Metabolizable lanthanum-coordination nanoparticles as efficient radiosensitizers for solid tumor therapy.

The clinical potential of radiotherapy cannot be realised as expected due to the inherent radioresistance of tumors. To overcome these problems, radiosensitizers containing heavy metal elements have been used in radiotherapy as efficient radiation dose enhancers. In the present study, we report the design and preparation of novel lanthanum-coordination nanoparticles, and their application as nano-sized radiosensitizers in radiotherapy against solid tumors. Via a simple one-pot hydrothermal route, these nanoparticles were fabricated without any expensive chemical reagents. The polyvinylpyrrolidone molecules used in a typical synthesis could highly enhance the dispersity and bio-compatibility of these nanoparticles. In vitro toxicity studies demonstrated that these nanoparticles had low cytotoxicity, negligible hemolysis, and no effect on blood coagulation. Upon exposure to high energy X-ray radiation, these nanoparticles possessed excellent radiosensitization effects and induced serious cellular death both in vitro and in vivo. In addition, time-dependent bio-distribution and long-term toxicity results for these nanoparticles after intravenous administration indicated their high bio-compatibility. More importantly, these metabolizable nanoparticles could be cleared up after intravenous administration along with time passing. These significant findings promise the prospective use of these nanoparticles as vigorous X-ray radiation-mediated therapeutic agents in coming cancer treatments.