Towards photodynamic therapy with ionizing radiation: nanoparticle-mediated singlet oxygen generation

Sandhya Clement*, Wei Deng, Elizabeth Camilleri, Brian Wilson, Ewa Goldys

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution


Photodynamic therapy (PDT) is a clinically approved method for the treatment of cancer by using singlet oxygen, a highly reactive oxygen generated from a photosensitizer drug upon photoactivation. Limited light penetration depth into to the tissue means that PDT is unsuitable for deep tissue cancer treatments. This can be overcome by using X-ray /gamma rays activated nanoparticles able to trigger the photosensitizer drug and generate singlet oxygen. Additionally, inorganic nanoparticles interact more strongly with X and/or gamma rays than the tissue, allowing to concentrate the effects of radiation near nanoparticle surface and they can also be molecularly targeted to cancer cells. In this work we synthesized and characterized CeF3 nanoparticles, a well-known scintillator material. The nanoparticles were conjugated with Verteporfin, a photosensitizer drug by electrostatic interaction. We assessed the performance of CeF3 and the conjugates to generate singlet oxygen exposed to X-ray radiation. The X-ray singlet oxygen quantum yield of the nanoparticle-photosensitizer system was accurately quantified for the first time. This provided realistic estimates of the singlet oxygen dose taking into consideration the dose partition of the radiation between CeF3 and the tissue. Furthermore, we investigated gold nanoparticle-photosensitizer systems. We confirmed that pure gold nanoparticles itself generate singlet oxygen which is attributed to plasmonic effects. We found enhanced singlet oxygen generation from gold-Rose Bengal conjugates and gold nanorod–verteporfin conjugates. These singlet-oxygen-generating nanomaterials add a new dimension to radiation-assisted PDT.
Original languageEnglish
Title of host publicationColloidal nanoparticles for biomedical applications XI
EditorsWolfgang J. Parak, Marek Osinski, Xing-Jie Liang
Place of PublicationBellingham, Washington
Number of pages1
ISBN (Print)9781628419566
Publication statusPublished - 2016
EventColloidal Nanoparticles for Biomedical Applications XI (2016) - San Francisco, California, United States
Duration: 13 Feb 201615 Feb 2016

Publication series

NameProceedings of SPIE
ISSN (Print)1605-7422


ConferenceColloidal Nanoparticles for Biomedical Applications XI (2016)
CitySan Francisco, California, United States

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