The studies on highly concentrated complex dispersions of gold nanoparticles and temperature-sensitive nanogels and their application as new blood-vessel-embolic materials with high-resolution angiography.

Recently temperature sensitive polymers have been developed as novel embolization materials. However, their flowability and embolization have been seriously impacted by iodine-based X-ray contrast agents. In order to resolve the drawbacks of these contrast agents, highly concentrated complex (HCC) dispersions of gold nanoparticles (GNPs) with p(N-isopropylacrylamide-co-butyl methylacrylate) (PIB) nanogels were developed as new blood-vessel-embolic materials with high-resolution angiography. Although GNPs have better X-ray attenuation than iodinated compounds, their poor dispersion stability limits their application in digital subtraction angiography (DSA). HCC dispersions show excellent X-ray attenuation ability which is 2.6 times higher than Omnipaque at 0.31 mol L-1. This can be attributed to the fact that the sol-gel transition of nanogel dispersions improves the colloid stability of GNPs. In the two sol-gel transition temperatures (Tg-s and T's-g) of nanogel dispersions, GNPs have no influence on T's-g, and a great influence on Tg-s. The in vivo experimental data indicate that HCC dispersions show high angiographic ability and good blood-vessel embolization, and can be used for postoperative examination for long periods owing to the entrapment of GNPs into the embolic sites. The HCC dispersions have potential to be developed as new blood-vessel-embolic materials with high-resolution angiography.