Modified rice straw/Fe3O4/polycaprolactone nanocomposites (ORS/Fe3O4/ PCL-NCs) have been prepared for the first time using a solution casting method. The RS/Fe3O4-NCs were modified with octadecylamine (ODA) as an organic modifier. The prepared NCs were characterized by using X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The XRD results showed that as the intensity of the peaks decreased with the increase of ORS/Fe3O4-NCs content in comparison with PCL peaks, the Fe3O4-NPs peaks increased from 1.0 to 60.0 wt. %. The TEM and SEM results showed a good dispersion of ORS/Fe3O4-NCs in the PCL matrix and the spherical shape of the NPs. The TGA analysis indicated thermal stability of ORS/Fe3O4-NCs increased after incorporation with PCL but the thermal stability of ORS/Fe3O4/PCL-NCs decreased with the increase of ORS/Fe3O4-NCs content. Tensile strength was improved with the addition of 5.0 wt. % of ORS/Fe3O4-NCs. The antibacterial activities of the ORS/Fe3O4/PCL-NC films were examined against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) by diffusion method using nutrient agar. The results indicated that ORS/Fe3O4/PCL-NC films possessed a strong antibacterial activity with the increase in the percentage of ORS/Fe3O4-NCs in the PCL.
This study aims to investigate the influence of different stirring time for synthesis of silver nanoparticles in glutathione (GSH) aqueous solution. The silver nanoparticles (Ag-NPs) were prepared by green synthesis method using GSH as reducing agent and stabilizer, under moderate temperature at different stirring times. Silver nitrate (AgNO3) was taken as the metal precursor while Ag-NPs were prepared in the over reaction time.
The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe(3)O(4)) nanoparticles on talc layers using an environmentally friendly process. The Fe(3)O(4) magnetic nanoparticles were synthesized using the chemical co-precipitation method on the exterior surface layer of talc mineral as a solid substrate. Ferric chloride, ferrous chloride, and sodium hydroxide were used as the Fe(3)O(4) precursor and reducing agent in talc. The talc was suspended in deionized water, and then ferrous and ferric ions were added to this solution and stirred. After the absorption of ions on the exterior surface of talc layers, the ions were reduced with sodium hydroxide. The reaction was carried out under a nonoxidizing oxygen-free environment. There were not many changes in the interlamellar space limits (d-spacing = 0.94-0.93 nm); therefore, Fe(3)O(4) nanoparticles formed on the exterior surface of talc, with an average size of 1.95-2.59 nm in diameter. Nanoparticles were characterized using different methods, including powder X-ray diffraction, transmission electron microscopy, emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. These talc/Fe(3)O(4) nanocomposites may have potential applications in the chemical and biological industries.
The sol-gel method was carried out to synthesize nanosized Yttrium Iron Garnet (YIG). The nanomaterials with ferrite structure were heat-treated at different temperatures from 500 to 1000 °C. The phase identification, morphology and functional groups of the prepared samples were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), respectively. The YIG ferrite nanopowder was composited with polyvinylidene fluoride (PVDF) by a solution casting method. The magnitudes of reflection and transmission coefficients of PVDF/YIG containing 6, 10 and 13% YIG, respectively, were measured using rectangular waveguide in conjunction with a microwave vector network analyzer (VNA) in X-band frequencies. The results indicate that the presence of YIG in polymer composites causes an increase in reflection coefficient and decrease in transmission coefficient of the polymer.
