Excretable, ultrasmall hexagonal NaGdF4:Yb50% Nanoparticles for bimodal imaging and radiosensitization

Abstract

Background In this study, we report on the synthesis, imaging properties and radiosensitizing properties of β-NaGdF4:Yb50% nanoparticles as a multifunctional theranostic platform. The synthesized nanoparticles act as potent bimodal contrast agents with superior imaging properties compared to existing agents used for magnetic resonance imaging (MRI) and computed tomography (CT). Clonogenic assays demonstrated that these nanoparticles can act as effective radiosensitizers, provided the nanoparticles are taken up intracellularly. Results A 2 Gy dose of X-ray induced ~ 20% decrease in colony survival when C6 rat glial cells were incubated with non-targeted nanoparticles (NaGdF4:Yb50%), whereas the same X-ray dose resulted in a ~ 60% decrease in colony survival with targeted nanoparticles conjugated to folic acid (NaGdF4:Yb50%-FA). Intravenous administration of nanoparticles resulted in clearance through urine and feces within a short duration, based on the ex vivo analysis of Gd3+ ions via ICP-MS. Conclusion These biocompatible and in vivo clearable ultra-small NaGdF4:Yb50% are promising candidates for further evaluation in image-guided radiotherapy applications.