Synthesis, Characterization and Biodistribution of GdF3:Tb3+@RB Nanocomposites.

Oleg E Polozhentsev,Alexander V Soldatov,Darya V Khodakova,Ilia A Pankin,Oleg I Kit,Aleksey Yu Maksimov,Anna S Goncharova,Pavel V Medvedev

doi:10.3390/ma15020569

Abstract

Herein we report the development of a nanocomposite for X-ray-induced photodynamic therapy (X-PDT) and computed tomography (CT) based on PEG-capped GdF3:Tb3+ scintillating nanoparticles conjugated with Rose Bengal photosensitizer via electrostatic interactions. Scintillating GdF3:Tb3+ nanoparticles were synthesized by a facile and cost-effective wet chemical precipitation method. All synthesized nanoparticles had an elongated “spindle-like” clustered morphology with an orthorhombic structure. The structure, particle size, and morphology were determined by transmission electron microscopy (TEM), X-ray diffraction (XRD), and dynamic light scattering (DLS) analysis. The presence of a polyethylene glycol (PEG) coating and Rose Bengal conjugates was proved by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and ultraviolet–visible (UV-vis) analysis. Upon X-ray irradiation of the colloidal PEG-capped GdF3:Tb3+–Rose Bengal nanocomposite solution, an efficient fluorescent resonant energy transfer between scintillating nanoparticles and Rose Bengal was detected. The biodistribution of the synthesized nanoparticles in mice after intravenous administration was studied by in vivo CT imaging.

Highlights

Photodynamic therapy (PDT) is a clinically approved therapeutic modality for the treatment of several types of cancer, infections, and some other diseases [1,2,3]
This work aims to develop universal nanocomposites for X-ray-induced photodynamic therapy of deep and superficial tumors based on scintillation Tb3+ doped GdF3 nanoparticles coated with a biocompatible surfactant and effectively conjugated with RB photosensitizer
The series of naked and polyethylene glycol (PEG)-capped GdF3:Tb3+ (x = 5, 10, 15, 20%) nanoparticles was synthesized by a wet chemical precipitation method in an aqueous solution at room temperature

Summary

Introduction

Photodynamic therapy (PDT) is a clinically approved therapeutic modality for the treatment of several types of cancer, infections, and some other diseases [1,2,3]. The irradiation of the target tissue with visible or near-infrared light of a certain wavelength activates PS, which leads to the generation of reactive oxygen species (ROS). Traditional visible light used in PDT (spectral range 400–700 nm) is limited to superficial lesions, and the penetration depth of light does not exceed 1 cm. This leads to the fact that only small superficial tumors can be treated within conventional PDT. This problem can be solved by using X-rays as an irradiation source since the penetration depth of X-ray radiation reaches up to 40 cm [8,9]

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Methods

Results