Journal of Nano Research Vol. 59

Abstract: Abstract:Purpose: The objective of this investigation was to evaluate the combined effects of ultrasound irradiation as a non-invasive and non-ionizing radiation with gold nanoparticles as ultrasound sensitizers on the HeLa cells.Materials and Methods: First, Gold nanoparticles (GNPs) were prepared, and the characterizations of nanoparticles were analyzed using TEM and UV-vis. Different concentrations of nanoparticles (0.2, 1, 5, 25 and 50 μg/ml) were used. Then, cytotoxicity of the GNPs was studied on HeLa cells, and finally concentrations of 0.2, 1 and 5 µg/mL were chosen for supplementary studies. The effects of nanoparticles and ultrasound irradiation with different intensities (0.5, 1 and 1.5 W/cm²) as well as the combination of ultrasound radiation with various concentrations of nanoparticles on 24, 48 and 72 h post-experiment cells’ viability were estimated by MTT and trypan blue assay.Results: Results showed that the sonosensitizing effect of nanoparticles mainly depended on the intensity of ultrasound waves and the concentration of GNPs. By increasing the concentration of GNPs and ultrasound intensity, the nanoparticle's effect of sensitizer was also increased. Moreover, as expected, the highest effect was observed at the highest intensities (1.5 W/cm²) of ultrasound wave and high concentrations (5 μg/ml) of GNPs 72 h after exposure to ultrasound irradiation.Conclusions: It is revealed that GNPs can be used as sonosensitizers of HeLa cells to ultrasound irradiation in order to produce an efficient treatment.

Abstract: Nanoparticles, smaller than 100 nm are synthesized by chemical and physical methods. Biological synthesis of nanoparticles is very popular in science recently. The aim of the study is green synthesis of zinc oxide nanoparticles (ZnO NPs) using the lichen extract (Ramalina fraxinea) and investigating the cytotoxic effects of ZnO NPs on human neuroblastoma cells (SHSY-5Y). Despite the widespread use of ZnO NPs, a limited number of studies have investigated the neurobiological effects of ZnO NP. Therefore, we tested the neurotoxic effect of green synthesized ZnO NPs administration and its neuroprotective effect against hydrogen peroxide-induced cell damage on SH-SY5Y human neuroblastoma cell line. The absorbance peak of the ZnO NPs was detected by UV–visible spectroscopy (UV-Vis) at 330 nm. The average diameter of ZnO NPs was measured as about 21 nm by Scanning Electron Microscope (SEM) and Field Emission Scanning Electron Microscope (FE-SEM) images. According to X-ray Diffraction (XRD) diagram, ZnO NPs were hexagonal in structure. The peaks observed in the Fourier Transform Infrared (FT-IR) test showed functional groups in the structure of the nanoparticles. According to our results, ZnO NPs may have beneficial effects at the low concentrations while neurotoxic effects at the higher doses in SH-SY5Y. In addition, we indicate that hydrogen peroxide-induced cell death could not reverse by ZnO NPs and its higher doses potentiated the neurodegenerative effect of hydrogen peroxide. In conclusion, here we report that ZnO NPs, widely used in various products, may have beneficial or harmful effects in a dose-dependent manner and play a role in neuropsychiatric disease, especially neurodegenerative diseases. This is the first study dealing with neurotoxicity on SHSY-5Y of Ramalina fraxinea extract based ZnO NPs.

Abstract: Mechanical alloying of a mixture of Fe₂O₃ and CoO powders has been applied for the preparation of nanocrystalline. Utilizing a ball-to-powder mass ratio of 20, milling time of 20 hours followed by annealing at 900°C, we could obtain a nanocrystalline of high crystallinity and composed of mainly CoFe₂O₄ phase with presence of Fe₂O₃ as revealed by X-ray diffraction (XRD) measurements. Magnetic measurements using vibrating sample magnetometer (VSM) reveal high saturation magnetization for the annealed sample close to CoFe₂O₄ phase value. The heating efficiency of the obtained nanocrystalline is studied under an alternating magnetic field and as a function of the concentration. It was found that the nanocrystalline generate a substantial amount of heat when exposed to an alternating magnetic field. In vitro hyperthermia experiment was carried out and our result clearly demonstrates the ability of the obtained nanocrystalline to kill cancer cell through magnetic hyperthermia.

