Temperature sensitive p(N-isopropylacrylamide-co-acrylic acid) modified gold nanoparticles for trans-arterial embolization and angiography

Temperature sensitive p(N-isopropylacrylamide-co-acrylic acid) modified gold nanoparticles (GNP@ PNA) were prepared via coordination bonding between gold and sulfur elements. Their diameter and zeta potential were 86 nm and -26.2 mV at 25 degrees C, and 47 nm and - 30.5 mV at 37 degrees C respectively. Thermogravimetric characterization of GNP@ PNA indicated that the PNA shell and the GNP core accounted for 19.2 wt% and 78.2 wt%, namely ca. 70-80 chains of PNA were combined on the surface of one GNP nanoparticle. GNP@ PNA showed much better X-ray attenuation ability, ca. 1.6-3.3 times higher than that of Omnipaque. In addition, the temperature sensitive sol-gel transition of GNP@ PNA dispersions could realize the so-called ``in situ casting" embolization from tumoral aorta to peripheral arteries, and improve their angiographic ability owing to the inhibition against GNP aggregation via gelation. Renal artery embolization on normal rabbits and TAE on VX2 tumor-bearing rabbits indicated that GNP@ PNA achieved better embolization for longer times than Ivalon and Lipiodol. Excellent biocompatibility of GNP@ PNA dispersions was also observed via the evaluation of cytotoxicity, hemolysis and hepatorenal function.