Journal of Nanomaterials The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Enhanced Heavy Oil Recovery in Mild Conditions by /- Solid Superacid Prepared by Different Methods Tue, 31 May 2016 11:34:20 +0000 The important key of heavy oil efficient exploring is to decrease the viscosity and increase the flowability. Solid acid catalyst is one of the commonly used catalysts to reducing the viscosity of heavy oil, but good dispersion in oil phase and better catalytic activity are difficult to achieve. Herein, ZrO2-TiO2 was selected as the fundamental catalyst because of its superior solid superacid properties, and CTAB was selected as the surfactant package coat to help enhance catalytic activity. The as-prepared catalysts were characterized systematically by TEM, XRD, FTIR, and N2 adsorption-desorption isotherms measurement. The reduction efficiency of the heavy oil viscosity achieved as high as 66.3% at 180°C. At the same time, the portion of asphaltenes and resins slipped down by 4.93% and 3.78%, respectively, while saturated and aromatic hydrocarbon component increased by 5.37% and 3.26%, respectively, indicating that our catalyst showed a good activity for reducing the viscosity and improving the quality of heavy crude oil. Chen Li, Lu Su, Qiuye Li, Xiaodong Wang, Xiaohong Li, Jianjun Yang, and Zhijun Zhang Copyright © 2016 Chen Li et al. All rights reserved. Zeolite Y Films as Ideal Platform for Evaluation of Third-Order Nonlinear Optical Quantum Dots Tue, 31 May 2016 06:27:34 +0000 Zeolites are ideal host material for generation and stabilization of regular ultrasmall quantum dots (QDs) array with the size below 1.5 nm. Quantum dots (QDs) with high density and extinction absorption coefficient have been expected to give high level of third-order nonlinear optical (3rd-NLO) and to have great potential applications in optoelectronics. In this paper, we carried out a systematic elucidation of the third-order nonlinear optical response of various types of QDs including PbSe, PbS, CdSe, CdS, ZnSe, ZnS, Ag2Se, and Ag2S by manipulation of QDs into zeolites Y pores. In this respect, we could demonstrate that the zeolite offers an ideal platform for capability comparison 3rd-NLO response of various types of QDs with high sensitivities. Hyun Sung Kim Copyright © 2016 Hyun Sung Kim. All rights reserved. Ag-Decorated Fe3O4@SiO2 Nanorods: Synthesis, Characterization, and Applications in Degradation of Organic Dyes Mon, 30 May 2016 13:08:37 +0000 Well-dispersed Ag nanoparticles (NPs) are successfully decorated on Fe3O4@SiO2 nanorods (NRs) via a facile step-by-step strategy. This method involves coating α-Fe2O3 NRs with uniform silica layer, reduction in 10% H2/Ar atmosphere at 450°C to obtain Fe3O4@SiO2 NRs, and then depositing Ag NPs on the surface of Fe3O4@SiO2 NRs through a sonochemical step. It was found that the as-prepared Ag-decorated magnetic Fe3O4@SiO2 NRs (Ag-MNRs) exhibited a higher catalytic efficiency than bare Ag NPs in the degradation of organic dye and could be easily recovered by convenient magnetic separation, which show great application potential for environmental protection applications. Chao Li, Junjie Sun, Duo Chen, Guangbing Han, Shuyun Yu, Shishou Kang, and Liangmo Mei Copyright © 2016 Chao Li et al. All rights reserved. Thermal Conductivity of Carbon Nanoreinforced Epoxy Composites Mon, 30 May 2016 08:49:37 +0000 The present study attempts to investigate the influence of multiwalled carbon nanotubes (MWCNTs) and graphite nanoplatelets (GNPs) on thermal conductivity (TC) of nanoreinforced polymers and nanomodified carbon fiber epoxy composites (CFRPs). Loading levels from 1 to 3% wt. of MWCNTs and from 1 to 15% wt. of GNPs were used. The results indicate that TC of nanofilled epoxy composites increased with the increase of GNP content. Quantitatively, 176% and 48% increase of TC were achieved in nanoreinforced polymers and nanomodified CFRPs, respectively, with the addition of 15% wt. GNPs into the epoxy matrix. Finally, micromechanical models were applied in order to predict analytically the TC of polymers and CFRPs. Lewis-Nielsen model with optimized parameters provides results very close to the experimental ones in the case of polymers. As far as the composites are concerned, the Hashin and Clayton models proved to be sufficiently accurate for the prediction at lower filler contents. C. Kostagiannakopoulou, E. Fiamegkou, G. Sotiriadis, and V. Kostopoulos Copyright © 2016 C. Kostagiannakopoulou et al. All rights reserved. Solid-State Nanopore-Based DNA Sequencing Technology Mon, 30 May 2016 07:26:02 +0000 The solid-state