Applied Nanoscience (v.8, #8)

In this work, the effect of an interfacial low-k dielectric layer such as SiO2 was suggested along with the effect of an interfacial high-k dielectric layer such as Al2O3 on the electrical characteristics and then the electrical properties of the a-ITZO TFT such as the equivalent oxide thickness (EOT) of gate dielectric, gate capacitance per unit area ($${C_{ ext{i}}}$$ Ci ), on-current ($${I_{{ ext{on}}}}$$ Ion ), on–off current ($${I_{{ ext{on}}}}/{I_{{ ext{off}}}}$$ Ion/Ioff ) ratio and field-effect mobility ($${mu _{{ ext{FE}}}}$$ μFE ) of the a-ITZO TFT. The main purpose of this study is to conduct a comparative study to highlight the impact of the interfacial high-k dielectrics such as Al2O3, compared to low-k SiO2, the existing between the a-ITZO active layer and high-k HfO2 layer in a-ITZO TFT based on the double-layered dielectric. Therefore, the several analyses were implemented through numerical simulation of the device by the Silvaco TCAD Atlas software that was used to carry out a detailed numerical analysis for investigating the relationship between different types of the interfacial (low-k and high-k)dielectric oxides and the performance of a-ITZO TFT. The results showed that TFT based on the double-layered dielectric (Al2O3/HfO2) with a physical thickness ($${ ext{PT}}=30,{ ext{nm}}$$ PT=30nm ) it can provide good electrical properties ($${ ext{EOT}}=6.33,{ ext{nm}}$$ EOT=6.33nm , $${C_{ ext{i}}}=5.45 imes {10^{ - 7}},{ ext{F}},{ ext{c}}{{ ext{m}}^{ - 2}}$$ Ci=5.45×10-7Fcm-2 , $${I_{{ ext{on}}}}=1.61 imes {10^{ - 5}},{ ext{A}}$$ Ion=1.61×10-5A , $${I_{{ ext{on}}}}/{I_{{ ext{off}}}}=1.56 imes {10^9}$$ Ion/Ioff=1.56×109 and $${mu _{{ ext{FE}}}}=24.11,{ ext{c}}{{ ext{m}}^2},{{ ext{V}}^{ - 1}},{{ ext{s}}^{ - 1}}$$ μFE=24.11cm2V-1s-1 ) better than the properties provided by TFT based on the double-layered dielectric (SiO2/HfO2) for the same physical thickness ($${ ext{EOT}}=12.23,{ ext{nm}}$$ EOT=12.23nm , $${{ ext{C}}_{ ext{i}}}=2.82 imes {10^{ - 7}},{ ext{F}},{ ext{c}}{{ ext{m}}^{ - 2}}$$ Ci=2.82×10-7Fcm-2 , $${I_{{ ext{on}}}}=8.54 imes {10^{ - 6}},{ ext{A}}$$ Ion=8.54×10-6A , $${I_{{ ext{on}}}}/{I_{{ ext{off}}}}=8.27 imes {10^8}$$ Ion/Ioff=8.27×108 and $${mu _{{ ext{FE}}}}=29.31,{ ext{c}}{{ ext{m}}^2},{{ ext{V}}^{ - 1}},{{ ext{s}}^{ - 1}}$$ μFE=29.31cm2V-1s-1 ). However, we cannot neglect the fundamental role of the interfacial low-k SiO2 layer between the channel and the high-k dielectric, which has some beneficial qualities with regard to the carrier mobility in the transistor channel. In addition, although there is a difference in the value of leakage between the two devices, its effect is very poor on the performance of the device and its reliability, especially for low gate tensions.
Keywords: A-ITZO; SiO2 ; Al2O3 ; TFT; High-k; EOT; Silvaco Atlas

