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Nanomedicine (Lond) ; 14(23): 3075-3088, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31797726


Aim: The field of nanotechnology promotes the development of innovative and more effective cancer therapies. This work is aimed to develop a hybrid system that combines the capacity of boron nitride nanotubes (BNNTs) to be internalized by tumor cells and the ability of nickel ferrite nanoparticles to efficiently release heat by induced AC magnetic heating. Materials & methods: The systems studied were characterized by using x-ray diffractometry, transmission electron microscopy, vibrating sample magnetometry and Mössbauer spectroscopy. Results: The ferrite nanoparticles attached to BNNT were able to achieve the required temperatures for magnetohyperthermia therapies. After cellular internalization, AC induced magnetic heating of BNNT@NiFe2O4 can kill almost 80% of Hela cells lineage in a single cycle. Conclusion: This system can be a highly efficient magnetohyperthermia agent in cancer therapy.

Chemosphere ; 159: 602-609, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27343867


Amphiphilic magnetic composites were produced based on chrysotile mineral and carbon structures by chemical vapor deposition at different temperatures (600-900 °C) and cobalt as catalyst. The materials were characterized by elemental analysis, X-ray diffraction, vibrating sample magnetometry, adsorption and desorption of N2, Raman spectroscopy, scanning electronic microscopy, and thermal analysis showed an effective growth of carbon structures in all temperatures. It was observed that at 800 and 900 °C, a large amount of carbon structures are formed with fewer defects than at 600 and 700 °C, what contributes to their stability. In addition, the materials present magnetic phases that are important for their application as catalysts and adsorbents. The materials have shown to be very active to remove the oil dispersed in a real sample of emulsified wastewater from biodiesel production and to remove methylene blue by adsorption and oxidation via heterogeneous Fenton mechanism.

Asbestos Serpentinas/química , Carbono/química , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/análise , Adsorção , Catálise , Azul de Metileno/química , Oxirredução , Análise Espectral Raman , Propriedades de Superfície , Difração de Raios X
Nanoscale ; 4(22): 7155-60, 2012 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-23069891


Compact rolled-up Co-Cu nanomembranes of high quality with different numbers of windings are realized by strain engineering. A profound analysis of magnetoresistance (MR) is performed for tubes with a single winding and a varied number of Co-Cu bilayers in the stack. Rolled-up nanomembranes with up to 12 Co-Cu bilayers are successfully fabricated by tailoring the strain state of the Cr bottom layer. By carrying out an angular dependent study, we ruled out the contribution from anisotropic MR and confirm that rolled-up Co-Cu multilayers exhibit giant magnetoresistance (GMR). No significant difference of MR is found for a single wound tube compared with planar devices. In contrast, MR in tubes with multiple windings is increased at low deposition rates of the Cr bottom layer, whereas the effect is not observable at higher rates, suggesting that interface roughness plays an important role in determining the GMR effect of the rolled-up nanomembranes. Furthermore, besides a linear increase of the MR with the number of windings, the self-rolling of nanomembranes substantially reduces the device footprint area.

J Colloid Interface Sci ; 379(1): 84-8, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22608147


In this work, hybrid magnetic amphiphilic composites were prepared by the catalytic growth of carbon nanotubes (CNTs) and nanofibers CNF on layered silicates fragments. SEM, TEM, Raman, XRD, Mössbauer, TG/DTA showed that CVD with CH(4) at 800°C produced CNF and magnetic Fe cores fixed on the surface of microfragments of silicates layers. Due to the amphiphilic character, the composites can be easily dispersed in water and efficiently adsorb hydrophobic contaminant molecules. For example, the composites showed remarkable adsorption capacities for the hormone ethinylestradiol, e.g. 2-4 mg m(-2), compared to ca. 0.1 mg m(-2) obtained for high surface area activated carbon and multiwall CNT. These results are discussed in terms of a high hydrophobic exposed surface area of the CNT and CNF fixed on the layered silicates fragments surface. Moreover, the composites can be easily removed from water by a simple magnetic separation process.

Etinilestradiol/química , Magnetismo , Nanofibras/química , Nanotubos de Carbono/química , Silicatos/química , Tensoativos/química , Adsorção , Tamanho da Partícula , Propriedades de Superfície