Particle Size of X-ray Pumped UVC-Emitting Nanoparticles Defines Intracellular Localization and Biological Activity Against Cancer Cells

Matthias Müller*, Ramtin Rahmanzadeh, Thao Tran, Jan Kappelhoff, Eman Aburieda Akam, Peter Caravan, Thomas Jüstel, Kathryn D. Held, R. Rox Anderson, Martin Purschke

*Corresponding author for this work
1 Citation (Scopus)

Abstract

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 LuPO4:Pr3+,Nd3+. A549 cells are treated with LuPO4:Pr3+,Nd3+ and X-rays. The surviving fraction is evaluated using the colony formation assay after treatment of cells with different particle sizes (D50 = 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.

Original languageEnglish
Article number2000201
JournalParticle and Particle Systems Characterization
Volume37
Issue number10
ISSN0934-0866
DOIs
Publication statusPublished - 01.10.2020

Research Areas and Centers

  • Academic Focus: Biomedical Engineering

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