Development of bovine serum albumin–capsaicin nanoparticles for biotechnological applications by Lino Sánchez-Segura; Neftalí Ochoa-Alejo; Ramón Carriles; Laura E. Zavala-García (1877-1886).
The main use of capsaicin is as a condiment in food industry. Pharmaceutical and biotechnological applications of capsaicin have been restricted by photooxidation, chemical decomposition and low solubility in water. Protein-based particles represent an alternative for encapsulation. The aim of this work was to develop bovine serum albumin (BSA)-capsaicin nanoparticles and analyse the effect of the capsaicin concentration on the properties of nanoparticles. We prepared nanoparticles at 0, 625, 1250, 1875 and 2500 µg/mL of capsaicin with BSA. The concentration of capsaicin was positively correlated with BSA (R = 0.9910) and encapsulated capsaicin (R = 0.9977). We found that at 1250 µg/mL of capsaicin the nanoparticles showed the highest encapsulated efficiency (82.3%), the smallest size (131 nm) and the lowest ζ-potential (-54.82 mV), while the aspect ratio (Ar = 1.08) and shape factor (Sf = 0.65) showed a circular shape with one single capsaicin core. In contrast, at 1875 and 2500 µg/mL of capsaicin, coalescence between particles increased, resulting in a larger size of nanoparticles with elliptical shape (Ar = 1.29; Sf = 0.59, and Ar = 1.55; Sf = 0.54, respectively).
Keywords: Capsaicin; Bovine serum albumin; Nanoparticles; Aspect ratio; Shape factor; ζ-Potential

One-dimensional nanocomposite containing multiwall carbon nanotubes (MWCNTs) and thin bismuth tellurite (Bi2Te3) nanotubes have been synthesized using ball-milling process. The primary focus of this work is to study the morphological, molecular bonding, and structure of the novel nanocomposite and to explore the underlying mechanism to synthesize a novel nanocomposite for thermoelectric applications. The experimental results from the high-resolution TEM revealed that MWCNTs are uniformly coated on the surface of the Bi2Te3 nanotubes consisting of a bundle of two. Furthermore, it indicated that minimal strain is present at the interface between MWCNTs and Bi2Te3 nanotubes which can add additional lattice scattering, and hence, the lattice contribution to the thermal conductivity can be further reduced due to phonon-blocking phenomena. Analytical analysis results further indicated that the MWCNTs incorporated in the nanocomposites showed less disorder and successfully formation of the nanocomposites. We believe that our approach provides the advantages of simplicity, efficient and opens a new way to prepare a novel 1D thermoelectric nanocomposite which can further improve the thermophysical properties for future energy-harvesting applications and thermoelectric devices.
Keywords: Bismuth telluride; Nanotubes; CNTs; Thermoelectric material; Nanocomposite

Charge-transfer peculiarities in mesoporous BiVO4 surfaces with anchored indoline dyes by Karolina Ordon; Victor Ishrayelu Merupo; Sandrine Coste; Olivier Noel; Nicolas Errien; Malgorzata Makowska-Janusik; Abdel hadi Kassiba (1895-1905).
Mesoporous thin films of bismuth vanadate were synthesized by sol–gel method with defined deposition parameters and annealing treatments leading to nano-textured surfaces. The stabilization of monoclinic BiVO4 structure was demonstrated by structural investigations and nano-islands morphology of the films illustrated by Atomic Force Microscopy (AFM) studies. Indoline dyes (D149) were used to sensitize the film surfaces able to show photoinduced charge transfer on the hybrid surfaces using Kelvin force microscopy (KFM). The distributions of the surface electrical potentials were compared as function of the surface texture and the sensitization by dyes. A model of the band alignment in hybrid systems was proposed to account for the observed charge transfer. The photocatalytic activity of the hybrid films was also investigated and discussed.
Keywords: Mesoporous BiVO4 ; Electrical surface potential; Kelvin force microscopy; Photocatalysis

Inkjet-printed, functional heterolayers of ZnO@CuO for stoma pouch monitoring by Alvaro Ortiz Perez; Haitao Gao; Xuemeng Lyu; Jürgen Wöllenstein; Vera Kallfaß; Jordi Fonollosa; Stefan Palzer (1907-1914).
Many bowel cancer patients are in need of an artificial stoma as part of their surgical treatment, and associated post-surgical odours caused by leaking stoma pouches may lead to social isolation, which is why inconspicuous monitoring of this situation is important for affected persons. The integration of micro- and nanotechnology may offer low-cost, low-power consumption and small solutions to this challenge. To this end, we present an inkjet-printed, heterostructured gas sensor that has been built by incorporating nanosized p-type semiconducting CuO in a porous n-type ZnO matrix. The functional layer is fabricated using a combination of a colloidal suspension and sol–gel approach optimized for inkjet printing thus offering an industry-ready method for integration of nanomaterials in microelectromechanical systems (MEMS) structures. Using a thermal modulation scheme we enhance the information content and classify different events. We demonstrate that a simple MEMS device using a novel hetero-nanomaterial may be used to reliably identify situations where stoma pouch content escapes.
Keywords: CuO; ZnO; Hybrid functional materials; Colloidal suspension; Inkjet printing; Additive manufacturing

