Synthesis and characterization of thermo-sensitive radio-opaque poly(N-isopropylacrylamide-co-PEG-2-iodobenzoate).

Radiopacity is required for embolic materials to be monitored by angiography during embolization. Covalently bound radio-opaque biomaterials would be ideal for embolization. Poly(N-isopropylacrylamide-co-PEG-acrylate) modified with 2-iodobenzoyl chloride was synthesized and characterized by (1)H-NMR, differential scanning calorimetry and X-ray opacity. Poly(N-isopropylacrylamide-co-PEG-2-iodobenzoate) shows radiopacity, as well as thermo-sensitivity. Cytotoxicity testing on these co-polymers shows little cytotoxicity. Phase-transition temperature and radiopacity varied according to the content of NIPAAm and 2-iodobenzoate. Increasing the content of 2-iodobenzoate raised the radiopacity and lowered the LCST.