Recent environmental problems and societal concerns associated with the disposal of petroleum based plastics throughout the world have triggered renewed efforts to develop new biodegradable products compatible with our environment. This article describes the preparation, characterization and biodegradation study of poly(lactic acid)/layered double hydroxide (PLA/LDH) nanocomposites from PLA and stearate-Zn(3)Al LDH. A solution casting method was used to prepare PLA/stearate-Zn(3)Al LDH nanocomposites. The anionic clay Zn(3)Al LDH was firstly prepared by co-precipitation method from a nitrate salt solution at pH 7.0 and then modified by stearate anions through an ion exchange reaction. This modification increased the basal spacing of the synthetic clay from 8.83 Å to 40.10 Å. The morphology and properties of the prepared PLA/stearate-Zn(3)Al LDH nanocomposites were studied by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), thermogravimetric analysis (TGA), tensile tests as well as biodegradation studies. From the XRD analysis and TEM observation, the stearate-Zn(3)Al LDH lost its ordered stacking-structure and was greatly exfoliated in the PLA matrix. Tensile test results of PLA/stearate-Zn(3)Al LDH nanocomposites showed that the presence of around 1.0-3.0 wt % of the stearate-Zn(3)Al LDH in the PLA drastically improved its elongation at break. The biodegradation studies demonstrated a significant biodegradation rate improvement of PLA in the presence of stearate-Zn(3)Al LDH nanolayers. This effect can be caused by the catalytic role of the stearate groups in the biodegradation mechanism leading to much faster disintegration of nanocomposites than pure PLA.
In order to develop a systemically administered safe and effective nonviral gene delivery system against avian influenza virus (AIV) that induced cytokine expression, the hemagglutinin (H5) gene of AIV, A/Ck/Malaysia/5858/04 (H5N1) and green fluorescent protein were cloned into a coexpression vector pIRES (pIREGFP-H5) and formulated using green synthesis of silver nanoparticles (AgNPs) with poly(ethylene glycol) and transfected into primary duodenal cells taken from 18-day-old specific-pathogen-free chick embryos. The AgNPs were prepared using moderated temperature and characterized for particle size, surface charge, ultraviolet-visible spectra, DNA loading, and stability. AgNPs and AgNP-pIREGFP-H5 were prepared in the size range of 13.9 nm and 25 nm with a positive charge of +78 ± 0.6 mV and +40 ± 6.2 mV, respectively. AgNPs with a positive surface charge could encapsulate pIREGFP-H5 efficiently. The ultraviolet-visible spectra for AgNP-pIREGFP-H5 treated with DNase I showed that the AgNPs were able to encapsulate pIREGFP-H5 efficiently. Polymerase chain reaction showed that AgNP-pIREGFP-H5 entered into primary duodenal cells rapidly, as early as one hour after transfection. Green fluorescent protein expression was observed after 36 hours, peaked at 48 hours, and remained stable for up to 60 hours. In addition, green fluorescent protein expression generally increased with increasing DNA concentration and time. Cells were transfected using Lipocurax in vitro transfection reagent as a positive control. A multiplex quantitative mRNA gene expression assay in the transfected primary duodenal cells via the transfection reagent and AgNPs with pIREGFP-H5 revealed expression of interleukin (IL)-18, IL-15, and IL-12β.
Green approach in synthesizing metal nanoparticles has gain new interest from the researchers as metal nanoparticles were widely applied in medical equipment and household products. The use of plants in the synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. A green synthetic route for the production of stable silver nanoparticles (Ag-NPs) by using aqueous silver nitrate as metal precursor and Artocarpus elasticus stem bark extract act both as reductant and stabilizer is being reported for the first time.
A gold nanoparticle (AuNP) has a localized surface plasmon resonance peak depending on its size, which is often utilized for surface-enhanced Raman scattering (SERS). To obtain information on the cholesterol (Chol)-incorporated lipid membranes by SERS, AuNPs (5, 100 nm) were first functionalized by 1-octanethiol and then modified by lipids (AuNP@lipid). In membrane surface-enhanced Raman spectroscopy (MSERS), both signals from 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and Chol molecules were enhanced, depending on preparation conditions (size of AuNPs and lipid/AuNP ratio). The enhancement factors (EFs) were calculated to estimate the efficiency of AuNPs on Raman enhancement. The size of AuNP100nm@lipid was 152.0 ± 12.8 nm, which showed an surface enhancement Raman spectrum with an EF2850 value of 111 ± 9. The size of AuNP5nm@lipid prepared with a lipid/AuNP ratio of 1.38 × 104 (lipid molecule/particle) was 275.3 ± 20.2 nm, which showed the highest enhancement with an EF2850 value of 131 ± 21. On the basis of fluorescent probe analyses, the membrane fluidity and polarity of AuNP@lipid were almost similar to DOPC/Chol liposome, indicating an intact membrane of DOPC/Chol after modification with AuNPs. Finally, the membrane properties of AuNP@lipid systems were also discussed on the basis of the obtained MSERS signals.