Three-dimensional nanofibrous microenvironment designed for the regulation of mesenchymal stem cells by Lin Jin; Xingcai Zhang; Zhanrong Li; Genxin Chen; Jingguo Li; Zhenling Wang; Yanzheng Gao (1915-1924).
The three-dimensional functional nanofibrous microenvironment plays a key role in the regulation of cellular growth, because it can mimic the natural extracellular matrix structure. As an important nanofibrous scaffold, 3D functional nanofibers display broad application prospects in biomedical areas, such as tissue engineering, drug release, and biosensors. Recently, these functional nanofibrous scaffolds based on biocompatible natural materials with excellent flexibility and biochemical characteristics show great potential in tissue engineering applications. Herein, we prepared 3D chondroitin sulfate surface-modified silk nanofibers (3D CS-SNFs) using a combination of electrospinning and chemical grafting methods. The as-prepared 3D CS-SNFs exhibited excellent biocompatible properties. Moreover, there are numerous deeply interconnected pores (larger than 20 µm) for enhanced cellular entry into CS-SNFs and for 3D cell culture in vitro. The 3D CS-SNFs are beneficial to cell adhesion, nutrient delivery, and excretion of excrement, which provides healthy growth environment and living conditions for those cells that penetrate into the interior of the scaffold. Our results indicate that the 3D CS-SNFs show much higher degrees of promotion of bone marrow mesenchymal stem cells adhesion and osteogenic differentiation, as compared with the 3D raw silk nanofibers. These results demonstrate that the as-prepared 3D CS-SNFs could provide a suitable 3D microenvironment for cellular growth, adhesion, and excellent osteogenic differentiation. This work paves a new way for 3D cell culture construction for damaged bone repair and regeneration.
Keywords: Silk; Three-dimensional nanofibers; Surface modification; BMSCs; Tissue engineering

Design and characterization of novel Al-doped ZnO nanoassembly as an effective nanoantibiotic by Varun Saxena; Pranjal Chandra; Lalit M. Pandey (1925-1941).
Nanoantibiotics are the new class of antibacterial agents that can be an alternative to the conventional antibiotics, which are expensive and require lengthy synthesis procedures. In view of such importance of nanoantibiotics, in the present study, we have systematically designed Al doped ZnO (AZO) via a co-precipitation method. ZnO nanoparticles own decent bactericidal activity against clinically isolated bacterial species, however, its bactericidal concentrations are compromised. To enhance the antibacterial efficiency of ZnO, different concentrations of Al was doped into ZnO lattice to design AZO nanorods, which were characterized using XRD, RAMAN, FESEM, DSC/TGA and Zetasizer. The XRD data confirmed a hexagonal wurtzite structure of AZO, while the bimetallic composition of the AZO was evaluated by RAMAN spectra and EDX. The average diameters of AZO nanorods were less than 100 nm. The zeta potential of ZnO was enhanced from 6.17 ± 0.5 to 22.7 ± 0.3 mV at 15% doping of Al. The biomedical value and commercial applicability of AZO nanorods were evaluated in terms of its biocompatibility using L929 mouse fibroblast and the antibacterial activity against Escherichia coli and Enterococcus hirae. The antibacterial activity was found to be significantly enhanced to ~ 19 times with MIC values of 14.33 ± 0.20 and 14.68 ± 0.20 µg/ml for AZO (15% doping) as compared to 254.88 ± 3.0 and 338.14 ± 9.0 µg/ml for ZnO against E. coli and E. hirae, respectively. The antibacterial mechanism was found to be electrostatic interaction between bacterial cell and AZO, followed by the intracellular accumulation of the Zn2+ ions. The release of Zn2+ ions from AZO was found to be kinetic controlled (diffusion limited). The synthesized nanorods showed excellent biocompatibility with more than 95 ± 3% of cell viability up to 6 days even at higher concentrations, indicating its promise for in vivo analysis. Hence, this study designates AZO as a plausible nanoantibiotic and unlocks its access for various other biomedical applications.
Keywords: Nanoantibiotics; Health care; AZO (Al-doped ZnO); Nano-assembly; Antibacterial mechanism; Minimum inhibitory concentration (MIC)

