Hyperbranched Polymeric ¹⁹F MRI Contrast Agents with Long T₂ Relaxation Time Based on β-Cyclodextrin and...

¹⁹F magnetic resonance imaging (¹⁹F MRI) is gaining attention as an emerging diagnostic technology. Effective ¹⁹F MRI contrast agents (CAs) for in vivo applications require a long transverse (or spin-spin) relaxation time (T₂), short longitudinal (or spin-lattice) relaxation time (T₁), high fluorine content, and excellent biocompatibility. Here, we present a novel hyperbranched polymeric ¹⁹F MRI CA based on β-cyclodextrin and phosphorylcholine. The influence of the branching degree and fluorine content on T₂ was thoroughly investigated. Results demonstrated a maximum fluorine content of 11.85% and a T₂ of 612 ms. This hyperbranched polymeric ¹⁹F MRI CA exhibited both great biocompatibility against cells and organs of mice and high-performance imaging capabilities both in vitro and in vivo. The research provides positive insights into the synthesis strategies, topological design, and selection of fluorine tags for ¹⁹F MRI CAs.