nanopore-based DNA sequencing technology is becoming more and more attractive for its brand new future in gene detection field. The challenges that need to be addressed are diverse: the effective methods to detect base-specific signatures, the control of the nanopore’s size and surface properties, and the modulation of translocation velocity and behavior of the DNA molecules. Among these challenges, the realization of the high-quality nanopores with the help of modern micro/nanofabrication technologies is a crucial one. In this paper, typical technologies applied in the field of solid-state nanopore-based DNA sequencing have been reviewed. Zewen Liu, Yifan Wang, Tao Deng, and Qi Chen Copyright © 2016 Zewen Liu et al. All rights reserved. Computational Modeling of the Effect of Sulci during Tumor Growth and Cerebral Edema Sun, 29 May 2016 14:07:49 +0000 This paper aims at studying the effect of sulci structures during tumor growth and cerebral edema in brain tissues. Motivated by the Intracranial Cerebral Pressure (ICP) monitoring during the brain surgery, a computational model has been created to study macroscopic behaviors of brain tissues with local volume expansion introduced by the tumor growth and cerebral edema. To consider the extra-large deformation during the tumor growth, a nonlinear finite element method has been adopted. Numerical simulation results reveal that sulci structures play significant roles in macroscopic volume expansion and maximum stress of brain tissues. Without considering the sulci structures, predictions on the ICP will be dramatically different from those including sulci structure. Therefore, it is strongly suggested that the sulci structure should be included in future studies on the brain modeling for investigating the space-occupying lesions. Dan Peng, Zhiheng Zhou, Yin Liu, Tianfu Guo, Ying Li, and Shan Tang Copyright © 2016 Dan Peng et al. All rights reserved. ZnO Nanocrystals as Anode Electrodes for Lithium-Ion Batteries Thu, 26 May 2016 09:23:38 +0000 ZnO nanocrystals were synthesized via a thermal decomposition method. X-ray diffraction, transmission electron microscopy, and photoluminescence were used to investigate the composition and nanostructure of the material. Compared with commercial ZnO nanoparticles, ZnO nanocrystals showed higher lithium storage capacity and better cycling characteristics and exhibited a reversible discharge capacity of 500 mAh g−1 after 100 cycles at 200 mA g−1. Wenhui Zhang, Lijuan Du, Zongren Chen, Juan Hong, and Lu Yue Copyright © 2016 Wenhui Zhang et al. All rights reserved. Effect of Na Doping on the Nanostructures and Electrical Properties of ZnO Nanorod Arrays Wed, 25 May 2016 07:35:32 +0000 The p-type ZnO nanorod arrays were prepared by doping Na with hydrothermal method. The structural, electrical, and optical properties were explored by XRD, Hall-effect, PL, and Raman spectra. The carrier concentrations and the mobility of Na-doped ZnO nanorod arrays are arranged from  cm−3 to  cm−3 and 0.45 cm2 v−1 s−1 to 106 cm2 v−1 s−1, respectively. Lu Yue, Zhiqiang Zhang, Yanyan Ma, and Wenhui Zhang Copyright © 2016 Lu Yue et al. All rights reserved. Ambient Air and Hole Transport Layer Free Synthesis: Towards Low Cost CH3NH3PbI3 Solar Cells Tue, 24 May 2016 11:33:58 +0000 Perovskite absorbers have witnessed a remarkable efficiency increase in last couple of years. To meet the commercialization challenge, reduced cost and improved efficiency are the two critical factors. We report on a hole transport layer free device synthesized under ambient air conditions of high humidity of 50% using TiO2-graphene oxide nanocomposite as electron selective contact. The devices achieved a power conversion efficiency of 5.9%. We introduce a novel synthesis route for TiO2-graphene oxide (GO) composite allowing superior charge transport properties. Incorporation of GO in TiO2 allows achieving higher power conversion efficiencies while working under ambient air conditions. Ambient air synthesis with hole transport free architecture has the potential to reduce the cost of this technology leading to commercial viability. Muhammad Imran Ahmed, Hareema Saleem, Ahmed Nawaz Khan, and Amir Habib Copyright © 2016 Muhammad Imran Ahmed et al. All rights reserved. Nanomaterials for Medical Applications: Benefits and Risks Tue, 24 May 2016 11:17:27 +0000 Ecaterina Andronescu, Jared M. Brown, Faik Nuzhet Oktar, Simeon Agathopoulos, Joshua Chou, and Akiko Obata Copyright © 2016 Ecaterina Andronescu et al. All rights reserved. The Optimum Fabrication Condition of p-Type Antimony Tin Oxide Thin Films Prepared by DC Magnetron Sputtering Mon, 23 May 2016 12:54:56 +0000 Transparent Sb-doped tin oxide (ATO) thin films were fabricated on quartz glass substrates via a mixed (SnO2 + Sb2O3) ceramic target using direct current (DC) magnetron sputtering in ambient Ar gas at a working pressure of 2 × 10−3 torr. