. All rights reserved. Preparation and Photocatalytic Performance of Ti3C2/TiO2/CuO Ternary Nanocomposites Mon, 03 Apr 2017 00:00:00 +0000 Ti3C2/TiO2/CuO nanocomposites were synthesized via the decomposition of a mixture of Ti3C2 (a novel two-dimensional carbide) and cupric nitrate under an argon atmosphere. The morphology and structures of the obtained samples were characterized. X-ray diffraction and energy dispersive spectrometer analysis indicate that the sample is composed of Ti3C2, anatase-TiO2, and CuO. Scanning electron microscopy images show that CuO and TiO2 nanoparticles were evenly distributed on the surface of Ti3C2. The particles size increased with an increase in the cupric nitrate content. Photocatalytic degradation of methyl orange shows that the Ti3C2/TiO2/CuO nanocomposite has good photocatalytic degradation efficiency. A possible photocatalytic mechanism of the Ti3C2/TiO2/CuO nanocomposites was proposed. The data indicated that CuO and Ti3C2 effectively promote the separation of photoelectrons from vacancies. Yang Lu, Meihuan Yao, Aiguo Zhou, Qianku Hu, and Libo Wang Copyright © 2017 Yang Lu et al. All rights reserved. TiO2 (Nano)Particles Extracted from Sugar-Coated Confectionery Mon, 03 Apr 2017 00:00:00 +0000 As the debate about TiO2 food additive safety is still open, the present study focuses on the extraction and characterisation of TiO2 (nano)particles added as a whitening agent to confectionary products, that is, chewing gum pellets. The aim was to (1) determine the colloidal properties of suspensions mutually containing TiO2 and all other chewing gum ingredients in biologically relevant media (preingestion conditions); (2) characterise the TiO2 (nano)particles extracted from the chewing gum coating (after ingestion); and (3) verify their potential photocatalysis. The particle size distribution, in agreement with the zeta potential results, indicated that a small but significant portion of the particle population retained mean dimensions close to the nanosize range, even in conditions of moderate stability, and in presence of all other ingredients. The dispersibility was enhanced by proteins (i.e., albumin), which acted as surfactants and reduced particle size. The particle extraction methods involved conventional techniques and no harmful chemicals. The presence of TiO2 particles embedded in the sugar-based coating was confirmed, including 17–30% fraction in the nanorange (<100 nm). The decomposition of organics under UV irradiation proved the photocatalytic activity of the extracted (nano)particles. Surprisingly, photocatalysis occurred even in presence of an amorphous SiO2 layer surrounding the TiO2 particles. Martina Lorenzetti, Anja Drame, Sašo Šturm, and Saša Novak Copyright © 2017 Martina Lorenzetti et al. All rights reserved. Formation and Investigation of Electrospun PLA Materials with Propolis Extracts and Silver Nanoparticles for Biomedical Applications Sun, 02 Apr 2017 07:52:32 +0000 An electrospun hydrophilic non-water-soluble biocompatible polylactic acid (PLA) nonwoven material was used as a delivery system for propolis ethanolic extract (PEE) and silver nanoparticles (AgNPs) that are known for their established antiseptic and antimicrobial activity. Combination of PEE and AgNPs in a single product should provide efficient antimicrobial protection and improved wound healing. Evaluations of PEE and AgNPs on morphology of electrospun materials, release kinetics of AgNPs and phenolic compounds, antibacterial properties, and cytotoxicity of electrospun PLA materials were performed. The presence of PEE or/and AgNPs resulted in denser mats formed by thicker PLA fibers. The average diameter of PLA microfibers was  nm. The average diameter of microfibers increased to and  nm when 10 wt% and 20 wt% ethanol were added, respectively. Addition of 10 wt% or 20 wt% PEE increased the diameter to and  nm, respectively. Suspension of AgNPs also caused the formation of thicker microfibers with  nm diameter. Electrospun PLA microfibers with PEE maintained viability of HaCaT cells. Testing of antimicrobial activity confirmed the ability of AgNPs containing PLA electrospun materials to inhibit the growth of microorganisms. Erika Adomavičiūtė, Solveiga Pupkevičiūtė, Vaida Juškaitė, Modestas Žilius, Sigitas Stanys, Alvydas Pavilonis, and Vitalis Briedis Copyright © 2017 Erika Adomavičiūtė et al. All rights reserved. Nanocomposites of NR/SBR Blend Prepared by Latex Casting Method: Effects of Nano-TiO2 