Nanoparticles (NPs) are, frequently, being utilized in multi-dimensional enterprises. Silver nanoparticles (AgNPs) have attracted researchers in the last decade due to their exceptional efficacy at very low volume and stability at higher temperatures. Due to certain limitations of the chemical method of synthesis, AgNPs can be obtained by physical methods including sun rays, microwaves and ultraviolet (UV) radiation. In the current study, the synthesis of pullulan mediated silver nanoparticles (P-AgNPs) was achieved through ultraviolet (UV) irradiation, with a wavelength of 365 nm, for 96 h. P-AgNPs were formed after 24 h of UV-irradiation time and expressed spectra maxima as 415 nm, after 96 h, in UV-vis spectroscopy. The crystallographic structure was "face centered cubic (fcc)" as confirmed by powder X-ray diffraction (PXRD). Furthermore, high resolution transmission electron microscopy (HRTEM) proved that P-AgNPs were covered with a thin layer of pullulan, with a mean crystalline size of 6.02 ± 2.37. The average lattice fringe spacing of nanoparticles was confirmed as 0.235 nm with quasi-spherical characteristics, by selected area electron diffraction (SAED) analysis. These green synthesized P-AgNPs can be utilized efficiently, as an active food and meat preservative, when incorporated into the edible films.
Green synthesis of silver nanoparticles is desirable practice. It is not only the required technique for industrial and biomedical purposes but also a promising research area. The aim of this study was to synthesize green curcumin silver nanoparticles (C-Ag NPs). The synthesis of C-Ag NPs was achieved by reduction of the silver nitrate (AgNO₃) in an alkaline medium. The characterizations of the prepared samples were conducted by ultraviolet visible (UV-vis) spectroscopy, powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and zeta potential (ZP) analyses. The formation of C-Ag NPs was evaluated by the dark color of the colloidal solutions and UV-vis spectra, with 445 nm as the maximum. The size of the crystalline nanoparticles, recorded as 12.6 ± 3.8nm, was confirmed by HRTEM, while the face-centered cubic (fcc) crystallographic structure was confirmed by PXRD and SAED. It is assumed that green synthesized curcumin silver nanoparticles (C-Ag NPs) can be efficiently utilized as a strong antimicrobial substance for food and meat preservation due to their homogeneous nature and small size.
The main objective of the current work is to investigate the effect of nickel-waste chicken eggshell modified Hydrogen exchanged Zeolite Socony Mobil-5 (Ni-WCE/HZSM-5) on pyrolysis of high-density polyethylene (HDPE). Ni-WCE/HZSM-5 was synthesized via the impregnation incipient wetness (IWI) method with Ni and WCE mass loading of 4 and 12 wt% respectively. HZSM-5, CaO, WCE, WCE/HZSM-5, and Ni/HZSM-5 were prepared for comparison purposes with Ni-WCE/HZSM-5. All the synthesized catalysts were characterized for phase analysis, metal loading, surface morphology, and textural properties. The impregnation of nickel and WCE had significantly affected the original framework of HZSM-5, where the crystallinity percentage and average crystal size of HZSM-5 dropped to 44.97% and increased to 47.90 nm respectively. The surface morphology of HZSM-5 has drastically changed from a cubic-like shape into a spider web-like surface after the impregnation of WCE. The BET surface area of HZSM-5 has been lowered due to the impregnation of nickel and WCE, but the total pore volume has increased greatly from 0.2291 cm3/g to 0.2621 cm3/g. The catalyst performance was investigated in the pyrolysis of HDPE via a fixed bed reactor and the pyrolysis oil was further analysed to evaluate the distribution of C6 to C9> hydrocarbons. Among the tested catalytic samples, the highest pyrolysis oil yield was achieved by WCE (80%) followed by CaO (78%), WCE/HZSM-5 (63%), HZSM-5 (61%), Ni/HZSM-5 (44%) and Ni-WCE/HZSM-5 (50%). For hydrocarbon distribution in pyrolysis oil, the Ni/HZSM-5 produced the highest of total C6 and C7 hydrocarbons at 12% and 27% respectively followed by WCE/HZSM-5 (4% and 20%), non-catalytic (5% and 13%), Ni-WCE/HZSM-5 (0% and 15%), WCE (0% and 10%), HZSM-5 (0% and 6%) and CaO (0% and 0%).