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Hall-effect, and UV-vis spectra measurements were performed to characterize the deposited films. The substrate temperature of the films was investigated in two ways: (1) films were annealed in Ar ambient gas after being deposited at room temperature or (2) they were deposited directly at different temperatures. The first process for fabricating the ATO films was found to be easier than the second process. The deposited films showed p-type electrical properties, a polycrystalline tetragonal rutile structure, and their average transmittance was greater than 80% in the visible light range at the optimum annealing temperature of 500°C. The best electrical properties of the film were obtained on a 10 wt% Sb2O3-doped SnO2 target with a resistivity, hole concentration, and Hall mobility of 0.55 Ω·cm, 1.2 × 1019 cm−3, and 0.54 cm2V−1s−1, respectively. Huu Phuc Dang, Quang Ho Luc, Tran Le, and Van Hieu Le Copyright © 2016 Huu Phuc Dang et al. All rights reserved. Preparation of Graphene Quantum Dots and Their Application in Cell Imaging Sun, 22 May 2016 13:43:06 +0000 Objective. This study aims to increase the fluorescence quantum yield by improving the conditions of preparing graphene quantum dots (GQDs) through the solvothermal route and observe the GQDs performance in imaging oral squamous cells. Methodology. The following experimental conditions of GQDs preparation through the solvothermal route were improved: graphene oxide (GO)/N-N dimethyl formamide (DMF) ratio, filling percentage, and reaction time. A fluorescence spectrophotometer was used to measure photoluminescence, and the peak values were compared. Methylthiazolyldiphenyl-tetrazolium (MTT) bromide was used to detect the cytotoxicity of GQDs, which was compared with that of cadmium telluride quantum dots (CdTe QDs). GQDs were cultured with tongue cancer cells. After the coculture, a laser scanning confocal microscope (LSCM) was used to observe cell imaging. Results. The optimal conditions of GQD preparation through the solvothermal route included the following: 10 mg/mL GO/DMF ratio, 80% filling percentage, 12 h reaction time, and 17.4% fluorescence quantum yield. As the cell concentration increased, the GQD and CdTe QD groups exhibited a decreasing cell survival rate, with the decrease in the CdTe QD group being more significant. The LSCM observations showed bright green fluorescence images. Conclusion. The improved experimental conditions increased the fluorescence quantum yield of GQDs. In this study, the prepared GQDs exhibited low cytotoxicity level and satisfactory cell imaging performance. Jie Zhang, Yong-qiang Ma, Na Li, Jing-li Zhu, Ting Zhang, Wei Zhang, and Bin Liu Copyright © 2016 Jie Zhang et al. All rights reserved. Lipid Reconstitution-Enabled Formation of Gold Nanoparticle Clusters for Mimetic Cellular Membrane Sun, 22 May 2016 12:40:16 +0000 Gold nanoparticles (AuNPs) encapsulated within reconstituted phospholipid bilayers have been utilized in various bioapplications due to their improved cellular uptake without compromising their advantages. Studies have proved that clustering AuNPs can enhance the efficacy of theranostic effects, but controllable aggregation or oligomerization of AuNPs within lipid membranes is still challenging. Here, we successfully demonstrate the formation of gold nanoparticle clusters (AuCLs), supported by reconstituted phospholipid bilayers with appropriate sizes for facilitating cellular uptake. Modulation of the lipid membrane curvatures influences not only the stability of the oligomeric state of the AuCLs, but also the rate of cellular uptake. Dynamic light scattering (DLS) data showed that 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), with its relatively small head group, is crucial for establishing an effective membrane curvature to encapsulate the AuCLs. The construction of phospholipid bilayers surrounding AuCLs was confirmed by analyzing the secondary structure of M2 proteins incorporated in the lipid membrane surrounding the AuCLs. When AuCLs were incubated with cells, accumulated clusters were found inside the cells without the lipids being removed or exchanged with the cellular membrane. We expect that our approach of clustering gold nanoparticles within lipid membranes can