and Polystyrene-Encapsulated Nano-TiO2 on the Cure Characteristics, Physical Properties, and Morphology Wed, 29 Mar 2017 00:00:00 +0000 Nanocomposites of 80/20 (w/w) natural rubber (NR)/styrene butadiene rubber (SBR) blend with four loadings of either nanosized titanium dioxide (nTiO2) or polystyrene-encapsulated nTiO2 (PS-nTiO2), ranging from 3 to 9 parts by weight per hundred of rubber (phr), were prepared by latex casting method. The PS-nTiO2 synthesized via in situ differential microemulsion polymerization displayed a core-shell morphology (nTiO2 core and PS shell) with an average diameter of 42 nm. The cure characteristics (scorch time, cure time, and cure rate index), mechanical properties (tensile properties, tear strength, and hardness), thermal stability, glass transition temperature, and morphology of the prepared nanocomposites were quantified and compared. The results showed that the cure characteristics of all the nanocomposites were not significantly changed compared to those of the neat NR/SBR blend. The inclusion of an appropriate amount of either nTiO2 or PS-nTiO2 into the NR/SBR blend apparently improved the tensile strength, modulus at 300% strain, tear strength, hardness, and thermal stability but deteriorated the elongation at break of the nanocomposites. Based on differential scanning calorimetry, the glass transition temperature of all the nanocomposites was similar to that of the neat NR/SBR blend. Moreover, the morphology of the PS-nTiO2-filled rubber nanocomposites fractured surface analyzed by scanning electron microscopy showed an improvement in the interfacial adhesion between the rubber phase and the nanoparticles. Anyaporn Boonmahitthisud, Peeraphong Pokphat, Phasawat Chaiwutthinan, and Saowaroj Chuayjuljit Copyright © 2017 Anyaporn Boonmahitthisud et al. All rights reserved. Linear Optical Properties of Zinc Borotellurite Glass Doped with Lanthanum Oxide Nanoparticles for Optoelectronic and Photonic Application Wed, 29 Mar 2017 00:00:00 +0000 Enhancing the optical properties of glasses for the sake of optical application in various fields is an ongoing challenge in materials science and technology. Thus, the optical properties of zinc borotellurite glass doped with lanthanum oxide nanoparticles (La2O3 NPs) with the chemical composition of {[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}1−x (La2O3 NPs)x, where = 0.01, 0.02, 0.03, 0.04, and 0.05 molar fraction, have been investigated. Characterization techniques such as x-ray diffraction, Fourier Transform Infrared Spectroscopy, and Ultraviolet-Visible Spectroscopy are employed to yield the structural properties and optical parameter of the glass. The amorphous nature of the fabricated glasses is confirmed with the presence of a broad hump via XRD diffraction pattern. The decreasing amount of high polarizable nonbridging oxygen as the concentration of La2O3 NPs increases has contributed to the increasing trend of energy band gap in the range of 2.70 to 3.52 eV and decreasing value of refractive index between 2.34 and 2.48. The fabricated glasses that have a higher refractive index than the widely used fiber material, pure silica glass, indicate that zinc borotellurite glass doped with lanthanum nanoparticles is a promising material to be applied as optical fibers. Faznny Mohd Fudzi, Halimah Mohamed Kamari, Amirah Abd Latif, and Azlan Muhammad Noorazlan Copyright © 2017 Faznny Mohd Fudzi et al. All rights reserved. Growth of MWCNTs on Flexible Stainless Steels without Additional Catalysts Tue, 28 Mar 2017 10:01:29 +0000 Multiwalled carbon nanotubes (MWCNTs) were synthesized on austenitic stainless steel foils (Type 304) using a home-built thermal chemical vapor deposition (CVD) under atmospheric pressure of hydrogen (H2) and acetylene (C2H2). During the growth, the stainless steel substrates were heated at different temperatures of 600, 700, 800, and 900°C. It was found that MWCNTs were grown on the stainless steel substrates heated at 600, 700, and 800°C while amorphous carbon film was grown at 900°C. The diameters of MWCNTs, as identified by scanning electron microscope (SEM) images together with ImageJ software program, were found to be 67.7, 43.0, and 33.1 nm, respectively. The crystallinity of MWCNTs was investigated by an X-ray diffractometer. The number of graphitic walled layers and the inner diameter of MWCNTs were investigated using a transmission electron microscope (TEM). The occurrence of Fe3O4 nanoparticles associated