Gadolinium neutron-capture therapy using novel gadopentetic acid-chitosan complex nanoparticles: in vivo growth suppression of experimental melanoma solid tumor

The potential of gadolinium neutron-capture therapy (Gd-NCT) for cancer was evaluated using chitosan nanoparticles as a novel gadolinium device. The nanoparticles, incorporating 1200 mu g of natural gadolinium, were administered intratumorally twice in mice bearing subcutaneous B16F10 melanoma. The thermal neutron irradiation was performed for the tumor site, with the fluence of 6.32 x 10(12) neutrons/cm(2), 8 h after the second gadolinium administration. After the irradiation, the tumor growth in the nanoparticle-administered group was significantly suppressed compared to that in the gadopentetate solution-administered group, despite radioresistance of melanoma and the smaller Gd dose than that administered in past Gd-NCT trials. This study demonstrated the potential usefulness of Gd-NCT using gadolinium-loaded nanoparticles. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.