be further developed to design a versatile nanoplatform. Jiyoung Nam, Yong-Tae Kim, Aeyeon Kang, Kook-Han Kim, KyoRee Lee, Wan Soo Yun, and Yong Ho Kim Copyright © 2016 Jiyoung Nam et al. All rights reserved. Combination of Photodynamic Therapy with Radiotherapy for Cancer Treatment Thu, 19 May 2016 17:17:07 +0000 Photodynamic therapy (PDT) is a promising treatment modality for the management of malignant diseases. However, general acceptance of PDT has been hampered due to the limited tissue penetration of light and unavailability of suitable photosensitizers (PSs). The innovative combination of the conventional radiotherapy (RT) with PDT might reduce the unacceptable normal tissue toxicity while maintaining the desired tumor suppression effect. There have been a number of attempts to examine the interaction of PDT and RT; however, the previous results presented are ambiguous. The exact mechanisms for the variable responses of diverse panel of cell lines to the combination therapeutic regimen are still unclear. Novel ways are being explored to overcome the weaknesses of the conventional PDT and RT treatment regimen. The novel application to enable PDT of deep cancers is the utilization of scintillating nanoparticles as an intracellular light source for PDT activation. Upon simulation by X-rays, the nanoparticles emit scintillation or persistent luminescence to activate the PS to generate singlet oxygen. For future clinical applications, several questions are worthy of further elucidation, including the specific light dose, PS dose, radiation dose, the risk of complications, and the accurate time interval between administration of PDT and administration of RT. Jing Xu, Jianqing Gao, and Qichun Wei Copyright © 2016 Jing Xu et al. All rights reserved. Efficient Photoelectrochemical Water Oxidation by Metal-Doped Bismuth Vanadate Photoanode with Iron Oxyhydroxide Electrocatalyst Wed, 18 May 2016 06:15:54 +0000 Intensive attention has been currently focused on the discovery of semiconductor and proficient cocatalysts for eventual applications to the photoelectrochemical water splitting system. A W-Mo-doped BiVO4 semiconductor was prepared by the surfactant-assisted thermal decomposition method on a fluorine-doped tin oxide conductive film. The W-Mo-doped BiVO4 films showed a porous morphology with the grain sizes of about 270 nm. Because the hole diffusion length of BiVO4 is about 100 nm, the W-Mo-doped BiVO4 film in this study is an ideal candidate for the photoelectrochemical water oxidation. Iron oxyhydroxide (FeOOH) electrocatalyst was chemically deposited on the W-Mo-doped BiVO4 to investigate the effect of the electrocatalyst on the semiconductor. The W-Mo-doped BiVO4/FeOOH composite electrode showed enhanced activity compared to the pristine W-Mo-doped BiVO4 electrode for water oxidation reaction. The chemical deposition is a promising method for the deposition of FeOOH on semiconductor. Eun Jin Joo, Gisang Park, Ji Seon Gwak, Jong Hyeok Seo, Kyu Yeon Jang, Kyung Hee Oh, and Ki Min Nam Copyright © 2016 Eun Jin Joo et al. All rights reserved. Fabrication of Nickel Nanotube Using Anodic Oxidation and Electrochemical Deposition Technologies and Its Hydrogen Storage Property Tue, 17 May 2016 13:59:40 +0000 Electrochemical deposition technique was utilized to fabricate nickel nanotubes with the assistance of AAO templates. The topography and element component of the nickel nanotubes were characterized by TEM and EDS. Furthermore, the nickel nanotube was made into microelectrode and its electrochemical hydrogen storage property was studied using cyclic voltammetry. The results showed that the diameter of nickel nanotubes fabricated was around 20–100 mm, and the length of the nanotube could reach micron grade. The nickel nanotubes had hydrogen storage property, and the hydrogen storage performance was higher than that of nickel powder. Yan Lv Copyright © 2016 Yan Lv. All rights reserved. Finite Element Modelling and Mechanical Characterization of Graphyne Tue, 17 May 2016 13:59:10 +0000 Graphyne is an allotrope of carbon with excellent mechanical, electrical, and optical properties. The scientific community has been increasingly interested in its characterization and computational simulation, using molecular dynamics (MD) simulations and density functional theory (DFT). The present work presents, for the first time (to the authors’ knowledge), a finite element (FE) model to evaluate the elastic properties of graphyne. After presenting a brief literature review on the latest developments of graphyne and its mechanical characterization through