Taming the Immiscibility of Gold, Iron, and Boron to Craft Chemodegradable Nanoparticles for Multimodal Imaging and Radiotherapy

: Despite more than half of all oncological patients undergo X-ray radiotherapy (XRT), significant efforts are required to improve its efficacy against hypoxic tumor regions and, at the same time, to expand the therapeutic window to spare normal tissues. The use of radiosensitizers, the personalization of radiation dose planning aided by imaging with magnetic resonance imaging (MRI) and X-ray computed tomography (CT), and the implementation of boron neutron capture therapy (BNCT) are three strategies to encompass the limits of XRT. Here, these three strategies are leveraged by designing and achieving a theranostic platform based on trimetallic Au-Fe-B nanoparticles (NPs). According to density functional theory calculations, chemodegradable Au-Fe-B nanostructures are not achievable under thermodynamic equilibrium conditions. Hence, Au-Fe-B NPs were synthesized by laser ablation in liquid, because it is a nonequilibrium process, followed by a tailored cleaning protocol. The Au-Fe-B NPs were coated with biocompatible polymers and showed several useful properties for nanomedicine application, such as chemical degradation in a physiological environment, contrast ability for MRI and CT, in vitro radiosensitization efficacy for XRT and BNCT, and consistent intracellular uptake. These functionalities can enable advanced studies on tumor treatment with complementary therapeutic strategies guided by anatomic imaging, leading to more effective oncological protocols.