Characterization of Micro‐ and Nanoscale LuPO₄:Pr³⁺,Nd³⁺ with Strong UV‐C Emission to Reduce X‐Ray Doses in Radiation Therapy

Abstract

UV‐C emitting nanoscale scintillators can be used to sensitize cancer cells selectively against X‐rays during radiation therapy, due to the lethal DNA lesions caused by UV‐C photons. Unfortunately, nanoscale particles (NPs) show decreased UV‐C emission intensity. In this paper, the influence of different Nd3+ concentrations on the UV‐C emission of micro‐ and nanoscale LuPO4:Pr3+ is investigated upon X‐ray irradiation and vacuum UV excitation (160 nm). Co‐doped LuPO4 results in increased UV‐C emission independent of excitation source due to energy transfer from Nd3+ to Pr3+. The highest UV‐C emission intensity is observed for LuPO4:Pr3+,Nd3+(1%,2.5%) upon X‐ray irradiation. Finally, LuPO4 NPs co‐doped with different dopant concentrations are synthesized, and the biological efficacy of the combined approach (X‐rays and UV‐C) is assessed using the colony formation assay. Cell culture experiments confirm increased cell death compared to X‐rays alone due to the formation of UV‐specific DNA damages, supporting the feasibility of this approach.

Conceptual Ultraviolet‐C Light Source Based on Up‐Conversion Luminescence

“…For a typical PC ultraviolet-C light source, the emission wavelength will be substantially determined by the use of PC materials, which generally need to meet the following two prerequisites: 1) The PC materials should contain ultraviolet-C-emitting ions, such as Pr 3þ , Nd 3þ , or Bi 3þ . [18][19][20][21] 2) The PC materials should be easily excitable by convenient light sources, such as commercial blue lightemitting diodes or lasers. Therefore, the key to a design of PC ultraviolet-C light sources is to find phosphor materials with appropriate emission and excitation performance.…”

Radiation Dose‐Enhancement Is a Potent Radiotherapeutic Effect of Rare‐Earth Composite Nanoscintillators in Preclinical Models of Glioblastoma

“…However, factors by which nanoscintillators can augment radiotherapy outcomes also include a potential synergism with radiotherapy [25] and the use of nanoscintillators that emit UV-C photons to expand the amount and types of DNA damage induced during radiotherapy. [26][27][28] However, translational studies of nanoscintillators for radiotherapeutic applications are challenged by the lack of biosafety and toxicity profiles. Moreover, the aforementioned proof-ofconcept studies have almost exclusively been performed on nude mice carrying subcutaneous xenografts, and thus carry limited clinical relevance.…”

“…However, factors by which nanoscintillators can augment radiotherapy outcomes also include a potential synergism with radiotherapy [ 25 ] and the use of nanoscintillators that emit UV‐C photons to expand the amount and types of DNA damage induced during radiotherapy. [ 26–28 ]…”

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

“…[28] Nanomaterials in the blood are usually cleared within minutes or hours by the phagocytic cells of the mononuclear phagocyte system (MPS) inside the liver and spleen. 10 To suppress clearance of the particles by the MPS in future animal Figure 6. Surviving fractions of A549 cells after the combined treatment with LuPO 4 :Pr 3+ ,Nd 3+ nano-a) and microparticles b) at different incubation times (0.5, 4, and 24 h) and a X-ray dose of 6 Gy.…”

“…This new generation of nanoparticles showed a 14-fold increase in UVC emission intensity compared to previously used single doped LuPO 4 :Pr 3+ . [10] LuPO 4 :Pr 3+ ,Nd 3+ also emit more UV photons in the range of 190-220 nm after X-ray excitation, which further improves the biological effect on cancer cells. UVC photons interact directly with the DNA to form cyclopyrimidine dimers as well as (6,4) photoadducts.…”