Influence of the particle size of gadolinium-loaded chitosan nanoparticles on their tumor-killing effect in neutron capture therapy in vitro.

Neutron capture therapy using 157Gd (Gd-NCT) is currently under development as a cancer radiotherapy. Melanoma cells were treated with gadolinium-loaded chitosan nanoparticles (Gd-nanoCPs) for Gd-NCT. Smaller Gd-nanoCPs had higher Gd content and better cellular association of Gd and thereby made the tumor-killing effect more efficient in comparison to larger Gd-nanoCPs. This indicates that Gd-nanoCP size reduction is an efficient method for improving the cellular affinity of Gd-nanoCPs and for enhancing the tumor-killing effect of Gd-NCT.