Gold nanoparticles as computerized tomography (CT) contrast agents

Gold nanoparticles (GNPs) are emerging as one of the most promising contrast agents for computerized tomography (CT) due to their remarkable properties including high X-ray absorption coefficient, low cytotoxicity, tailored surface chemistry, excellent biocompatibility, and unique surface plasmon resonance. Moreover, GNPs with tumor cell targeting molecules can specifically show the tumor tissues, leading to an intriguing feature of molecular imaging. In this article we provide a historical perspective on the GNPs used as CT contrast agents. We summarize the CT imaging principles of GNPs, review the current status of available methodologies for their preparation and surface modification, and highlight the recent achievements in their contrast effect and toxicity. Finally, the future opportunities and challenges of GNPs used as CT contrast agents are addressed for our understanding.