Luminescent mesoporous LaVO4:Eu3+ core-shell nanoparticles: synthesis, characterization, biocompatibility and their cytotoxicity

Abstract

A general and facile method was used for preparation of water-soluble silica coated LaVO₄:Eu³⁺ core-shell nanoparticles. In the present study, we have discussed and compared the cytotoxicity characteristics of the synthesized LaVO₄:Eu³⁺ and silica coated LaVO₄:Eu³⁺ core-shell nanoparticles. X-ray diffraction (XRD), field-emission transmission electron microscopy (FE-TEM), energy dispersive X-ray analysis (EDX), Fourier-transform infrared spectroscopy (FTIR), UV/Vis absorption spectroscopy and photoluminescence spectroscopic techniques were employed to characterize the structure and morphology of the prepared products. To obtain high aqueous solubility, luminescent LaVO₄:Eu³⁺ nanoparticles were encapsulated with silica groups, giving the nanoparticles a negatively charged surface at physiological pH. The results of XRD confirm the formation of a well-crystallized LaVO₄:Eu³⁺ phase with a tetragonal zircon structure. Optical absorption spectra show that the optical properties of silica-coated LaVO₄:Eu³⁺ core-shell nanoparticles are related to their sizes and shapes. Further, in order to assess cytotoxicity, we investigated whether the LaVO₄:Eu³⁺ nanoparticles could alter biological samples once they enter human H522 and peripheral blood mono nuclear cells (PBMCs). An MTT assay was performed to measure the mitochondrial activity that reflects the number of viable cells. Silica coated LaVO₄:Eu³⁺ core-shell nanoparticles exhibited no significant effect on the viability of both types of cells up to 24 h after exposure. Strikingly, no dose effects were detected, even at highest concentrations.