Ou Chen

Significance Gadolinium (Gd)-based contrast agents (GBCAs) are currently the mainstream clinical MRI contrast agents. Some GBCAs have shown a long-term toxicity—nephrogenic systemic fibrosis (NSF)—and Gd depositions in the brain. The NSF has triggered a Food and Drug Administration (FDA) black-box warning and a contraindication of some GBCAs. The finding of Gd depositions led to an ongoing FDA investigation to monitor their possible long-term adverse effects. Here, we present T 1 -weighted contrast-enhanced MR imaging and angiography using zwitterion-coated exceedingly small superparamagnetic iron oxide nanoparticles (ZES-SPIONs) in mice and rats. Renal clearance and biodistribution results further demonstrate that ZES-SPIONs are qualitatively different from previously reported SPIONs. This work may open up opportunities to develop exceedingly small SPIONs that show effective T 1 contrast as Gd-free alternatives to GBCAs.

Shape dependent: Fluorescent quantum-dot-based nanospheres and nanorods with identical hydrodynamic size and surface properties but different aspect ratios were developed for real-time in vivo tumor imaging. The nanorods exhibited superior transport and distribution into mammary tumors in vivo versus nanospheres of similar plasma half-life. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.