One of mankind's biggest concerns is water pollution. Textile industry emerged as one of the main contributors with dyes as the main pollutant. Presence of dyes in water is very dangerous due to their toxicity; thus, it is important to remove them from water. In these recent years, heterogeneous advance oxidation process surfaced as a possible dyes' removal technique. This process utilizes semiconductor as photocatalyst to degrade the dyes in presence of light and zinc oxide (ZnO) appears to be a promising photocatalyst for this process. In this study, pullulan, a biopolymer, was used to produce porous ZnO microflowers (ZnO-MFs) through green synthesis via precipitation method. The effects of pullulan's amount on the properties of ZnO-MFs were investigated. The ZnO-MF particle size decreased with the increased of pullulan amount. Interestingly, formation of pores occurred in presence of pullulan. The synthesized ZnO-MFs have the surface area ranging from 6.22 to 25.65 m2 g-1 and pore volume up to 0.1123 cm3 g-1. The ZnO-MF with the highest surface area was chosen for photocatalytic degradation of methyl orange (MO). The highest degradation occurred in 300 min with 150 mg catalyst dosage, 10 ppm initial dye concentration, and pH 7 experimental conditions. However, through comparison of photodegradation of MO with all synthesized ZnO-MFs, 25PZ exhibited the highest degradation rate. This shows that photocatalytic activity is not dependent on surface area alone. Based on these results, ZnO-MF has the potential to be applied in wastewater treatment. However, further improvement is needed to increase its photocatalytic activity.
Small sized magnetite iron oxide nanoparticles (Fe3O4-NPs) with were successfully synthesized on the surface of rice straw using the quick precipitation method in the absence of any heat treatment. Ferric chloride (FeCl3·6H2O), ferrous chloride (FeCl2·4H2O), sodium hydroxide (NaOH) and urea (CH4N2O) were used as Fe3O4-NPs precursors, reducing agent and stabilizer, respectively. The rice straw fibers were dispersed in deionized water, and then urea was added to the suspension, after that ferric and ferrous chloride were added to this mixture and stirred. After the absorption of iron ions on the surface layer of the fibers, the ions were reduced with NaOH by a quick precipitation method. The reaction was carried out under N2 gas. The mean diameter and standard deviation of metal oxide NPs synthesized in rice straw/Fe3O4 nanocomposites (NCs) were 9.93 ± 2.42 nm. The prepared rice straw/Fe3O4-NCS were characterized using powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDXF) and Fourier transforms infrared spectroscopy (FT‒IR). The rice straw/Fe3O4-NCs prepared by this method have magnetic properties.
Fe3O4/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from aqueous solutions. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the variables. The adsorption parameters such as adsorbent dosage, removal time, and initial ion concentration were used as the independent variables and their effects on heavy metal ion removal were investigated. Analysis of variance was incorporated to judge the adequacy of the models. Optimal conditions with initial heavy metal ion concentration of 100, 92 and 270 mg/L, 120 s of removal time and 0.12 g of adsorbent amount resulted in 72.15%, 50.23%, and 91.35% removal efficiency for Cu(II), Ni(II), and Pb(II), respectively. The predictions of the model were in good agreement with experimental results and the Fe3O4/talc nanocomposite was successfully used to remove heavy metals from aqueous solutions.
