ANDRADE NETO, Davino Machado. Magnetic ressonance imaging contrast agents obtained by fast sonochemistry approach. 2016. 84 f. Dissertação (Mestrado em Química)-Universidade Federal do Ceará, Fortaleza, 2016. / Submitted by Aline Mendes (alinemendes.ufc@gmail.com) on 2017-01-25T19:35:32Z No. of bitstreams: 1 2016_dis_dmandradeneto.pdf: 4658452 bytes, checksum: 4d05fbe6bccc67518a89306c468793a6 (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2017-01-26T20:28:31Z (GMT) No. of bitstreams: 1 2016_dis_dmandradeneto.pdf: 4658452 bytes, checksum: 4d05fbe6bccc67518a89306c468793a6 (MD5) / Made available in DSpace on 2017-01-26T20:28:31Z (GMT). No. of bitstreams: 1 2016_dis_dmandradeneto.pdf: 4658452 bytes, checksum: 4d05fbe6bccc67518a89306c468793a6 (MD5) Previous issue date: 2016 / Functionalized Fe3O4 nanoparticles (NPs) have emerged as a promising contrast agent for magnetic resonance imaging (MRI). Their synthesis and functionalization methodology strongly affects their performance in vivo. Although thermal decomposition is the most commonly used growth methodology reported in the literature, it has proven to be time-consuming, expensive, and laborious. Therefore, this work describes a rapid and facile sonochemical methodology to synthesize and functionalize Fe3O4 NPs with excellent physico-chemical properties for MRI. In this work, a sonochemistry approach was used to produce, in 12 min, Fe3O4 NPs functionalized with polysodium acrylate (PAANa), trisodium citrate (CIT), branched polyethylenimine (BPEI), and sodium oleate. X-ray diffraction and transmission electron microscopy demonstrated that the NPs were composed of a single inverse spinel phase with an average diameter of 9–11 nm and a narrow size distribution. It was confirmed by Mössbauer spectroscopy and magnetic measurements that the obtained NPs were transitioning to the superparamagnetic regime and possessed excellent magnetization saturation values (59–77 emu/g). Fourier transform infrared spectroscopy proved that the sonochemistry approach provided conditions that induced a strong interaction between Fe3O4 and the capping agents. Furthermore, dynamic light scattering experiments evidenced that samples coated with PAANa, CIT, and BPEI possess colloidal stability in aqueous solvents. Emphasis must be placed on PAANa-coated NPs, which also presented remarkable colloidal stability under simulated physiological conditions. Finally, the obtained NPs exhibited great potential to be applied as an MRI contrast agent. The transverse relaxativity values of the NPs synthesized in this work (277–439 mM-1s-1) were greater than those of commercial NPs and those prepared using other methodologies. Therefore, this work represents significant progress in the preparation of Fe3O4 NPs, providing a method to prepare high-quality materials in a rapid, cost-effective, and facile manner. / Nanopartículas (NPs) funcionalizadas emergiram como promissores candidatos para serem aplicadas como agente de contraste para imagem por ressonância magnética nuclear e sua metodologia de síntese e funcionalização afetam fortemente sua performance in vivo. A metodologia mais utilizada para a produção dessas NPs funcionalizadas é a decomposição térmica, a qual tem provado ser financeiramente desfavorável, laboriosa além de requisitar longos tempos de execução. Portanto, este trabalho tem como objetivo descrever uma metodologia fácil e rápida, através do método sonoquímico, para a síntese e funcionalização de NPs de Fe3O4 com excelentes propriedades físico-químicas com objetivo de serem aplicadas como agente de contraste para imagem por ressonância magnética nuclear. Neste trabalho, o método sonoquímico foi usado para produzir, em 12 min, NPs de Fe3O4 funcionalizadas com policrilato de sódio, citrato de sódio, polietilenamina ramificada e oleato de sódio. Difração de raios-X e microscopia eletrônica de transmissão demonstraram que as NPs produzidas são compostas de uma única fase de espinélio inverso de 9-11 nm de diâmetro e uma distribuição de tamanho estreita. Foi confirmado por meio da espectroscopia Mössbauer e medidas magnéticas que as NPs sintetizadas estão em transição para o regime superparamagnético e que possuem excelente valor de magnetização de saturação (59-77 emu/g) para aplicações biomédicas. Espectroscopia de infravermelho por transformada de Fourier provou que a radiação sonoquímica forneceu condições adequadas para que acontecesse uma interação forte entre o núcleo magnéticos e os agentes fucionalizantes. Além disso, experimentos de espalhamento dinâmico de luz confirmaras que as amostras recobertas com moléculas orgânicas hidrofílicas possuem estabilidade coloidal em solventes aquosos. Destaque deve ser dado a nanopartícula magnética recoberta com poliacrilato de sódio, que demonstrou excelente estabilidade coloidal em condições fisiológicas simuladas. Finalmente, as NPs obtidas se mostraram serem promissores candidatos a agentes de contraste. Uma vez que seus valores de relaxatividade transversal foram maiores que os agentes de contraste comerciais e daqueles preparados por outras metodologias sintéticas. Portanto, este trabalho trás um grande avanço no que se refere a preparação de NPs de Fe3O4 funcionalizadas para aplicações biológicas, uma vez que materiais de alta qualidade foram preparados de forma rápida e fácil.

New derivatives of carbon nanostructures: nanotubes, nano-onions and nanocrystalline diamonds were obtained through fluorination and subsequent functionalization with sucrose. Chemically modified nanocarbons show high solubility in water, ethanol, DMF and can be used as biomaterials for medical applications. It was demonstrated that sucrose functionalized nanostructures can find applications in nanocomposites due to improved dispersion enabled by polyol functional groups. Additionally, pristine and chemically derivatized carbon nanotubes were studied as nanofillers in epoxy composites. Carbon nanotubes tailored with amino functionalities demonstrated better dispersion and crosslinking with epoxy polymer yielding improved tensile strength and elastic properties of nanocomposites. Reductive functionalization of nanocarbons, also known as Billups reaction, is a powerful method to yield nanomaterials with high degree of surface functionalization. In this method, nanocarbon salts prepared by treatment with lithium or sodium in liquid ammonia react readily with alkyl and aryl halides as well as bromo carboxylic acids. Functionalized materials are soluble in various organic or aqueous solvents. Water soluble nanodiamond derivatives were also synthesized by reductive functionalization of annealed nanodiamonds. Nanodiamond heat pretreatment was necessary to yield surface graphene layers and facilitate electron transfer from reducing agent to the surface of nanoparticles. Other carbon materials such as activated carbon and anthracite coal were also derivatized using reductive functionalization to yield water soluble activated carbon and partially soluble in organic solvents anthracite. It was shown that activated carbon can be effectively functionalized by Billups method. New derivatives of activated carbon can improve water treatment targeting specific impurities and bio active contaminants. It was demonstrated that functionalized carbon nanotubes are suitable for real time radiation measurements. Radiation sensor incorporating derivatized carbon nanotubes is lightweight and reusable. In summary, functionalization of carbon nanomaterials opens new avenues for processing and applications ranging from biomedicine to radiation sensing in space.