A. Joseph Nathanael

Hydrophilic polymer coated monodispersed Fe3O4 nanostructures and their cytotoxicity

Surface functionalized monodispersed Fe3O4 magnetic nanoparticles were synthesized by the polyol method. Surfactants were used to control size, shape and agglomeration of the magnetic nanoparticles during the preparation. The size of these nanoparticles was in the range of 10–30 nm as observed in transmission electron microscopy (TEM). The formation of monodispersed shapes was controlled by varying the surfactants without changing the reaction conditions. The x-ray diffraction (XRD) pattern validates the phase purity and cubic structure even after the addition of surfactants. The functional groups were observed from Fourier transform infrared (FTIR) spectroscopy analysis, confirming the surface modification with polymer molecules in the polyol medium. The saturation magnetization value decreases from 89 to 59 emu g−1 for the surfactant coated Fe3O4 nanoparticles and it also shows superparamagnetic behavior at room temperature. Cell viability rate and percentage of dead cells were accurately identified in human breast carcinoma cell lines using in vitro cell viability experiments, which confirms that pristine and surfactant coated Fe3O4 nanoparticles are non-toxic and can be used for biomedical applications.

Rice husk ash nanosilica to inhibit human breast cancer cell line (3T3)

AbstractnNaOH treatment on phase, purity and particle size of rice husk nanosilica were investigated employing alkaline-extraction–acid-precipitation method. Mild reaction at lower NaOH (1.5xa0N) revealed small and fine particles (600xa0nm) due to moderate reaction rate. Morphology of human breast cancer cell line (3T3) revealed that suggestive cell distress effects were more pronounced at 500xa0µg/ml silica dosages which are in agreement with cell viability decrease (~50xa0%). Among different silica dosages, 10xa0µg/ml was found to have highest cell viability (∼70xa0±xa02xa0%) capable of increasing dissolved oxygen level while viability was almost decreased to 27xa0±xa05xa0% due to toxic effect caused at higher SiO2 dosage and could be a potential candidate best suited for biomedical applications through development of sustainable materials.

Antibacterial and Wash Durability Properties of Untreated and Treated Cotton Fabric Using MgO and NiO Nanoparticles

We report an antibacterial and wash durability behaviour of MgO and NiO nanoparticles treated cotton fabric using sodium alginate as cross linker. The metal oxide nanoparticles treated cotton fabric using sodium alginate as a crosslinker was characterized employing SEM-EDX and their antibacterial activity was analyzed. The enhanced zone of inhibition and wash durability behaviour was observed for NiO nanoparticles treated fabric. However, MgO nanoparticles showed less significant antibacterial and wash durabilty activities when compared to NiO nanoparticles treated cotton fabrics.

Nanocomposited and Functionally Graded ZrN/HA Coatings on cp-Ti by RF Magnetron Sputtering

Nanocomposited and Functionally graded (FG) ZrN/hydroxyapatite coatings with good mechanical strength and biocompatibility were prepared on cp-Ti substrate for biomedical applications and detailed analysis of the nanocomposite coatings for its structural, morphological, topographical and biocompatibility properties were carried out. Crystallite size of the coating for the functionally graded coatings was smaller compared to that of nanocomposite coatings. The arrangement of grains was observed to be denser in the FG coatings due to the decrease in the grain size. Hardness and modulus of FG coatings were observed to be greater than those of nanocomposite coating, which was attributed to the reduction in the crystallite size in FG coatings. Both ZrN/HA nanocomposite and functionally graded coatings was found to induce biomineralization formation, suggesting both are promising candidates for the future biomedical applications.

A Comparative Study on Antibacterial and Wash Durability Behaviour of ZnO and CuO Nanoparticles Treated Cotton Fabric Using Sodium Alginate as Cross Linker

The effects of ZnO and CuO nanoparticles on antibacterial and wash durability behaviour of nanoparticles treated cotton fabric using sodium alginate as cross linker were studied. The metal oxide nanoparticles treated cotton fabric using sodium alginate as a crosslinker was characterized employing SEM-EDX and their antibacterial activity was analyzed. The obtained zone of inhibition and estimated wash durability behaviour is in the order of ZnO>CuO.

