Inorganic Nanoparticles for X-Ray Computed Tomography Imaging.

In the last two decades, nanoparticle contrast agents have emerged as an essential tool for preclinical imaging and diagnosis. Besides their main advantage, related to their size range inhibiting glomerular filtration, they exhibit excellent X-ray attenuation when fabricated with heavy metal and thus high contrast in tomodensitometry. Another strength of inorganic nanoparticles, making them very adaptable to preclinical imaging applications, is the modularity of their surface chemistry, which is compatible with decoration by ligands and biomolecules. The present review draws a state-of-the art picture of the different inorganic nanoparticles synthesized as X-ray contrast agents. We present the panel of heavy metals and materials used, their X-ray attenuation properties, related applications, potential surface modifications, and in vitro and in vivo behaviors. An important aspect of this review is that the majority of inorganic nanoparticles are based on gold. We summarize the latest technologies for targeting nanoparticles designed to improve imaging techniques and advanced diagnostic methods.