computational methods, the FE model of graphyne sheet is presented in detail and the calculation of its elastic properties described. The linear elastic properties (Young’s modulus, Poisson’s ratio, bulk modulus, and shear modulus) obtained from the proposed FE models are in general agreement with those previously obtained by other authors using more complex computational models (MD and DFT). The influence of van der Waals (vdW) interatomic forces on the linear elastic properties of planar graphyne is negligible and can be disregarded if small strain hypothesis is adopted. The FE models also show that graphyne exhibits marginal orthotropic behavior, that is, “quasi-isotropic” behavior, a fact that agrees with the conclusions reported by other researchers. Ricardo Couto and Nuno Silvestre Copyright © 2016 Ricardo Couto and Nuno Silvestre. All rights reserved. Facet-Dependent Activity of Pt Nanoparticles as Cocatalyst on TiO2 Photocatalyst for Dye-Sensitized Visible-Light Hydrogen Generation Tue, 17 May 2016 09:40:27 +0000 The photocatalytic activities of polyoriented and preferential Pt() nanoparticles supported on TiO2 (Pt(poly)/TiO2 and Pt()/TiO2) were investigated by the photocatalytic hydrogen generation from water under visible-light irradiation. The photocatalytic hydrogen production rate of Pt()/TiO2 was 1.6 times higher than that of Pt(poly)/TiO2. The corresponding apparent activation energy on Pt()/TiO2 was about 2.39 KJ/mol, while on Pt(poly)/TiO2, it was about 4.83 KJ/mol. The difference in the apparent activation energies was probably due to the diversity in the number of surface atoms at corners and edges between the Pt(poly) and Pt() nanoparticles. The photocurrent of Pt()/TiO2 was also bigger than that of Pt(poly)/TiO2, implying that the surface structure of Pt() nanoparticles can improve the transfer efficiency of photo-induced electrons from the conduction band of TiO2 to Pt nanoparticles. As a result, the surface structure of Pt nanoparticles played an important role in the reactivity and kinetics performance of hydrogen evolution. Therefore, the photocatalytic properties of Pt/TiO2 strongly depended on the surface structure of Pt nanoparticles. Entian Cui, Guihua Hou, Rong Shao, and Rongfeng Guan Copyright © 2016 Entian Cui et al. All rights reserved. Plasmon-Exciton Resonant Energy Transfer: Across Scales Hybrid Systems Tue, 17 May 2016 08:38:50 +0000 The presence of an excitonic element in close proximity of a plasmonic nanostructure, under certain conditions, may lead to a nonradiative resonant energy transfer known as Exciton Plasmon Resonant Energy Transfer (EPRET) process. The exciton-plasmon coupling and dynamics have been intensely studied in the last decade; still many relevant aspects need more in-depth studies. Understanding such phenomenon is not only important from fundamental viewpoint, but also essential to unlock many promising applications. In this review we investigate the plasmon-exciton resonant energy transfer in different hybrid systems at the nano- and mesoscales, in order to gain further understanding of such processes across scales and pave the way towards active plasmonic devices. Mohamed El Kabbash, Alireza Rahimi Rashed, Kandammathe Valiyaveedu Sreekanth, Antonio De Luca, Melissa Infusino, and Giuseppe Strangi Copyright © 2016 Mohamed El Kabbash et al. All rights reserved. 3D Plasmonic Ensembles of Graphene Oxide and Nobel Metal Nanoparticles with Ultrahigh SERS Activity and Sensitivity Tue, 17 May 2016 06:09:13 +0000 We describe a comparison study on 3D ensembles of graphene oxide (GO) and metal nanoparticles (silver nanoparticles (AgNPs), gold nanoparticles (GNPs), and gold nanorods (GNRs)) for surface-enhanced Raman scattering (SERS) application. For the first time, GNRs were successfully assembled on the surfaces of GO by means of electrostatic interactions without adding any surfactant. The SERS properties of GO/AgNPs, GO/GNPs, and GO/GNRs were compared using 2-mercaptopyridine (2-Mpy) as probing molecule. We found that GO/AgNPs and GO/GNPs substrates are not suitable for detecting 2-Mpy due to the very strong π-π stacking interaction between the 2-Mpy molecules and sp2 carbon structure of GO. Conversely, the GO/GNRs substrates show ultrahigh SERS activity and sensitivity of 2-Mpy with the detection limit as low as ~1 M, which is ~2-3 orders of magnitude higher than that of the corresponding GNRs. Jing Lin, Xiansong Wang, Guangxia Shen, and Daxiang Cui Copyright © 2016 Jing Lin et al. All rights reserved. Structure-Dependent Mechanical Properties of ALD-Grown Nanocrystalline BiFeO3 Multiferroics