Polyhydroxybutyrate (PHB)/polycaprolactone (PCL)/stearate Mg-Al layered double hydroxide (LDH) nanocomposites were prepared via solution casting intercalation method. Coprecipitation method was used to prepare the anionic clay Mg-Al LDH from nitrate salt solution. Modification of nitrate anions by stearate anions between the LDH layers via ion exchange reaction. FTIR spectra showed the presence of carboxylic acid (COOH) group which indicates that stearate anions were successfully intercalated into the Mg-Al LDH. The formation of nanocomposites only involves physical interaction as there are no new functional groups or new bonding formed. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the mixtures of nanocomposites are intercalated and exfoliated types. XRD results showed increasing of basal spacing from 8.66 to 32.97 Å in modified stearate Mg-Al LDH, and TEM results revealed that the stearate Mg-Al LDH layers are homogeneously distributed in the PHB/PCL polymer blends matrix. Enhancement in 300% elongation at break and 66% tensile strength in the presence of 1.0 wt % of the stearate Mg-Al LDH as compare with PHB/PCL blends. Scanning electron microscopy (SEM) proved that clay improves compatibility between polymer matrix and the best ratio 80PHB/20PCL/1stearate Mg-Al LDH surface is well dispersed and stretched before it breaks.
Copper nanoparticle synthesis has been gaining attention due to its availability. However, factors such as agglomeration and rapid oxidation have made it a difficult research area. In the present work, pure copper nanoparticles were prepared in the presence of a chitosan stabilizer through chemical means. The purity of the nanoparticles was authenticated using different characterization techniques, including ultraviolet visible spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The antibacterial as well as antifungal activity of the nanoparticles were investigated using several microorganisms of interest, including methicillin-resistant Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella choleraesuis, and Candida albicans. The effect of a chitosan medium on growth of the microorganism was studied, and this was found to influence growth rate. The size of the copper nanoparticles obtained was in the range of 2-350 nm, depending on the concentration of the chitosan stabilizer.
DNA formulations provide the basis for safe and cost effective vaccine. Low efficiency is often observed in the delivery of DNA vaccines. In order to assess a new strategy for oral DNA vaccine formulation and delivery, plasmid encoding hemagglutinin (HA) gene of avian influenza virus, A/Ck/Malaysia/5858/04 (H5N1) (pcDNA3.1/H5) was formulated using green synthesis of sliver nanoparticles (AgNP) with polyethylene glycol (PEG). AgNP were successfully synthesized uniformly dispersed with size in the range of 4 to 18 nm with an average size of 11 nm. Cytotoxicity of the prepared AgNP was investigated in vitro and in vivo using MCF-7 cells and cytokine expression, respectively. At the concentration of -5 log₁₀AgNP, no cytotoxic effects were detected in MCF-7 cells with 9.5% cell death compared to the control. One-day-old specific pathogen-free (SPF) chicks immunized once by oral gavage with 10 μl of pcDNA3.1/H5 (200 ng/ml) nanoencapsulated with 40 μl AgNP (3.7×10⁻² μg of Ag) showed no clinical manifestations. PCR successfully detect the AgNP/H5 plasmid from the duodenum of the inoculated chicken as early as 1h post-immunization. Immunization of chickens with AgNP/H5 enhanced both pro inflammatory and Th1-like expressions, although no significant differences were recorded in the chickens inoculated with AgNP, AgNP/pcDNA3.1 and the control. In addition, serum samples collected from immunized chickens with AgNP/H5 showed rapidly increasing antibody against H5 on day 14 after immunization. The highest average antibody titres were detected on day 35 post-immunization at 51.2±7.5. AgNP/H5 also elicited both CD4+ and CD8+ T cells in the immunized chickens as early as day 14 after immunization, at 7.5±2.0 and 20±1.9 percentage, respectively. Hence, single oral administrations of AgNP/H5 led to induce both the antibody and cell-mediated immune responses as well as enhanced cytokine production.
The interactions of p-cresol photocatalytic degradation components were studied by response surface methodology. The study was designed by central composite design using the irradiation time, pH, the amount of photocatalyst and the p-cresol concentration as variables. The design was performed to obtain photodegradation % as actual responses. The actual responses were fitted with linear, two factor interactions, cubic and quadratic model to select an appropriate model. The selected model was validated by analysis of variance which provided evidences such as high F-value (845.09), very low P-value (