Solvothermal Synthesis and Detailed Analysis of Hydroxyapatite Nanostructure

Hydroxyapatite (HA) nanostructures may be an advanced candidate in biomedical applications for an apatite substitute of bone and teeth than other form of HA. In contrast, well-defined size and shape control in synthesizing HA nanostructures is always difficult. Solvothermal synthesis method was adopted to prepare highly ordered hydroxyapatite nanostructures. The morphological analysis by FESEM confirms that the preparation conditions greatly influences the morphological characterization. X-ray Diffraction (XRD) measurements indicate the formation of crystalline hexagonal hydroxyapatite. The crystillinity of HA decreased with increasing ethyline glycol.

Mechanical Properties of Cu-Ag Microcomposites Thermo-Mechanically Processed by Equal Channel Angular Pressing (ECAP)

Equal channel angular pressing (ECAP) combined with intermediate heat treatment was carried out on Cu-15 wt.% Ag at room temperature. ECAPed Cu-15 wt. Ag exhibited ultrafine structure with the shape and distribution of Ag phase dependent on the processing routes. The initial lamellae of Ag phase were elongated along the shear direction and developed into filaments in route A whereas the initial lamellae became finer by fragmentation with no pronounced change of the shape in route Bc. The application of intermediate heat treatment at 330 � C was found to increase the hardness greatly for all three different routes. The network lamella structure usually observed in route C without intermediate heat treatment was not well developed in the specimen with one intermediate heat treatment. The dissolution Ag lamellae with high strain energy and re-precipitation of Ag precipitates is thought to be responsible for the irreversible slip in route C since Ag precipitates in the matrix are likely to act as obstacles to the reversible slip of dislocations, leading to the easier modification of thin-walled network-like structure. The presence of more precipitates in Cu-15 wt.Ag specimens ECAPed with intermediate heat treatment supports the effect of Ag precipitation on the microstructure and the hardness.

Effect of Nitrogen Flow Rate on the Structure and Properties of TiN Thin Films Deposited onto β-Type Ti-15Mo-3Nb-3Al-0.2Si Alloy Substrates by Reactive Magnetron Sputtering

Titanium Nitride (TiN) thin film was deposited on β-type Ti-15Mo-3Nb-3Al-0.2Si alloy plates by RF magnetron sputtering method. The effect of nitrogen flow rate on the structure and properties of the TiN thin films were studied. The preferred orientation of TiN thin films changed from (111) to (200) as the nitrogen flow rate increased due to the effect of the kinetic energy of the bombarding particles. The coating thickness was found to decrease with increasing nitrogen concentration, which also favors (200) orientation with increasing nitrogen flow rate. With increase of nitrogen flow, the morphology of the TiN thin films films changed from characteristic pyramidal shaped grains to columnar-shaped grains. The roughness analysis of the coating shows that the average roughness of the coating decreased with increasing nitrogen flow rate. The increase of hardness with increasing nitrogen flow rate is attributed to the decrease in grain size.

Morphological Variations of Hydroxyapatite Nanostructures by Different Synthesis Methods

Multiform morphologies of hydroxyapatite nanostructures were synthesized by different methods. Some novel methods were adopted for preparing different morphologies. The morphological analysis confirms that the preparation method greatly influences the morphological characterization. The morphological analysis further confirmed by the TEM analysis. The nanostructure clearly depicts the growth stages of the HAp. The interplanar distances measured in segments (fringes) of the HRTEM micrograph were ~0.35 nm, corresponding to the interplanar spacing of the [002] plane of the hexagonal hydroxyapatite. X-ray Diffraction (XRD) measurements indicate the formation of crystalline hexagonal hydroxyapatite. The morphological dependent properties were analyzed in detail.