Bulk turbostratic graphene deposition on aluminum substrates via high-pressure graphite blasting by Abdul Hai Alami; Kamilia Aokal; Di Zhang; Bassel Soudan (1943-1950).
This work presents the mechanical exfoliation of graphite into graphene nanoplatelets via high-pressure blasting onto metallic substrates. After ensuring successful graphene deposition via Raman spectroscopy, the substrates are then tested to detect the enhancement of their thermal, optical, and electrochemical properties. The process is facile and straightforward, with no special requirements in terms of energy addition or isolation and is capable of depositing graphene over large surface areas. The application of such approach is especially suitable for solar thermal absorbers enhancement, as the thermal, optical, and corrosion resistance properties of metallic plates made of copper or aluminum benefit from the deposition at the macroscale.
Keywords: Graphene deposition; Mechanical synthesis; Mechanical deposition; Sandblasting; Compressed air

Evaluation of desulfurization activity of SPION nanoparticle-coated bacteria in the presence of magnetic field by Sayyed Shahryar Rahpeyma; Arezou Dilmaghani; Jamshid Raheb (1951-1972).
Sulfur content in diesel fuel is an environmental concern because sulfur is converted to sulfur oxides (Sox) during combustion, which not only contributes to acid rain, but poisons the catalytic converter for exhaust emission treatment. Hydrodesulfurization (HDS) method, a conventional procedure used for desulfurization of petroleum, is not efficient for desulfurization of aromatic components such as dibenzothiophene (DBT). However, biological processes require relatively mild conditions (low pressures and low temperatures) and also in BDS bacteria are able to uptake the sulfur without breaking the structure of the compounds which results in maintaining the value of fuel. In this study, functionalized magnetic iron oxide nanoparticles were synthesized and coated on Rhodococcus erythropolis IGTS8 cells to evaluate the biodesulfurization activity. Fe3O4 nanoparticles and silica-coated magnetite nanoparticles were synthesized. The morphology and properties of the synthesized nanoparticles were examined by SEM, FT-IR, XRD, DLS and zeta potential measurements. In the next stage, the bacterial cells were coated with nanoparticles and the desulfurizing activity was tested with Gibbs’s assay, HPLC and external magnet field. The results from Gibb’s assay showed that bacteria coated with functionalized nanoparticles have more desulfurization ability compared to that of uncoated bacterial cells. An external magnetic field showed rapid separation of coated bacterial cells from the reaction mixture. Thus, the necessity for a more efficient process is required to enhance the use of bionanotechnology and design a recombinant strain with a stable activity to improve the efficiency of biodesulfurization.
Keywords: Biodesulfurization; Coated bacteria; Nanoparticles; Hydrodesulfurization; Fuel

Efficient “turn-on” nanosensor by dual emission-quenching mechanism of functionalized Se doped ZnO nanorods for mercury (II) detection by A. V. R. Krishna Rao; Ramesh B. Reddy; Sagnik Sengupta; Venkatesh Chelvam (1973-1987).
Mercury, a highly toxic contaminant is a detrimental environmental pollutant that causes severe health problems in human beings and developing an economical, rapid, and efficient technique for determination of Hg2+ ions at low concentrations remains a challenge. Herein, we report the preparation and application of orange-red luminescent Se doped ZnO nanorods (NRs), by a mechanothermal method, that was coated with 3-mercaptopropionic acid (3MPA), a chelating ligand to detect mercury ions because of strong affinity of –SH functionality. The formation of nanosensor with MPA was confirmed by the presence of an S2p3/2 peak at 162.7 eV, an absence of –SH stretching bond at 2566 cm−1 and reduction of crystalline nature from XPS, FTIR and XRD techniques, respectively. In the presence of Hg2+ ions, 3MPA–Se doped ZnO nanoprobe show efficient turn-on (restoration) photoluminescence over dual emission-quenching phenomenon owing to increased zeta potential (− 17.06 mV) and anti-aggregation effect induced by rapidly separated 3MPA surface ligands bound to selenium doped ZnO within 30 s. Additionally, a linear fit of photoluminescence (PL) spectrum for various concentrations of Hg2+ ions provide compelling evidence for emission (R 2 = 0.990) over quenching (R 2 = 0.888) mechanism which is in support of our proposed mechanism. Therefore, this “turn-on” MPA-coated Se doped ZnO nanosensor is employed for selective detection of Hg2+ ions with the lowest limit of concentration to 1 pM. These results demonstrate that our direct, rapid and effective approach for mercury detection using this nanoprobe will offer a great potential for monitoring Hg2+ ions from the environment and in healthcare applications.
Keywords: Se doped ZnO Nanorods; 3-Mercaptopropionic acid capped nanosensor; Dual emission-quenching; Turn-on photoluminescence; Mercury detection

