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Spectroscopic, structural and in vitro cytotoxicity evaluation of luminescent, lanthanide doped core@shell nanomaterials GdVO4:Eu3+5%@SiO2@NH2

Szczeszak, Agata, Ekner-Grzyb, Anna, Runowski, Marcin, Szutkowski, Kosma, Mrówczyńska, Lucyna, Kaźmierczak, Zuzanna, Grzyb, Tomasz, Dąbrowska, Krystyna, Giersig, Michael, Lis, Stefan
Journal of colloid and interface science 2016 v.481 pp. 245-255
X-ray diffraction, biocompatibility, coatings, coprecipitation, crystallites, cytotoxicity, elemental composition, endothelial cells, energy-dispersive X-ray analysis, erythrocytes, europium, glycerol, humans, hydrolysis, ions, light scattering, luminescence, lungs, magnetism, nanoparticles, polyacrylic acid, silane, silica, spectral analysis, spectroscopy, transmission electron microscopy
The luminescent GdVO4:Eu³⁺5%@SiO2@NH2 core@shell nanomaterials were obtained via co-precipitation method, followed by hydrolysis and co-condensation of silane derivatives: tetraethyl orthosilicate and 3-aminopropyltriethoxysilane. Their effect on human erythrocytes sedimentation and on proliferation of human lung microvascular endothelial cells was examined and discussed. The luminescent nanoparticles were synthesized in the presence of polyacrylic acid or glycerin in order to minimalize the agglomeration and excessive growth of nanostructures. Surface coating with amine functionalized silica shell improved their biocompatibility, facilitated further organic conjugation and protected the internal core. Magnetic measurements revealed an enhanced T1-relaxivity for the synthesized GdVO4:Eu³⁺5% nanostructures. Structure, morphology and average grain size of the obtained nanomaterials were determined by X-ray diffraction, transmission electron microscopy and dynamic light scattering analysis. The qualitative elemental composition of the nanomaterials was established using energy-dispersive X-ray spectroscopy. The spectroscopic characteristic of red emitting core@shell nanophosphors was completed by measuring luminescence spectra and decays. The emission spectra revealed characteristic bands of Eu³⁺ ions related to the transitions ⁵D0-⁷F0,1,2,3,4 and ⁵D1-⁷F1. The luminescence lifetimes consisted of two components, associated with the presence of Eu³⁺ ions located at the surface of the crystallites and in the bulk.