Abstract: It is important to analyze cell monolayer adherence for the development of biomedical devices of anti-thrombogenic vascular grafts. Endothelial cells must be firmly attached to the biomaterials when cells are seeded in order to create a natural lining. Polystyrene (PS) is presented as a reproducible implant model substrate for studying cell – material interactions. Polystyrene was deposited as a thin layer on a thiol functionalized gold electrode. Fibronectin (Fn), a protein promoting the cell monolayer adhesion was adsorbed on PS surface. The different steps of this multilayer assembly were characterized by Surface Plasmon Resonance (SPR) technique. A right shift of the SPR resonance angle θ_SPR was observed leading an increase from 65.5 deg in the case of gold electrode to 66.8 deg in the case where cell monolayer was cultured onto functionalized gold substrate. A shift in the SPR peak minimum intensity was detected in the SPR response of Au/Thiol/PS/Fn and Au/Thiol/PS/Fn/Cell multilayer assembly structures. This result is explained using Atomic Force Microscopy (AFM) images and according transverse profiles which indicate surface morphological modifications in term of thickness.

Abstract: The present study aims to develop bilayer polymeric nanofiber patch (PNP) fabricated by electrospinning technique using for wound dressing. The nanofiber was prepared by various concentrations of polyvinyl alcohol (PVA) and modified tamarind seed gum loaded with clindamycin HCl (CM) in first layer and Eudragit^® S100 for a second layer. ​According to the SEM result, the physical appearance, the sprayed products prepared from PVA, mixture of PVA and gum, Eudragit^® S100 were in round fiber with different diameter size ranged from 153-1830 nm. The polymer concentration, solution conductivity and surface tension affected on the appearance of the nanofiber. The patch was successfully prepared in form of two layer welded with the nanofiber under the optimized electrospinning condition which are 20 kV of applied voltage, 20 cm of injection distance, 0.25 mL of solution feed rate and 48 rpm of collector rolling rate. The DSC and PXRD indicated that the drug in PNPs was in amorphous form. Biological test revealed that bilayer PNPs contained PVA 10%, modified tamarind seed gum 5% and clindamycin 1% had an efficiency to inhibit Staphylococcus aureus. These results show the possibility of improving nanofiber patch strength by using Eudragit^® S100 and modified tamarind gum seed as a natural material in nanofiber patch formulation.

Abstract: Polymers such as sodium polyacrylate; polysaccharides in starch; polyamino acids, which are the products of alpha-amino acid condensation; and polypeptides are widely used in cosmetics and pharmaceuticals. They are used as viscosity agent, emulsifying agent, and carriers for drug delivery. However, we studied the function of polymers as activity agent, especially that of synthesized poly(aspartic acid). Poly(aspartic acid) is a biocompatible synthetic polymer. It is a water-soluble polyamide containing carboxylic pendants prepared from polysuccinimide, the polycondensate of aspartic acid monomer, by hydrolysis. In this study, we prepared poly(aspartic acid) derivatives conjugated with L-lysine or L-lysine and other materials. The chemical structure of these polymers was confirmed by FT-IR and ¹H-NMR spectroscopy. Moreover, these novel poly(aspartic acid) derivatives stimulated typeⅠcollagen biosynthesis and inhibited MMP-1(collagenase) activity. We could conclude that the microfludization process improved skin permeability and confirmed better permeability than that achieved with existing nano emulsions.