Mon, 16 May 2016 13:57:59 +0000 The present paper pertains to mechanical properties and structure of nanocrystalline multiferroic BeFiO3 (BFO) thin films, grown by atomic layer deposition (ALD) on the Si/SiO2/Pt substrate. The usage of sharp-tip-nanoindentation and multiple techniques of structure examination, namely, grazing incidence X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectrometry, enabled us to detect changes in elastic properties and hardness of BFO after stages of annealing and observe their relation to the material’s structural evolution. Our experiments point towards an increase in structural homogeneity of the samples annealed for a longer time. To our best knowledge, the present report constitutes the first disclosure of nanoindentation mechanical characteristics of ALD-fabricated BeFiO3, providing a new insight into the phenomena that accompany structure formation and development of nanocrystalline multiferroics. We believe that our systematic characterization of the BFO layers carried out at consecutive stages of their deposition provides pertinent information which is needed to control and optimize its ALD fabrication. Anna Majtyka, Anna Nowak, Benoît Marchand, Dariusz Chrobak, Mikko Ritala, Jyrki Räisänen, and Roman Nowak Copyright © 2016 Anna Majtyka et al. All rights reserved. Preparation, Characterization, and Antitumor Evaluation of Electrospun Resveratrol Loaded Nanofibers Mon, 16 May 2016 07:36:38 +0000 Resveratrol has been reported as a potential antitumor agent for several years. The possible application was greatly hampered by its poor solubility. The current study reported the construction of electrospun Resveratrol loaded nanofibers with methoxypolyethylene glycol-poly(caprolactone) (mPEG-PCL) block copolymers as drug carriers. Characterization studies showed the successful encapsulation of Rsv in the nanofibers with an in vitro sustained release pattern. In vitro XTT assay suggested the superior cytotoxicity of Rsv-NFs with more apoptosis induction on cancer cells. Cells that exposed to Rsv-NFs showed less clonogenic ability when compared to the equivalent dose of free Rsv. In addition, the migration and invasion ability of cells were also significantly lower when treated with Rsv-NFs. In the in vivo study, local implantation of Rsv-NFs greatly increased the growth inhibitory effect compared to free Rsv. Therefore, results from the current study demonstrated a promising way to improve the antitumor effect of Rsv by nanofiber delivery. Hui Zhou, Xiaoxing Liu, Fenglei Wu, Junting Zhang, Zhen Wu, Haitao Yin, and Hui Shi Copyright © 2016 Hui Zhou et al. All rights reserved. Preparation and Characterization of Modified Polyethyleneimine Magnetic Nanoparticles for Cancer Drug Delivery Mon, 16 May 2016 07:34:13 +0000 Magnetic nanoparticles with polymeric coating have great significance in drug delivery purpose. We intended to prepare a modified amphiphilic polymer with targeting susceptibility to reduce side effects to normal cells. In this study polyethyleneimine (PEI) as a polycationic polymer reacted with sebacoyl chloride to make a new amphiphilic polymer and folic acid as a targeting agent to reduce cytotoxicity of polymer and increase specific entrance of nanoparticles to cancerous cells. The obtained polymer (PEI-Sb-FA) was then coated on magnetic nanoparticles (MNPs) to stabilize them. The core-shell nanoparticles were characterized by different methods such as scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). Curcumin was finally loaded on PEI-Sb-FA-MNPs and the release behavior was studied in different pH. Curcumin loading of 28.2% was obtained and released drug in acidic pH = 4.5 was more than pH = 7.4, showing drug release sensitivity toward pH of media. Sedighe Arabi, Hamid Akbari Javar, and Mehdi Khoobi Copyright © 2016 Sedighe Arabi et al. All rights reserved. Effects of End-Terminal Capping on Transthyretin (105–115) Amyloid Protofibrils Using Steered Molecular Dynamics Sun, 15 May 2016 12:54:41 +0000 Numerous degenerative diseases are associated with amyloidosis, which can be caused by amyloid proteins. These amyloid proteins are generated from misfolded and denatured amyloid monomers under physiological conditions. Changes in protonation state, pH, ionic strength, and temperature, in addition to mutations, are related to the promotion of amyloidosis. Specifically, an understanding of the mechanical characteristics of amyloid protofibrils is important, since amyloid growth proceeds by a mechanism involving cycles of fragmentation and elongation. However, there remains a lack