Cellular uptake and cytotoxicity of unmodified Pr³⁺:LaF<inf>3</inf> nanoparticles

Abstract

© 2019, Springer Nature B.V. Pr3+:LaF3 (CPr = 1%) nanoparticles were characterized by means of transmission electron microscopy (TEM), X-ray diffraction, energy-dispersive spectroscopy, and optical spectroscopy. The obtained 14 nm Pr3+:LaF3 (CPr = 1%) crystalline hexagonal-structured nanoparticles contain Pr, La, and F only. The luminescent spectra emission bands corresponded to the emission bands of Pr3+ions. The Pr3+:LaF3 (CPr = 1%) nanoparticles effectively interact with A 549, LEС, and MDCK cells. By means of TEM, it was revealed that after 2 h of the nanoparticle exposure, A 549, MDCK, and LEС cells internalized the nanoparticles and 20–300 nm agglomerates of the nanoparticles packed into 200–500 nm vesicles were found into the cytoplasm. It seems that the internalization occurs via macropinocytosis. In A 549 cells, some vesicles were disrupted and the nanoparticles escaped the vesicles floating freely in the cytoplasm. Flow cytometry showed that all the cells effectively interact with nanoparticles. This interaction leads to cell granularity change. Specifically, A 549, MDCK, and LEС, and cells treated by nanoparticles have the values of size scattered signal 16 ± 2, 20 ± 3, and 39 ± 3%, respectively, comparing with the untreated cells. The Pr3+:LaF3 (CPr = 1%) nanoparticles were not found into the cellular organelles. The cytotoxicity of the Pr3+:LaF3 (CPr = 1%) nanoparticles is not significant at concentrations of 0.05, 0.1, 0.25, and 0.5 g/L.