Particle Size of X‐ray Pumped UVC‐Emitting Nanoparticles Defines Intracellular Localization and Biological Activity Against Cancer Cells. (18th August 2020)

• Record Type: Journal Article
• Authors: Müller, Matthias; Rahmanzadeh, Ramtin; Tran, Thao; Kappelhoff, Jan; Akam, Eman Aburieda; Caravan, Peter; Jüstel, Thomas; Held, Kathryn D.; Anderson, R. Rox; Purschke, Martin
• Is Part Of: Particle and particle systems characterization. Volume 37:Number 10(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-08-18
• Subjects: cancer treatment -- nanoparticles -- radiation oncology -- UVC radiation; Particles -- Periodicals; 620.43
• DOI: 10.1002/ppsc.202000201
• Languages: English
• ISSNs: 0934-0866

Abstract

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 :Pr 3+, Nd 3+ . A549 cells are treated with LuPO4 :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. Abstract : The influence of particle size and incubation time on the cytotoxic effect of UVC‐emitting LuPO4 :Pr 3+, Nd 3+ particles after excitation with X‐rays is investigated. Despite a decreasing UVC emission intensity of LuPO4 :Pr 3+, Nd 3+ with decreasing particle size, the cytotoxic effect of the combined treatment increases when reducing the particle size and prolonging the incubation time.