International Journal Of Bio-Inorganic Hybrid Nanomaterials
Volume:1 Issue: 1, Spring2012

Multiwall carbon nanotubes (MWCNTs) are grown via chemical vapour deposition method directly on a stainless steel substrate. Raman spectroscopy and transmission electron microscopy are the techniques chosen to characterize the structure of the synthesized carbon nanotubes: few structural defects are detected. After their removal from the stainless steel substrate, the as-grown MWCNTs are then airbrushed on a crystalline n-type silicon substrate to build up a simple photovoltaic device based on the MWCNT/Si Schottky heterojunction. Several devices have been made up by varying the thickness of the MWCNT film. External quantum efficiency (EQE) measurements performed in planar configuration show that Si substrate plays the major role in the generation of the electron-hole pairs upon illumination. For this reason, the EQE lineshape closely resembles the behaviour of a p-n junction solar cell. In addition, a sizeable variation of the EQE as a function of the MWCNT film thickness is observed. On-off cycles, performed on the device showing the larger value of EQE (18%), illustrate the genuine photovoltaic effect of our MWCNT/Si device.

LnxSb2-xS3 (Ln: Yb3+, Er3) based nanomaterials were synthesized by a co-reduction method. Powder XRD patterns indicate that the LnxSb2-xS3 crystals (Ln = Yb3+, Er3+, x = 0.00-0.09) are isostructural with Sb2S3. The cell parameter a and c increase for Ln = Er3+ and Yb3+ upon increasing the dopant content (x), while b decreases. SEM images show that doping of the lanthanide ions in the lattice of Sb2S3 result in nanoflowers and nanoparticles. Emission spectra of Yb3+ doped materials, in addition to the characteristic red emission peaks of Sb2S3 emission, show other bands originating very probably from the 2F5/2􀁰2F7/2 in case of Yb3+ doped crystals.The electrical conductance of Ln-doped Sb2S3 is higher than pure Sb2S3 and increase with temperature.

In this work, we report high biological performance of silicon substituted nano hydroxyapatite (nHA) prepared by immersion of calcium phosphate and sodium silicate as precursors in Simulated Body Fluid (SBF) solution for 24, 36, 48 and 72 hrs at 37°C. Characterization and chemical analysis of the synthesized powders were performed by Fourier transform, infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and Dispersive x-ray analysis (EDAX). In vitro biocompatibility test was then carried out by using Bone Marrow Stem Cells (BMSCs) as seeding cells. The MTT assays revealed that, silicon substituted nHA enhance proliferation of the cells and cell cultures showed no negative effect on the cell morphology, viability and proliferation.

The acidity constants of some amino acids (Am) were determined by potentiometric pH titration. The stability constants of the 1:1 complexes formed between M2+: Ca2+, Mg2+, Mn2+, Co2+, Ni +, Cu2+ or Zn2+ and Am2-, were determined by potentiometric pH titration in aqueous solution (I = 0.1 M, NaNO3, 25°C). The order of the stability constants was reported. It is shown that the stability of the binary M(Am) complexes is solely determined by the basicity of the carboxyl or amino group. All the stability constants reported in this work show the usual trend. The obtained order is Ca2+Zn2+. The observed stability order for Am follows the Irving-Williams sequence. It is shown that regarding to M ion-binding properties vital differences on complex bilding were considered. It is demonstrated that in MAm complexes, Mion is coordinated to the carboxyl group, M ion is also able to bild macrochelate over amino group. The up mentioned results demonstrate that for MAm complex the stability constants is also largely determined by the affinity of Cu2+ for amino group. It is shown that Am can exert a direct influence on reaction mechanism through different kinds of metal ions and donor groups of Am.

Keywords: Tryptophan, methionine, cysteine, glutamine, aspartic acid, glycine, amino acids, divalent metal ions, potentiometric titration, acidity, stability constants

In this work, we report synthesis of silver nanoplates by a simple reduction process of silver nitrate in the presence of polyvinyl alcohol (PVA) and N,N'-dimethyl formamide (DMF).The Characterization of the samples were carried out using X-ray diffraction (XRD), Transmission-electron microscopy (TEM) and UV-vis spectroscopy. Absorption spectra of the nanoplates in comparison with that of the silver spherical silver NPs proved a quite different feature due to the silver nanoparticle anisotropic shape. It may be due to the specific interaction between OH groups and Ag+ ions, which affect the selective growth of various planes of silver nanocrystals.

Two new samples of poly(amide-imide)/nanocomposites containing bicyclo segment and dibenzalaceton moiety in the main chain were synthesized by a solution intercalation technique. Poly(amide-imide) (PAI) 8 as a source of polymer matrix was synthesized by the direct polycondensation reaction of N,N´-bis(4-carboxyphenyl)bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic diimide 3 with 2,6-bis(4-aminobenzylidene)cyclohexanone 7 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PAI-nanocomposite films 9a and 9b with 5 and 10% silicate particles were characterized by FTIR spectroscopy and X-ray diffraction (XRD). The effect of clay dispersion and the interaction between clay and polymeric chains on the thermal properties of nanocomposites films were investigated by using thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC).

A new simple and reliable method for rapid and selective extraction and determination of trace levels of Zn(II) ion is developed. Zn(II) ions are adsorbed quantitatively during passage of aqueous samples through PET-AA/AAm nano fiber modified. Almost all matrix elements were found to pass through the nano fiber to drain. Modified Poly (ethylene terephthalate)-grafted-Acrylic acid/Acryl amide Nano fiber was prepared by adding of acrylic nano fibers to methanolamine (PET-AA/AAm) with different concentration solutions. The stability of a chemically modified PETAA/ AAm nano fiber especially in concentrated hydrochloric acid which was then used as a recycling and pre-concentration reagent for further uses of Modified PET-AA/AAm nano fiber. The application of this modified PET-AA/AAm nano fiber for sorption of a series of metal ions was performed by using different controlling factors such as the pH of metal ion solution and the equilibration shaking time by the static technique. Zn(II) was found to exhibit the highest affinity towards extraction by these modified PET-AA/AAm nano fiber phases. The pronounced selectivity was also confirmed from the determined distribution coefficient (Kd) of all the metal ions, showing the highest value reported for Zn(II) to occur by modified PET-AA/AAm nano fiber. The potential applications of modified PET-AA/AAm nano fiber for selective extraction of Zn(II) to occur from aqueous solution were successfully accomplished as well as pre-concentration of low concentration of Zn(II) (60 pg ml-1) from natural tap water with a pre-concentration factor of 100 for Zn(II) off-line analysis by flame atomic absorption analysis.

In this work needle like hydroxy apatite were synthesized in a reverse microemulsion droplets of water in cyclohexane, separated by a cationic surfactant and co-surfactant, in the presence of Na-polyacrylate (PAA) as an anionic polyelectrolyte. Characterization of the as formed HAp nanoparticles at the room temperature were carried out by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Size and morphology of the samples were investigated using scaning and transmission electron microscopy (SEM and TEM). The results obtained confirm incorperation of PAA as a template in controlling of the size and morphology of HAp nanoparticles into the individual microemulsion droplets.