Application of silver nanotriangles as a novel contrast agent in tumor computed tomography imaging.

This study aimed to prepare chitosan-coated silver nanotriangles (AgNTs) and assess their computed tomography (CT) contrast property by in vitro and in vivo experiments. AgNTs with a range of sizes were synthesized by a seed-based growth method, and subsequently characterized by transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy and dynamic light scattering. The X-ray attenuation capability of all prepared AgNTs was evaluated using micro CT. The CT contrast effect of AgNTs with the highest X-ray attenuation coefficient was investigated in MDA-MB-231 breast cancer cells and a mouse model of breast cancer. The TEM results displayed that all synthesized AgNTs were triangular in shape and their mean edge lengths ranged from 60 to 149 nm. All AgNTs tested exhibited stronger X-ray attenuation capability than iohexol at the same mass concentration of the active elements, and the larger the AgNTs size, the higher the X-ray attenuation coefficient. AgNTs with the largest size were selected for further research, due to their strongest X-ray attenuation capability and best biocompatibility. The attenuation coefficient of breast cancer cells treated with AgNTs increased in a particle concentration-dependent manner. In vivo CT imaging showed that the contrast of the tumor injected with AgNTs was significantly enhanced. These findings indicated that AgNTs could be a promising candidate for highly efficient tumor CT contrast agents.