Novel Scintillating Nanoparticles for Potential Application in Photodynamic Cancer Therapy

Abstract

The development of X-ray-absorbing scintillating nanoparticles is of high interest for solving the short penetration depth problem of visible and infrared light in photodynamic therapy (PDT). Thus, these nanoparticles are considered a promising treatment for several types of cancer. Herein, gadolinium oxide nanoparticles doped with europium ions (Gd2O3:Eu3+) were obtained by using polyvinyl alcohol as a capping agent. Hybrid silica nanoparticles decorated with europium-doped gadolinium oxide (SiO2-Gd2O3:Eu3+) were also prepared through the impregnation method. The synthesized nanoparticles were structurally characterized and tested to analyze their biocompatibility. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy confirmed the high crystallinity and purity of the Gd2O3:Eu3+ particles and the homogeneous distribution of nanostructured rare earth oxides throughout the fumed silica matrix for SiO2-Gd2O3:Eu3+. Both nanoparticles displayed stable negative ζ-potentials. The photoluminescence properties of the materials were obtained using a Xe lamp as an excitation source, and they exhibited characteristic Eu3+ bands, including at 610 nm, which is the most intense transition band of this ion. Cytotoxicity studies on mouse glioblastoma GL261 cells indicated that these materials appear to be nontoxic from 10 to 500 μg·mL−1 and show a small reduction in viability in non-tumor cell lines. All these findings demonstrate their possible use as alternative materials in PDT.

Highlighted Advances in Therapies for Difficult-To-Treat Brain Tumours Such as Glioblastoma

“…These can be sensitive to specific wavelengths, include molecules that increase tissue oxygenation (e.g., catalase and haemoglobin), and can be functionalized with ligands higher for tumour tissue specificity [ 121 ]. Recently, Silva and colleagues [ 136 ] developed X-ray-absorbing scintillating europium-doped gadolinium oxide nanoparticles. Their goal was to create particles capable of converting X-ray radiation to ultraviolet-visible (UV-Vis) light for more efficient activation of PS.…”

Systematic Review of Photodynamic Therapy in Gliomas

“…Over the last (almost) 50 years, the utility of photosensitizers (PS) in the context of fluorescence-guided surgery (FGS) and photodynamic therapy (PDT) in glioma have advanced with rapidly growing momentum [13][14][15][16]. PDT is a two-stage treatment that combines light energy with a drug (photosensitizer, PS) designed to destroy cancerous and precancerous cells after light activation (Figure 1).…”