Journal of Advances in Nanomaterials

12

Authors: Goutam Ghosh, Archana Mukherjee, Hari Narayan Bhilwade, Alka Gupta, Aruna Korde, Rita Mukhopadhyaya

The cytotoxicity of counterions-conjugated charged iron oxide nanoparticles (IONPs) was studied with lymphoblastoid Raji cells and was compared with peripheral blood lymphocytes. IONPs were coated either with tri-potassium citrate (TKC), or with cetylpyridinium chloride (CPC). TKC coated IONPs were negatively charged and K+ counterions conjugated nanoparticles, and CPC coated IONPs were positively charged Cl- counterions conjugated nanoparticles. The cells were incubated with IONPs at 37 °C for 24 h and the cytotoxicity was studied by measuring the cell viability using MTT and LDH assays. The cytotoxicity of IONPs was further assessed through DNA fragmentation assay. Morphology of Raji cells was also observed by TEM. We have used a modified membrane lysis model to understand the cell death via cell membrane lysis due to counterions diffusion upon binding of IONPs.

7

Authors: Asmathunisha. N, Anburaj. R, Kathiresan. K

The present study investigated the biosynthesis of silver and gold nanoparticles by marine cyanobacteria derived from coastal mangrove sediment of southeast India. Marine cyanobacteria were able to produce both silver and gold nanoparticles, as confirmed by visual observation, UV-Vis spectroscopy. Appearance of brown colour is an indication of silver nanoparticles, while ruby colour indicates the synthesis of gold nanoparticles in the reaction mixture. Control without silver nitrate and tetra chloro auric acid did not exhibit any colour change. The nanoparticles synthesized were mostly cubical, ranging in size from 70 to 85 nm for both silver and gold nanoparticles as evident by scanning electron microscopy (SEM) and Atomic force microscopy (AFM). The X-ray diffraction pattern confirmed the presence of crystallized nature of nanoparticles. Zeta potential value (-49.10 mV) of the silver nanoparticles and (-64.32 mV) of the gold nanoparticles revealed good stability of the nanoparticles up to 2 months. This work highlighted the possibility of using mangrove derived cyanobacteria for synthesis of silver and gold nanoparticles.

8

Authors: Lili Li, Cong Wang, Yanli Sui, Hui Li, Yibo Feng

A novel sunlight sensitive composite as a wastewater purification material is presented. The substitute material is a thermoresponsive hydrogel, and the photocatalyst are uniformly dispersed tungsten trioxide nanoparticles. These nanocomposites confining poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) tri-block copolymer (EPE) molecules have packaged visible light driven isopolytungstate nano-buildings within the pores of copolymer fiber nets. The networks are provided (formed) by N-Isopropyl acrylamide (Nipam) and Acrylamide (AM). In wastewater solution, the Nipam-co-AM hydrogel is utilized to be a switchable and efficient filter for larger sized residue when subjected to temperature variation. By adding isopolytungstate nanoparticles as photocatalyst monomer, the small sized toxic organic materials can be effectively degraded. Such a hydrogel with distinct thermal and sunlight responsive properties can be produced as a functional material for wastewater dye degradation and large sized residue treatment of great significance in environmental friendly applications.

28

Authors: Alireza Heidari

In the current paper, Glucose (Dextrose), Fructose and Galactose–oxidase enzymes are used as stabilization medium due to its more efficiency, ability for more accurate controlling the enzyme reaction, protecting against wasting of enzyme as well as simple and easy use and exchange of enzyme medium after performing some levels of surface modification and developing Nano Endohedral Fullerenes (Endofullerenes) on Californium plate. For better connecting and stabilizing the enzyme on the medium, the prepared medium is washed by high concentration Sulfuric Acid and Nitric Acid and a large volume of deionized water and for protecting enzyme from devastating effect of Californium and prohibiting them to become inactive, surface is covered with Cystamine before stabilization. Regarding the large size of Glucose (Dextrose), Fructose and Galactose–oxidase enzymes compared to surface of medium, a connective material with amid at one end and Pyrine at the other end is used as transfer agent and for stabilizing this connection, the prepared medium is placed into dimethylformamide (DMF) solution for a couple of hours. Activity of stabilized enzyme at 460 (nm) wavelength recorded by spectroscope was depicted against time to evaluate its stability in various times. The prepared medium, which has a large amount of Glucose (Dextrose), Fructose and Galactose–oxidase enzymes, can be used as electrode in sensors. Furthermore, qualitative and quantitative measurement of food components is of great importance due to high cost of traditional methods, in addition to tendency for more accurate and sensitive detecting of these components. Glucose (Dextrose), Fructose, Galactose and Cholesterol and Cholesterol are such compounds that they frequently measure. Various methods are used to detect these food elements. However, the necessity for accurate measurement of these two compounds with high sensitivity, especially for food health issue, leads to developing biological methods, especially biosensors. Among them, biosensors based on conductive polymer nanostructures, especially Polyaniline (PANI), have been recently interested due to their unique characteristics. The current paper aims to introduce and investigate the previously performed studies about Polyaniline (PANI)–based biosensors for detecting Glucose (Dextrose), Fructose, Galactose and Cholesterol and Cholesterol. In addition, Glucose (Dextrose), Fructose and Galactose–oxidase electrochemical sensor is one of the best methods for detecting low amount of Glucose (Dextrose), Fructose and Galactose and applying Californium colloidal nanoparticles as a supplementary material in the structure of biosensor can be effective for improving its efficiency and optimum performance.

9

Authors: Junlong Li, Caixia Kan, Yang Liu, Juan Xu, Changshun Wang, Yuan Ni, Shanlin Ke

Shapes and structures of seeds are critically important for the seed-mediated synthesis of anisotropic nanostructures. By the deposition of Cu atoms on different Au seeds, Cu nanostructures of different shapes could be synthesized. In experiments Cu nanorods formed with Au nanobipyramids as seeds, and the growth of Cu nanorods was studied through a series of experiments. It is found that the growth direction Cu nanorod is along the penta-twinned axis of Au nanobipyramids and bound by {200} side facets. For the case of low Cu2+ concentration in reaction system, Cu atoms would prefer to deposit on one end of Au nanobipyramids. Nevertheless, Cu atoms would deposit on two ends of Au nanobipyramids for the case of high Cu2+ concentration. Due to the different deposition and migration rates of Cu atoms at two ends of Au nanobipyramids, the Cu nanorods products exhibited different morphologies. Similarly, Cu nanopolyhedrons and Cu nanocubiods were synthesized with Au nanospheres and nanorods as seeds, respectively. Our work is of great significance for further fundamental research and applications of the Cu nanostructure-based nanomaterials in catalytic and electronic fields.

11

Authors: Jean-Pierre Aime, Juan Elezgaray, Oscar Mendoza

In this note we investigate the diffusive behaviour and the boundary conditions of DNA nanodevices using the toe hold mediated strand displacement method. The goal is to extract the basic principles governing the difference observed in diluted solution and in confined environment where the devices are tethered on a DNA Origami. We note that the excluded volume interaction between the two strands running in opposite direction must give a sub diffusive behaviour that can lead to very long waiting times between jumps. When the Boundary Conditions generate a strong asymmetry in the device, the probability to perform the logical operation, thus to remove the output strand, is one. However, we envision unexpected marked differences between diluted solutions and confined environment both for controlling the boundary condition and the sub diffusive behaviour. These differences rise new questions on the interest to use the toe hold mediated strand displacement method on DNA Origamis