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Particle Size of X‐ray Pumped UVC‐Emitting Nanoparticles Defines Intracellular Localization and Biological Activity Against Cancer Cells
Author(s) -
Müller Matthias,
Rahmanzadeh Ramtin,
Tran Thao,
Kappelhoff Jan,
Akam Eman Aburieda,
Caravan Peter,
Jüstel Thomas,
Held Kathryn D.,
Anderson R. Rox,
Purschke Martin
Publication year - 2020
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.202000201
Subject(s) - nanoparticle , cytotoxicity , incubation , intracellular , irradiation , particle size , biophysics , chemistry , particle (ecology) , transmission electron microscopy , radiochemistry , analytical chemistry (journal) , materials science , nanotechnology , in vitro , biochemistry , biology , chromatography , physics , ecology , nuclear physics
Effectiveness of radiation treatment for cancer is limited in hypoxic tumors. Previous data shows that UVC‐emitting nanoparticles enhance cytotoxicity of X‐ray irradiation in hypoxic tumor cells. This study examines the impact on cell killing, particle size, uptake into cells, incubation time, and UV emission intensity of LuPO 4 :Pr 3+ ,Nd 3+ . A549 cells are treated with LuPO 4 :Pr 3+ ,Nd 3+ and X‐rays. The surviving fraction is evaluated using the colony formation assay after treatment of cells with different particle sizes ( D 50 = 0.16 and 5.05 µm) and after different incubation times before X‐ray irradiation. Nanoparticle uptake into cells is verified by transmission electron microscopy and quantified by inductively coupled plasma mass spectrometry. The microparticles exhibit a five times higher emission intensity compared to nanoparticles. Both particle sizes show an increased cytotoxic effect after X‐ray excitation with prolonged incubation times. Surprisingly, the smaller nanoparticles show a significantly higher biological effect compared to the larger particles, despite their significantly lower UVC emission. Nanoparticles accumulate more quickly and closer to the nucleus than the microparticles, resulting in higher localized UVC emission and greater lethality. The results suggest that the number of intracellular particles and their proximity to the cell DNA is more important than the emission intensity of the particles.