This review focuses on the radiosensitization strategies that use high-Z nanoparticles. It does not establish an exhaustive list of the works in this field but rather propose constructive criticisms pointing out critical factors that could improve the nano-radiation therapy. Whereas most reviews show the chemists and/or biologists points of view, the present analysis is also seen through the prism of the medical physicist. In particular, we described and evaluated the influence of X-rays energy spectra using a numerical analysis. We observed a lack of standardization in preclinical studies that could partially explain the low number of translation to clinical applications for this innovative therapeutic strategy. Pointing out the critical parameters of high-Z nanoparticles radiosensitization, this review is expected to contribute to a larger preclinical and clinical development.

Tb 2 O 3 coated with a polysiloxane layer is a biocompatible nanoscintillator that exhibits an appropriate pattern of biodistribution after injection. In this contribution, we combine this nanosystem with porphyrin molecules that are able to generate singlet oxygen, a major cytotoxic agent for photodynamic therapy application. Using time-resolved laser spectroscopy and singlet oxygen probes, we demonstrate this combination is suitable for singlet oxygen generation induced by X-ray and provide a physical study of the energy transfer observed between the nanoscintillator and the porphyrin. Combined with a radiotherapy protocol, the proposed nanohybrid system presents a combination of physical, chemical, and biological properties that make it a good candidate for photodynamic effects in deep tissues.

Photodynamic therapy has emerged as an alternative to chemotherapy and radiotherapy for cancer treatment. Nanoparticles have recently been proposed as effective carriers for photosensitizers. Depending on their chemical composition, these can be used for diagnosis and therapy due to the selective accumulation of the photosensitizer in cancer cells in vitro or in tumors in vivo. Multifunctional nanoplatforms combining several applications within the same nano-object emerge as potential important theranostic tools. This review, based on the chemical nature of the nanoparticles will discuss recent advances in the area of non polymeric nanoparticles for photodynamic therapy applications.

The microwave-assisted synthesis of zinc 5-(4-carboxyphenyl)-10,15,20-triphenylporphyrin and zinc 5-(4-carboxyphenyl)-10,15,20-triphenylchlrorin are described and compared to classic conditions of synthesis in terms of time of reaction and yields obtained. The new experimental protocols are easy to implement required small amounts of reagents and solvents and lead to short reaction times. All compounds have been characterized by 1 H NMR, MS and spectroscopic techniques.

We report the design and synthesis of europium-doped gadolinium oxysulfide nanoscintillators Gd O S:Eu conjugated with two different photosensitizers (PSs): a zinc chlorin (ZnTPC) and a zinc phtalocyanine (ZnPc) by covalent bonding through a layer of N-(3-trimethoxysilylpropyl)diethylenetriamine (TPDA). These conjugates were designed to be activated under X-ray excitation to allow a photodynamic effect, although this desired outcome was not achieved in this study. The monodispersed nanoparticles of ∼70 nm diameter were pegylated to be stabilized in aqueous suspension. It was shown that the PSs conserved their photophysical properties once conjugated to the nanoscintillator and efficient singlet oxygen was obtained upon photo-irradiation. However, no energy transfer was observed from the nanoscintillator to the photosensitizer neither under photo- nor X-ray irradiation.