with carbon element can be used to reveal the behavior of Fe in stainless steel as catalyst. Raman spectroscopy was used to confirm the growth and quality of MWCNTs. The results obtained in this work showed that the optimum heated stainless steel substrate temperature for the growth of effective MWCNTs is 700°C. Chemical states of MWCNTs were investigated by X-ray photoelectron spectroscopy (XPS) using synchrotron light. Udomdej Pakdee, Surasak Chiangga, Suchat Suwannatus, and Pichet Limsuwan Copyright © 2017 Udomdej Pakdee et al. All rights reserved. Synthesis of Nanocrystalline Boron Carbide by Direct Microwave Carbothermal Reduction of Boric Acid Mon, 27 Mar 2017 09:56:28 +0000 The excellent physical and chemical properties of boron carbide make it suitable for many applications. However, its synthesis requires a large amount of energy and is time-consuming. Microwave carbothermal reduction is a fast technique for producing well crystallized equiaxial boron carbide nanoparticles of about 50 nm and very few amounts of elongated nanoparticles were also synthesized. They presented an average length of 82 nm and a high aspect ratio (5.5). The total reaction time was only 20 minutes, which disfavor the growing process, leading to the synthesis of nanoparticles. Microwave-assisted synthesis leaded to producing boron-rich boron carbide. Increasing the forward power increases the boron content and enhances the efficiency of the reaction, resulting in better crystallized boron carbide. Rodolfo F. K. Gunnewiek, Pollyane M. Souto, and Ruth H. G. A. Kiminami Copyright © 2017 Rodolfo F. K. Gunnewiek et al. All rights reserved. Room Temperature Ferromagnetic and Optical Properties of Chrome Doped ZnS Nanorods Prepared by Hydrothermal Method Mon, 27 Mar 2017 00:00:00 +0000 Cr doped S nanorods with different concentration ratio (, 0.01, 0.03, and 0.05) were successfully synthesized by hydrothermal method. The crystal microstructure, morphology, chemical composition, and optical and magnetic properties of the samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS), diffuse-reflectance spectroscopy (DRS), photoluminescence (PL) spectra, and the vibrating sample magnetometer (VSM). All the samples synthesized by this method exhibited single-phase wurtzite structure with good crystallization as demonstrated by XRD studies, which indicated that all Cr ions successfully substituted for the lattice site of Zn2+ and generated single-phase S. DRS revealed the band gap of doped S underwent blue shift compared to that of the bulk ZnS. PL spectra showed obvious ultraviolet emission peak at 375 nm and two blue emissions appear about 500 and 580 nm. The blue emissions intensity of doped samples improved with the increase of Cr concentration, comparing to pure ZnS. Magnetic measurements indicated that the undoped and doped ZnS nanorods exhibited well-defined ferromagnetic behavior at room temperature. The saturation magnetization weakened significantly with increasing Cr concentration comparing to pure ZnS and reached minimum for 3% Cr. Wenhua Zhao, Zhiqiang Wei, Li Zhang, Xiaojuan Wu, Xuan Wang, and Jinlong Jiang Copyright © 2017 Wenhua Zhao et al. All rights reserved. Antibacterial Efficacy of Gold and Silver Nanoparticles Functionalized with the Ubiquicidin (29–41) Antimicrobial Peptide Sun, 26 Mar 2017 09:33:09 +0000 Recent studies have demonstrated that drug antimicrobial activity is enhanced when metallic nanoparticles are used as an inorganic support, obtaining synergic effects against microorganisms. The cationic antimicrobial peptide ubiquicidin 29–41 (UBI) has demonstrated high affinity and sensitivity towards fungal and bacterial infections. The aim of this research was to prepare and evaluate the antimicrobial efficacy of engineered multivalent nanoparticle systems based on silver or gold nanoparticles functionalized with UBI. Spectroscopy techniques demonstrated that NPs were functionalized with UBI mainly through interactions with the -NH2 groups. A significant increase in the antibacterial activity against Escherichia coli and Pseudomonas aeruginosa was obtained with the conjugate AgNP-UBI with regard to that of AgNP. No inhibition of bacterial growth was observed with AuNP and AuNP-UBI using a nanoparticle concentration of up to 182 μg mL−1. Nonetheless, silver nanoparticles conjugated to the UBI antimicrobial peptide may provide an alternative therapy for topical infections. Enrique Morales-Avila, Guillermina Ferro-Flores, Blanca