Multi-walled carbon nanotubes (MWCNTs) are non-polar carbon tubes having poor dispersion capability in different solvents. To overcome this limitation, the oxidative unzipping of MWCNTs was done and results in the preparation of unzipped multi-walled carbon nanotube oxide (UMCNOs). The UMCNOs was characterized using field-emission scanning electron microscope, Fourier transformed infrared spectrophotometer, and X-ray diffractometer. The hybrid structure was able to improve the accessible areas significantly due to the availability of both outer and inner walls of MWCNTs. UMCNOs-cotton sponge was prepared by dipping commercial cotton in unzipped carbon nano-oxide dispersion and drying in a vacuum oven. UMCNOs-Cot sponge exhibits hydrophilic and hydrophobic properties at different conditions showed its amphiphilic nature. Hydrophobic properties of UMCNOs lower the interfacial energy of the coated cotton surface with a maximum water contact angle of 145° and super-oleophilicity showed the absorption capacity of oil from an oil/water mixture. These UMCNOs-Cot sponges were applied for the separation of oils, organic solvents with absorption capacities in the range of 21–43 times as compared to its weight. A significant loss of bacterial cell viability up to 99% was also achieved with this UMCNOs-Cot sponge.
Keywords: Cotton; UMCNOs; Oil sorbent; Dye removal; Antimicrobial; Wastewater

We have successfully realized a nonvolatile resistive memory structure by rf-magnetron sputtering technique using nanoparticles synthesized by sol–gel method. The resistive switching (RS) related to the Au/TiO2 Schottky contact was grafted on a photosensitive structure ITO/ZnO:Al/p-Si allowing memory effect switching optically activated. The RS takes place via tunneling path through potential barrier located at the Au/TiO2 interface. The memory effect persists under illumination and the Arrhenius plot of the surface of the V–I cycle shows an activation energy of about 160 meV in dark and 100 meV under visible illumination. This behavior of the RS optically activated is closely related to the electronic states in the Au/TiO2 interface which leads to perform an optical switching of the memory effect with the presented structure.
Keywords: Sol–gel; Resistive switching; Memory effect; Nanoparticles

Effects of two nano-ZnO processing technologies on the properties of rubber by Qiang He; Yangjing Zhou; Guangfei Wang; Bo Zheng; Ming Qi; Xingjia Li; Linghao Kong (2009-2020).
Two different technologies (direct mixing and three-roll milling) were applied to facilitate the dispersion of nano-ZnO in a nitrile rubber (NBR) composite. The vulcanization, mechanical, friction, and wear characteristics of the two resulting rubbers were studied. Wear surfaces were measured and analyzed via 3D scanning, scanning electron microscopy, and X-ray photoelectron spectroscopy. Results showed that the three-roll milling rubber had faster vulcanization rate, delayed optimum cure time, and better tensile strength (4.1% higher) and tear strength (6% higher). The hardness, tensile elongation and compression deformation were also improved in the three-roll milling NBR composite (this greatly enhanced its comprehensive mechanical properties). The wear resistance performance of the three-roll milling NBR composite experienced a significant improvement too (the wear loss in the three-roll milling NBR composite was 14% of that in the direct mixing NBR composite). Three-roll milling produced a better dispersion of the ZnO nanoparticles in the rubber matrix facilitating the vulcanization, crosslinking and hardening of the rubber matrix. Moreover, the formation of a covalent bond between ZnO and S further enhanced mechanical properties, friction reduction, and anti-wear capacity.
Keywords: Three-roll milling; Ultrasonic dispersion and mixing; Nano-ZnO; Nitrile rubber; Mechanical properties; Friction; Wear

