Highly-iodinated fullerene as a contrast agent for X-ray imaging

The first fullerene-based X-ray contrast agent (CA) has been designed, synthesized, and characterized. The new CA is an externally functionalized derivative of C60 that is conceptually based on contemporary X-ray CA, all of which use iodine as the X-ray attenuating vehicle and are based on the 2,4,6-triiodinated-benzene-ring substructure. Using a modified Bingel-type reaction, a single addend containing 6 iodine atoms and 8 protected hydroxyl groups was appended to C60 followed by the addition of 4 more addends each containing 4 protected hydroxyl groups. Final deprotection afforded the highly water-soluble (>460 mg/mL), non-ionic, highly-iodinated (24% I) fullerene for application as an X-ray contrast agent.