Recent Development of Gold Nanoparticles as Contrast Agents for Cancer Diagnosis

SIMPLE SUMMARY: The development of nanotechnology has brought revolution to the diagnosis and therapy of diseases, with a high precision and efficacy. Because nanoparticles can integrate multifunctions together including imaging, targeting, and therapeutics, they are more efficient than the standalone diagnostic or therapeutic entities. Among which, gold nanoparticles are most extensively investigated due to their excellent biocompatibility, versatility and ease of functionalization. Excepting the using of gold nanoparticles as vehicles for therapeutics delivery, they are also good candidates as contrast agents for imaging diagnosis, from magnetic resonance imaging, CT and nuclear imaging, fluorescence imaging, photoacoustic imaging to X-ray fluorescence imaging. We summarize their recent applications in these imaging modalities and challenges for their clinical translation. ABSTRACT: The last decade has witnessed the booming of preclinical studies of gold nanoparticles (AuNPs) in biomedical applications, from therapeutics delivery, imaging diagnostics, to cancer therapies. The synthetic versatility, unique optical and electronic properties, and ease of functionalization make AuNPs an excellent platform for cancer theranostics. This review summarizes the development of AuNPs as contrast agents to image cancers. First, we briefly describe the AuNP synthesis, their physical characteristics, surface functionalization and related biomedical uses. Then we focus on the performances of AuNPs as contrast agents to diagnose cancers, from magnetic resonance imaging, CT and nuclear imaging, fluorescence imaging, photoacoustic imaging to X-ray fluorescence imaging. We compare these imaging modalities and highlight the roles of AuNPs as contrast agents in cancer diagnosis accordingly, and address the challenges for their clinical translation.