Abstract: The usage of biopolymers in developing biodegradable food packaging films that are sustainable and safe towards environment has been restricted because of the poor mechanical and barrier properties of the biopolymers. This study aims to enhance the limited properties of biopolymers particularly polylactic acid (PLA) for food packaging applications by investigating the effects of incorporating different types (montmorillonite (MMT) and halloysite) and concentrations (0–9 wt.%) of nanoclays on the mechanical, oxygen barrier, and transparency properties of the films. PLA with 3 wt.% concentration of nanoclays resulted in the optimum mechanical and oxygen barrier properties due to the strong interaction between nanoclays and torturous path length created by nanoclays respectively. Nevertheless, these properties reduced as more nanoclays (≥5 wt.%) was added into the films due to agglomeration of nanoclays. PLA incorporated with MMT nanoclay exhibited better properties compared to halloysite nanoclay due to the nanoclay structure in nature. Addition of 3 wt.% nanoclays into virtually transparent PLA film have only small effects on the transparency of the film whereby the reduction in light transmittance was only around 10%. This study is crucial to improve the feasibility of biopolymers usage for food packaging applications.

Abstract: Nanoparticles are considered unique sensing material as they are small and deliver sensitivity as low as parts per billion compared to their bulk counterparts used in the conventional devices. Zinc Oxide (ZnONPs) nanoparticles are considered one of the promising sensing materials due to their high surface-to-volume ratio compared to other conventional sensing materials. They have been found useful for sensing of hydrogen gas, carbon monoxide, ammonia and ethanol. Ethanol sensing forms a platform for monitoring various processes in medical and food industries. Herein, zinc oxide nanoparticles were synthesized using Spathodea campanulata plant extract as reducing and stabilizing agent. The biosynthesized nanoparticles were used to fine tuning a glassy carbon electrode (GCE) for ethanol sensing. Ethanol sensing capability of the modified GCE electrode was gauged upon its amperometric responses to different ethanol concentrations. The high surface to volume ratio of the nanoparticles greatly enhanced peak currents of the modified electrodes leading to signal towards ethanol detection.

Abstract: The effect of anealing temperature on structural properties of Lanthanum Iron Garnet (LIG) nanofiber has been studied. The LIG nanofiber were prepared by electrospinning technique. This technique has been extensively developed as a simple and efficient method for drawing nanofibers from polymer solutions. The viscous LIG solution were loaded in syringe and were pumped at 0.05 mL/h. The nanofibers were collected on aluminium foil and were treated at 700 °C, 750 °C and 1000 °C in order to study the effect of annealing temperature to the nanofibers structure. X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) were employed to study the phase formation and morphology of the samples. The XRD results of LIG nanofiber reveals that as the annealing temperature increases from 700 °C to 1000 °C, the corresponding peaks become sharper and narrower, which demonstrate the improvement of crystallinity and crystallite size. The FESEM images of LIG nanofiber demonstrates that the nanofibers treated at 700 °C have continuous structure with a relatively rough surface and their diameter range is within 41.3 nm and 58.7 nm. Subsequently, when the calcination temperature increase further, the morphology of the sample is dramatically changed. As calcinations temperature rises to 750 °C, the surface of resultant nanofibers start to become agglomerate due to the growth and coalescence of the particle in the nanofibers under the calcination process and the nanofibers structure change back to continuous structure with bigger diameter at 1000 °C as compared to calcination temperature of 700 °C.

Abstract: The electrochemical properties of the nitrogen-enriched carbons obtained by plant raw treatment as electrode material for supercapacitors were investigated by electrochemical impedance spectroscopy, cycling voltammetry and galvanostatic charge-discharge cycling in KOH aqueous electrolyte. The effect of activation agent (NaOH) concentration and carbonization temperature were analyzed. The separation of double layer and redox capacitance components was done. The dominating role of microporosity for capacitive properties was demonstrated. The capacitance of model capacitors based on carbons obtained at different modes was calculated from both from cycling voltammetry and galvanostatic charge-discharge data. The maximal values of specific capacitance of carbon materials carbonized at 600°C and 900°C are about 100 and 120 F/g, respectively.