WO3–TiO2 nanocomposites for paracetamol degradation under visible light by Khadijah S. Namshah; Reda M. Mohamed (2021-2030).
TiO2 has wide band gap energy and also it has fast recombination rate for electron and hole. Therefore, titanium dioxide excited by ultraviolet light and its photocatalytic activity is small. Enlargement of titanium dioxide activity can be carried out by separation of electron–hole pairs. In this, TiO2–WO3 nanocomposites with various percent of WO3 were synthesis by sol–gel technique in existence of hexadecyltrimethylammonium bromide as template. Physical, photocatalytic and structural properties of titanium dioxide and TiO2–WO3 nanocomposites were measured by many characterizations tools. Performance of titanium dioxide and TiO2–WO3 nanocomposites were measured for paracetamol degradation using visible light. Titanium dioxide band gap can be tailored by control tungsten trioxide weight percent. 3 wt% of tungsten trioxide reduce band gap to 2.63 eV. The optimum weight percent of tungsten trioxide is 3 wt% at which photocatalytic performance for paracetamol degradation is larger than that of TiO2, TiO2–WO3—1 wt%, TiO2–WO3—2 wt% and TiO2–WO3—4 wt% by 33.3, 2.1, 1.6 and 1 times, respectively. TiO2–WO3—3 wt% has photocatalytic stability for five times.
Keywords: WO3–TiO2 ; Visible light; Paracetamol degradation

Optical sensors based on quantum dots have been a promising alternate for the organic dyes or fluorophores for detection label which have applications in biological sensing. The present work examines a technique that utilizes hybrid nanostructures for the detection of glucose and behaves as an optical sensor. This technique has exemplified the detection of glucose under various oxidases and enables the hybrid Au–CdSe nanostructures as sensor. The method demonstrates the effect of hydrogen peroxide (H2O2) on the fluorescence intensity of Au–CdSe QDs by modifying H2O2 concentration. The prepared samples were then characterized by high-resolution transmission electron microscopy for its structural morphology of the nanoparticles and their hybrids and photoluminescence (PL) spectroscopy for their optical properties. Because of the presence of Au NPs in the samples, initially there was an enhancement in the PL intensity by adding few micro-liters of H2O2 resulting in 70 mM and up to 130 mM concentration of H2O2, after which it suddenly showed a dramatic decrease in the PL intensity with increase in the concentration of H2O2 beyond 130 mM in the hybrid Au–CdSe nanostructures due to the inner field effect. The quenching percentage when calculated was found to be 80%. In comparison to the other available techniques the presented method is very simple, reproducible with effective sensitivity for sensing glucose and is quiet economical too.
Keywords: Hybrid Au–CdSe QDs; Hydrogen peroxide; Photoluminescence emission; Optical sensors

Size-dependent skin penetration of silver nanoparticles: effect of penetration enhancers by Kenneth Maduabuchi Ezealisiji; Hannah Ndidiamaka Okorie (2039-2046).
Penetration enhancers are usually surfactants, and co-surfactants added to dermatological applications (creams) to solubilize lipophilic active principles. They have the potential to alter the lipid integrity within the stratum corneum. Transdermal preparations such as antibiotics are now gaining a lot of interest. The present study evaluates the effect of penetration enhancers and different nanoparticle sizes of silver nanoparticles with respect to their impact on nanoparticle-skin penetration, expressed as the flux (J), the Permeability Coefficient (PC) and Enhancement Ratio (ER). In this study, the modified Franz diffusion glass cell method was adapted to measure the primary skin permeability parameters. Drug delivery depends so much on the ability of vehicles to overcome the skin barrier and deliver their content deeply into tissue layers. Hence the need for the present studies which aims to evaluate the quantity of different sizes of silver nanoparticles permeating the skin per unit time in the presence of penetration enhancers. The observed flux for the different sizes was 26, 18, 30, and 4.2 µg/cm2/h, respectively, for 4.0% Tween 80; 28, 22, 34, and 8 µg/cm2/h, respectively, for 20% Propylene Glycol (PG); 18, 14, 24 and 2.8 µg/cm2/h, respectively, for 20.0% Poly Ethylene Glycol (PEG) and 34, 28, 46 and 12 µg/cm2/h, respectively, for 4.0% sodium lauryl sulfate when compared to an aqueous solution of AgNPs (22 NM). Considering the size of AgNPs and choice of penetration enhancers could pave way for developing an ideal dermatological preparation requiring the use of nanoparticles.
Keywords: Transdermal; Franz diffusion glass cell; Permeability coefficient; Penetration enhancers

