Synthesis of 19F MRI Nanotracers by Dispersion Polymerization- Induced Self-Assembly of N‑(2,2,2-Trifluoroethyl)acrylamide in Water

19F magnetic resonance imaging (MRI) using
fluoropolymer tracers has recently emerged as a promising, noninvasive
diagnostic tool in modern medicine. However, despite its
potential, 19F MRI remains overlooked and underused due to the
limited availability or unfavorable properties of fluorinated tracers.
Herein, we report a straightforward synthetic route to highly
fluorinated 19F MRI nanotracers via aqueous dispersion polymerization-
induced self-assembly of a water-soluble fluorinated
monomer. A polyethylene glycol-based macromolecular chaintransfer
agent was extended by RAFT-mediated N-(2,2,2-
trifluoroethyl)acrylamide (TFEAM) polymerization in water, providing fluorine-rich self-assembled nanoparticles in a single step.
The resulting nanoparticles had different morphologies and sizes ranging from 60 to 220 nm. After optimizing their structure to
maximize the magnetic relaxation of the fluorinated core, we obtained a strong 19F NMR/MRI signal in an aqueous environment.
Their non-toxicity was confirmed on primary human dermal fibroblasts. Moreover, we visualized the nanoparticles by 19F MRI, both
in vitro (in aqueous phantoms) and in vivo (after subcutaneous injection in mice), thus confirming their biomedical potential.