Nanopartículas superparamagnéticas de óxido de ferro modificadas com Ln3+: preparação, caracterização estrutural, espectroscópica e magnética
Data
2022-11-25
Autores
Lojudice, Thaís Brancaglion 
Orientadores
Ferreira, Paula Silvia Haddad
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
O estudo e desenvolvimento de materiais nanoparticulados tem despertado o interesse da comunidade cientifica, como possíveis aplicações em áreas da engenharia, indústria e tecnologia. As nanopartículas superparamagnéticas têm sido alvo de muitas pesquisas devido as suas possibilidades de bioaplicações e carreamento magnético de fármacos. Da mesma forma, nanopartículas luminescentes contendo íons terras rara vêm atraindo atenção para bioaplicações em terapia e diagnóstico (teranóstica). Essas possíveis aplicações em conjunto foram a base para o desenvolvimento deste trabalho, cujo foco é a síntese e caracterização de nanopartículas superparamagnéticas de óxido de ferro (SPIONs- Superparamagnetic Iron Oxide Nanoparticles) modificadas com íons Eu3+ e Yb3+. As SPIONs foram obtidas através do método de coprecipitação de sais de Fe. A incorporação dos íons lantanídeos se dividiu em dois métodos distintos, método direto e core-shell. As nanopartículas (NPs) foram caracterizadas por difratometria de raio X (DRX), espectroscopia vibracional na região do infravermelho (IV), magnetização (DSIQ - dispositivo supercondutor de interferência quântica), espalhamento de luz dinâmico (EDL) e potencial zeta, espectrofotometria na região do UV-Vis e espectroscopia eletrônica de fotoluminescência (FL). Os ensaios estruturais e magnéticos mostram que a modificação com Ln3+ não altera a estrutura cristalina e o caráter superparamagnético da NP. As NPs sintetizadas pelo método direto não apresentaram bons sinais de fotoluminescência devido a interferências com a matriz, já as NPs sintetizadas pelo método core-shell apresentaram bons resultados de fotoluminescência, com a principal emissão do íon Eu3+ sendo observada tanto pela emissão direta quanto pelo efeito de conversão ascendente de energia.
The study and development of nanomaterials has aroused the interest of the scientific community, as possible applications in areas of engineering, industry and technology. Superparamagnetic nanoparticles have been the subject of much research due to their potential for bioapplications and magnetic drug delivery. Likewise, luminescent nanoparticles containing rare earth ions have attracted attention for bioapplications in therapy and diagnosis (theranostics). These possible applications together were the basis for the development of this work whose focus is the synthesis and characterization of superparamagnetic iron oxide nanoparticles (SPIONs) modified with Eu3+ and Yb3+ ions. SPIONs were obtained using the Fe salt coprecipitation method. The incorporation of the lanthanide ions was divided into two distinct methods, direct method and core-shell. The nanoparticles (NPs) were characterized by X-ray diffractometry (XRD), infrared spectroscopy (IR), magnetic measurements (SQUID), dynamic light scattering (DLS), UV-Vis spectrophotometry and photoluminescence spectroscopy (PL). Structural and magnetic test show that modification with Ln3+ does not change the crystal structure and superparamagnetic properties of NP. The NPs synthesized by the direct method did not show good photoluminescence signals due to matrix interferences, while the NPs synthesized by the core-shell method showed good photoluminescence results, with the main emission of the Eu3+ ion being observed both by the direct emission and by the up-conversion effect.
The study and development of nanomaterials has aroused the interest of the scientific community, as possible applications in areas of engineering, industry and technology. Superparamagnetic nanoparticles have been the subject of much research due to their potential for bioapplications and magnetic drug delivery. Likewise, luminescent nanoparticles containing rare earth ions have attracted attention for bioapplications in therapy and diagnosis (theranostics). These possible applications together were the basis for the development of this work whose focus is the synthesis and characterization of superparamagnetic iron oxide nanoparticles (SPIONs) modified with Eu3+ and Yb3+ ions. SPIONs were obtained using the Fe salt coprecipitation method. The incorporation of the lanthanide ions was divided into two distinct methods, direct method and core-shell. The nanoparticles (NPs) were characterized by X-ray diffractometry (XRD), infrared spectroscopy (IR), magnetic measurements (SQUID), dynamic light scattering (DLS), UV-Vis spectrophotometry and photoluminescence spectroscopy (PL). Structural and magnetic test show that modification with Ln3+ does not change the crystal structure and superparamagnetic properties of NP. The NPs synthesized by the direct method did not show good photoluminescence signals due to matrix interferences, while the NPs synthesized by the core-shell method showed good photoluminescence results, with the main emission of the Eu3+ ion being observed both by the direct emission and by the up-conversion effect.