of knowledge of amyloid structural conformations and their mechanical characteristics, particularly considering end-terminal capping effects. In the present study, we investigated the mechanical characteristics of transthyretin amyloid protein (TTR), which have been implicated in cardiovascular disease, and specifically considered the contribution of end-terminal capping effects. Using steered molecular dynamics (SMD) simulations, we report different structural behaviors between uncapped and capped TTR amyloid protofibrils. We show that end-terminal capping strengthens the structural stability and improves the mechanical properties of amyloid protofibrils. This study provides useful information concerning the structural and mechanical characteristics of TTR amyloid protofibrils, with a particular emphasis on end-terminal capping effects. Myeongsang Lee, Hyunsung Choi, and Sungsoo Na Copyright © 2016 Myeongsang Lee et al. All rights reserved. Influence of the Copper-Containing SBA-15 Silica Fillers on the Mechanical Properties of High Density Polyethylene Thu, 12 May 2016 17:19:51 +0000 The paper concerns the mechanical properties of the high density polyethylene (HDPE) with the copper-containing SBA-15 silica filler. The considered filler is the SBA-15 mesoporous silica containing copper ions bounded inside channels via propyl-phosphonate anchoring groups. With its help, we can impart the biocidal properties to this plastic. Research covered mechanical properties, thermal analysis, colour, shine, and nanomolecular structure. Dynamical properties of the samples like modulus changes and mechanical core loss angle tangent versus temperature and vibration frequency were tested using DMTA method. Level of crystallinity was tested using DSC method while their structure was observed with going through light by optical microscope. Hardness and toughness of obtained samples were also defined. Colour and shine changes of the samples were observed for PE-HD with filler contents 0.5% and 1%. Modulus value changes versus temperature and frequency were notified for the samples with modifier. There were no differences in modulus changes versus temperature for samples with and without filler and frequencies 1 and 10 Hz. It was detected that melting enthalpy of the samples with the modifier decreases. Moreover, some influence of the samples with filler on colour and shine was observed. Adam Gnatowski, Jerzy Jelonkiewicz, Łukasz Laskowski, and Magdalena Laskowska Copyright © 2016 Adam Gnatowski et al. All rights reserved. Multishelled NiO Hollow Spheres Decorated by Graphene Nanosheets as Anodes for Lithium-Ion Batteries with Improved Reversible Capacity and Cycling Stability Thu, 12 May 2016 08:50:18 +0000 Graphene-based nanocomposites attract many attentions because of holding promise for many applications. In this work, multishelled NiO hollow spheres decorated by graphene nanosheets nanocomposite are successfully fabricated. The multishelled NiO microspheres are uniformly distributed on the surface of graphene, which is helpful for preventing aggregation of as-reduced graphene sheets. Furthermore, the NiO/graphene nanocomposite shows much higher electrochemical performance with a reversible capacity of 261.5 mAh g−1 at a current density of 200 mA g−1 after 100 cycles tripled compared with that of pristine multishelled NiO hollow spheres, implying the potential application in modern science and technology. Lihua Chu, Meicheng Li, Yu Wang, Xiaodan Li, Zipei Wan, Shangyi Dou, and Yue Chu Copyright © 2016 Lihua Chu et al. All rights reserved. Experiment Research on Deformation Mechanism of CNT Film Material Thu, 12 May 2016 06:32:15 +0000 Nanometer composite usually has multilevel structure, and deformation mechanism of its multilevel structure is the hot spot at present. The paper studies deformation mechanism of multilevel structure of CNT film material under tension loading and its influence on film mechanical properties by jointing multiscale experiment methods such as tensile test, digital image correlation, SEM observation, and in situ micro-Raman spectroscopy. The result shows that, during film loading process, the deformation of CNTs inside the film endures elastic elongation and glide successively, with very small axial elongation, which is about 7% of film deformation; the deformation of CNT bundle network structure endures deformation mechanism such as CNT bundle extension, rotation, and glide, and this structure deformation occupies about 93% of film deformation that large structure deformation makes CNT film have good toughness; during film