Carbon-coated Nanomagnets : Synthesis, Characterization And Feasibility For Magnetic Hyperthermia

This work addresses the development of novel synthesis procedures for carbon-coated magnetic nanoparticles and their detailed characterization regarding structure, morphology, and magnetic properties. To be specific, the high pressure chemical vapour deposition technique (HPCVD) has been applied to successfully produce carbon-coated nanoparticles with various magnetic core materials, such as Fe, Co, Ni, FeRu, CoRu, NiRu, NiPt, and CoPt. The morphological and structural characterization of the materials has been done by means of transmission electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Particular emphasis has been given to the investigation of the magnetic properties and its dependence on, e.g., core size and stoichiometry of the core alloys, which can be tailored by adjusting the synthesis conditions. A particular advantage of carbon-coated nanomagnets is oxidation protection of the magnetic core material which implies feasibility for biomedical applications. Here, the feasibility for magnetic hyperthemia therapies is exploited by investigating induced heating under applied alternating magnetic fields

Improving the Dielectric Properties of High Density Polyethylene by Incorporating Clay-Nanofiller

Polymer nanocomposites have been used for various important industrial applications. The preparation of high density polyethylene composed with Na-montmorillonite nanofiller using melt compounding method for different concentrations of clay-nano filler of 0%, 2%, 6%, 10%, and 15% has been successfully done. The morphology of the obtained samples was optimized and characterized by scanning electron microscope showing the formation of the polymer nanocomposites. The thermal stability and dielectric properties were measured for the prepared samples. Thermal gravimetric analysis results show that thermal stability in polymer nanocomposites is more than that in the base polymer. It has been shown that the polymer nanocomposites exhibit some very different dielectric characteristics when compared to the base polymer. The dielectric breakdown strength is enhanced by the addition of clay-nano filler. The dielectric constant (εr) and dissipation factor (Tan δ) have been studied in the frequency range 200 Hz to 2 MHz at room temperature indicating that enhancements have been occurred in εr and Tan δ by the addition of clay-nano filler in the polymer material when compared with the pure material

Synthesis and toxicity characterization of carbon coated iron oxide nanoparticles with highly defined size distributions

Background Iron oxide nanoparticles hold great promise for future biomedical applications. To this end numerous studies on iron oxide nanoparticles have been conducted. One aspect these studies reveal is that nanoparticle size and shape can trigger different cellular responses through endocytic pathways, cell viability and early apoptosis. However, systematic studies investigating the size dependence of iron oxide nanoparticles with highly defined diameters across multiple cells lines are not available yet. Methods Iron oxide nanoparticles with well-defined size distributions were prepared. All samples were thoroughly characterized and the cytotoxicity for four cell lines (HeLa Kyoto, human osteosarcoma (U2OS), mouse fibroblasts (NIH 3T3) and mouse macrophages (J7442)) where investigated. Results Our findings show that small differences in size distribution (ca. 10 nm) of iron oxide nanoparticles do not influence cytotoxicity, while uptake is size dependent. Cytotoxicity is dose-dependent. Broad distributions of nanoparticles are more easily internalized as compared to the narrow distributions for two of the cell lines tested (HeLa Kyoto and mouse macrophages (J7442)). Conclusion The data indicate that it is not feasible to probe changes in cytotoxicity within a small size range (10 nm). However, TEM investigations of the nanoparticles indicate that cellular uptake is size dependent. General significance The present work compares narrow and broad distributions for various samples of carbon-coated iron oxide nanoparticles. The data highlights that cells differentiate between nanoparticle sizes as indicated by differences in cellular uptake. This information provides valuable knowledge to better understand the interaction of nanoparticles and cells. © 2013 Elsevier B.V.116171sciescopu