Developing a new sensitive solid-phase microextraction fiber based on carbon nanotubes for preconcentration of morphine by Bamdad Riahi-Zanjani; Mahdi Balali-Mood; Ahmad Asoodeh; Zarrin Es’haghi; Adel Ghorani-Azam (2047-2056).
The ability of extraction and preconcentration of small amounts of substances from biological samples is important in forensic medicine. In the present study, we produced a new solid-phase microextraction fiber based on carbon nanotube (CNTs) for extraction and preconcentration of small amount of morphine in urine sample. Raw nanofibers were first carboxylated with H2SO4/HNO3 (3:1) and then functionalized with ethylenediamine. Functionalization was confirmed by FTIR and Raman spectroscopy as well as SEM analysis. The functionalized CNTs were coated on a porous polypropylene hollow fiber. A new electrical device was designed and manufactured for adsorption–desorption of the analyte, in which the voltage could be reversed and the analytes could desorb into the washing solution for HPLC analysis. The results showed that the prepared fiber could adsorb a very low concentration of morphine (0.5 ppb) in urine matrix, and was successfully used for up to 50 times with no significant loss in the extraction efficiency. Recovery of the fiber was 77% at 0.5 ppb. The optimum condition for the fiber was 2 min at 1 V of the manufactured electrical catalyst controller. This fiber can be used for the detection of a small amount of morphine in biological samples, which are not detectable by conventional methods. Simple mechanism of this fiber in preconcentrating morphine makes it a novel candidate for detection of other opiates and drugs of abuses in crime scene investigations and postmortem examinations several days after exposure. The prepared electric microextraction device could also efficiently concentrate the morphine in the urine matrix.
Keywords: HPLC; Immunoblotting; Morphine; Nanocomposite; Preconcentration; Electrical-accelerated hollow fiber–solid-phase microextraction (EAHF–SPME)

Effect of spraying time on the structural and electrical properties of InAs nanowires by Ali M. Mousa; Rana K. Abdulnabi; Raid A. Ismail (2057-2064).
Indium arsenide (InAs) nanowire thin films were grown on glass substrates at 250 °C with different thicknesses (50–275 nm) using chemical spray pyrolysis technique. The structural and electrical properties of grown InAs film prepared at different spraying times were investigated. X-ray diffraction pattern confirmed the formation of polycrystalline InAs of hexagonal wurtzite structure with dominant peaks along the (200) plane for film deposited at 2 and 3 min. Hall effect measurements at 300K revealed that the electron mobility decreases as film thickness increases. InAs film with thickness of 55 nm exhibited a minimum electrical conductivity of 10−5 (Ω cm)−1. SEM investigation showed the formation of nanowires for film prepared at 3 min. The variation of the microstructural parameters such as crystallite size, FWMH, lattice constant, and d-value with film thickness was investigated. The experimental results revealed that the crystallite size increased with increase in the thicknesses of the film. EDX measurements and analysis were conducted and showed that the films deposited at 2 and 3 min give good stoichiometric InAs film. AFM data revealed that the average grain size of the film increased from 33 to 66 nm and root mean square of surface roughness of the film was increased from 4.3 to 6.3 nm as spraying time increased from 1 to 3 min.
Keywords: InAs; Thin film; Nanowires; Spraying time; Electrical properties

Studies on polarization effect of polyethylene-based polymer electrolyte in dye and quantum dot sensitized solar cells by Karan Surana; Nitin A. Jadhav; Pramod K. Singh; B. Bhattacharya (2065-2069).
As the required energy demand of humans keep increasing rapidly, the quest for developing new and efficient alternative energy resources progresses. Keeping the future energy crisis in mind, solar cells, particularly the low-cost dye and quantum dot sensitized solar cells seem to be a promising solution. Using solid polymer electrolyte in such solar cells proves to be a viable alternative as it contributes to the overall stability of the cell. However, there are certain details pertaining to solar cells where polymer electrolyte is used which have not yet been discussed in length. In this paper, we discuss the polarization effect of PEO-based quasi-solid electrolyte in DSSC and QDSC.
Keywords: Polarization effect; PEO; DSSC; QDSC; Electrolyte

Structure changes of aligned carbon nanotubes in thermoplastics below percolation revealed by impedance spectroscopy by Muchao Qu; Maik-Ivo Terasa; Rainer Adelung; Dirk W. Schubert (2071-2075).
In this study, poly(methyl methacrylate) (PMMA)/carbon nanotube (CNT) composite has been prepared using a melt-mixing procedure and an anisotropic filament has been extruded using a capillary rheometer. The electrical properties have been investigated using fast-Fourier transform impedance spectroscopy (FFT-IS), which allows to develop an equivalent circuit. The proposed electrical circuit contains two resistors and two capacitors, which mirrors the structure change of the CNTs in the composites. Some results are counter-intuitive but are explained by a novel microscopic model.
Keywords: Melt spinning; Aligned CNTs; Below percolation; Impedance spectroscopy