loading process, the formation of CNT bundle long chain and glide mechanism in the chains help to improve film strength and toughness. Qiu Li, Yong Ge, Xiaohua Tan, Qiang Yu, and Wei Qiu Copyright © 2016 Qiu Li et al. All rights reserved. Dual-Modality Imaging Probes with High Magnetic Relaxivity and Near-Infrared Fluorescence Based Highly Aminated Mesoporous Silica Nanoparticles Wed, 11 May 2016 14:29:56 +0000 Dual-modal imaging by combining magnetic resonance (MR) and near-infrared (NIR) fluorescence can integrate the advantages of high-resolution anatomical imaging with high sensitivity in vivo fluorescent imaging, which is expected to play a significant role in biomedical researches. Here we report a dual-modality imaging probe (NIR/MR-MSNs) fabricated by conjugating NIR fluorescent heptamethine dyes (IR-808) and MR contrast agents (Gd-DTPA) within highly aminated mesoporous silica nanoparticles (MSNs-NH2). The dual-modality imaging probes NIR/MR-MSNs possess a size of ca. 120 nm. The NIR/MR-MSNs show not only near-infrared fluorescence imaging property with an emission peak at 794 nm, but also highly MR relaxivity of 14.54 mM−1 s−1, which is three times more than Gd-DTPA. In vitro experiment reveals high uptake and retention abilities of the nanoprobes, while cell viability assay demonstrates excellent cytocompatibility of the dual-modality imaging probe. After intratumor injection with the NIR/MR-MSNs, MR imaging shows clear anatomical border of the enhanced tumor region while NIR fluorescence exhibits high sensitive tumor detection ability. These intriguing features suggest that this newly developed dual-modality imaging probes have great potential in biomedical imaging. Zhu Fei-Peng, Chen Guo-Tao, Wang Shou-Ju, Liu Ying, Tang Yu-Xia, Tian Ying, Wang Jian-Dong, Wang Chun-Yan, Wang Xin, Sun Jing, Teng Zhao-Gang, and Lu Guang-Ming Copyright © 2016 Zhu Fei-Peng et al. All rights reserved. The Effect of Structural Properties of Cu2Se/Polyvinylcarbazole Nanocomposites on the Performance of Hybrid Solar Cells Wed, 11 May 2016 14:18:41 +0000 It has been said that substitution of fullerenes with semiconductor nanocrystals in bulk heterojunction solar cells can potentially increase the power conversion efficiencies (PCE) of these devices far beyond the 10% mark. However new semiconductor nanocrystals other than the potentially toxic CdSe and PbS are necessary. Herein we report on the synthesis of Cu2Se nanocrystals and their incorporation into polyvinylcarbazole (PVK) to form polymer nanocomposites for use as active layers in hybrid solar cells. Nearly monodispersed 4 nm Cu2Se nanocrystals were synthesized using the conventional colloidal synthesis. Varying weight % of these nanocrystals was added to PVK to form polymer nanocomposites. The 10% polymer nanocomposite showed retention of the properties of the pure polymer whilst the 50% resulted in a complete breakdown of the polymeric structure as evident from the FTIR, TGA, and SEM. The lack of transport channels in the 50% polymer nanocomposite solar cell resulted in a device with no photoresponse whilst the 10% polymer nanocomposite resulted in a device with an open circuit voltage of 0.50 V, a short circuit current of 7.34 mA/cm2, and a fill factor of 22.28% resulting in a PCE of 1.02%. S. Govindraju, N. Ntholeng, K. Ranganathan, M. J. Moloto, L. M. Sikhwivhilu, and N. Moloto Copyright © 2016 S. Govindraju et al. All rights reserved. Sensitivity Analysis for the Mechanical Properties of DNA Bundles Wed, 11 May 2016 13:52:37 +0000 In structural DNA nanotechnology, programming a three-dimensional shape into DNA bundles has been a primary design objective. However, the mechanical properties of these DNA bundle structures are another important factor to be considered in the design process. While the mechanics of the individual DNA double helix has been explored extensively and hence its properties are well known, the mechanical properties of structural motifs such as DNA junctions and strand breaks important to bundle mechanics have not been well characterized due to experimental limitations, rendering it difficult to predict the mechanical properties of DNA bundles. Here, we investigate the effect of these structural motifs on the global bundle rigidities by performing sensitivity analysis on a six-helix DNA bundle structure using the finite element modeling approach. Results reveal the primary structural features and their parametric values required to reproduce the experimental bundle rigidities. Young-Joo Kim and Do-Nyun Kim Copyright © 2016 Young-Joo Kim and Do-Nyun Kim. All rights reserved.