E. Ocampo-García, Gustavo López-Téllez, Johnny López-Ortega, Diana G. Rogel-Ayala, and Diego Sánchez-Padilla Copyright © 2017 Enrique Morales-Avila et al. All rights reserved. An Efficient Method for Cellulose Nanofibrils Length Shearing via Environmentally Friendly Mixed Cellulase Pretreatment Thu, 23 Mar 2017 09:28:43 +0000 Cellulose nanofibrils (CNFs) have potential applications in the development of innovative materials and enhancement of conventional materials properties. This paper focused on the mixed cellulase hydrolysis with major activity of exoglucanase and endoglucanase on the cellulose length shearing. By the cooperation of two-step production route, including (1) enzymatic pretreatment using cellulase from Trichoderma viride and (2) mechanical grinding twice, a shorter cellulose nanofiber was fabricated. The influence of enzymatic charge and hydrolysis time on cellulose fibers was analyzed by using scanning electron microscopy (SEM), Fourier Transform Infrared Spectrometer (FTIR), and X-ray diffractometer (XRD). SEM images revealed that the surface morphology change, effective diameter sharpening, and length shearing of cellulose fibers are as a result of cellulase hydrolysis. The XRD suggested that the cellulase acted on the amorphous regions more strongly than the crystalline domains during layer-by-layer hydrolysis. The enzymatic charge and hydrolysis time significantly affected the yields and hydrolysis products concentration. The enzymatic pretreatment assisted mechanical grinding could improve the uniformity of CNF and helped to obtain CNF with exact length according to the requirement for special applications. Yuan Chen, Yuchan He, Dongbin Fan, Yanming Han, Gaiyun Li, and Siqun Wang Copyright © 2017 Yuan Chen et al. All rights reserved. Dual Role of a Ricinoleic Acid Derivative in the Aqueous Synthesis of Silver Nanoparticles Thu, 23 Mar 2017 07:56:05 +0000 We show that sodium 9,10-epoxy-12-hydroxytetradecanoate (SEAR), an epoxidized derivative of ricinoleic acid, simultaneously functioned as reducing and stabilizing agents in the synthesis of silver nanoparticles in alkaline aqueous medium. The advantage of using SEAR is its biodegradability and nontoxicity, which are important characteristics for mitigation of environmental impact upon discharge of nanoparticles into terrestrial and aquatic ecosystems. The SEAR concentration was found to impact considerably the size distribution of silver nanoparticles (AgNPs). A concentration below the SEAR critical micelle concentration (CMC) generated 23 nm sized AgNPs with 10 nm standard deviation, while 50 nm sized AgNPs ( nm) were obtained at a concentration above the SEAR CMC. FTIR analysis revealed that the carboxylate that constitutes the SEAR hydrophilic head binds directly to the AgNPs surface promoting stabilization in solution. Finally, AgNPs turned into Ag2S upon contact with wastewater samples from Wastewater Treatment Plant at Federal University of Rio Grande do Norte (UFRN), Brazil, which is an interesting result, since Ag2S is more environmentally friendly than pure AgNPs. Isadora Dantas Costa, Alcides de Oliveira Wanderley Neto, Heloiza Fernanda Oliveira da Silva, Edgar Perin Moraes, Eryka Thamyris Damascena Nóbrega, Celso Sant’Anna, Mateus Eugenio, and Luiz Henrique da Silva Gasparotto Copyright © 2017 Isadora Dantas Costa et al. All rights reserved. Study of the Carbonization and Graphitization of Coal Tar Pitch Modified with SiC Nanoparticles Thu, 23 Mar 2017 06:51:07 +0000 Silicon carbide nanoparticles (nSiC) have been used to modify coal tar pitch (CTP) as a carbon binder. The influence of ceramic nanoparticles on the structure and microstructure was studied. The structure of CTP-based carbon residue with various nSiC contents was analyzed by using SEM with EDAX, Raman spectroscopy, and X-ray diffraction. The effect of ceramic nanofiller on the crystallite sizes (, ) and the -axis spacing () in carbonized samples after heating from 1000 to 2800°C was analyzed. Ceramic nanofillers inhibit structural changes in carbonized samples heated to 1000°C. After heating CTP with nSiC above 2000°C, the carbon samples contained two carbon components differing in structural ordering. Ceramic nanoparticles increase carbon crystallite growth, while their impact on the -axis spacing is low. Maciej Gubernat, Tomasz Lis, Janusz Tomala, Jakub Kawala, Aneta Fraczek-Szczypta, and Stanislaw Blazewicz Copyright © 2017 Maciej Gubernat et al. All rights reserved.