Green chemistry offers several benefits over other synthesis routes of nanoparticles due to their eco-friendly attributes during their formulation as well as application stages. In the present study, an aqueous extract of Ananas comosus (Pineapple) peel waste was successfully exploited for the synthesis of ultra small (average size 14–20 nm) silver nanoparticles (AgNPs) without adding any reducing or stabilizing agents. Two major factors, i.e., concentration ratio between silver ion precursor versus peel extract and synthesis pH were found to be influential for achieving monodispersed and stable AgNPs. Biogenic AgNPs adorned with natural moieties demonstrated good photocatalytic activity against methylene blue (MB) dye under sunlight illumination for various conditions. The process variable, e.g., solution pH, initial MB concentration and contact time were optimized using response surface methodology (RSM) based on three levels Box-Behnken design. A maximum MB removal of 98.04% was achieved at optimized values of 9.96 pH, 40 ppm initial dye concentration and 173 min of contact time. The kinetics of MB removal was best fitted to its first order kinetic model (R 2 = 0.996) in concurrence with intraparticle diffusion-mediated adsorption. AgNPs were also found to be effective to kill pathogenic bacterial strains, Pseudomonas aeruginosa and Bacillus subtilis as characterized from zone of inhibition (ZoI) and viability tests. Undergoing photochemical reactions, the generation of reactive oxygen species (ROS) was elucidated as the major mechanism of AgNPs’ toxicity modulating membrane permeability. This strategy is not only economically viable and environmentally benign, synthesized AgNPs were capable to remove methylene blue dye almost completely under ambient conditions through solar energy.
Keywords: Green synthesis; Methylene blue; Response surface methodology; Photocatalytic activity; Reactive oxygen species; Antibacterial mechanism

Unfortunately, the title was published incorrectly in the online published article. The correct title is given below.Photocatalytic activity of photo-catalysts could be enhanced through many parameters. Along these parameters, segregation of the holes from the photo-generated electrons which could be considered an essential one. This issue could be attained via deposition of the co-catalysts over the surface of the semiconductor. In this investigation, the hydrothermal technique has been carried out to prepare nanosheets of SnO2. After that, SnO2 nanosheets were decorated by various contents of AgI nanoparticles (5–20%). the resultant AgI/SnO2 nanocomposites were subjected to photo-catalytic efficacy evaluation which were correlated with those of neat SnO2 as well as AgI for norfloxacin degradation upon Visible light irradiation. The obtained data proved that AgI nanoparticles content is considered an important aspect in improving the photo-catalytic efficiency of SnO2. It was shown that 15% AgI-dopant could be used as an optimum percent. Evidently, the photocatalytic efficiency of 15% AgI/SnO2 nano-composite was about 1.43 and 33.3 times larger than the photocatalytic efficiencies of pure AgI and SnO2, respectively. Moreover, AgI/SnO2 nanocomposite containing 15% AgI showed higher photocatalytic stability. The existence of AgI nanoparticles as cocatalyst may be the main explanation for the modification of the photo-catalytic efficiency of the AgI/SnO2 photo-catalyst. In fact, AgI nanoparticlaes facilitate adequate segregation of the charge carriers of SnO2 rather than the enlargement of the surface area and the decreasing of the band gap.
Keywords: SnO2 nanosheets; AgI nanoparticles; Visible light; Norfloxacin degradation

Unfortunately, the title was published incorrectly in the online published article. The correct title is given below.

Correction to: Absorption of calcium ions on oxidized graphene sheets and study its dynamic behavior by kinetic and isothermal models by Mahmoud Fathy; Th. Abdel Moghny; Mahmoud A. Mousa; Moaz M. Abdou; Abdel-Hameed A-A. El-Bellihi; Ahmed E. Awadallah (2105-2105).
In the original publication, the author group has been published incorrectly. The correct author group is given below.

Correction to: Cation exchange resin nanocomposites based on multi-walled carbon nanotubes by Mahmoud Fathy; Th. Abdel Moghny; Mahmoud A. Mousa; Moaz M. Abdou; Abdel-Hameed A-A. El-Bellihi; Ahmed E. Awadallah (2107-2107).
In the original publication, the author group has been published incorrectly.